Sertularella Allmani Hartlaub, 1901: 81, pl. 5 figs 12, 13; pl. 6 figs 1, 8 (replacement name for Sertularia secunda Allman, 1888). – (?) Jäderholm, 1903: 283.

non Sertularella Allmani. – Jäderholm, 1905: 32, pl. 12 fig. 11 (= Sertularella subantarctica Galea, sp. nov.).

Sertularella allmani. – Hartlaub, 1905: 649, fig. O⁴. – Bedot, 1916: 199; 1918: 234. – Billard, 1924: 61. – El Beshbeeshy, 2011: 121, fig. 37F.

non Sertularella allmani. – Naumov & Stepanjants, 1962: 86 [= Sertularella gaudichaudi (Lamouroux, 1824)].

Sertularia secunda Allman, 1888: pl. 25 figs 2, 2a, 2b (replacement name for Sertularia unilateralis Allman, 1888: 53). – Vervoort, 1972: 108, fig. 33 (reexamination of holotype).

non Sertularella secunda Kirchenpauer, 1884: 50, pl. 15 figs 7, 7a [= Symplectoscyphus secundus (Kirchenpauer, 1884)].

Sertularia unilateralis Allman, 1888: 53 {non Sertularia unilateralis Lamouroux, 1824: 615, pl. 90 figs 1–3 [= Symplectoscyphus unilateralis (Lamouroux, 1824)]; non Sertularia unilateralis Allman, 1885: 139, pl. 13 figs 5–7 [= Amphisbetia bispinosa (Gray, 1843)]}.

(?) Sertularella paessleri Hartlaub, 1901: 80, pl. 6 figs 3, 19. – Hartlaub, 1905: 654, fig. S⁴.

Sertularella mediterranea asymmetrica Millard, 1958: 191, fig. 7B. – Millard, 1964: 45. – Millard, 1975: 295, fig. 96A [non Sertularella mediterranea Hartlaub, 1901].

Sertularella antarctica. – Blanco, 1963: 170, figs 5, 6. – Stepanjants, 1979: 84, pl. 15 fig. 3. – Blanco, 1994: 198. – Galea et al., 2009: 7, figs 2J-N, 3A-B [non Sertularella antarctica Hartlaub, 1901].

Material examined: ZMH C04177; Chile, Región de Magallanes y de la Antártica Chilena, Isla Navarino, west of Puerto Pantalón del Weste, ca. 12 m, coll. Michaelsen no. 180; 31.12.1892; several fertile fragments (only part of the whole sample examined herein), up to 3.8 cm high, largest with accessory tubes on stem. There is obviously a crossing-out in the ZMH catalogue for this material: although it bears the official no. 180, it was indicated as no. 189 by Hartlaub (1901), as both share the same collection data. However, no. 189 corresponds to another specimen, ZMH C04178, assignable to S. picta (Meyen, 1834). As indicated by Hartlaub, the material is well-preserved and fertile. Since the 2nd specimen (from Port Stanley, Falkland Is., coll. Paessler, 12.04.1893) on which S. allmani was equally based upon was destroyed during WWII (H. Roggenbuck, pers. comm.), the specimen ZMH C04177 is designated here as the lectotype of S. allmani. – NHML 1888.11.13.101; French Southern and Antarctic Lands, Kerguelen Is., ca. 36 m, coll. Challenger; holotype of Sertularia secunda Allman, 1888 (= Sertularia unilateralis Allman, 1888), three male colony fragments (3.0, 1.5 and 1 cm high) in ethanol, as well as two slides; one slide (Fig. 1B), labeled “type” contains a 1.1 cm high, fertile colony fragment, and bears the mention “Challenger Stat 149D, Kerguelen, Depth 20 faths, Sertularia secunda (unilateralis)”; the second slide (Fig. 1A) is a 1.7 cm high, fertile, branched colony fragment and bears the label “Challenger Coll., Sertularella secunda (Allman), Kerguelen (d. 20 fms), B. carm.”. – MHNGINVE-62835; Chile, Región de los Lagos, south of Isla Yencouma (south Chiloé), -42.40958° -74.08353°, 8 m, coll. HSFS, HF6, lot A521; 24.02.2008; several stems up to 1.6 cm high bearing male gonothecae. – HRG-0637; Chile, Región de Magallanes y de la Antártica Chilena, Islotes Gemelos, -54.91942° -67.36308°, 13 m, coll. HSFS, HF9, lot C132; 15.12.2010; several stems up to 5 cm high, richly bearing either male or female gonothecae, the latter with acrocysts. – HRG-0314; Chile, Región de los Ríos, Corral, La Amistad (San Carlos), -39.85744° -73.44024°, 5–10 m, coll. D. Schories, pooled lots 02 and 06; 26.05.2011; colony on seaweed, composed of many stems up to 4.3 cm high, bearing male gonothecae. – HRG-0634; Chile, Región de los Ríos, north of Corral, Chaihuin, -39.95730° -73.60245°, 6–12 m, coll. D. Schories; 27.10.2011; profuse colonies with up to 5 cm high stems, bearing either male or female gonothecae, the latter with acrocysts. – HRG-0644; Chile, Región de los Ríos, north of Corral, Chaihuin, -39.95730° -73.60245°, 6–12 m, coll. D. Schories; 27.10.2011; male colony on seaweed, composed of numerous stems up to 5 cm high. – HRG-0636; Chile, Región de los Ríos, Niebla, Bonifacio, -39.69002° -73.37940°, 10–15 m, coll. D. Schories; 09.10.2012; numerous colonies on seaweed, with up to 3.5 cm high stems, bearing either male or female gonothecae, the latter with acrocysts.

Description: Creeping, branching, anastomosing stolons giving rise to erect, bushy, irregularly-pinnate colonies, up to 6 cm high. Stems either mono- or lightly fascicled basally; in the first case, with 2–5 twists above origin from stolon. Both stems and branches divided into regularly-short, almost collinear internodes by means of deep, slightly oblique constrictions of the perisarc; the latter typically dark-brown at nodes, and almost transparent elsewhere; each internode with slight bulges at each end, and distally bearing a hydrotheca, or a hydrotheca and a lateral apophysis arising immediately from below its base. Hydrothecae, apophyses and side branches shifted on to one side of the colony at an acute angle, giving it two obvious, frontal and dorsal sides, respectively. Branching profuse, with a general, characteristic pattern: a couple of two consecutive, alternate side branches is separated from the next couple of branches by 1–2 (occasionally 0) internodes devoid of apophyses; occasionally, only one branch of a “pair” occurs (Fig. 2C); there are up to 3rd order branches. Hydrothecae biseriate, alternate, flask-shaped, moderately-long, adnate for about 1/3rd of their length, distinctly swollen adaxially, narrowing below aperture; abaxial wall nearly straight, free adaxial wall sigmoid, convex for most of its length, becoming concave a short distance below the aperture; rim thickened, provided with four, unequal cusps (abaxial one conspicuously produced, adaxial one the shortest, and the laterals asymmetrical and of intermediate length, the “anterior” one comparatively shorter than its “posterior” counterpart); cusps separated by deep, rounded embayments; 3 internal, submarginal cusps (2 latero-adaxial, 1 abaxial), not always present; operculum composed of 4 triangular flaps forming a conical roof. Gonothecae borne on both stems and side branches, arising from below the hydrothecal bases; broadly ovoid, with 6–8 transverse ridges, not always distinct; distally a short neck provided with generally 4 (occasionally 2–5) blunt projections of perisarc surrounding a central, rounded aperture; acrocysts in female. Perisarc of colonies either thin or thick.

Dimensions: See Table 1.

Remarks: When Allman (1888) realized that his Sertularia unilateralis (main text, p. 53) was a homonym (of Sertularia unilateralis Lamouroux, 1824 and Sertularia unilateralis Allman, 1885), he introduced the replacement name Sertularia secunda (legend of pl. 25, figs 2, 2a, 2b). However, Hartlaub (1901) correctly placed Allman's species in the genus Sertularella Gray, 1848 and noted that, there, it becomes a junior synonym of Sertularella secunda Kirchenpauer, 1884 (the latter is now assigned to the genus Symplectoscyphus Marktanner-Turneretscher, 1890). He therefore introduced a second replacement name, viz. S. allmani.

Calder (2015, p. 239, note 39), influenced by the opinion originally expressed by Vervoort (1972) and subsequently followed by Galea et al. (2009), decided to reject as invalid the binomena Sertularia unilateralis Allman, 1888 (a species of Sertularella Gray, 1843), its replacement name Sertularia secunda Allman, 1888 and, in turn, its replacement name Sertularella allmani Hartlaub, 1901, in the belief that all were synonyms of the frequently reported Sertularella antarctica Hartlaub, 1901 and its senior objective synonym Sertularella unilateralis Allman, 1876 (Calder, pers. comm.). However, in light of the present study, S. allmani is considered as a valid species, distinct from S. antarctica (see also remarks under the latter). Consequently, Calder's (2015) suggestion, according to which a “case could be made (ICZN Art. 59.3.) for retention of Sertularella secunda Allman, 1888 [sic!] as the valid name of the species”, resurfaces, but it appears today to not carry enough weight according to the requirements of the Code. Indeed, Art. 59.3. stipulates that Sertularia secunda Allman, 1888, as a junior secondary homonym of Sertularella secunda Kirchenpauer, 1884, and replaced before 1961, be permanently invalid unless the substitute name, Sertularella allmani Hartlaub, 1901, is not in use and the relevant taxa are no longer considered congeneric (Sertularia secunda Allman, 1888 belongs actually to Sertularella Gray, 1843, and Sertularella secunda Kirchenpauer, 1884 to Symplectoscyphus Marktanner-Turneretscher, 1890), in which case the junior homonym is not to be rejected on grounds of that replacement. In light of the synonymy given above, it appears that the binomen S. allmani was used more often than S. secunda. Consequently, Hartlaub's (1901) S. allmani is retained as the valid name of the species.

The typical shape of the colonies of S. allmani is illustrated by Galea et al. (2014, pl. 3D, as S. antarctica), while several gonothecae are depicted by Galea et al. (2009, fig. 3B, as S. antarctica). The branching pattern in this species is irregularly pinnate. In some parts of very profuse colonies, nearly all internodes give rise to alternate side branches, although in more sparingly branched ones, there is a tendency to form groups of two consecutive, alternate side branches separated by 1–2 stem internodes devoid of apophyses. Occasionally, though not rarely, more irregular side branches, separated by a varied number of internodes with no apophyses, may arise successively on the same side of the stem.

In all specimens from Chile, the stems are monosiphonic in habit, and give rise to side branches of up to 3rd order. Polysiphonic stems were reported only in rare instances [Hartlaub 1901, as both S. allmani and S. paessleri (see below for the taxonomic status of the latter)]. The perisarc of the colonies (including the hydrothecae) may be either thin (as in the Chilean material) or thick (Hartlaub, 1901; Blanco, 1963, as S. antarctica). The hydrothecal margin is always thickened, and the abaxial marginal cusp is generally distinctly produced, though its length may vary among various colonies, or even within the same stem. The gonothecae of both sexes are either distinctly transversely ringed (e.g. HRG-0637, HRG-0644), or only wrinkled to nearly smooth (e.g. HRG-0634, HRG-0636). Material of Sertularella paessleri Hartlaub, 1901 is no longer extant in collections of ZMH (H. Roggenbuck, pers. comm.). However, Hartlaub emphasized the large size and the smooth appearance of the gonothecae in the obviously young colony available. Otherwise, the characters of the trophosome alone (branching almost regularly pinnate, with consecutive, alternate “pairs” of side branches separated by 2 internodes devoid of apophyses; invariably short internodes; short, adaxially-swollen hydrothecae shifted on to one side, and adnate for 1/3rd their length; abaxial cusp produced; rim thickened) agree well with the present concept of S. allmani, including the presence of fascicled stems, as those observed in the lectotype, ZMH C04177.

The variety asymmetrica, created by Millard (1958) for a hydroid assigned to S. mediterranea Hartlaub, 1901, is likely conspecific with the present species. Although all her specimens were represented by small, unbranched stems, their microscopic structure displays all the distinctive characters of S. allmani, notably: short internodes, thick-walled hydrothecae conspicuously shifted on to one side of the stem, a produced abaxial cusp, the noteworthy asymmetry of the laterals, as well as the presence of 3 internal, submarginal cusps.

Distribution: Chile – Región de los Ríos [around Corral (Galea & Schories, 2012a, as S. antarctica)]; Región de los Lagos [south of Isla Grande de Chiloé (Galea et al., 2009, as S. antarctica)]; Región de Magallanes y de la Antártica Chilena [west of Puerto Pantalón del Weste, Isla Navarino (Hartlaub, 1901; 1905); Islote Gemellos (present study); Magellan Strait (? Jäderholm, 1903)]. Argentina – Provincia de Santa Cruz [Punta Peñas, San Julián (Blanco, 1963; 1994, both as S. antarctica)]. Falkland Is. – Port Stanley (Hartlaub, 1901; 1905); Port Williams (Hartlaub, 1901; 1905, both as S. paessleri). French Southern and Antarctic Lands, Kerguelen Is. – off Accessible Bay [Allman 1888, as Sertularia secunda (= Sertularia unilateralis)]. South Africa – Millard (1958; 1964; 1975, all as S. mediterranea var. asymmetrica).

Sertularella antarctica Hartlaub, 1901: 82, pl. 6 figs 27, 28 (replacement name for Sertularella unilateralis Allman, 1876: 114). – (?) p.p. Jäderholm, 1903: 283. – Hartlaub, 1905: 650, fig. P⁴, Q⁴. – Bedot, 1916: 200; 1918: 235. – Billard, 1924: 61. – (?) Vervoort, 1972: 106, fig. 32. – El Beshbeeshy, 2011: 119, fig. 37D.

non Sertularella antarctica. – p.p. Jäderholm, 1903: 283 [= Sertularella gaudichaudi (Lamouroux, 1824)]. – Jäderholm, 1905: 32, pl. 13 fig. 1 (= Sertularella subantarctica Galea, sp. nov.). – Blanco, 1963: 170, figs 5–6 (= Sertularella allmani Hartlaub, 1901).

Sertularella unilateralis Allman, 1876: 114. – Allman, 1879: 282, pl. 18 figs 10, 11. – Studer, 1879: 120. – Kirchenpauer, 1884: 40.

non Sertularia unilateralis Lamouroux, 1824: 615, pl. 90 figs 1–3 [= Symplectoscyphus unilateralis (Lamouroux, 1824)].

Sertularella allmani. – (?) Nutting, 1904: 84, pl. 18 figs 3–6 [non Sertularella allmani Hartlaub, 1901].

Sertularella gigantea. – Billard, 1906: 12, fig. 4 [non Sertularella gigantea Mereschkowsky, 1878].

Sertularella ? lagena. – Galea & Schories, 2012a: 41, fig. 4K-L [non Sertularella lagena Allman, 1876].

Sertularella sanmatiasensis. – (?) Peña Cantero, 2006: 939, fig. 3L. – (?) Peña Cantero & Gili, 2006: 767. – (?) Peña Cantero, 2008: 459, fig. 2C. – (?) Peña Cantero & Vervoort, 2009: 87, fig. 2B. – Peña Cantero, 2012: 858, fig. 4A; 2013: 130 [non Sertularella sanmatiasensis El Beshbeeshy, 2011].

Material examined: ZMH C04161; Chilean-Argentinean border, Dungeness Point, beach, coll. Michaelsen no. 104; 15.10.1892; a few fragments (only a part of the whole sample examined herein), up to 2.2 cm high. According to Hartlaub (1901), this appears to be the sole material on which he based his species upon. As no holotype was designated by him, it is here regarded as the lectotype of S. antarctica. – ZMH C11879; FRV Walther Herwig, Argentine Shelf, no additional data; several sterile colony fragments, up to 5.2 cm high, with almost only the perisarc left, identified as S. antarctica Hartlaub, 1901. – MHNGINVE-79773; Antarctica, King George I., Ras Tu, -62.22139° -58.88694°, 15–20 m, coll. D. Schories, lot Ant. 12/2011; 21.02.2010; fully fertile (female) colony with stems up to 6.5 cm high. – MHNGINVE-79776; Antarctica, King George I., Ras Tu, -62.22139° -58.88694°, 15–20 m, coll. D. Schories, lot Ant. 03/2011; 21.02.2010; numerous stems and fragments up to 5.5 cm high, some bearing female gonothecae. – HRG-0534; Antarctica, King George I., Ras Tu, -62.22139° -58.88694°, 10–40 m, coll. D. Schories, lot Ant. 08/2010; 12.02.2010; numerous stems and fragments, up to 4 cm high, one bearing a female gonotheca. – HRG-0290; Antarctica, Low I., -63.43009° -62.2038°, 82 m, coll. Bentart 2006, leg. A.L. Peña Cantero; 02.2006; numerous fertile stems, up to 9.5 cm high, sex could not be ascertained [part of the material from Stn. Low 44 studied by Peña Cantero (2013)]. – HRG-0362; Chile, Región de Magallanes y de la Antártica Chilena, Punta Arenas, Faro San Isidro, -53.78174° -70.97391°, 40 m, coll. D. Schories, lot #25; 04.01.2011; three minute sterile stems [material assigned to Sertularella ? lagena Allman, 1876 by Galea & Schories (2012a)].

Description: Inspected colonies up to 9.5 cm high, arising from creeping, branching stolon. Stems monosiphonic, provided basally with 3–5 annuli above origin from stolon, then divided into uniform, moderately-long internodes by deep, oblique constrictions of perisarc slanting in alternate directions. A hydrotheca, or a hydrotheca and a short, lateral apophysis arising from below its base, confined to the distal end of each internode; proximally a couple of spiral twists (occasionally only one, or two incomplete), and distally a bulge. Hydrothecae, apophyses, and side branches shifted on to one side of the stem, at a wide angle, not giving the colony a markedly fronto-dorsal aspect. Branching pattern irregularly pinnate, with side branches originating every 0–18 stem hydrothecae, either alternately or many on the same side; up to 4th order branching; structure similar to that of stem; 1st internode with 2 (rarely 3) spiral twists basally, length generally greater (occasionally shorter, or equal) than that of subsequent internodes. Hydrothecae long, flask-shaped, adnate for 1/3rd of their length to the corresponding internode, swollen adaxially at varied degrees; abaxial wall almost straight; free adaxial wall sigmoid, convex for most of its length, becoming concave immediately below aperture; aperture surrounded by 4 unequally-developed, triangular cusps: abaxial one produced, thought at varied degrees, adaxial the shortest, and the laterals asymmetrical; rim thickened, renovations occasional; 3 intrathecal, submarginal cusps (2 latero-adaxial, 1 abaxial), not always discernible; a 4-flapped operculum. Gonothecae borne on both stems and side branches, male similar to female; elongated-ovoid, walls transversely-wrinkled, especially on distal half, aperture mounted on short neck region and surrounded by generally 4 blunt cusps (up to 6 possible).

Dimensions: See Table 2.

Remarks: Hartlaub (1901) introduced the replacement name Sertularella antarctica for Sertularella unilateralis Allman, 1876 in order to avoid the secondary homonymy with Sertularia unilateralis Lamouroux, 1824, the latter considered by him as belonging to the group of 3-cusped Sertularella species (presently accepted as Symplectoscyphus Marktanner-Turneretscher, 1890).

Calder (2015, p. 239, note 39) expressed the view that Hartlaub's (1901) binomen “has been used only sparingly […], and nomenclatural stability is not greatly threatened by adopting its senior synonym (Sertularella unilateralis Allman, 1876a) for the species”. However, in light of the present study, his opinion changed (Calder, pers. comm.) taking into account that secondary homonymy no longer exists in the case of S. unilateralis, and the substitute name S. antarctica has come into rather frequent use for the species (ICZN Art. 59.3.).

Type material of S. unilateralis is likely no longer extant in NHML (A. Cabrinovic, pers. comm.), and a comparison with the lectotype of S. antarctica is therefore impossible, leaving some doubts as to the conspecificity between these two nominal species. Indeed, the colony silhouette illustrated by Allman (1879, pl. 18 fig. 10) does not differ much from that of his Sertularia secunda (= Sertularia unilateralis) (Allman, 1888, pl. 25 figs 2, 2a) (= S. allmani Hartlaub, 1901, see previous species). El Beshbeeshy (2011) was right in stating that S. allmani and S. antarctica are two distinct, well-defined species. A contrary opinion was expressed earlier by Vervoort (1972), who founded his conclusion based exclusively on Hartlaub's (1901) accounts (p. 81 and 82, respectively), but not on the reexamination of the corresponding materials studied by the German author. This erroneous opinion was subsequently followed by Galea et al. (2009, as S. antarctica, p. 7 figs 2J-N, 3A-B) and Galea & Schories (2012a, as S. antarctica, p. 22, footnote 2, pl. 3D). However, the reexamination of the lectotypes of both S. allmani and S. antarctica for the purpose of the present study, leaves no doubts about the correctness of El Beshbeeshy's statement.

The typical shape of a colony of this species is illustrated in Galea & Schories (2012b, pl. 1R), while its gonothecae appear in the insert of the same plate, as well as in fig. 2S of the same paper.

The development of the perisarc in various colonies ranges from rather thin (e.g. HRG-0290, HRG-0405, HRG-0524, and HRG-0534) to exceedingly hypertrophied (e.g. ZMH C04161, ZMH C11879). The adaxial side of the hydrotheca is swollen at varied degrees but, generally, approaches an almost tubular shape; in some colonies, the hydrothecae are distinctly swollen, resembling those of S. allmani but, in this case, the colony shape is diagnostic. The hydrothecal rim is conspicuously thickened, though less so in younger thecae; renovations were observed in only several instances (Billard, 1906, as S. gigantea; specimen HRG-0524). The abaxial, marginal cusp is always produced, though at varied extents. On the other hand, the submarginal, intrathecal projections of perisarc may be either absent or only lightly indicated (e.g. HRG-0534), present only on adaxial side (e.g. HRG-0405), or fully displayed (3 cusps, e.g. HRG-0290, ZMH C04161, ZMHC11879).

Type material of Sertularella lagena Allman, 1876, a poorly-described nominal species, obviously based on a young specimen, could not be located in collections of NHML (A. Cabrinovic, pers. comm.). However, the illustration provided by Allman (1879) places it closest to the present species, an opinion already expressed by Hartlaub (1901, p. 83, fig. 53; 1905, p. 647, figs M⁴-N⁴). The scarce material studied earlier by Galea & Schories (2012a), and provisionally assigned to S. lagena, was reexamined. It belongs to a very young colony whose stems do not exceed 5 internodes. Their hydrothecae are not obviously shifted unilaterally, and no intrathecal, submarginal cusps are present, although a careful inspection shows that the rims of some hydrothecae are slightly, but characteristically thickened. This, added to the typical shape and size of its internodes, suggests strong affinities with S. antarctica.

Through the courtesy of A.L. Peña Cantero, one of us (HRG) was able to examine a specimen from Low I., Antarctica (HRG-0290) identified by him as S. sanmatiasensis El Beshbeeshy, 2011 (Peña Cantero, 2013). In light of the present observations, there is no doubt that this material belongs to the present species. Consequently, it is assumed that at least some earlier records of El Beshbeeshy's species in the various papers (co)authored by Peña Cantero also belong to S. antarctica. However, since there are no formal descriptions of the materials involved and, occasionally, no illustrations of them, uncertainties subsist as to their real taxonomic statuses. In only rare instances (e.g. Peña Cantero, 2012), the morphology of both internodes (length, presence of proximal twists) and hydrothecae (thickened margin) leaves little doubt about the identity of the materials involved.

Distribution: Chile – Región de Magallanes y de la Antártica Chilena [(?) Isla Lennox, (?) Lennox Cove, and (?) Borgin Bay (Jäderholm, 1903); (?) Magellan Strait (Nutting, 1904, as S. allmani; Vervoort, 1972); south of Peninsula Brunswick (Galea & Schories, 2012a, as S. ? lagena)]. Chilean-Argentinean border – Dungeness Point (Hartlaub, 1901; 1905; El Beshbeeshy, 2011). Argentina – Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [(?) off the NE coast of Islas de los Estados (Vervoort, 1972)]. French Southern and Antarctic Lands, Kerguelen Is. – Swains Bay (Allman, 1876; 1879, both as S. unilateralis). Antarctica – Wandel I. (Billard, 1906, as S. gigantea), Bellingshausen Sea (Peña Cantero, 2012, as S. sanmatiasensis), Low I. (Peña Cantero, 2013, as S. sanmatiasensis), King George I. (Galea & Schories, 2012b, as S. gaudichaudi).

Sertularella asymmetra Galea & Schories, 2014 in Galea et al., 2014: 31, figs 6A-B, 7A.

Material examined: MHNG-INVE-86230; Chile, Región de los Ríos, Corral, Chaihuin/Huiro, -39.95000° -73.61667°, 10 m, coll. D. Schories, lot #05; 27.10.2011; a 4 cm high colony with female gonothecae (holotype). – MHNG-INVE-86231; Chile, Región de los Ríos, Corral, Chaihuin/Huiro, -39.95000° -73.61667°, 10 m, coll. D. Schories, lot #26; 03.10.2011; a 2.5 cm high colony with male gonothecae.

Description: Colonies arising from creeping, branching, anastomosing hydrorhiza. Stems erect, up to 4 cm high, monosiphonic, spirally-twisted above origin from stolon, then divided into short, slightly geniculate internodes by deep, oblique constrictions of the perisarc. Side branches arise irregularly from below the bases of stem hydrothecae, either laterally, or slightly displaced towards the front or the rear side of the colony; structure similar to that of stem. Hydrothecae biseriate, alternate, fusiform, adnate for about 1/3rd their adaxial side to the corresponding internode; free adaxial wall swollen proximally, and provided with 2–3 weak, transverse ridges; abaxial wall with smooth perisarc, slightly concave proximally, becoming convex below the aperture; the latter facing upwards, and composed of four triangular cusps separated by shallow embayments, abaxial cusp produced; a 4-flapped operculum; three internal, submarginal cusps: 2 latero-adaxial and 1 abaxial. Gonothecae arising from below the hydrothecal bases; elongated-ovoid, walls more or less transversely ridged; male similar to female, though slenderer and longer; aperture surrounded by 3–4 perisarc projections in male and 5 in female; the latter producing 12–18 oocytes.

Dimensions: Internodes 560–730 μm long and 140–230 μm wide at nodes. Hydrothecal free adaxial length 285–355 μm, adnate adaxial length 230–280 μm, abaxial length 535–590 μm, maximum width 250–285 μm, diameter at aperture 230–240 μm. Length of the female gonotheca ca. 1695 μm, and of the male ca. 1890 μm; maximum width of the female gonotheca ca. 795 μm, and of the male ca. 710 μm.

Remarks: The gonothecae of this species are illustrated by Galea et al. (2014, fig. 7A).

Distribution: Chile – Región de los Ríos [Corral (Galea et al., 2014)].

Sertularella blanconae El Beshbeeshy, 2011: 125, fig. 39. – Galea & Schories, 2012a: 37, fig. 3P-S. – Galea et al., 2014: 32, pl. 3A, figs 6C, 7B.

Sertularella geodiae. – Blanco, 1976: 39, pl. 3 figs 7–8. – (?) Millard, 1977: 23, fig. 6E-F. – Blanco, 1994: 199 [non Sertularella geodiae Totton, 1930].

Sertularella conica. – Blanco, 1982: 154, figs 2–5. – Blanco, 1994: 198 [non Sertularella conica Allman, 1877].

Sertularella Gayi. – p.p. Jäderholm, 1903: 281 [non Sertularella gayi (Lamouroux, 1821)].

(?) Sertularella gayi gayi. – Vervoort, 1972: 116, fig. 36A, B [non Sertularella gayi (Lamouroux, 1821)].

(?) Sertularella gayi var. gayi. – Stepanjants, 1979: 87, pl. 16 fig. 4A, B [non Sertularella gayi (Lamouroux, 1821)].

Material examined: MHNG-INVE-86243; Chile, Región de Aysén, Isla Teresa, -44.95713° -73.79447°, 21.6 m, coll. HSFS, HF11, lot C234; 27.11.2011; a profuse, sterile colony with stems up to 16 cm high. – MHNG-INVE-86244; Chile, Región de Aysén, Isla Level, -44.47348° -7420472°, 25 m, coll. HSFS, HF11, lot C128; 24.11.2011; a ca. 7 cm high, fragmentary colony with male gonothecae. – HRG-0392; Chile, Región de Magallanes y de Antártica Chilena, Punta Arenas, Faro San Isidro, -53.78174° -70.97391°, 40 m, coll. D. Schories, lot #27; 04.01.2011; three sterile colony fragments 1.2–1.7 cm high. – HRG-0696; Chile, Región de Magallanes y de Antártica Chilena, Isla Santibañez, -54.91725° -68.36317°, 29 m, coll. HSFS, HF9, lot C247; 16.12.2010; very fragmented colony with lightly fascicled stems, some bearing spent gonothecae. – HRG-0694; Chile, Región de Aysén, southern exist of Canal Williams, -45.60103° -74.47819°, 8.9 m, coll. HSFS, HF11, lot C009; 19.11.2011; a profuse, ca. 8 cm high, sterile colony composed of several polysiphonic stems. – HRG-1168; Chile, Región de los Lagos, southern Chiloé, Isla Yencouma, -43.419316° -74.081766°, 10 m, coll. HSFS, HF22, lot #65; 18.01.2015; two profuse, ca. 7 cm high, infertile colonies with polysiphonic stems. – SMNH 123866; Chile, Punta Arenas, coll. Swedish Tierra del Fuego Expedition 1895–1896; 05.12.1895; microslide (Fig. 1C) containing two sterile colony fragments, 2.0 and 2.3 cm high [material identified by Jäderholm (1903) as S. gayi (Lamouroux, 1821)].

Comparison material: HRG-1006; France, Roscoff, Trou aux Singes, 48.7961° -3.9708°, 72 m, leg. P. Schuchert; 08.09.2014; a 4.5 cm high, fertile colony of Sertularella gayi (Lamouroux, 1821). – HRG-0553; France, Brittany, depth unrecorded, coll. F. Ziemski; (day and month unavailable) 2011; a few infertile stems and fragments, up to 3.7 cm high, of S. gayi.

Description: Large, fan-shaped colonies, up to 16 cm high arising from broad, rhizoid stolon firmly attached to substrate; stems giving rise to irregularly-ramified side branches, up to the 3rd order; both stems and branches highly fascicled for most of their length; monosiphonic parts with regularly-pinnate structure. Both stems and branches divided into short, almost collinear internodes by means of weak, oblique constrictions of the perisarc. Each internode with a hydrotheca, or a hydrotheca and a short apophysis immediately below its base; apophyses alternate, arising generally every three hydrothecae. Hydrothecae biseriate, alternate, flask-shaped, adnate for about half their length; free adaxial wall slightly swollen and provided with 3–4 undulations, more prominent proximally, weaker distally, prolonged as inconspicuous transverse ridges at surface, not reaching the abaxial wall; the latter slightly concave to almost straight for most of its length, becoming convex below the aperture, surface smooth; aperture mounted on short, constricted neck region, expanding at rim; the latter with 4 pointed, equal, triangular cusps separated by moderately-deep, rounded embayments; margin occasionally renovated; 4 triangular opercular flaps with concentric striae; no intrathecal, submarginal cusps. Gonothecae (only male known) elongated-ovoid, lateral walls with up to 8 transverse ridges, of which 5–6 distalmost are complete and prominent, while the remaining ones become obsolete towards the base; aperture borne on the summit of a short neck region, and is flanked by 4 blunt-ended projections of perisarc.

Dimensions: See Table 3.

Remarks: The typical shape of a well-developed colony is illustrated in Galea et al. (2014, pl. 3A), and a male gonotheca in fig. 7B of the same paper. This species has been previously confused with S. gayi (Lamouroux, 1821) by a number of authors (see synonymy). Their morphological differences are obvious by comparing Fig. 3A, C-H and Fig. 3B, I.

Distribution: Chile – Región de los Lagos [southern Chiloé (present study)]; Región de Aysén [Isla Level, Isla Teresa (Galea et al., 2014); Canal Williams (present study)]; Región de Magallanes y de la Antártica Chilena [south of Peninsula Brunswick (Galea & Schories, 2012a); Isla Dawson and Punta Arenas (Jäderholm, 1903, as S. gayi); Isla Santibañez (present study)]. Tierra del Fuego, no exact locality (? Stepanjants, 1979, as S. gayi var. gayi). Argentina – Provincia del Chubut [(?) off Península Valdés (Vervoort, 1972, as S. gayi gayi), off Cabo Dos Bahías (Blanco, 1982; 1994, both as S. conica)]; Provincia de Santa Cruz [Puerto Deseado (Vervoort, 1972, as S. gayi gayi)]; Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [off the eastern entrance of the Magellan Strait (Blanco, 1976; 1994, both as S. geodiae); around Península Mitre (Blanco, 1982; 1994, both as S. conica)]; numerous scattered records from the Argentine Shelf between ca. 40°-54° S (El Beshbeeshy, 2011). Falkland Is. [(?) Stepanjants (1979, as S. gayi var. gayi); off the N coast (Blanco, 1982; 1994, both as S. conica); off the SE coast (El Beshbeeshy, 2011)]. (?) French Southern and Antarctic Lands – Crozet Shelf (Millard, 1977, as S. geodiae).

Sertularia clausa Allman, 1888: 54, pl. 25 figs 3, 3a. – Bedot, 1916: 219.

Sertularella clausa. – Nutting, 1904: 93, pl. 21 figs 3–4 (reexamination of the type). – Bedot, 1918: 236. – Milstein, 1976: 84, figs 24, 35.

non Sertularella clausa. – Fraser, 1938: 141, pl. 20 fig. 10; 1948: 241.

Sertularella argentinica El Beshbeeshy, 2011: 121, fig. 38 (syn. nov.). – Soto Àngel & Peña Cantero, 2015: 993, fig. 7A-B.

non Sertularella argentinica. – Galea, 2007: 59, fig. 14A-C. – Galea et al., 2007c: 312, fig. 3I (= Sertularella robustissima Galea, Häussermann & Försterra, sp. nov.).

Sertularella gayi gayi. – Blanco, 1982: 157, figs 6–9 [non Sertularella gayi (Lamouroux, 1821)].

Material examined: NHML 1888.11.13.41; Uruguay, off Montevideo, ca. 1097 m; colony composed of ca. 15 sterile stems, up to 1.2 cm high, as well as a slide (now dried out, Fig. 1D) containing a ca. 1.5 cm high, branched colony fragment, labeled “Challenger Stat. 320, Sertularia clausa, type, Monte Video, Depth 600 faths”. – ZMH C11882; FRV Walther Herwig, Argentine Shelf, no additional data; several colony fragments, up to 2 cm high, at least one gonotheca, identified as Sertularella argentinica El Beshbeeshy, 2011. – ZMH C12145; FRV Walther Herwig 31, Stn. 676, Argentine Shelf, off Provincia del Chubut, -43.80500° -59.53333°, 570 m; 22.06.1976; fragmentary, fertile colony with monosiphonic stems, on axis of dead antipatharian [material studied by El Beshbeeshy (2011), as S. argentinica].

Description: Large, up to ca. 17 cm high, bushy, irregularly and much branched colonies with either mono- or reportedly polysiphonic stems. Monosiphonic parts divided into short, almost collinear, rather thick internodes, by means of oblique constrictions of the perisarc slanting in alternate directions, not always clearly demarcated; distally, a hydrotheca to each internode. Side branches originating not laterally, but in either front or rear side of the stem, from below the hydrothecal bases; 1st internode slightly longer than subsequent ones; remainder of branches with similar structure as the stem; tips of branches commonly forming anastomoses with neighboring counterparts, resulting in much tangled, three-dimensional structure. Hydrothecae short, tronconical, adnate for slightly more than half their length to the corresponding internode; abaxial wall nearly straight to imperceptibly concave for most of its length, becoming convex below aperture; free adaxial wall slightly convex to nearly straight, surface smooth to wavy; rim with 4 short, triangular cusps separated by shallow embayments; renovations occasional; a 4-flapped operculum. Gonothecae borne on side branches, arising from below the hydrothecal bases; male similar to female; long, slender, tubular to spindle-shaped, tapering abruptly above origin, slightly constricted apically; lateral walls undulated; aperture distal, large, surrounded by 4 triangular cusps, and provided with a 4-flapped operculum.

Dimensions: See Table 4.

Remarks: Upon the comparison of the holotype of S. clausa with the Argentinean material assigned by El Beshbeeshy (2011) to his supposedly undescribed species, S. argentinica, it appears that both are indistinguishable morphologically (compare Figs 5A, B and 5C, D, as well as their respective measurements in Table 4). The former is an obviously young, sterile colony, with monosiphonic, unbranched or sparingly-branched stems, not surpassing 1.2 cm in height. Their mode of branching, with side branches arising in either the front or rear side of the stems, is peculiar and distinctive. Additionally, the frequent occurrence of terminal stolonization characterizes this species [present study; Blanco (1982, as S. gayi gayi)].

Distribution: Uruguay – off Montevideo (Allman, 1888). Argentina – scattered records from the Argentine Shelf, between 40°-53°S (El Beshbeeshy, 2011, as S. argentinica); Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [ca. 80 km off the northeastern coast of Isla de los Estados (Blanco, 1982, as S. gayi gayi)]. Burdwood Bank – Soto Àngel & Peña Cantero (2015, as S. argentinica). Falkland Is. – off the SE coast (El Beshbeeshy, 2011, as S. argentinica).

Sertularella contorta Kirchenpauer, 1884: 39, pl. 15 figs 2, 2a. – p.p. Hartlaub, 1901: 83, pl. 4 fig. 26, pl. 6 figs 14–16 (reexamination of the cotype). – Nutting, 1904: 85, pl. 18 figs 7–9. – Hartlaub, 1905: 647. – Jäderholm, 1905: 31, pl. 12 figs 9–10. – Ritchie, 1907: 76. – Bedot, 1916: 202; 1918: 236. – Billard, 1924: 61. – p.p. Rees & Thursfield, 1965: 133.

(?) Sertularella lagena Allman, 1876: 114. – Allman, 1879: 283, text-fig. – Studer, 1879: 120. – Kirchenpauer, 1884: 40. – Bedot, 1912: 355; 1916: 207; 1918: 240. – Stechow, 1925: 475, fig. 34.

non Sertularella ? lagena. – Galea & Schories, 2012a: 41, fig. 4K-L (= Sertularella antarctica Hartlaub, 1901).

Sertularella polyzonias. – p.p. Jäderholm, 1910: 4. – p.p. Vanhöffen, 1910: 322 [non Sertularella polyzonias (Linnaeus, 1758)].

Material examined: NMSZ 1921.143.1351.C; Falkland Is., Cape Pembroke, coll. Scottish National Antarctic (Scotia) Expedition 1902–1904, shore; 01.1903–01.1904; a profuse, fertile (female) colony with numerous stems, up to 4.5 cm high, on pneumatocyst of Macrocystis pyrifera [material studied by Ritchie (1907), and listed by Rees & Thursfield (1965, p. 133)]. – NMSZ 1921.143.1351.D; Falkland Is., Cape Pembroke, coll. Scottish National Antarctic (Scotia) Expedition 1902–1904, shore; 01.1903–01.1904; a fertile (female) colony composed of several stems, up to 6 cm high, on Macrocystis pyrifera [material studied by Ritchie (1907), and listed by Rees & Thursfield (1965, p. 133)]. – SMNH 123884; Falkland Is., Port William, 5 m, Swedish Magellanic Expedition 1907–1909, coll. C. Skottsberg; 10.02.1908; microslide (Fig. 1E) containing several fragments (up to 1.3 cm high) of a fertile colony, assigned by Jäderholm (1910) to Sertularella polyzonias (Linnaeus, 1758). – SMNH 123851; Falkland Is., Port William, 40 m, coll. Swedish South Polar Expedition 1901–1903, Stn. 39; 04.07.1902; microslide (Fig. 1G) containing 2 species: 1) on the left-hand side, a ca. 2 cm high, fertile colony assigned to the present species by Jäderholm (1905), re-illustrated herein in Fig. 6C, I; 2) on the right-hand side, two sterile colonies fragments, 1.3 and 1.5 cm high, assignable to S. subantarctica sp. nov. (see below), but identified by Jäderholm (1905) as S. allmani Hartlaub, 1901, and illustrated by him in his pl. 12 fig. 11, re-illustrated herein in Fig. 16K, O). – ZMB Cni945; French Southern and Antarctic Lands, Kerguelen Is., Observatory Bay, coll. Deutsche Südpolar (Gauss) Expedition 1901–1903; 15.02.1902; a sterile, fragmentary colony, 2.5 cm high [material studied by Vanhöffen (1910), as S. polyzionias]. – ZMN Cni620; French Southern and Antarctic Lands, Kerguelen Is., Port Gazelle, coll. Deutsche Tiefsee (Valdivia) Expedition 1898–1899; 28.12.1898; a fully fertile (male) colony, 2.5 cm high. – ZSM 20050442; French Southern and Antarctic Lands, Kerguelen Is., coll. Deutsche Tiefsee (Valdivia) Expedition 1898–1899, Stn. 160; 28.12.1898; microslide (Fig. 1F) containing two fertile (female) colony fragments, 9 and 13 mm high [material identified by Stechow (1925) as S. lagena Allman, 1876].

Description: Colonies erect, bushy, up to 6 cm high in inspected material (but up to 8 cm in the type), arising from dense mat of branching, intertwined stolonal fibers. Stems and basal parts of side branches either monosiphonic or fascicled in older colonies; divided into regular, slightly geniculate, rather short internodes by means of oblique constrictions of the perisarc; each internode with a couple of proximal twists, a distal swelling, and a hydrotheca, or a hydrotheca and a short, lateral apophysis below its base, confined to its distal part; branching pattern more or less regular, with generally every two consecutive apophysis-bearing internodes separated by a couple of internodes not supporting side branches; occasionally, only one apophysis-bearing internode is given off, instead of two consecutive ones, or successive apophysis-bearing internodes or couples of them are separated by 1 or 3 (instead of 2) internodes devoid of apophyses (Fig. 7A). Branching pattern of side branches similar to that of stem, though more irregular, with much spaced successive branchlets; proximal most internode generally slightly longer than subsequent ones, and provided with 2–3 spiral twists basally; branching up to at least 6th order. Basalmost side branches generally longer, hence more developed, than uppermost ones. Branches and hydrothecae shifted on to one side of the stem and forming an angle of less than 90°. Hydrothecae flask-shaped, distinctly swollen adaxially, adnate for about 1/3rd or less to corresponding internode; abaxial wall slightly concave to nearly straight for most of its length; free adaxial wall sigmoid, convex in middle; hydrotheca expanding below rim on both ab- and adaxial sides; rim thickened, provided with 4 triangular cusps, of which the abaxial one is distinctly produced, and the laterals asymmetrical; three internal, submarginal cusps (2 latero-adaxial and 1 abaxial) of varied development, sometimes absent. Gonothecae arising from below the hydrothecal bases; male similar to female; broadly ovoid, tapering below, transversely wrinkled, distally with 4 short spines. The perisarc of the colony may be either thin or thick.

Dimensions: See Table 5.

Remarks: Although quite succinct, the description of Sertularella contorta given by Kirchenpauer (1884) does not allow an indisputable identification to be made in the absence of a reexamination of the type material (N.B.: this material could not be found in ZMB, where Kirchenpauer's “herbarium” was recently located; C. Lüter, pers. comm.). Some statements provided in the original account proved inaccurate, as for example the lack of unilateral arrangement of the hydrothecae, which was subsequently disputed by Hartlaub (1901). The latter author reexamined the (then extant) cotype material, and provided more accurate details on its morphology, allowing a somehow easier identification of this species. The materials NMSZ 1921.143.1351.C&D assigned to S. contorta by Rees & Thursfield (1965), and reexamined here, agree with the available data on this species.

Sertularella contorta comes close to S. gaudichaudi (Lamouroux, 1824) through the shape (but not the size) of its internodes, and both the shape and size of its hydrothecae. Indeed, the length of the internodes in the later varies considerably (from short to exceedingly long), while it is uniformly short in the present species (this feature results also from Kirchenpauer's pl. 15 fig. 2). In addition, the mode of branching of S. contorta recalls that met with in S. allmani (with stem internodes devoid of lateral apophyses intercalating among those bearing these structures), while S. gaudichaudi exhibits a much denser branching pattern (with almost every stem internode bearing an apophysis supporting a branch). However, these differences should, perhaps, not be regarded as purely species-specific, especially given that a quite limited number of samples corresponding to both nominal species have been examined in the frame of the present study. Future collecting and molecular analyses are expected to clarify their relationships.

The Chilean material collected by Philippi and assigned by Hartlaub (1901) to the present species, although quite similar morphologically, should be better assigned to S. gaudichaudi (Lamouroux, 1824) owing to the presence of long stem internodes among the otherwise short ones (see remarks under the latter species).

Distribution: Falkland Is. (Kirchenpauer, 1884; Jäderholm, 1905; Ritchie, 1907; Jäderholm, 1910, as S. polyzonias). Le Maire Strait (Kirchenpauer, 1884). French Southern and Antarctic Lands – Kerguelen Is. (Allman, 1876; 1879, both as S. lagena; Vanhöffen, 1910, as S. polyzonias; Stechow, 1925, as S. lagena; present study).

Sertularella cruzensis El Beshbeeshy, 2011: 128, fig. 40.

Sertularella grandensis El Beshbeeshy, 2011: 20 [new name for Nutting's (1904, p. 79) record of Sertularella conica Allman, 1877; nomen nudum].

Sertularella conica. – p.p. Nutting, 1904: 79. – Vervoort, 1972: 123, fig. 38 [non Sertularella conica Allman, 1877].

Material examined: ZMH C11556; FRV Walther Herwig, Stn. 384, -39.93333° -57.18333°, 95 m; 19.07.1966; a 1.3 cm high sterile stem or branch fragment, with only the perisarc left (holotype).

Description: Colonies up to 3 cm high, composed of short, monosiphonic, sparingly-branched stems. Both stems and branches divided into rather short internodes delimited by oblique constrictions of perisarc slanting in alternate directions; a hydrotheca to the distal end of each internode; perisarc thick throughout the colony. Side branches, if present, arising laterally from below the bases of stem hydrothecae, and not branched further; 1st internode usually longer than subsequent ones. Hydrothecae biseriate, alternate, strictly coplanar; large, cylindrical, adnate for less than half their length to their corresponding internodes; slightly swollen basally, especially on adaxial side; abaxial wall almost straight for most of its length, slightly curving outwards below aperture; free adaxial wall wavy, with 3–5 undulations of the perisarc; aperture facing outwards, rim with 4 small, equally-developed, triangular cusps separated by shallow, semicircular embayments; margin usually renovated many times; a 4-flapped operculum, also renovated. Gonothecae unknown.

Dimensions: See Table 6.

Remarks: The description given above is based on the reexamination of the holotype, combined with the account of Vervoort (1972, as S. conica). The material from Albatross Stn. 2771 assigned to S. conica by Nutting (1904) was reexamined by Vervoort, and it is here included in the synonymy of the present species.

Distribution: Chile – Región de Magallanes y de la Antártica Chilena [Magellan Strait (Vervoort, 1972, as S. conica)]. Argentina – Provincia de Buenos Aires [off Bahía Blanca (Vervoort, 1972, as S. conica; El Beshbeeshy, 2011)]; Provincia de Santa Cruz [records from both off the eponymous city (Nutting, 1904, as S. conica) and the province's coast (Vervoort, 1972, as S. conica)]; Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [off the southern coast of the Península Mitre (Vervoort, 1972, as S. conica)]. Falkland Is. – off the northwest coast (Vervoort, 1972, as S. conica).

Sertularella curta Galea & Schories, 2014 in Galea et al., 2014: 34, figs 6D-E, 7C.

Sertularella geniculata. – Leloup, 1974: 28, fig. 23 [non Sertularella geniculata Hincks, 1874 = Sertularella tenella (Alder, 1857)].

Material examined: MHNG-INVE-86236; Chile, Región de Antofagasta, Taltal, -25.38333° -70.51667°, 12–20 m, coll. D. Schories, lot #24; 24.04.2012; a 1.8 cm high, male colony (holotype). – MHNGINVE-86237; Chile, Región de Antofagasta, Taltal, -25.38333° -70.51667°, 12–20 m, coll. D. Schories, lot #25; 22.04.2012; a 1.6 cm high, male colony (paratype).

Description: Colonies arising from creeping, branching stolon. Stems erect, up to 1.8 cm high, monosiphonic; basal part very short and ahydrothecate, either smooth or with up to 4 annuli; remainder of stem slightly geniculate, divided into short internodes by means of inconspicuous constrictions of the perisarc; a hydrotheca to the distal end of each internode. Side branches, when present (up to 3 per stem), short and arising irregularly from below a stem hydrotheca, either in front or the rear side of the colony; occasionally, the branches arise from within the stem hydrothecae; up to 2nd order branching observed. Hydrothecae biseriate, alternate, fusiform, adnate for about 2/3rd their length to the corresponding internode; free adaxial wall with about 3 transverse ridges prolonged abaxially; abaxial wall slightly concave, aperture expanding below rim, and perpendicular to long axis of the theca; margin with 4 equally-developed, triangular cusps separated by rounded, moderately-deep embayments; a 4-flapped operculum; 3 internal, submarginal cusps (2 latero-adaxial, 1 abaxial), not always noticeable. Gonothecae (only male known) originating from below the hydrothecal bases; ovoid-fusiform, walls with 6–7 transverse ridges, aperture surrounded by 4 perisarc projections.

Dimensions: Internodes 340–490 μm long and 170–210 μm wide at nodes. Hydrothecal free adaxial length 345–380 μm, adnate adaxial length 230–270 μm, abaxial length 485–515 μm, maximum width 250–270 μm, diameter at aperture 210–230 μm. Male gonotheca 1440–1660 μm long and 575–620 μm wide.

Remarks: The gonotheca of this species is illustrated by Galea et al. (2014, fig. 7C).

Distribution: Chile – Región de Antofagasta [Bahía de Tocopilla (Leloup, 1974, as S. geniculata), Taltal (Galea et al., 2014)].

Sertularella curvitheca Galea & Schories, 2012a: 38, pl. 3E, fig. 4A-E.

Sertularella gayi. – Galea, 2007: 62. – Galea et al., 2007b: 161. – Galea et al., 2007c: 312 [non Sertularella gayi (Lamouroux, 1821)].

Sertularella polyzonias. – Leloup, 1974: 32, fig. 26. – Galea, 2007: 64, fig. 15A-D. – Galea et al., 2007b: 161. – Galea et al., 2007c: 312 [non Sertularella polyzonias (Linnaeus, 1758)].

Material examined: MHNG-INVE-79665; Chile, Región de los Lagos, Caleta la Arena, Caleta Yerbas Buenas, -41.67263° -72.65650°, 20 m, coll. D. Schories, lot #05; 25.04.2007; colony composed of several profusely-branched, polysiphonic stems, up to 10 cm high, some bearing male gonothecae (holotype). – HRG-1178; Chile, Región de Aysén, Isla Waller, -46.7648° -75.2312°, 20 m, coll. HSFS, HF24, lot #128; 20.04.2015; three colonies with polysiphonic stems, 4.5, 5.8, and 7.0 cm high, the latter bearing a male gonotheca.

Description: Colonies erect, up to 10 cm high, arising from creeping, branching stolon. Stems either mono- or polysiphonic. Basal part of monosiphonic stems of varied length, not constricted above origin from stolon, ahydrothecate, with smooth perisarc; remainder of stem composed of a succession of moderately-long, slightly geniculate internodes delimited by rather indistinct, oblique nodes sloping in alternate directions. A hydrotheca, or a hydrotheca and a short, lateral apophysis immediately below its base, confined to the distal end of each internode. Branching pattern alternate and coplanar, with generally 3 hydrothecae between successive side branches, but possibly 1 to 9; up to 3rd order branching observed; branches with similar structure as the stem, though 1st internode comparatively longer than subsequent ones. Hydrothecae tubular, distinctly curved outwards, adnate for about half their length to the corresponding internode; abaxial wall straight for 3/4th its length, conspicuously curved outwards below rim; free adaxial wall slightly convex, perisarc smooth to wavy, in the latter case provided with 2–3 indistinct undulations, more conspicuous proximally; hydrothecal aperture expanding just below rim; the latter provided with 4 acute cusps separated by moderately-deep, semi-circular embayments; operculum composed of 4 triangular flaps, with concentric, closely-set striae. Gonothecae arising from below the hydrothecal bases; male and female similar, though of slightly different size; broadly ovoid, with 6–7 transverse ribs, the 3–4 distalmost well-marked, becoming obsolete towards base; aperture mounted on short, terminal collar, truncate distally and provided with 4 blunt perisarc projections; female with acrocysts.

Dimensions: See Table 7.

Remarks: The typical shape of the colonies of this species is illustrated in Galea & Schories (2012a, pl. 3E, fig. 4A), and its gonothecae in both Galea (2007, fig. 15B, D) and Galea & Schories (2012a, fig. 4E).

Distribution: Chile – Región de los Lagos [Fjord Comau (Galea, 2007, as both S. gayi and S. polyzonias), Gulf of Ancud (Leloup, 1974, as S. polyzonias), Seno de Reloncaví (Galea & Schories, 2012a)]; Región de Aysén [Canal Puyuhuapi (Galea et al., 2009, as S. cf. gayi); Isla Waller (present study)]; Región de Magallanes y de la Antártica Chilena [Canal Adalberto and Isla Camello (Galea, 2007, as S. gayi), Canal Fallos (Galea, 2007, as S. polyzonias)].

Sertularella fuegonensis El Beshbeeshy, 2011: 131, fig. 41. – (?) Vervoort & Watson, 2003: 161, fig. 37A-B. – Galea, 2007: 60, fig. 14D-F. – Galea et al., 2007c: 312, fig. 4A.

Sertularella picta. – Vervoort, 1972: 114, fig. 35A-B [non Sertularella picta (Meyen, 1834)].

non Sertularella picta. – Vervoort, 1972: 113, figs 34, 35C [= Sertularella implexa (Allman, 1888)].

Material examined: ZMH C11884; FRV Walther Herwig, Stn. 280, Argentine Shelf, off Provincia de Santa Cruz, -51.50000° -68.50000°; 11.02.1971; a few infertile stems, up to 2 cm high, with remains of coenosarc. – MHNG-INVE-53441; Chile, Región de Magallanes y de la Antártica Chilena, Canal Vicuña, -52.16222° -73.27617°, 15–25 m, coll. HSFS, HF3, lot #142; 06.03.2006; several sterile colony fragments, up to 6 cm high. – MHNG-INVE-53447; Chile, Región de Magallanes y de la Antártica Chilena, Canal Vicuña, -52.16222° -73.27617°, 15 m, coll. HSFS, HF3, lot #143; 06.03.2006; a colony, ca. 6 cm high, and smaller fragments, all sterile.

Description: Colonies much branched, with no definite main stems, arising from rhizoid stolon. Both stems and branches divided into moderately-long, geniculate internodes by means of weak, oblique constrictions of the perisarc, sloping in alternate directions; each internode with a distally-placed hydrotheca, or a hydrotheca and a lateral apophysis immediately below its basis; apophyses given off irregularly every 1–10 hydrothecae; side branches, up to the 3rd order, generally alternate and coplanar. Hydrothecae biseriate, alternate, either coplanar or imperceptibly shifted on to one side of the stem; flask-shaped, adnate for 2/5th their adaxial length, constricted below aperture; free adaxial wall slightly sigmoid, surface either smooth or with 2–5 shallow wrinkles; 4 triangular, marginal cusps of unequal development (abaxial one the longest, adaxial one the shortest, and the two laterals of intermediate length), separated by rather deep, rounded embayments; occasionally 3 internal, submarginal cusps (2 latero-adaxial, 1 abaxial); renovations of the margin occur; 4 triangular opercular flaps. Gonothecae unknown.

Dimensions: See Table 8.

Remarks: The colony structure is illustrated by Galea (2007, fig. 14D). The free adaxial wall may be either smooth (Chilean material) or wrinkled (El Beshbeeshy, 2011), though colonies with hydrothecae exhibiting both situations may occur (e.g. Vervoort, 1972, fig. 35A, as S. picta). Intrathecal cusps occur variably among the hydrothecae of the same colony, with the abaxial one generally more conspicuous than the two latero-adaxial ones.

Distribution: Chile – Región de Magallanes y de la Antártica Chilena – Canal Vicuña (Galea, 2007). Argentina – scattered records from the Argentine Shelf between 41°-53° S (El Beshbeeshy, 2011); Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [off the northern coast of the tip of Península Mitre (Vervoort, 1972, as S. picta)]. (?) New Zealand (Vervoort & Watson, 2003).

Sertularia gaudichaudi Lamouroux, 1824: 615, pl. 90 figs 4, 5. – Van Praët, 1979: 901, fig. 47 (reexamination of schizoholotypes).

Sertularella gaudichaudi. – Bedot, 1905: 105. – Billard, 1909: 317, fig. 4A (reexamination of the holotype). – Bedot, 1910: 360; 1912: 354; 1916: 204; 1918: 238. – Billard, 1924: 61 (reexamination of the holotype). – Van Praët, 1979: 901, fig. 47. – Ramil et al., 1992: 518, fig. 15 (reexamination of schizoholotypes).

non Sertularella gaudichaudi. – Cornelius, 1979: 282, fig. 20 [= S. ellisii (Deshayes & Milne-Edwards, 1836), S. fusiformis (Hincks, 1861), and S. mediterranea Hartlaub, 1901]. – García Corrales et al., 1980: 30, fig. 10 [= S. ellisii (Deshayes & Milne-Edwards, 1836)]. – Gili et al., 1989: 101, fig. 26B, C (= S. cf. mediterranea Hartlaub, 1901).

Sertularella gaudichaudii. – Kirchenpauer, 1884: 38 (incorrect subsequent spelling).

Sertularia picta Meyen, 1834: 201, pl. 34 figs 1–3 (syn. nov.). – Hartlaub, 1901: 77, pl. 5 fig. 14, pl. 6 figs 17, 18 & 20 (reexamination of the cotype). – Jäderholm, 1903: 282. – Nutting, 1904: 90, pl. 20 figs 5–7. – Bedot, 1905: 105; 1910: 361. – Hartlaub, 1905: 645, fig. L⁴. – Billard, 1922: 106, fig. 2B. – Stechow, 1923a: 187, fig. B¹ (reexamination of cotype). – Naumov & Stepanjants, 1962: 88. – Blanco, 1963: 175, figs 3–4. – (?) Millard 1971: 405, fig. 6A; 1977: 25, fig. 6A-D. – Blanco, 1994: 199. – Branch & Williams, 1993: 12, text-fig. – El Beshbeeshy, 2011: 138, fig. 44.

non Sertularella picta. – Blanco, 1967: 112, pl. 3 figs 1–7 (= Sertularella mediterranea Hartlaub, 1901). – Millard, 1971: 405, fig. 6B (= S. subantarctica Galea, sp. nov.). – Vervoort, 1972: 113, figs 34, 35C [= Sertularella implexa (Allman, 1888)]. – Vervoort, 1972: 114, fig. 35A, B (= Sertularella fuegonensis El Beshbeeshy, 2011).

Sertularella protecta p.p. Hartlaub, 1901: 79, pl. 6 figs 21–26 (syn. nov.). – Hartlaub, 1905: 652, fig. R⁴. – Billard, 1924: 62. – p.p. Jäderholm, 1903: 282. – Rees & Thursfield, 1965: 135.

(?) Sertularella margaritacea Allman, 1885: 133, pl. 7 figs 3, 4. – Nutting, 1904: 95, pl. 22 fig. 1. – Hartlaub, 1905: 657, fig. V⁴. – Bedot, 1916: 208; 1918: 240. – Billard, 1924: 60.

Sertularella allmani. – Naumov & Stepanjants, 1962: 86 (non Sertularella allmani Hartlaub, 1901).

Sertularella antarctica. – p.p. Jäderholm, 1903: 283 (non Sertularella antarctica Hartlaub, 1901).

Sertularella contorta. – p.p. Hartlaub, 1901: 83 (non Sertularella contorta Kirchenpauer, 1884).

Sertularella polyzonias. – p.p. Vanhöffen, 1910: 322 [non Sertularella polyzonias (Linnaeus, 1758)].

Material examined: ZMH C04172; Chile, Región de Magallanes y de la Antártica Chilena, Isla Lennox, coll. Michaelsen no. 181; 22.12.1892; fertile colony (stranded on beach) with multiple fascicled stems, up to ca. 7.5 cm high [material examined by Hartlaub (1901, p. 79) and assigned by him to S. picta (Meyen, 1834)]. – ZMH C04173; Chile, Región de Magallanes y de la Antártica Chilena, Lennox Cove, coll. Michaelsen no. 182; 24.12.1892; fertile colony with multiple monosiphonic stems, up to 4 cm high, on kelp (type of S. protecta Hartlaub, 1901). – SMNH 123894; Chile, Región de Magallanes y de la Antártica Chilena, Lennox Cove, coll. Swedish Tierra del Fuego Expedition 1895–1896; 05.02.1896; microslide (Fig. 1J) containing 2 badly preserved, fertile colony fragments, both ca. 2.5 cm high [material identified by Jäderholm (1903) as S. protecta Hartlaub, 1901]. – SMNH 123881; Chile, Región de Magallanes y de la Antártica Chilena, Isla Lennox, 18–45 m, coll. Swedish Tierra del Fuego Expedition 1895–1896; 07.02.1896; microslide (Fig. 1H) containing 3 colony fragments 1.7–2.0 cm high, two of which bear gonothecae [material identified by Jäderholm (1903) as S. picta (Meyen, 1834)]; with small, epizootic colony of Halecium annuliforme Galea & Schories, 2012a, bearing an incipient gonophore of unassignable sex. – SMNH 123837; Chile, Región de Magallanes y de la Antártica Chilena, Isla Nueva, coll. Swedish Tierra del Fuego Expedition 1895–1896; 07.02.1896; microslide (Fig. 1I) containing a ca. 6 cm high, fertile colony fragment [material identified by Jäderholm (1903) as S. antarctica Hartlaub, 1901; a second identification, contorta, was subsequently added to the label]. – NMSZ 1959.33.472; Patagonia; microslide (Fig. 1K) comprising 2 colony fragments, 0.5 and 1.0 cm high, the largest bearing 2 gonothecae [material belonging to Ritchie's collection, identified by Stechow as S. protecta Hartlaub, 1901, and listed by Rees & Thursfield (1965, p. 135)]. – ZMB Cni1122; Chile, coll. Philippi, no additional data; a very fragmented, badly preserved fertile colony composed of numerous pieces up to 1.6 cm high, with fascicled portions of stem [material studied by Hartlaub (1901) and assigned by him to S. contorta Kirchenpauer, 1884]. – ZMB Cni946; French Southern and Antarctic Lands, Kerguelen Is., Royal Sound, coll. Deutsche Südpolar (Gauss) Expedition 1901–1903; 01.01.1902; a fully fertile (male) colony, 3 cm high [material studied by Vanhöffen (1910), as S. polyzonias].

Description: Slender, straggling, repeatedly branched, tangled colonies, up to 21 cm high, with mono- or polysiphonic stems and branches; these divided by oblique nodes into internodes of highly variable length, from short to exceedingly long and slender; each internode with a couple of spiral twists proximally, a hydrotheca distally, and a short, lateral apophysis below its base; apophyses alternate, supporting side branches with the same structure as the stem, though internodes generally shorter; first internode with 2–4 spiral twists basally. Side branches and hydrothecae shifted on to one side (“anterior”) of the colony, the two rows forming a moderately wide angle. Hydrothecae short, flask-shaped, distinctly swollen adaxially; abaxial wall straight or nearly so; free adaxial wall convex for most of its length, becoming concave below aperture; margin with 4 short, triangular, unequally-developed cusps: abaxial one generally produced, occasionally less so; adaxial one the shortest; lateral ones asymmetrical, the “anterior” one comparatively shorter than “dorsal” one; rim generally thickened; internal, submarginal cusps of varied development: from absent, to 2 latero-adaxial, to a complete set of 3 (one abaxial and 2 latero-adaxial); a variously developed perisarc plug at the end of the adnate adaxial wall, forming an incomplete foramen for the passage of the hydranth. Gonothecae borne on both stems and branches; broadly ovoid, with 3–4 transverse ridges in distal half, smooth in the lower half; aperture on short collar surrounded by generally 4 blunt spines (occasionally 3–5).

Dimensions: See Table 9.

Remarks: The holotype colony of Sertularia gaudichaudi, stored in Caen, France, and reexamined earlier by Billard (1909; 1922), was lost during WWII (Redier, 1967). However, two schizoholotype slides (MNHN H.L. 615 & 616) were prepared by Billard from that colony (Van Praët, 1979), and were reexamined subsequently by Ramil et al. (1992). Unfortunately, those slides could not be located for the purpose of the present study (A. Andouche, Muséum national d'Histoire naturelle, Paris, pers. comm.).

The cotype of Sertularia picta was reexamined by Hartlaub (1901) and Stechow (1920; 1923a), who provided additional information and more accurate illustrations.

The synonymy between these two nominal species was suspected by Meyen (1834), Kirchenpauer (1884), Hartlaub (1901; 1905), Bedot (1910), Billard (1909; 1910), and Galea & Schories (2012b). In contrast, Stechow (1920) and Billard (1922) provided arguments in favor of their specific separation, but their reliability could be contested in light of the new data available in the subsequent literature, and through the present observations. Stechow, who compared the redescription of S. gaudichaudi given by Billard (1909) with the cotype of S. picta, emphasized the following differences: 1) Lamouroux’ species does not have hydrothecae with thickened rims, a statement invalidated later on by Billard (1922), who showed that this character is inconstant, an opinion equally shared by us; 2) the abaxial cusp is conspicuously produced in S. picta, although it is now recognized that its shape varies within the same colony (present study); 3) the gonothecae of S. picta have only wavy walls, while those of S. gaudichaudi are clearly transversely ringed, an argument not only contradicted by several observations (Blanco 1963; present study, material ZMH C04172), but also recognized as dependent on their state of maturation.

Billard (1922), for his part, emphasized the following distinguishing characters exhibited by S. picta: 1) the conspicuously hypertrophied abaxial hydrothecal cusp described by Stechow (1920), which is now recognized as a variable character; 2) the comparatively thickened hydrothecal rim, although the distalmost, youngest hydrothecae have evidently unthickened rims; 3) the more conspicuous internal, submarginal cusps, though it was demonstrated that this is an inconstant character (Blanco 1963); 4) the broad perisarcal plug at the base of the hydrotheca, although obvious differences are seen in the hydrothecae from various, or even the same, colonies (present study).

It appears, therefore, that none of the arguments provided by Stechow and Billard are reliable specific characters. In addition, a comparison of the available data (Table 10) and illustrations (Fig. 10) from various sources based on the examination of the types of both nominal species demonstrate, with little doubt, that they are coterminous, with Lamouroux's species having priority.

A typical, fully formed colony of S. gaudichaudi is illustrated by both Lamouroux (1824) and Billard (1922), while the gonotheca is depicted in a number of papers, e.g. Billard (1909), Stechow (1923a, as S. picta), Ramil et al. (1992), and El Beshbeeshy (2011, as S. picta). The habit of the stem varies in this species, and could be either monosiphonic (Blanco, 1963; El Beshbeeshy, 2011; specimen ZMH C04173 examined here) or polysiphonic (material ZMH C04172 examined here).

Type material of S. protecta [not designated by Hartlaub (1901), but indicated on the label of sample ZMH C04173] is characterized by: 1) the occurrence of long (up to 2 mm) internodes among the otherwise most numerous, much shorter stem internodes; 2) the profuse branching, with almost every stem internode giving rise to a side branch, the latter alternate in position; 3) short and conspicuously adaxially-swollen hydrothecae. The perisarc of this material is comparatively hypertrophied with respect to that of sample ZMH C04172 assigned to S. picta by Hartlaub himself, giving the colony a more “peculiar”, rigid appearance. The higher occurrence of short vs. long internodes does not justify the placement of this species close to S. allmani as suggested by Hartlaub, because long internodes have never been observed in the latter. On the contrary, their presence is a typical feature of S. gaudichaudi, and their length may reach as much as 4 mm (e.g. SMNH 123881 and 123894).

Two other specimens, one from Elizabeth I. (Magellan Strait) and the other from South Georgia were also assigned to S. protecta by Hartlaub. The former is possibly no longer extant in ZMH (H. Roggenbuck, pers. comm.) and, for the latter, there is no certainty whether it is the same specimen as ZMH C04384, now recognized as a distinct species, S. subantarctica Galea, sp. nov.

The Chilean material collected by Philippi and assigned by Hartlaub (1901, p. 83) to S. contorta Kirchenpauer, 1884 was reexamined, and should be better assigned to the present species. Indeed, quite long internodes (Fig. 9E) co-occur with otherwise uniformly short internodes in some stem fragments.

Billard (1924) reexamined the type of Sertularella margaritacea Allman, 1885 and noted the presence of a thickened hydrothecal rim, of a conspicuous abaxial cusp, as well as the apparent lack of internal, submarginal projections of the perisarc. In addition, the branching pattern illustrated in the original account (Allman, 1885, pl. 7 fig. 3) fits those provided by both Lamouroux (1824) and Billard (1922) for S. gaudichaudi. Although not evident from his pl. 7 fig. 4, Allman also stated that the hydrothecae of his species were “distant” and this is, indeed, noticeable on the lower part of the stem and a couple of side branches, suggesting that both short and long internodes occur within the same colony, which is a character typically exhibited by S. gaudichaudi.

Distribution: Chile – Región de Magallanes y de la Antártica Chilena [Isla Navarino (Hartlaub, 1901; 1905, both as S. picta); Isla Lennox (Hartlaub, 1901; 1905, as both S. picta and S. protecta; Jäderholm, 1903, as S. picta); Lennox Cove (Hartlaub, 1901; Jäderholm, 1903; both as S. protecta); Cape Horn (Billard, 1922, as S. picta); Isla Nueva (Jäderholm, 1903, as S. antarctica); Magellan Strait (Allman, 1885, as S. margaritacea)]. Patagonia – no exact locality (Rees & Thursfield, 1965, as S. protecta). Argentina – scattered records from the Argentine Shelf between ca. 47° S and the east of Península Mitre (El Beshbeeshy, 2011); Provincia del Chubut [Puerto Madryn (Blanco, 1963, as S. picta)]; Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [Isla de los Estados (Blanco, 1994, as S. picta); eastern coast of Tierra del Fuego (Meyen, 1834, as S. picta)]. Between Tierra del Fuego and the Falkland Is. (Naumov & Stepanjants, 1962, as S. allmani). Falkland Is. (Lamouroux, 1824; Meyen, 1834, as S. picta) and off their eastern coast (El Beshbeeshy, 2011). French Southern and Antarctic Lands – Kerguelen Is. (Vanhöffen, 1910, as S. polyzonias; Naumov & Stepanjants, 1962, as S. picta; Millard, 1977, as S. picta); Crozet Shelf (Millard, 1977, as S. picta). (?) South African Subantarctic Islands: Marion I. (Millard, 1971; Branch & Williams, 1993; both as S. picta), Prince Edward I. (Branch & Williams, 1993, as S. picta).

Sertularella geodiae Totton, 1930: 196, text-fig. 43, pl. 3 figs 7–8.

non Sertularella geodiae. – Vervoort, 1972: 120, fig. 37 (= ? S. hermanosensis El Beshbeeshy, 2011). – Blanco, 1976: 39, pl. 3 figs 7–8; 1994: 199 (= Sertularella blanconae El Beshbeeshy, 2011).

(?) Sertularella geodia. – ? Naumov & Stepanjants, 1962: 86, fig. 10 (incorrect subsequent spelling).

Description: Colonies up to 15 cm high, arising from large rooting masses; irregularly pinnate; stems and branches fascicled and well defined, divided into rather short, slightly geniculate internodes by means of oblique constrictions of the perisarc slanting in alternate directions; a hydrotheca to the distal end of each internode. Side branches given off laterally from below the bases of stem hydrothecae; structure similar to that of stem. Hydrothecae biseriate, alternate, coplanar; large, flask-shaped, adnate for 3/5th their adaxial length, swollen adaxially; a typical notch at junction between proximal part of free adaxial wall with corresponding internode; abaxial wall slightly sigmoid (imperceptibly concave for most of its length, becoming suddenly convex below aperture); free adaxial wall with slight “shoulder” proximally, perisarc undulated; margin with 4 short, sharp, triangular cusps separated by very shallow, semicircular embayments; occasionally 3 submarginal, intrathecal projections of perisarc, 2 latero-adaxial, and one abaxial; a 4-flapped operculum. Gonothecae borne on both stem and side branches, arising from below the hydrothecal bases; elongated-ovoid, wall transversely-wrinkled, aperture surrounded by 3–4 apical cusps.

Dimensions: See Table 11.

Remarks: The description given above combines the original account with that provided by Vervoort & Watson (2003). As stated by these authors, S. geodiae differs from S. gayi (Lamouroux, 1821) through its much larger hydrothecae, the occasional presence of submarginal cusps, and the apical part of its gonotheca. The typical shape of a colony fragment is illustrated by Totton (1930, pl. 3 fig. 8).

Distribution: (?) Chile – Región de Magallanes y de la Antártica Chilena [eastern coast of Tierra del Fuego (Naumov & Stepanjants, 1962, as S. geodia). New Zealand and New Caledonia (Vervoort & Watson, 2003).

Sertularella hermanosensis El Beshbeeshy, 2011: 133, fig. 42.

Sertularella geodiae. – p.p. Vervoort, 1972: 120, fig. 37. [non Sertularella geodiae Totton, 1930]

Material examined: ZMH C11885; FRV Walther Herwig, Argentine Shelf, no additional data; four sterile colony fragments 7.0–1.4 cm high, each bearing several hydrothecae, with only the perisarc left. – NHML 1888.11.13.42; between Cabo Virgenes, Argentina, and the Falkland Is., Challenger Stn. 314, ca. 128 m; 3 infertile colony fragments (6, 12 and 18 mm high) among the holotype of Sertularella implexa (Allman, 1888) (for more details, see under this species), and a microslide (Fig. 12A).

Description: Colonies composed of erect, monosiphonic, unbranched or sparingly-branched stems arising from stolonal fibers firmly adhering to substrate. Both stems and side branches divided into moderately long (though varied in length), imperceptibly geniculate to collinear internodes, by means of faint, oblique constrictions of the perisarc slanting in alternate directions. A hydrotheca to the distal end of each internode. Side branches generally arising from below the bases of every 3 stem hydrothecae by means of short, lateral apophyses. Hydrothecae biseriate, alternate, coplanar; flask-shaped, adnate for slightly more than half their length to the corresponding internode, slightly tumid adaxially; abaxial wall straight to slightly concave proximally, suddenly becoming convex below aperture; free adaxial wall wavy to distinctly transversely-ridged, ridges occasionally reaching abaxial wall; aperture with 4 short, equal, triangular cusps, separated by shallow embayments; renovations occasional; a 4-flapped operculum. Gonothecae unknown.

Dimensions: See Table 12.

Remarks: According to El Beshbeeshy (2011), his species has hydrothecae with different forms, and this is also evident from his fig. 42. As not all his material was reinspected for the purpose of the present study, it is assumed that those differences could indicate the presence of a mix of species.

Distribution: Chile – Región de Magallanes y de la Antártica Chilena [Magellan Strait (Vervoort, 1972, as S. geodiae)]. Argentina – scattered records from the Patagonian Shelf, between ca. 41° S and Península Mitre (El Beshbeeshy, 2011). Elsewhere – between Cabo Virgenes, Argentina, and the Falkland Is. [present study (material co-occurring with the type of S. implexa); El Beshbeeshy, 2011]; off the NE coast of Falkland Is. (El Beshbeeshy, 2011); a large perimeter including the Strait of Magellan, the Falkland Is., the Burdwood Bank, Isla de los Estados, and Cape Horn (Vervoort, 1972, as S. geodiae).

Sertularia implexa p.p. Allman, 1888: 54, pl. 26 figs 1, 1a. – Hartlaub, 1901: 90. – Bedot, 1916: 223.

non Sertularella implexa. – Galea & Schories, 2012a: 40, pl. 3 fig. 4F-J (= Sertularella recta Galea & Schories, sp. nov.)

Sertularella picta. – Vervoort, 1972: 113, figs 34, 35C [non Sertularella picta (Meyen, 1834)].

non Sertularella picta. – Vervoort, 1972: 114, fig. 35A-B [= Sertularella fuegonensis El Beshbeeshy, 2011].

Material examined: NHML 1888.11.13.42; a vial containing numerous sterile colony fragments in alcohol (designated here as the lectotype of S. implexa), as well as two slides. One slide (Fig. 12A), marked as “type”, bears the label “Challenger Stat. 314, Falklands, Depth 70 faths, Sertularia implexa”, and contains a 1.1 cm high colony fragment bearing 3 side branches. This material clearly does not belong to Allman's species; in addition, its hydrothecae were quite distorted upon squashing between slide and coverslip. The other slide (Fig. 12B), labeled “Challenger Coll., Sertularia implexa, bet. Cape Virgins & Falkland Is., 24″ is a 1.6 cm high colony fragment bearing 5 side branches, and is in agreement with both the bulk of the alcohol-preserved material and Allman's pl. 26 fig. 1A. This second slide is selected here as the paralectotype of S. implexa. Among the alcohol-preserved material, three colony fragments (6, 12 and 18 mm high) could be identified as Sertularella hermanosensis El Beshbeeshy, 2011, and are possibly conspecific with the material mounted in the “type” slide; they were transferred to a separate vial.

Description: Colonies growing in loosely entangled tufts, up to ca. 7.5 cm high; profusely and irregularly branched in all directions, with no definite main stems. Stems and side branches strictly monosiphonic, divided into long, slender internodes by means of oblique nodes; first internode with a proximal twist, and comparatively longer than subsequent ones; a hydrotheca, or a hydrotheca and a short apophysis arising laterally from below its base, confined to the distal part of each internode; hydrothecae in two alternate rows; rows coplanar or slightly shifted on to one side of the colony. Side branches originating every 1–14 hydrothecae; up to 3rd order branching observed. Hydrothecae long, adnate for 2/5th their length to the corresponding internode; swollen adaxially; perisarc either smooth or with 1–2 faint wrinkles forming shallow ridges not extending completely abaxially; abaxial wall nearly straight; abaxial cusp produced, remaining cusps triangular with rounded tips, separated by deep embayments; no intrathecal, submarginal projections of the perisarc. Gonothecae arising from below the hydrothecae; broadly ovoid, tapering below, distal half provided with ca. 6 transverse ridges; aperture on top, surrounded by 4 small cusps.

Dimensions: See Table 13.

Remarks: The typical silhouette of a colony is accurately depicted by Allman (1888) in his pl. 26 fig. 1. Part of Vervoort's (1972) material assigned to S. picta (Meyen, 1834), notably that from Vema 18–16 (described in detail), shows the following features: 1) the colony is bushy, composed of “irregularly intertwining, fine […] repeatedly branched, side-branches”; 2) both the stems and branches are monosiphonic throughout; 3) the internodes are moderately long; 4) the hydrothecae are “arranged in two planes, that make a very obtuse angle”; 5) their free adaxial wall is “about 1.5–2 times the length of the fused part, […] distinctly undulated, though the mode of development of the undulations is variable”. Taken together, these represent distinctive features of S. implexa. Vervoort's material was fertile, and his account represents the first description of the gonotheca of this species.

Distribution: Chile – Región de Magallanes y Antártica Chilena [off Isla Nueva (Vervoort, 1972, as S. picta)]. Argentina – Provincia de Santa Cruz [off Deseado (Vervoort, 1972, as S. picta)]; Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [off Isla de los Estados (Vervoort, 1972, as S. picta)]. Between Cabo Virgenes and the Falkland Is. (Allman, 1888).

Sertularella polyzonias. – p.p. Jäderholm, 1910: 4. – p.p. Hartlaub, 1905: 655 [non Sertularella polyzonias (Linnaeus, 1758)].

Holotype material: SMNH 123883; Chile, Juan Fernández archipelago, 35 m, Swedish Magellanic Expedition 1907–1909, coll. C. Skottsberg; 24.08.1908; microslide (Fig. 12C) with three colony fragments 7–20 mm long, the largest bearing 4 gonothecae, the smallest unbranched, and the remaining two provided with two side branches each [material identified by Jäderholm (1910) as S. polyzonias (Linnaeus, 1758)].

Paratype material: ZMB Cni4421; Chile, Juan Fernández archipelago; coll. Plate, det. Hartlaub (1905, as S. polyzonias); a 3.8 cm high colony represented by a single, ramified, sterile stem.

Comparison material: HRG-0550; France, Brittany, depth unrecorded, coll. F. Ziemski; (day and month unavailable) 2011; numerous sterile, unbranched or sparingly-branched stems and fragments, up to 4.5 cm high, of S. polyzonias.

Diagnosis: Erect, coplanar colonies with monosiphonic, irregularly pinnate stems; internodes moderately-long, slightly geniculate; hydrothecae flask-shaped, decidedly facing outwards, adnate for half their length, free adaxial wall convex; gonothecae broadly ovoid, transversely wrinkled, aperture mounted on constricted neck region, surrounded by 4 blunt spines.

Etymology: Named after its (presently known) area of occurrence.

Description: Colonies erect (though flaccid when out of liquid), up to 3.8 cm high, arising from creeping, branching stolon. Stems monosiphonic, unbranched; basal part of varied length (ca. 1.5 cm long in paratype) and ahydrothecate; above, divided into moderately-long, slightly geniculate internodes by means of oblique constrictions of the perisarc slanting in alternate directions; one hydrotheca confined to the distal end of each internode; side branches arising generally singly (occasionally in pairs) immediately below the base of a hydrotheca, either laterally or slightly shifted on to the front of stem, giving the colony a globally planar appearance; there are no distinct apophyses supporting the branches; 1–4 hydrothecae between successive side branches; branches not strictly alternate, several successive ones may be given off on same side of the stem; up to 2nd order branches observed; first internode comparatively longer than subsequent ones; remainder with structure similar to that of stem. Hydrothecae biseriate, alternate, flask-shaped, smooth-walled, adnate for half their length to the corresponding internode, with distinct outward bend; free adaxial wall convex for most of its length, slightly upturned distally; abaxial wall concave for 3/4th its length, and distinctly convex below aperture; rim tilted away from stem/branches, and provided with 4 pointed, triangular cusps separated by moderately-deep embayments; a four-flapped operculum; three conspicuous internal, submarginal, lamellar projections of the perisarc, one abaxial and two latero-adaxial, the latter could be absent in distalmost, hence youngest, hydrothecae. Gonothecae arising laterally from the internodes, a short distance below the hydrothecal bases; broadly ovoid, transversely wrinkled (up to 6 distinct ridges in upper 2/3rd), tapering below into short, indistinct pedicel, distally bearing a constricted neck region on the top of which is found the aperture surrounded by 4 short, blunt spines; sex could not be ascertained, although a single, ovoid, central mass is carried on by the blastostyle.

Dimensions: See Table 14.

Remarks: This species has been incorrectly assigned to Sertularella polyzonias (Linnaeus, 1758) by both Hartlaub (1905) and Jäderholm (1910). Its morphological differences with the Linnean species are easily noted by comparing Fig. 13E, F and 13G, and Fig. 13H, I and 13J, respectively.

The hydrothecae of S. juanfernandezensis are very similar to those of a number of congeners, notably: 1) S. arbuscula (Lamouroux, 1816), but this species possesses very short internodes (Millard, 1957), and its gonothecae are fusiform and, most often, smooth-walled (Millard 1975); 2) S. crassiuscula Bale, 1924, but this species has comparatively smaller hydrothecae, its internodes are very short, and its gonothecae are large and devoid of the distinctly constricted neck region met with in the present species (Bale, 1924; Ralph, 1961); 3) S. falsa Millard, 1957, but this species has relatively short internodes, there are 4 submarginal, intrathecal projections of the perisarc alternating with the hydrothecal cusps, and its gonothecae are spindle-shaped (Millard, 1957).

Distribution: Only known from Chile – Juan Fernandez archipelago (Hartlaub, 1905; Jäderholm, 1910).

Sertularella kerguelensis Allman, 1876: 113. – Studer, 1879: 120. – Kirchenpauer, 1884: 40.

Description: Stem monosiphonic, up to 2.5 cm high, profusely and irregularly branched. Internodes with shallow annulations basally, each bearing a hydrotheca distally; the latter somewhat tumid below, tapering distally, aperture slightly incurved adaxially. Gonothecae arising from below the hydrothecal bases, ovoid, transversely-ringed in upper half and becoming smooth towards the base; distally a short, tubular neck bearing apically an aperture surrounded by 4 perisarc projections.

Remarks: This species, succinctly described and not illustrated in the original account, is unrecognizable among its congeners recorded subsequently from Kerguelen, especially given that its type material could not be located in collections of NHML (A. Cabrinovic, pers. comm.). According to Allman (1876), it is “nearly allied to S. polyzonias”, with which it has been synonymized later on (Allman, 1879). However, there are no relevant records of the Linnean species from the study area, as earlier assignments to it proved erroneous (see Appendix I).

Since the binomen S. kerguelensis has apparently not been used since 1899, it should be considered as a nomen dubium.

Distribution: French Southern and Antarctic Lands, Kerguelen Is. – Swains Bay (Allman, 1876).

Sertularia leiocarpa Allman, 1888: 52, pl. 25 figs 1, 1a.

Sertularella leiocarpa. – Stechow, 1925: 477, fig. 35. – Galea, 2015: 9, fig. 3P.

Material examined: HRG-1056; Tristan da Cunha group of islands, E of Inaccessible I., -37.32000° 12.60000°, 160 m, coll. British Antarctic Survey, Stn. 80, lot DB12-0340; 24.05.2013; a ca. 5 cm high, sterile stem bearing a single side branch.

Description: Colonies up to ca. 7.5 cm high, arising from thin hydrorhizal fibers. Stems mono- or lightly polysiphonic basally, moderately stiff, giving rise to roughly alternate, coplanar side branches; stems and branches divided into moderately long, slender, geniculate internodes by means of indistinct oblique nodes; a hydrotheca confined to the distal end of each internode; side branches given off irregularly, directly (no apophyses present) and laterally from below a stem hydrotheca; up to 2nd order branches. Hydrothecae long, tubular, adnate for ca. 1/3rd their length to the corresponding internode, then curving gently outwards; abaxial wall almost straight, free adaxial wall slightly convex proximally, then nearly straight for most of its length; aperture facing outwards, provided with 4 small, triangular cusps separated by very shallow embayments; usually without intrathecal, submarginal cusps, but occasionally 2–4 present, one below each embayment; a 4-flapped operculum. Gonothecae arising from the stem internodes at level of hydrothecal bases, on opposite side to hydrotheca; spindle-shaped, walls entirely smooth, apically 3–4 short spines.

Dimensions: See Table 15.

Remarks: The colony shape and the gonotheca are illustrated by both Allman (1888) and Millard (1975). Although generally absent, internal, submarginal hydrothecal cusps may occasionally occur (Vervoort, 1966; Gili et al., 1989).

Distribution: Tristan da Cunha group of islands, Namibia, New Caledonia, New Zealand, as well as scattered records from the south and southeast Indian Ocean (Galea, 2015).

Sertularella mediterranea Hartlaub, 1901: 86, pl. 5 figs 10–11, 15–16. – Genzano, 1990: 47, figs 13–15. – Blanco, 1994: 199. – Genzano & Zamponi, 2003: 308.

Sertularella uruguayensis Mañé Garzón & Milstein, 1973: 21, fig. 1 (syn. nov.). – Milstein, 1976: 85, figs 25, 28, 29, 36.

Sertularella picta. – Blanco, 1967: 112, pl. 3 figs 1–7 [non Sertularella picta (Meyen, 1834)].

Material examined: HRG-0001; France, La Ciotat, 43.174850° 5.611921°, 0.5 m, coll. H.R. Galea; 16.03.2003; male colony composed of numerous stems, up to 4 cm high.

Description: Stems erect, up to 1.5 cm high, monosiphonic, sparingly and irregularly branched. Internodes rather short, delimited by deep, oblique constrictions of the perisarc, basally with a more or less marked bulge; first internodes of side branches comparatively longer than subsequent ones, with 2–3 basal twists; distally a hydrotheca to each internode. Hydrothecae flask-shaped, adnate for less than half their length, swollen basally (notably on adaxial side), constricted below aperture; rim with 4 cusps, abaxial one conspicuously produced, adaxial one the shortest, and recurved outwards; rim not thickened; 3 internal, submarginal projections of perisarc (2 latero-adaxial, 1 abaxial). Gonothecae arising from below the hydrothecal bases, broadly ovoid, walls with 6–9 transverse ridges, aperture surrounded by 4 (rarely 5) pointed cusps.

Dimensions: See Table 16.

Remarks: The description given above is based on Argentinean material, and combines both Blanco's (1967, as S. picta) and Genzano's (1990) accounts. Blanco (1994) regarded her earlier record as conspecific with the present species, although El Beshbeeshy (2011) still believed that it belonged to Meyen's hydroid.

The occurrence of S. mediterranea Hartlaub, 1901 in Argentina is plausible, as additional remote records are, for instance, from South Africa (Millard, 1975).

There are no objective reasons to separate specifically S. uruguayensis Mañé Garzón & Milstein, 1973 from the Argentinean hydroid. Both form colonies composed of short, erect, sparingly branched stems, their internodes are short, and each bears a flask-shaped hydrotheca, conspicuously swollen adaxially, and provided with a produced abaxial, marginal cusp, as well as with 3 internal, submarginal perisarc projections [Mañé Garzón & Milstein (1973); Genzano (1990)]. In addition, the measurements given by these authors for their respective materials are comparable (see Table 16 herein), and both originate from localities close to one another.

Distribution: Uruguay – Cabo Polonio (Mañé Garzón & Milstein, 1973, as S. uruguayensis). Argentina – Provincia de Buenos Aires [Mar del Plata (Blanco, 1967, as S. picta; Genzano 1990)]. Elsewhere – widely distributed in the Mediterranean and the eastern Atlantic, from Spitzbergen to South Africa (Ramil et al., 1992).

Sertularella microtheca Leloup, 1974: 30, fig. 24.

Sertularella robusta. – p.p. Vervoort, 1972: 129, fig. 40B (non figs 40A, 41A = S. robusta Coughtrey, 1876). – p.p. El Beshbeeshy, 2011: 144, fig. 46E-H (non fig. 46A-D = S. robusta) [non Sertularella robusta Coughtrey, 1876].

Material examined: HRG-1095; Chile, Región de Aysén, southeastern point of Canal Ultima Esperanza, -45.97608° -74.01133°, 23 m, coll. HSFS, HF21, lot #216; 10.04.2014; small colony composed of several sterile stems, up to 1 cm high.

Description: Stolonal hydrothecae or short (up to 1 cm high), erect, unbranched or sparingly-branched stems, arising from creeping, branching, filiform hydrorhiza. Stems and, when present, side branches divided into up to 10 exceedingly long, slender, geniculate internodes by means of indistinct, oblique constrictions of the perisarc; the latter relatively thick throughout the colony; side branches borne on short stem apophyses arising from below a hydrothecal base, apophyses displaced towards one side of the stem, not laterally and, consequently, not in the same plane; 1st internode of a side branch comparatively longer than subsequent ones; remainder of branch with same structure as the stem; no further branching observed. A hydrotheca confined to the distal end of each internode; fusiform, adnate for ca. 1/4th its length, transversely-ridged (generally 4, occasionally 5 ridges present), distally a short, smooth neck region; aperture with 4 pointed, triangular cusps separated by rather deep, semicircular embayments; 3 large, lamellar, submarginal, internal projections of perisarc (2 latero-adaxial, 1 abaxial); a 4-flapped operculum. Gonotheca stolonal, barrel-shaped, transversely ridged (with ca. 6 ridges), distally a neck region bearing apically an aperture surrounded by 4 spines.

Dimensions: See Table 17.

Remarks: The present material is composed of erect stems only, while Leloup (1974) reported the co-occurrence of stolonal hydrothecae within colonies otherwise comprising erect stems.

This species shows striking resemblances to S. robusta Coughtrey, 1876, a species with which it has been synonymized earlier (e.g. El Beshbeeshy, 2011; Galea, 2007). When colonies of both are examined side by side, obvious differences arise, such as: proportionally longer and much slender internodes, as well as smaller and much slender hydrothecae in S. microtheca.

Distribution: Chile – Región de los Lagos [Canal Calbuco (Leloup, 1974)]; Región de Aysén [Canal Ultima Esperanza (present study)]. Argentina – Provincia de Santa Cruz [off Deseado (p.p. Vervoort, 1972, as S. robusta)].

Sertularella mixta Galea & Schories, 2012a: 42, fig. 5A-G.

Sertularella sanmatiasensis. – Galea et al., 2009: 12, fig. 3C-E [non Sertularella sanmatiasensis El Beshbeeshy, 2011].

Sertularella ellisii f. lagenoides. – Leloup, 1974: 28, fig. 22 [non Sertularella ellisii (Milne-Edwards, 1836); non S. lagenoides Stechow, 1919].

Sertularella peregrina. – Leloup, 1974: 31, fig. 25 [non Sertularella peregrina Bale, 1926].

Material examined: MHNG-INVE-79667; Chile, Región de Coquimbo, Punta Choros, Bajo Tiburon, -29.2551° -71.5265°, 17 m, coll. D. Schories, lot DS206; 01.11.2009; colony composed of numerous fertile and sterile stems (holotype). – HRG-0642; Chile, Región de los Ríos, north of Corral, Chaihuin, -39.95730° -73.60245°, 6–12 m, coll. D. Schories; 08.10.2012; four male stems 2.3–3.4 cm high. – HRG-0646; Chile, Región de los Ríos, north of Corral, Chaihuin, -39.95730° -73.60245°, 6–12 m, coll. D. Schories; 16.11.2011; female colony composed of numerous stems up to 2.5 cm high. – HRG-0332; Chile, Región de los Lagos, southern Chiloé, Punta Inio, -43.39300° -74.11769°, 15.6 m, coll. HSFS, HF6, lot A128; 22.02.2008; two female stems, 1.5 and 2.2 cm high.

Description: Colonies arising from creeping, branching, anastomosing hydrorhiza. Stems short, up to 2.8 cm high, monosiphonic, unbranched or sparingly-branched in one plane; basal part of varied length, though generally short, with a few twists above origin from stolon; remainder of stem composed of numerous short, almost collinear, hydrothecate internodes; the latter delimited by oblique nodes sloping in alternate directions. Side branches, when present, borne on short stem apophyses arising from below the bases of stem hydrothecae; occasionally, branches given off from within the hydrothecae; the latter tubular, slightly swollen basally, especially on adaxial side; adnate for about half their length to the corresponding internode; abaxial wall straight to slightly concave basally; aperture mounted on short neck region, expanding at rim; abcauline cusp slightly longer than the three others, though all relatively short, and separated by shallow, rounded embayments; three internal, submarginal perisarc projections (2 latero-adaxial, 1 abaxial). Gonothecae arising from below the hydrothecal bases; ovoid, with several transverse ridges in upper half, much attenuated to absent in lower half; aperture mounted on short, quadrangular neck region, carrying four blunt projections of perisarc.

Dimensions: See Table 18.

Remarks: The gonothecae of this species are illustrated by both Galea et al. (2009, fig. 3E, as S. sanmatiasensis) and Galea & Schories (2012a, fig. 5F).

Distribution: Chile – Región de Coquimbo [Península de Coquimbo (Leloup, 1974, as S. ellisii f. lagenoides); vicinity of Punta de Choros (Galea & Schories, 2012a)]; Región de Bío-Bío [Bahía de Lota, Golfo de Arauco (Leloup, 1974, as S. ellisii f. lagenoides)]; Región de los Ríos [vicinity of Corral (present study)]; Región de los Lagos [south of Isla Grande de Chiloé (Galea et al., 2009, as S. sanmatiasensis)]; Región de Aysén [Guaitecas Archipelago (Leloup, 1974, as S. peregrina)].

Sertularella novarae Marktanner-Turneretscher, 1890: 226, pl. 4 figs 3, 3A, 3B. – Bedot, 1916: 208.

Sertularella polyzonias. – p.p. Vanhöffen, 1910: 322, fig. 39 [non S. polyzonias (Linnaeus, 1758)].

Material examined: ZMB Cni944; French Southern and Antarctic Lands, St. Paul I., coll. Deutsche Südpolar (Gauss) Expedition 1901–1903, stranded on beach; 26.03.1903; six stems and fragments, 0.5–1.4 cm high, of which four bear one gonotheca each [material studied by Vanhöffen (1910), as S. polyzonias].

Description: Upright, up to 2.5 cm high, monosiphonic, sparingly-branched stems arising from filamentous hydrorhiza; divided by faintly-indicated, oblique nodes into moderately-long, geniculate internodes with 1–2 basal twists and a hydrotheca distally; terminal stolonization occurs. Side branches arising irregularly from below the bases of stem hydrothecae, as well as from within their lumena; up to 2nd order branching, giving the colonies a somewhat bushy appearance. Hydrothecae biseriate, alternate, long, about 1/3rd adnate, tumid proximally, tapering distally, with 4 triangular marginal cusps separated by shallow embayments; 5 internal, submarginal cusps (2 latero-adaxial, 2 latero-abaxial, and 1 abaxial). Gonothecae arising from below the hydrothecal bases; elongated-ovoid, transversely wrinkled, tapering abruptly below into indistinct pedicel, aperture surrounded by 3–4 blunt, apical projections.

Dimensions: See Table 19.

Remarks: As noted by Vanhöffen (1910), there is no doubt that his material from St. Paul belongs to the present species. Indeed, both the measurements of the hydrothecae and the illustration provided by him are in agreement with the original account on this species. However, his specimens from Kerguelen, also assigned to it, were reexamined and proved to belong to both S. contorta Kirchenpauer, 1884 and S. gaudichaudi (Lamouroux, 1824) (see under these species).

Curiously, Vanhöffen overlooked the rather obvious specific differences between a number of closely-related subantarctic species [viz. S. allmani Hartlaub, 1901, S. antarctica Hartlaub, 1901, S. contorta Kirchenpauer, 1884, S. novarae, S. paessleri Hartlaub, 1901, S. picta (Meyen, 1834), and S. protecta Hartlaub, 1901], and assigned them all to the synonymy of S. polyzonias (Linnaeus, 1758), a species not known to occur in the study area (see Appendix I).

As underlined by him, the present species is a true Sertularella, in possessing 4 hydrothecal cusps, not 3, as erroneously stated by Marktanner-Turneretscher (1890). A typical colony of this species is accurately illustrated by Vanhöffen (1910, p. 325, fig. 39).

Distribution: French Southern and Subantarctic Lands – St. Paul (Marktanner-Turneretscher, 1890; Vanhöffen, 1910, as S. polyzonias).

Holotype material: MHNG-INVE-97916; Chile, Región de Magallanes y de la Antártica Chilena, Isla Desolación, Cabo Pilar, -52.71578° -74.68245°, 10 m, coll. HSFS, HF26, lot #221; 21.09.2015; female colony composed of multiple, highly ramified stems, up to 2.8 cm high.

Diagnosis: Colonies with indistinct stems, divided subdichotomously several times. Internodes moderately-long, slender, geniculate. Hydrothecae adnate for 2/5th, almost tubular, tapering towards aperture, indistinctly swollen adaxially, abaxial cusp produced, two latero-adaxial, internal, submarginal cusps. Gonotheca elongated-ovoid, transversely wrinkled, aperture distal, surrounded by 4 pointed cusps.

Etymology: From the Latin oblongus, -a, -um, meaning elongated, making reference to the distinctive shape of its hydrothecae.

Description: Colony bushy, composed of a bunch of stems, up to 2.8 cm high, arising from creeping stolon. Basal part of stems of varied length, provided with a number of twists above origin from stolon; remainder divided into regular internodes by means of oblique nodes sloping in alternate directions. Internodes relatively short, decidedly geniculate, with smooth, rather thin perisarc, each bearing distally a hydrotheca. Branching subdichotomous, starting among the proximal most internodes, thus making the main stems indistinct; side branches originate from below the bases of stem hydrothecae, either laterally or decidedly shifted to one side of the stem; 1–6 hydrothecae between successive side branches; occasionally, aberrant side branches are given off from within some basal stem hydrothecae; up to 5th or 6th order branching observed; tips of branchlets from various planes often form tendrils, creating anastomoses with neighboring branches; structure of branches identical to that of stem, except for the first internode that may be longer than the subsequent ones. Hydrothecae biseriate, alternately directed left and right, coplanar or nearly so; adnate for about 2/5th their length to the corresponding internode; flask shaped, slightly swollen basally, more conspicuously on adaxial side; free adcauline wall slightly sigmoid, abcauline wall nearly straight; hydrothecal margin with four unequally developed cusps: abaxial one the longest, adaxial one the shortest and conspicuously flaring, and the two laterals of intermediate length; rim not thickened; two latero-adaxial, internal, submarginal cusps; operculum composed of four triangular flaps with concentric striae. Gonothecae (only female known) arising laterally from below the hydrothecal bases; broadly ovoid, surface provided with 5–7 more or less developed wrinkles; aperture mounted on short distal collar, and surrounded by six rather short spines; embryo development in acrocysts.

Dimensions: Ordinary internodes 515–930 μm long, first internodes of side branches 715–1200 μm long; all 170–210 μm wide at nodes. Hydrothecal free adaxial length 320–345 μm, adnate adaxial length 220–230 μm, abaxial length 545–595 μm, maximum width 275–295 μm, diameter at aperture 230–270 μm. Female gonotheca 1690–1925 μm long and 790–910 μm wide.

Remarks: The mode of branching, giving rise to three-dimensional, bushy colonies is distinctive. Its hydrothecae recall those of S. ellisii (Deshayes & Milne-Edwards, 1836) and S. mediterranea Hartlaub, 1901, but the branching pattern is different in these species with otherwise much larger hydrothecae (Ramil et al., 1992).

Distribution: Only known from Chile – Región de Magallanes y de Antártica Chilena [Isla Desolación (present study)].

Sertularia patagonica d'Orbigny, 1842: pl. 11 figs 3–5; 1847: 25. – Hartlaub, 1905: 643, figs H⁴, J⁴. – Nutting, 1904: 81, pl. 16 fig. 3.

Sertularella striata Stechow, 1923b: 10 (syn. nov.). – Stechow, 1925: 470, fig. 30. – Millard, 1964: 47, fig. 15. – (?) Blanco, 1974: 44, figs 2–8. – Millard, 1975: 304, fig. 97E-F. – Genzano, 1990: 45, figs 11–12. – Blanco, 1994: 201. – Genzano & Zamponi, 2003: 308.

non Sertularella striata. – Gili et al., 1989: 104, fig. 29A.

Sertularella mogotesensis El Beshbeeshy, 2011: 20 [new name for both Blanco's (1967, p. 115) record of Sertularella atlantica Stechow, 1920 and her 1974 record (p. 44) of Sertularella striata Stechow, 1923b; nomen nudum].

Sertularella atlantica. – Blanco, 1967: 115, pl. 3 figs 8–12, pl. 4 figs 1–4 [non Sertularella atlantica Stechow, 1920: 21, fig. 2A].

Description: Colonies composed of either stolonal hydrothecae or short (up to 11 mm high), erect shoots arising from sinuous, smooth-walled stolon. Cauli thick, monosiphonic, usually unbranched, occasionally sparingly branched (1–3 short, roughly alternate side branches), smooth or with a reduced number (up to 3–4) of basal wrinkles; divided into internodes of varied length, though generally short, by means of rather indistinct, oblique nodes slanting in alternate directions. Proximal end of internodes provided with a couple of spiral twists, distally a hydrotheca. Side branches, when present, arising laterally from below the base of a stem hydrotheca. The latter close to one another, fusiform, free from the corresponding internodes for more than half their adaxial length; walls with 6–8 transverse ridges encircling their whole surface; aperture provided with 4 short, triangular cusps separated by shallow embayments; no submarginal, intrathecal cusps; a 4-flapped operculum. Perisarc thick throughout the colonies. Gonothecae arising from below the hydrothecal bases, broadly ovoid, walls provided with ca. 10 transverse ridges on nearly the whole surface, apically 3–4 minute spines surrounding the aperture, female with acrocysts.

Dimensions: See Table 20.

Remarks: One of the original illustrations by d'Orbigny (1842, pl. 11 fig. 5) can be misleading when attempting to compare this species with contemporary records from the study area, as the hydrothecae are figured with a decidedly scaly appearance. However, a similar illustration was provided by Hincks (1868) for S. rugosa (Linnaeus, 1758), while recent and more accurate drawings (e.g. Cornelius, 1995; Schuchert, 2001) show a quite common condition of the hydrothecae, typical of a species with transversely ringed walls.

Type material of S. patagonica is likely lost, as no mention of it was made by Van Praët (1979) in his catalogue of the type specimens housed in the Muséum national d'Histoire naturelle of Paris, France.

The typically short internodes, twisted basally, and the transversely annulated hydrothecae emphasized by d'Orbigny (1847) are characters also noted in Blanco's (1967, as S. atlantica Stechow, 1920) account, and it is therefore assumed that both hydroids are conspecific. The latter nominal species, however, originates from the northern hemisphere, and is probably a synonym of S. tenella (Alder, 1857) (Picard, 1956; Cornelius, 1995). In a subsequent paper, Blanco (1974) considered her earlier record as conspecific with her newly-obtained material assignable to S. striata Stechow, 1923b. Finally, Blanco (1994) recognized S. striata as a synonym of S. patagonica but, curiously, kept the former as the valid binomen.

According to the accounts of both Stechow (1925) and Millard (1964), S. striata exhibits the same morphological characters as S. patagonica, and their respective measurements are highly concordant (see Table 20 herein). For this reason, both nominal species are considered here as coterminous, with d'Orbigny's hydroid name having priority.

The Namibian and South African records by Gili et al. (1989) most probably do not belong here, owing to the large size of the hydrothecae in their material.

The morphological similarity between S. patagonica and S. rugosa Linnaeus, 1758 invoked by both Kirchenpauer (1884) and Hartlaub (1901) is only superficial, and resides in particular in the ringed condition of the hydrothecal wall. However, the hydrothecal aperture is conspicuously tilted downwards in the latter species (Cornelius, 1995; Schuchert, 2001), thus differing from the illustrations provided by both d'Orbigny (1842) and Blanco (1967). In addition, both species are certainly distinct on the account of their very remote areas of occurrence.

Distribution: Argentina – Provincia de Buenos Aires [off Mar del Plata (Blanco, 1967, as S. atlantica; Genzano, 1990, as S. striata)]; Provincia de Río Negro [Ensenada de Ros (d'Orbigny, 1847); Barranca final (Blanco, 1974; 1994, both as S. striata)]. Elsewhere – South Africa (Stechow, 1923b; 1925; Millard, 1964; 1975).

Sertularella pauciramosa Galea & Schories, 2014 in Galea et al., 2014: 35, pl. 3B, figs 6F & H, 7D.

Material examined: MHNG-INVE-86235; Chile, Región de Antofagasta, Taltal, -25.38333° -70.46667°, 22 m, coll. D. Schories, lot #17; 23.04.2012; a 6 cm high, male colony (holotype). – MHNG-INVE-86234; Chile, Región de Antofagasta, Taltal, Punta Morada, -25.36667° -70.45000°, 15 m, coll. D. Schories, lot #13; 20.04.2015; a 4 cm high, female colony (paratype).

Description: Colonies arising from creeping, branching, anastomosing stolon. Stems erect, up to 6 cm high, monosiphonic, slightly geniculate to almost straight; a varied number of annuli immediately above origin from stolon, followed by short, smooth, ahydrothecate part; remainder of caulus divided into short internodes by slightly marked to indistinct, oblique constrictions of the perisarc, slanting in alternate directions. Side branches, when present, arising irregularly from below the bases of stem hydrothecae, generally laterally (giving the colony a coplanar appearance), or occasionally slightly in front or the rear side of the stem; base of branch delimited from stem by a rather distinct node (no apophysis present); 1st internode generally longer than subsequent ones. A hydrotheca confined to the distal end of each internode; biseriate, alternate, flask-shaped, slightly curving outwards; adnate for 2/5th their length; free adaxial wall smooth to wavy (in which case provided with 2–3 weak undulations); abaxial wall varied in shape, from slightly concave to straight, to rarely convex; aperture perpendicular to long axis of the theca, constricted below rim; 4 pointed, triangular cusps separated by shallow embayments; operculum 4-flapped. Gonothecae given off from below the bases of stem hydrothecae; ovoid, walls undulated to occasionally rather smooth; male and female similar in shape, though the former longer and slender; aperture mounted on short neck region provided with 3–4 distal projections of perisarc; female with ca. 20 oocytes.

Dimensions: Internodes 815–1140 μm long and 195–230 μm wide at nodes. Hydrothecal free adaxial length 390–425 μm, adnate adaxial length 315–380 μm, abaxial length 635–690 μm, maximum width 335–365 μm, diameter at aperture 220–275 μm. Length of the female gonotheca 1490–1710 μm, and of the male 1710–1965 μm; maximum width of the female gonotheca 660–805 μm, and of the male 660–730 μm.

Remarks: The typical shape of a colony of this species is illustrated in Galea et al. (2014, pl. 3B).

Distribution: Chile – Región de Antofagasta [around Taltal (Galea et al., 2014)].

Calamphora quadrispinosa Watson, 2003: 168, fig. 18.

Description: Colonies comprising both stolonal hydrothecae and short, unbranched or sparingly-branched, erect stems arising from creeping, branching, tubular hydrorhiza. Stolonal hydrothecae pedicellate, barrel-shaped, slightly asymmetrical in lateral view, narrowing a little below aperture, walls smooth to weakly undulated, especially on lower third; base pierced by central, circular hydropore with short, upturned collar; hydrothecal margin quadrate, distinctly everted, provided with 4 broad, sharply-pointed cusps separated by low, semicircular embayments; a 4-flapped operculum; hydranths with ca. 16 filiform tentacles. Gonothecae stolonal, arising in the vicinity of a hydrotheca; pedicellate, barrel-shaped, walls provided with 6–9 transverse flanges, deepest in distal third, shallower proximally; aperture apical, surrounded by 4 prominent, equidistant, more or less inwardly-curved spines.

Dimensions: Length of the hydrothecal pedicel 64–224 μm. Total length of hydrotheca 1100–1280 μm, maximum width 506–561 μm, diameter at aperture 440–480 μm. Length of the gonothecal pedicel 120–176 μm. Maximum width of gonotheca 520–640 μm.

Remarks: The present species is included in the genus Sertularella because its colonies, besides the commonest stolonal hydrothecae, comprise short, unbranched or sparingly-branched, erect stems. Indeed, Choong et al. (2012) stated that “colony form may be an insufficient criterion for assigning species of pedicellate Sertularella with individual hydrothecae rising from their hydrorhizae to a separate genus Calamphora”. The gonotheca of S. quadrispinosa is illustrated by Watson (2003).

Distribution: Only known from Macquarie I., Australia (Watson, 2003).

Sertularella ? implexa. – Galea & Schories, 2012a: 40, pl. 3 fig. 4F-J [non Sertularella implexa (Allman, 1888)].

Sertularella polyzonias. – Allman, 1888: 55, pl. 26, figs 3, 3A. – El Beshbeeshy, 2011: 141, fig. 45 [non Sertularella polyzonias (Linnaeus, 1758)].

Holotype material: MHNG-INVE-79627; Chile, Región de Magallanes y de la Antártica Chilena, Punta Arenas, Faro San Isidro, -53.78174° -70.97391°, 40 m, coll. D. Schories, lot #11; 05.01.2011; colony composed of several fertile stems, up to 5.5 cm high.

Additional material: ZMH C11895; Argentine Shelf, no additional data; several branched and unbranched colony fragments, up to 1.5 cm high, one of which bears 3 female gonothecae. – ZMH C11888; FRV Walther Herwig, Stn. 327, -51.18333°, -56.95000°, 225 m; 29 Jun. 1966; two small, sterile colony fragments likely not belonging to the present species, although considered as conspecific by El Beshbeeshy (2011).

Diagnosis: Irregularly-pinnate colonies, with monosiphonic stems branched several times; internodes moderately long, slightly geniculate; hydrothecae flask-shaped, adnate for 1/3rd their length, swollen adaxially, abaxial cusps slightly produced, rim not thickened, internal cusps absent; gonothecae broadly ovoid, transversely wrinkled, aperture surrounded by 3–4 spines.

Etymology: From the Latin rectus, -a, -um (rego), meaning straight, with reference to the macroscopic appearance of both stems and branches.

Description: Hydrorhiza missing, but stems above origin from stolon comprising a monosiphonic, ahydrothecate basal part of varied length, with several proximal wrinkles; remainder of stems divided into moderately-long, slightly geniculate internodes by means of oblique constrictions of the perisarc slanting in alternate directions; nodes brownish in older parts of the colony, becoming transparent in younger ones. Branching pattern irregular, with side branches arising every 1–8 stem hydrothecae, immediately below their bases, through short, lateral apophyses; branching repeated several times, introducing a slight torsion in lower-order branches so as to accommodate the newly-formed ones, giving the colony a somewhat three-dimensional appearance, though it is rather compressed antero-posteriorly. Stems and branches of similar structure, except for the first internodes of the latter, which are comparatively longer than the subsequent ones, and provided with a couple of basal wrinkles. Hydrothecae placed distally on internodes, biseriate, alternate, adnate for about 1/3rd their adaxial length; free adaxial wall conspicuously swollen basally, decidedly convex, becoming concave towards aperture; abaxial wall straight or nearly so basally, becoming convex distally, where it forms a neck region, widening towards aperture; the latter tilted outwards and upwards, provided with 4 pointed, triangular cusps separated by deep, rounded embayments; no submarginal, intrathecal cusps. Gonothecae borne on stems and side branches, arising from below bases of hydrothecae; broadly ovoid, walls transversely wrinkled, wrinkles more obvious distally, becoming obsolete proximally; aperture surrounded by 3–4 pointed perisarc projections.

Dimensions: See Table 21.

Remarks: The material from the Falkland Is. assigned by Allman (1888) to S. polyzonias (Linnaeus, 1758) shows striking resemblances to the present species, and is thought to be conspecific (N.B.: Allman's specimen could not be examined, as it is apparently no longer extant in the collection of NHML; A. Cabrinovic, pers. comm.).

In addition, the reexamination of El Beshbeeshy's (2011) sample ZMH C11895, assigned to the Linnean taxon, revealed that it belongs to the new species described herein. Among the material described by El Beshbeeshy, some colonies are reportedly said to reach as much as 19 cm high, their stems remaining always monosiphonic.

The typical shape of the colonies is illustrated in Galea & Schories (2012a, pl. 3F, as S. ? implexa), and a gonotheca in fig. 4J of the same paper.

Distribution: Chile – Región de Magallanes y de la Antártica Chilena [south of Peninsula Brunswick (Galea & Schories, 2012a, as S. ? implexa)]. Argentina – scattered records from the Patagonian Shelf, between 43°-53°S (El Beshbeeshy, 2011, as S. polyzonias). Falkland Is. (Allman, 1888; El Beshbeeshy, 2011; both as S. polyzonias).

Sertularella robusta Coughtrey, 1876: 27, pl. 3 fig. 6. – Leloup, 1960: 234, fig. 7. – Blanco, 1968: 215, pl. 4 figs 4–7. – p.p. Vervoort, 1972: 129, figs 40A, 41A. – Leloup, 1974: 33, fig. 27. – Blanco, 1976: 42, pl. 4 figs 1–3; 1994: 200. – Galea, 2007: 66, fig. 15E-I. – Galea et al., 2009: 2, 4. – p.p. El Beshbeeshy, 2011: 144, fig. 46A-D.

non Sertularella robusta. – p.p. Vervoort, 1972: 129, fig. 40B (= Sertularella microtheca Leloup, 1974). – p.p. El Beshbeeshy, 2011: 144, fig. 46E-H (= S. microtheca). – Soto Àngel & Peña Cantero, 2015: 996, fig. 7G [= (?) Sertularella tenella (Alder, 1856)].

Sertularella tenella. – Jäderholm, 1905: 31, pl. 12 fig. 8. – Ritchie, 1907: 78. – p.p. Rees & Thursfield, 1965: 138. – Blanco, 1963: 173, figs 7–8 [non Sertularella tenella (Alder, 1856)].

Sertularella stepanyantae El Beshbeeshy, 2011: 20 [new name for Vervoort's (1972, p. 129) record of S. robusta Coughtrey, 1876; nomen nudum].

Material examined: HRG-0626; Chile, Región de los Lagos, southern Chiloé, west of Punta Inio, -43.39300° -74.11769°, 26 m, coll. HSFS, HF6, lot A565; 22.02.2008; male colony composed of both stolonal and erect stems, up to 5 mm high, epizoic on Symplectoscyphus milneanus (d'Orbigny, 1842). – HRG-0356; Chile, Región de Magallanes y de Antártica Chilena, Punta Arenas, Faro San Isidro, -53.78174° -70.97391°, 10 m, coll. D. Schories, lot PTA002; 25.02.2010; colony composed of numerous sterile stems, up to 15 mm high. – HRG-0797; Chile, Región de los Ríos, north of Corral, Chaihuin, -39.95730° -73.60245°, 6–12 m, coll. D. Schories; 06.03.2012; sterile stolonal colony epizoic on Halecium sp. – HRG-0788; Chile, Región de Aysén, west of Canal Messier, -47.86020° -74.76023°, 5.3 m, coll. HSFS, HF13, lot C176; 16.03.2012; small colony composed of both stolonal hydrothecae and up to 4 mm high erect stems, bearing single male gonotheca. – HRG-1099; Chile, Región de los Lagos, Roca Gloria, -45.662433° -73.849266°, 20 m, coll. HSFS, HF21, lot #99; 05.04.2014; rich, fully fertile (male) colony composed mainly of stolonal hydrothecae and, occasionally, of short, erect stems (2–4 hydrothecate internodes), epizoic on Symplectoscyphus filiformis (Allman, 1888). – HRG-1173; Chile, Región de los Lagos, southern Chiloé, Isla Yencouma, -43.4193° -74.0818°, 10 m, coll. HSFS, HF22, lot #65; 18.01.2015; a male colony composed of mostly stolonal hydrothecae, and a few, up to 3 mm high, erect stems. – NMSZ 1959.33.499; Burdwood Bank, -54.41667° -57.53333°, ca. 102 m, coll. Scottish National Antarctic (Scotia) Expedition 1902–1904; 01.12.1903; microslide (Fig. 12D) comprising 4 sterile stem fragments, 6–8 mm high, one of them branched once [material studied by Ritchie (1907, as S. tenella), and listed by Rees & Thursfield (1965, p. 138)].

Description: Stolonal hydrothecae or short, erect, unbranched or sparingly-branched stems arising from creeping, branching, filiform hydrorhiza. A varied number of annuli at the stem bases, immediately above origin from stolon. Stems and side branches, when present, exclusively monosiphonic, divided into moderately-long, geniculate internodes by means of oblique nodes slanting in alternate directions. A hydrotheca, or a hydrotheca and a lateral apophysis immediately below its basis, confined to the distal end of each internode; basally, a twist. Branches arise irregularly (every 1–7 stem hydrothecae) and in the same plane as the stem; up to 2nd order branching observed; structure similar to stem, though 1st internode comparatively longer than subsequent ones. Hydrothecae biseriate, alternate, coplanar; flask-shaped, swollen basally, adnate for 2/5th their adaxial length; surface provided by 4–6 transverse ridges; rim with 4 small, triangular, equally-developed cusps separated by deep, rounded embayments; 3 distinctive, plate-shaped, internal projections of perisarc below the hydrothecal aperture (2 latero-adaxial, 1 abaxial); operculum composed of 4 triangular flaps forming a pyramidal roof. Gonothecae arising from below the hydrothecal bases; broadly ovoid, surface with 6–7 transverse ribs, aperture apical, surrounded by 4 pointed cusps; external acrocysts in female.

Dimensions: See Table 22.

Remarks: The typical shape of a stolonal colony is illustrated in Galea (2007, fig. 15E), and of an erect stem in Galea (2007, fig. 15F). The gonothecae are illustrated in Galea (2007, fig. 15G, I).

Distribution: Chile – Región de los Ríos [north of Corral (present study)]; Región de los Lagos [around Isla Grande de Chiloé (Leloup, 1974; Galea et al., 2009); Golfo de Ancud (Leloup, 1974); Roca Gloria (present study)]; Región de Aysén [Guaitecas Archipelago (Leloup, 1974; Galea, 2007); Canal Puyuhuapi (Galea et al., 2009); Canal Messier (present study)]; Región de Magallanes y de la Antártica Chilena [Canals Castillo, Copihue, Pasaje, and Pitt Chico, as well as Angostura Inglesa and Isla Camello (Galea, 2007); around Punta Arenas (present study); Magellan Strait (p.p. Vervoort, 1972)]. Patagonia – no localities given (Leloup, 1960). Argentina – Provincia de Río Negro [Golfo de San Matías (Blanco, 1994)]; Provincia de Santa Cruz [Puerto Deseado, Bahía Uruguay (Blanco, 1963, as S. tenella)]; Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [Argentinean waters off the northern coast of Isla Nueva, Tierra del Fuego (Blanco, 1968); off the eastern entrance of the Magellan Strait (Blanco, 1976); south of Sloggett Bay, Beagle Canal (Jäderholm, 1905, as S. tenella; p.p. Vervoort, 1972); around Península Mitre (p.p. Vervoort, 1972)]; numerous scattered records from the Patagonian Shelf, between 40°-54° S (p.p. El Beshbeeshy, 2011). Between Tierra del Fuego and the Falkland Is. (p.p. Vervoort, 1972). Burdwood Bank (Ritchie, 1907, as S. tenella).

Sertularella argentinica. – Galea, 2007: 59, fig. 14A-C. – Galea et al., 2007c: 312, fig. 3I [non Sertularella argentinica El Beshbeeshy, 2011 = Sertularella clausa (Allman, 1888)].

Holotype material: MHNG-INVE-53268; Chile, Región de Aysén, Guaitecas Archipelago, NW of Melinka, -43.88333° -73.71667°, 10–15 m, coll. HSFS, HF1; 08.03.2005; a 8 cm high, sterile colony.

Additional material: HRG-0611; Chile, Región de Magallanes y de la Antártica Chilena, Canal Copihue, -50.33979° -75.37834°, 16 m, coll. HSFS, HF16, lot #084; 16.04.2013; a 8 cm high, sterile colony.

Diagnosis: Colonies bonsai-like, with strongly fascicled stems and dark brown perisarc; internodes slightly demarcated, short, almost collinear; hydrothecae short, tubular, curved outwards, marginal cusps separated by large, shallow embayments.

Etymology: A superlative of the Latin rōbustus, -a, -um, with reference to the sturdiness of the stems of this species.

Description: Colonies bonsai-like, up to 8 cm high, arising from well-developed, rhizoid mass of stolonal fibers firmly attached to substrate; composed of single, thick, strongly fascicled stem, unbranched in lower half, and forming numerous, irregularly-directed side branches in upper half; main branches polysiphonic proximally, giving rise to bundles of 2–4 basally parallel, distally diverging, monosiphonic branchlets, up to 3 cm long, each branched again up to 2 times; branching almost regular, alternate, every 3 consecutive hydrothecae (rarely 2). Both stem and branches delimited into rather short, almost collinear internodes by means of oblique nodes slanting in alternate directions; a hydrotheca, or a hydrotheca and a lateral apophysis below its base, confined to the distal end of each internode. Hydrothecae rather short, tubular, distinctly curved outwards, adnate to the corresponding internode for slightly more than half their length; free adaxial wall smooth to slightly undulated; aperture with 4 small, triangular cusps separated by very shallow embayments; operculum composed of 4 triangular flaps with concentric striae; 1–2 closely-set renovations of the margin. Gonothecae unknown.

Dimensions: Internodes 310–493 μm long and 310–352 μm wide at nodes. Hydrothecal free adaxial length 337–393 μm, adnate adaxial length 356–477 μm, abaxial length 477–573 μm, maximum width 399–444 μm, diameter at aperture 337–376 μm.

Remarks: The colony structure is illustrated in both Galea (2007, fig. 14A) and Galea et al. (2007c, fig. 3I).

Distribution: Chile – Región de Aysén [Guaitecas Archipelago (Galea, 2007, as S. argentinica)]; Región de Magallanes y de la Antártica Chilena [Canal Copihue (present study)].

Sertularella sanmatiasensis El Beshbeeshy, 2011: 148, fig. 47. – Soto Àngel & Peña Cantero, 2015: 996, fig. 7H-I.

non Sertularella sanmatiasensis. – (?) Peña Cantero, 2006: 939, fig. 3L. – (?) Peña Cantero & Gili, 2006: 767. – (?) Peña Cantero, 2008: 459, fig. 2C. – (?) Peña Cantero & Vervoort, 2009: 87, fig. 2B. – Peña Cantero, 2012: 858, fig. 4A; 2013: 130 (possibly all = Sertularella antarctica Hartlaub, 1901).

Sertularella polyzonias. – Blanco, 1984: 37, pls 31–36; 1994: 200 [non Sertularella polyzonias (Linnaeus, 1758)].

Material examined: ZMH C11560; FRV Walther Herwig, Stn. 283, Argentine Shelf, -42.21667° -58.1000°, 500 m; 21.06.1966; numerous colony fragments up to 2.3 cm high, all sterile, with only the perisarc left (holotype).

Description: Colonies composed of upright, monosiphonic, unbranched or sparingly-branched stems, up to 5 cm high; a few basal annuli above origin from stolon; divided by oblique nodes into internodes of varied length, longer basally, gradually decreasing distally; a hydrotheca, or a hydrotheca and a short, lateral apophysis below its base, confined to the distal end of each internode. Branching pattern with a tendency to alternate; first internode with a number of spiral twists proximally, and comparatively longer than subsequent ones. Hydrothecae biseriate, alternate, coplanar to occasionally slightly shifted on to one side of the colony; large, flask-shaped, adnate for about 1/3rd their adaxial length; a characteristic notch at origin of free adaxial wall, then hydrotheca conspicuously swollen on same side, till below the aperture, where it is constricted; perisarc either smooth or with up to 3 undulations; abaxial wall straight to slightly concave; 4 marginal, blunt-ended triangular cusps of equal development separated by shallow, semicircular embayments; 3 intrathecal, submarginal cusps (2 latero-adaxial, 1 abaxial), variably present; rim not thickened, margin occasionally renovated up to 3 times. Gonothecae arising from below the hydrothecae; broadly ovoid, tapering below, walls undulated to nearly smooth; aperture distal, surrounded by 4 pointed cusps in male, less developed or absent in female; acrocysts in the latter.

Dimensions: See Table 23.

Remarks: The gonothecae of this species, absent in the material studied by El Beshbeeshy (2011), were documented earlier by Blanco (1984, as S. polyzonias). The intrathecal, submarginal cusps occur very inconstantly: sometimes only the abaxial one is present, sometimes only the pair of latero-adaxial, and occasionally the complete set of three occurs.

It was stated under S. antarctica that it is likely that some records assigned to S. sanmatiasensis in various papers (co)authored by Peña Cantero belong in fact to Hartlaub's (1901) species. For instance, it is certain that the materials dealt with in Peña Cantero (2012, 2013) belong to the latter.

Distribution: Argentina – between Provincia de Río Negro and Provincia del Chubut [off Golfo San Matías (El Beshbeeshy, 2011)]. Scotia Arc – South Sandwich Is. (Soto Àngel & Peña Cantero, 2015). Antarctica – Isla Baja (Blanco, 1984, as S. polyzonias), Palmer Archipelago (Blanco, 1994, as S. polyzonias).

Sertularella protecta p.p. Hartlaub, 1901: 79.

Sertularia (Sertularella) polyzonias. – Pfeffer, 1889: 54 [non Sertularella polyzonias (Linnaeus, 1758)].

Sertularella Allmani. – Jäderholm, 1905: 32, pl. 12 fig. 11; 1910: 5 [non Sertularella allmani Hartlaub, 1901].

Sertularella antarctica. – Jäderholm, 1905: 32, pl. 13 fig. 1 [non Sertularella antarctica Hartlaub, 1901)].

Sertularella sp. – El Beshbeeshy, 2011: 121, fig. 37E.

(?) Sertularella picta. – p.p. Millard, 1971: 405, fig. 6B [non S. picta (Meyen, 1834)].

non Sertularella picta. – Millard, 1971: 405, fig. 6A [= (?) Sertularella gaudichaudi (Lamouroux, 1824)].

Holotype material: SMNH 123839; South Georgia, Cumberland Bay, coll. Swedish South Polar Expedition 1901–1903; 09.05.1902; microslide (Fig. 12F) comprising three sterile colony fragments, 2.6, 3.0 and 3.5 cm high [material incorrectly assigned to S. antarctica Hartlaub, 1901 by Jäderholm (1905); illustrated by him in his pl. 13 fig. 1, re-illustrated herein in Fig. 17A; note that the identification written down on the label of the slide is “Sertularella Allmani Hartl”].

Paratype material: ZMH C04206; South Georgia, German International Polar Year Expedition 1882–1883, coll. K. von den Steinen; (day and month unavailable) 1883; a colony composed of numerous sterile stems, up to 3.2 cm high, on stem of tubulariid hydroid and unidentified substrate, labeled S. protecta Hartlaub, 1901, and suspected by El Beshbeeshy (2011) to belong to an undescribed species.

Additional material: SMNH 123851; Falkland Is., Port William, coll. Swedish South Polar Expedition 1901–1903, Stn. 39, 40 m; 04.07.1902; microslide (Fig. 1G) containing 2 species: 1) on the right-hand side, two sterile colony fragments, 1.3 and 1.5 cm high, assignable to S. subantarctica Galea sp. nov., but identified by Jäderholm (1905) as S. allmani Hartlaub, 1901, and illustrated by him in his pl. 12 fig. 11, re-illustrated herein in Fig. 16K, P; 2) on the left-hand side, a ca. 2 cm high, fertile colony of S. contorta Kirchenpauer, 1884, illustrated by Jäderholm (1905, pl. 12 figs 9–10), and re-illustrated herein in Fig. 6C, I. – SMNH 123835; Falkland Is., Port William, 12 m, Swedish Magellanic Expedition 1907–1909, coll. C. Skottsberg; 07.11.1907; microslide (Fig. 12E) containing 3 colony fragments, 0.5–1.5 cm, the largest bearing two female gonothecae [material assigned by Jäderholm (1910) to S. allmani Hartlaub, 1901]. – ZMH C04384; South Georgia, German International Polar Year Expedition 1882–1883, coll. K. von den Steinen; (day and month unavailable) 1883; two sterile fragments 1.7 and 3.8 cm high (most probably branches) on seaweed, labeled S. protecta Hartlaub, 1901 (it cannot be excluded that this material is part of ZMH C04206). – ZMH C04211; South Georgia, German International Polar Year Expedition 1882–1883, coll. A. Zschau, no additional data; likely 1883; about 3 short (up to 7 mm high), sterile stems (material labeled S. protecta Hartlaub, 1901).

Diagnosis: Stems monosiphonic, densely and pinnately branched; internodes uniformly short and thick; both hydrothecae and side branches shifted on to one side of the stem at a very acute angle, not exceeding 90°; hydrothecae big, though short (with respect to their width) and swollen adaxially, abaxial cusp produced, rim thickened, 3 internal, submarginal projections of perisarc, not always present.

Etymology: Named after its area of distribution.

Description: Undamaged colonies most probably exceeding 4 cm high; arising from tortuous, creeping, branching stolon; stems monosiphonic in all material inspected, with 1–5 basal twists; densely and pinnately branched; both stems and branches divided into uniformly short, thick internodes, by means of deep, oblique nodes slanting in alternate directions; a hydrotheca, or a hydrotheca and a short apophysis immediately below its base, confined to the distal end of each internode; a bulge at each end of the internodes; both hydrothecae and apophyses conspicuously shifted on to one side of the colony, giving it an anterior and a posterior side; angle between the two rows of branches acute, not exceeding 90°. Branching pattern (Fig. 16L) distinctive: branches occur in “pairs” composed of two successive internodes bearing lateral apophyses in opposite directions; each pair of branches is separated from the next one through one (upper part of the stem) or two (lower part of the stem) hydrothecate internodes devoid of apophyses. Branches with similar structure as the stems, except for the 1st internode that is imperceptibly longer than subsequent ones, and provided basally with a couple of distinct twists. Hydrothecae large, flask-shaped, adnate for about 2/5th their adaxial side to the corresponding internode, conspicuously swollen adaxially; abaxial wall slightly concave in middle, to nearly straight throughout; free adaxial wall distinctly sigmoid: convex for most of its length, becoming suddenly concave below aperture; the latter quadrate, surrounded by 4 prominent, triangular cusps; abaxial one conspicuously produced, adaxial one the shortest, lateral ones unequally developed (“anterior” one shorter than “posterior” one); rim thickened, without renovations; 3 internal, submarginal projections of the perisarc (2 latero-adaxial, 1 abaxial), inconstantly present; a 4-flapped operculum. Perisarc thick throughout the colony. Gonothecae borne on side branches, given off from below the base of a hydrotheca; urn-shaped, transversely wrinkled, tapering below, distally provided with a short, neck region, bearing apically the aperture surrounded by 4 short, though strong spines.

Dimensions: See Table 24.

Remarks: The internal, submarginal cusps are variably present either among the hydrothecae of various stems, or among those of the same stem. For example, in sample SMNH 123839, the abaxial cusp is nearly always present, while the 2 latero-adaxial occur less frequently; conversely, in sample SMNH 123851, the cusps seem to be constantly absent.

Distribution: South Georgia – Pfeffer (1889, as S. polyzonias); p.p. Hartlaub (1901, as S. protecta); Jäderholm (1905, as S. antarctica in text, and S. allmani on the label of slide material); El Beshbeeshy (2011, as S. sp. nov.). Falkland Is. – Port William (Jäderholm, 1905, p.p. 1910, both as S. allmani). (?) South African Subantarctic Islands – Marion I. (Millard, 1971, as S. picta).

Sertularia tenella Alder, 1856: 357, pl. 13 figs 3–6. – Galea & Schories, 2012a: 45, fig. 5H-J.

non Sertularella tenella. – Jäderholm, 1905: 31, pl. 12 fig. 8. – Ritchie, 1907: 78. – p.p. Rees & Thursfield, 1965: 138. – Blanco, 1963: 173, figs 7–8 [all = Sertularella robusta Coughtrey, 1876].

Sertularella jorgensis. – Galea, 2007: 63, fig. 14G, H. – Galea et al., 2007b: 312, fig. 4B [non Sertularella jorgensis El Beshbeeshy, 2011 = Sertularella valdiviae Stechow, 1923b].

(?) Sertularella robusta. – Soto Àngel & Peña Cantero, 2015: 996, fig. 7G [non Sertularella robusta Coughtrey, 1876].

Material examined: MHNG-INVE-53215; Chile, Région de Magallanes y de la Antártica Chilena, Canal Farquhar, -48.48853° -74.20714°, 32 m, coll. HSFS, HF2, lot #45; 29.03.2005; a colony composed of both stolonal hydrothecae and erect stems up to 1.2 cm high, formerly identified as S. jorgensis (see Galea, 2007). – HRG-0361; Chile, Región de los Lagos, Caleta La Arena, Caleta Yerbas Buenas, -41.67263° -72.65650°, 20 m, coll. D. Schories, lot DS095; 08.03.2009; two sterile stems, 4 and 7 mm high. – HRG-0359; Chile, Región de los Lagos, Caleta La Arena, Caleta Yerbas Buenas, -41.67263° -72.65650°, 20 m, coll. D. Schories, lot S15; 26.04.2011; several sterile stems, 4–11 mm high, on worm tube. – HRG-1244; France, Brittany, N of Pointe Penmarc’h, off Gaouac’h rock, 23 m, coll. F-X. Decaris; 14.05.2016; a sterile colony, 2.5 cm high.

Description: Short (up to 1.2 cm high), erect, monosiphonic, unbranched stems or stolonal hydrothecae arising from creeping hydrorhiza; divided into relatively long, slender, geniculate internodes by means of oblique constrictions of the perisarc slanting in alternate directions; a hydrotheca distally to each internode. Hydrothecae biseriate, alternate, coplanar, tronconic, adnate for 1/3rd to their corresponding internodes; abcauline wall straight to slightly concave, with smooth to slightly wrinkled perisarc; free adcauline wall with 3–4 undulations, not always reaching abcauline side; rim somewhat everted, provided with 4 pointed triangular cusps separated by moderately-deep, semicircular embayments; closing apparatus composed of 4 opercular flaps with concentric striations; no internal, submarginal cusps. Gonothecae absent in all material from the study area.

Dimensions: See Table 25.

Remarks: The typical silhouette of a stem is shown in Galea (2007, fig. 14G). The hydrothecae in this material are less wrinkled than those of European specimens (compare Fig. 17F, G and H).

The material assigned earlier to S. jorgensis El Beshbeeshy, 2011 by Galea (2007) (now recognized as a junior synonym of S. valdiviae Stechow, 1923b, see below) differs from that nominal species mainly through the morphology of its hydrothecae (compare Fig. 17F, G and Fig. 18A-C).

The rather thick internodes and the hydrothecae devoid of submarginal, intrathecal cusps in the material identified as S. robusta Coughtrey, 1876 by Soto Àngel & Peña Cantero (2015) equally point towards the present species.

Distribution: Chile – Región de los Lagos [Seno de Reloncaví (Galea & Schories, 2012a)]; Región de Magallanes y de la Antártica Chilena [Canal Farquhar (Galea, 2007; Galea et al., 2007b; both as S. jorgensis)]. Scotia Arc – Burdwood Bank, South Sandwich Is. (Soto Àngel & Peña Cantero, 2015, as S. robusta).

Sertularella valdiviae Stechow, 1923b: 11. – Stechow, 1925: 471, fig. 31. – Ruthensteiner et al., 2008: 23.

Sertularella jorgensis El Beshbeeshy, 2011: 136, fig. 43 (syn. nov.). – Soto Àngel & Peña Cantero, 2015: 994, fig. 7E-F.

non Sertularella jorgensis. – Galea, 2007: 63, fig. 14G, H. – Galea et al., 2007c: 312, fig. 4B [= Sertularella tenella (Alder, 1856)].

Sertularella gayi parva. – Blanco, 1968: 217, pl. 4 figs 8–11; 1994: 199 [non Sertularella gayi (Lamouroux, 1821) var. parva Billard, 1925].

Material examined: ZSM 20050521; French Southern and Antarctic Lands, 7 km west off St. Paul, -38.66667° -77.64333°, 672 m, coll. Deutsche Tiefsee (Valdivia) Expedition 1898–1899, Stn. 165; 03.01.1899; microslide (Fig. 12G) comprising five colony fragments of Sertularella valdiviae Stechow, 1923, 3–23 mm high, one of which is fertile and bears 8 empty gonothecae. – ZSM 20050522; French Southern and Antarctic Lands, 7 km west off St. Paul, -38.66667° -77.64333°, 672 m; 03.01.1899; coll. Deutsche Tiefsee (Valdivia) Expedition 1898–1899, Stn. 165, microslide (Fig. 12H) comprising three colony fragments (one of which bearing a gonotheca) of S. valdiviae, 6–14 mm high. – ZMH C11886; FRV Walther Herwig, Stn. 257, Argentine Shelf, -53.93333° -63.85000°, depth not recorded; 06.02.1971; several sterile, erect stems of Sertularella jorgensis El Beshbeeshy, 2011, up to 5 mm high, showing terminal stolonization, as well as a number of stolonal hydrothecae on the same hydrorhiza, both with remains of coenosarc only. – ANT XIX/5 ID.91; RV Polarstern, cruise ANT XIX/5, Stn. 253, Elephant I., -61.40050° -55.41200°, 276–282 m; 25.04.2012; sterile colony composed of several stems up to 3.5 cm high [material studied by Soto Àngel & Peña Cantero (2015), as S. jorgensis].

Description: Monosiphonic, slender, irregularly and sparingly-branched stems, up to 4 cm high, arising from creeping, filiform hydrorhiza; prisarc smooth or with 2–3 basal twists above origin from stolon. Stems and branches divided into long, geniculate internodes; nodes oblique, not always clearly demarcated; a hydrotheca confined to the distal end of each internode. Branches arising from below a stem hydrotheca, not always strictly laterally, but shifted on to the anterior or posterior sides of the stem, giving the colony a three-dimensional appearance; up to 4th order branching observed; branches with similar structure as that of stem; 1st internode comparatively longer than subsequent ones, and provided with 1–2 basal twists. Hydrothecae biseriate, alternate, distant from one another, occasionally not strictly coplanar; rather long, tronconical to almost tubular, adnate for a varied length, from 1/2 to 2/5th fused with the corresponding internode; abaxial wall slightly concave to straight, free adaxial wall with 2–4 wrinkles extending towards abaxial wall; 4 small, triangular marginal cusps separated by shallow embayments; a 4-flapped operculum; rim occasionally renovated; hydranths with 14–18 tentacles. Gonothecae given off from below the bases of cladial hydrothecae, elongated-ovoid, significantly tapering below, distally rounded, devoid of a neck region and perisarcal projections, walls with 4–6 transverse wrinkles.

Dimensions: See Table 26.

Remarks: By comparing parts of El Beshbeeshy's (2011) and Soto Àngel & Peña Cantero's (2015) materials assigned to S. jorgensis to the type of S. valdiviae Stechow, 1923b, it appears that there are no morphological differences between them (compare Fig. 17I, J and K, respectively). Both nominal species prove coterminous, with S. valdiviae having priority over El Beshbeeshy's species. The gonothecae, not already known in S. jorgensis, are only present in the St. Paul material.

Distribution: Argentina – Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [off the southeastern coast of Isla de los Estados (Blanco, 1968; 1994, both as S. gayi parva)]; scattered records from the Argentine Shelf, ranging between 42°-46° S (El Beshbeeshy, 2011, as S. jorgensis). Between Península Mitre and the Falkland Is. (El Beshbeeshy, 2011, as S. jorgensis). Scotia Arc – South Sandwich Is., Elephant I. (Soto Àngel & Peña Cantero, 2015, as S. jorgensis). French Southern and Antarctic Lands – St. Paul (Stechow, 1923b, 1925).

Sertularella vervoorti El Beshbeeshy, 2011: 151, fig. 48. – Watson & Vervoort, 2001: 167, fig. 9. – Soto Àngel & Peña Cantero, 2015: 996, fig. 7J-K.

Sertularella cylindritheca. – Vervoort, 1972: 126, fig. 39A. – Stepanjants, 1979: 90, pl. 14 fig. 5A [non Sertularella cylindritheca (Allman, 1888) = Sertularelloides cylindritheca (Allman, 1888)].

Material examined: ZMH C11552; FRV Walther Herwig, Stn. 327, Argentine Shelf, off Provincia de Santa Cruz, -51.18333° -56.95000°, 225 m; 29.06.1966; sterile, fragmentary colony (fragments 0.5–1.5 cm long) [material studied by El Beshbeeshy (2011)].

Description: Erect, though flaccid, up to 3.5 cm high colonies arising from creeping stolon. No definite main stem, the original stem branching several times subdichotomously; whole colony monosiphonic in habit. Both stems and branches divided into long, curved, slender internodes through distinct, oblique nodes; a hydrotheca, or a hydrotheca and one or two lateral, indistinct apophysis(es) immediately below its base; lower order branches arising not laterally, but almost perpendicular (in front or rear side) from their higher order counterparts. Hydrothecae strongly shifted to one side of the colony; very large, tubular, adnate to the corresponding internode for only a short part of their adaxial length, then curving outwards; abaxial wall almost straight for most of its length, slightly expanded below aperture; free adaxial wall gently curving basally, then straight; perisarc thin and smooth throughout; margin with 4 small, pointed cusps separated by shallow, semicircular embayments; renovations occasional; a 4-flapped operculum; hydranths with 18–20 filiform tentacles. Gonothecae arising from below the hydrothecal bases; elongated-ovoid, tapering basally, walls transversely-wrinkled; aperture distal, large, 4-cusped, and provided with a 4-flapped operculum.

Dimensions: See Table 27.

Remarks: The gonothecae of this species were described by Watson & Vervoort (2001), and subsequently found by Soto Àngel & Peña Cantero (2015).

Distribution: Argentina – Provincia de Buenos Aires [scattered records from offshore waters (El Beshbeeshy, 2011)]; Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur [off the NE coast of Isla de los Estados (Vervoort, 1972, as S. cylindritheca)]. Falkland Is. – off the NE coast (El Beshbeeshy, 2011). Scotia Arc – Burdwood Bank, South Georgia (Soto Àngel & Peña Cantero, 2015). Tasmanian seamounts (Watson & Vervoort, 2001).