A new species of the bee genus Tetralonia subgenus Thygatina is described and figured from southern India. Tetralonia (Thygatina) macroceps, new species is particularly noteworthy for macrocephaly in males, among other characters. Previously the Oriental fauna of Thygatina was thought to consist of a single described species. Aside from T. (T.) fumida (Cockerell) and the new species proposed herein, the fauna also includes T. wickwari (Bingham), erroneously placed in Eucara (as a genus), and herein recognized as a species of Thygatina, which is thereby newly transferred to the genus Tetralonia (new combination). In addition, there remains at least one additional undescribed species, but owing to confusion surrounding the association of sexes for T. fumida and T. wickwari this material is left unnamed. The need for additional collecting in southern India and Sri Lanka is stressed in order to resolve this difficulty. Lectotypes and paralectotypes are designated for T. fumida and T. wickwari.
Introduction
Thygatina is a small group of eucerine bees confined to peninsular India and Africa south of the Sahara and presently considered a subgenus of Tetralonia (Michener, 2000). Like other Tetralonia (i.e., Eucara and Tetralonia proper), species of Thygatina are small to medium-sized bees with relatively short antennae in the males and in the females sparse scopae, adapted to carrying large pollen grains. Eucara is found only in Africa, with seven species extending as far north as Burkina Faso and Ethiopia, while Tetralonia proper is principally palearctic, with one widely distributed, polytypic species [Tetralonia (Tetralonia) malvae (Rossi): southern and central Europe, Levant, east to Iran and Central Asia] and a second in northeastern Africa [T. (T.) gossypii Cockerell]. The three groups are generally quite similar; indeed, the distinctions between Eucara and Thygatina are relatively minor, particularly given that the new species discussed herein is rather Eucara-like in character (vide infra). Known pollen sources for the genus include Malvaceae for Tetralonia s. str. (genera Gossypium, Lavatera, Malva) and Eucara (genus Gossypium), as well as Convolvulaceae (genera Ipomoea, Argyreia) and Malvaceae (genus Hibiscus) for Thygatina. Species of the genus have a sparse and distinctive metatibial scopa, presumably adapted for the collection of the large pollen grains typical for these plants.
The African species of Thygatina were treated by Eardley (1989: as Tetralonia), leaving only the Indian taxa unstudied. We herein provide a brief taxonomic summary of the known species of Thygatina (table 1), with a particular emphasis on the Indian fauna, and highlight where further collecting and work needs to be undertaken. The Indian species Tetralonia wickwari Cockerell was mistakenly referred to Eucara (Brooks, 1988) but is herein returned to Thygatina. Morphological terminology follows that of Michener (2000) and Engel (2001), while the format for the description generally follows that of Eardley (1989) for African Thygatina. Photomicrographs were prepared with a Microptics PhotoImaging System.
Table 1
Species of Thygatina
Systematics
Figure 1–3
Photomicrographs of male holotype of Tetralonia (Thygatina) macroceps, new species. 1. Lateral habitus; 2. dorsal habitus; 3. facial view.
Figure 4
Labiomaxillary complex and detail of maxilla depicting maxillary palpus of male holotype of Tetralonia (Thygatina) macroceps, new species. Scale bars = 1 mm.
Figure 5–11
Holotype male of Tetralonia (Thygatina) macroceps, new species. 5. Facial view; 6. base of antenna showing scape, pedicel, and first three flagellomeres; 7. metapretarsus; 8. seventh metasomal tergum (left half is dorsal, right half is ventral); 9. seventh metasomal sternum; 10. eighth metasomal sternum; 11. genitalic capsule. Scale bars = 1 mm (bar between mandibles for fig. 5; bar beneath distitarsus for figs. 6–8; bar at bottom of right column for figs. 9–11).
Figure 12–14
Photomicrographs of female of Tetralonia (Thygatina) macroceps, new species. 12. Lateral habitus; 13. dorsal habitus; 14. facial view.
Diagnosis
Males with head strongly transverse and genae broad (figs. 1, 2), inner orbits of compound eyes divergent ventrally (figs. 3, 5); mandibles elongate, falciform (figs. 1–3, 5); maxillary palpi reduced (fig. 4) (four- or five-segmented in other species); galeae, labial palpi, paraglossae, and glossa all approximately coterminous (i.e., apices reaching to approximately the same point) (fig. 4); antennae short (scarcely as long as twice compound eye length); mesonotal pubescence pale (figs. 1, 2); terminalia as figured (figs. 8–11). Females with head broad, inner orbits divergent ventrally (fig. 14); face with exclusively white pubescence (fig. 14); pale mesonotal pubescence (fig. 13).
Description
As for the genus and subgenus with the following additions: Male. Total body length 12.4 mm (11.9–12.4 mm); forewing length 8.3 mm (8.0–8.3 mm). Head strongly transverse [width 4.2 mm (4.0–4.2 mm), length 2.9 mm (2.8–2.9 mm)] distance between inner orbits greater than compound eye length (figs. 3, 5); inner orbits of compound eyes distinctly divergent ventrally (figs. 3, 5); vertex in frontal aspect almost uniformly weakly convex, not depressed between compound eyes and lateral ocelli (fig. 5); gena broad (fig. 1). Antennae short (fig. 2), flagellum scarcely as long as twice compound eye length, scape about one-third compound eye length, distinctly less than combined lengths of first through third flagellomeres (fig. 6); second and third flagellomeres of approximately equal length (fig. 6). Clypeus protuberant, without submarginal fascia (fig. 3); epistomal sulcus obscure medial to anterior tentorial pits except as faint line medially bordering short supraclypeal area (fig. 5). Mandible elongate, flaciform, longer than compound eye length (figs. 1–3, 5). Maxillary palpus short, three-segmented (fig. 4), first palpomere strongly sclerotized, second and third palpomeres (combined length ca. 0.19 mm) weakly sclerotized; galeae, labial palpi, paraglossae, and glossa all approximately coterminous (i.e., apices reaching to approximately the same point) (fig. 4). Intertegular distance 3.1 mm (2.9–3.1 mm). Mesofemur without ventral carina (vide infra); mesotibia slender, with mesotibial spur unmodified (vide infra); mesotarsus elongate, mesobasitarsus long, slender, parallel-sided; metafemur unmodified, without ventral dentition (vide infra); metatibia without process (vide infra); metabasitarsus slender, parallel-sided through its entire length; metatarsomeres II and III distinctly not elongate, similar in length to metatarsomere IV, with abundant pubescence as on surrounding tarsomeres; distitarsi long and strongly arched (fig. 7) (typical in Thygatina although less strongly so in most species); pretarsal ungues (claws) with slender, inner tooth. Male terminalia as depicted in figures 8–11.
Integument without markings, generally dark brown except black or nearly so on face, mesosoma, and metasomal terga (except apical margins dark brown); wing veins dark brown, membrane hyaline. Head imbricate with coarse, contiguous or nearly contiguous punctures, punctures more faint on vertex, gena, postgena, apical half of clypeus. Mesosoma imbricate with faint, coarse, contiguous or nearly contiguous punctures; basal area of propodeum rugulose; lateral and posterior surfaces imbricate. Anterior-facing surface of first metasomal tergum smooth, remainder of tergum and remaining terga strongly imbricate with scattered, faint, small punctures except apical margins smooth; metasomal sterna imbricate with scattered minute punctures on central discs except smooth between mediolateral setal patches of fifth sternum.
Vestiture of face white; mandible with ventral brush of long, white setae (fig. 1); vestiture of mesosoma white except off-white dorsally (i.e., white tinged with faint infuscation, although still quite pale); vestiture of legs as on dorsum of mesosoma except infuscation stronger on hind legs, particularly inner surfaces of hind leg podites; vesiture of metasoma white except infuscated on setae of seventh metasomal tergum (fig. 8); anterior-facing surface of T1 abundantly covered with elongate, plumose, white setae; metasomal terga II–V with white, tomentose bands in basal halves, such bands weaker on third and fourth terga (fig. 2); fifth metasomal sternum with subapical, mediolateral patches of dense black setae.
Female. As described for the male aside from usual sexual differences and with the following minor emendations: total body length 11.6 mm (11–11.8 mm); forewing length 7.6 mm (6.9–7.8 mm). Head broad [width 3.9 mm (3.7–4.0 mm), length 2.6 mm (2.6–2.7 mm)]; lower distance between inner orbits of compound eyes greater than length of compound eye, upper distance between inner orbits of compound eyes about as long as length of compound eye. Mandible about as long as compound eye, outer apical half sometimes amber colored, apex minutely notched (appearing bluntly rounded in worn specimens). Intertegular distance 3.0 mm (2.9–3.2 mm). Pygidial plate acutely rounded at apex, lateral margins gently convex and tapering in apical half to apex; surface minutely and transversely striate.
Scopal setae fuscous; white, tomentose bands of metasomal terga II–V stronger than those of male (figs. 12, 13); apical fimbriae of fifth and sixth metasomal terga fuscous except laterally white on fifth tergum; sterna with transverse apical brushes of dense, fuscous setae.
Holotype
Male, labeled “South India: Madras State, Coimbatore, vii 1957, P. Susai Nathan”. The holotype is in the Donald and Madge Baker Collection, Division of Entomology, University of Kansas Natural History Museum.
Paratypes
One female labeled “S. India: Madras State, Coimbatore, 1400 ft., viii 1971, T.R.S. Nathan”; two males, two females labeled “India: Tamil Nadu, Mudumalai Preserve, 1200 m, 30 km NW Udagamandalam ( = Ooty), 16 August 1990, Charles D. Michener, ex: Argerria cuneata [for Argyreia cuneata Ker-Gawl., Convolvulaceae]”; one male, three females labeled “India: Tamil Nadu, Mudumalai Preserve, 1100 m, 30 km NW Udagamandalam ( = Ooty), 16 August 1990, Charles D. Michener, ex: Argerria cuneata [for Argyreia cuneata Ker-Gawl., Convolvulaceae]”; one male labeled “India: Tamil Nadu, 5 km S Theppakadu, Mudumalai Preserve, 1–3 August 1990, William T. Wcislo”; one male labeled “India: Tamil Nadu, Mudumalai Preserve, Centre for Ecological Studies, 4 August 1990, William T. Wcislo”. All paratypes are in the Division of Entomology, University of Kansas Natural History Museum (the specimen collected by Nathan is in the Donald and Madge Baker Collection, the remainder is in the Snow Entomological Collection).
Etymology
The specific epithet is a reference to the enlarged head, particularly of males, in this species.
Floral Records
Males and females of this species have been collected at flowers of Argyreia cuneata Ker-Gawl. (Convolvulaceae).
Comments
The head structure of T. macroceps is quite Eucara-like in character; i.e., the head is broad and the compound eyes are diverging ventrally (figs. 3, 5). Indeed, the overall shape of the head is quite similar to T. (Eucara) macrognatha (Gerstäcker), widely distributed in Africa [material from Zimbabwe (labeled “S. Rhodesia”) examined], or T. (E.) penicillata (Friese) from central East Africa (material from Abyssinia examined). The new species otherwise embodies all of the defining features for Thygatina. The validity of the current subgeneric system for Tetralonia should be critically reevaluated.
Tetralonia macroceps can be distinguished from T. wickwari (Bingham), the only other named Oriental species known in the male sex, by the following features (those of T. wickwari mentioned, with alternates for T. macroceps in parentheses): clypeus with narrow, submarginal yellow fascia (such fascia absent in T. macroceps: fig. 3); second flagellomere less than half length of third flagellomere (second and third flagellomeres of approximately equal lengths in T. macroceps: fig. 6); head strongly transverse, except inner orbits not conspicuously divergent ventrally (inner orbits divergent in T. macroceps: figs. 3, 5); mesofemur deeply, ventrally carinate, carina abruptly, arcuately contracted basally (mesofemur without ventral carina in T. macroceps); mesotibia expanded apically, with mesotibial spur unguiform (slender and unmodified, with mesotibial spur unmodified in T. macroceps); metafemur ventrally strongly dentate basally (metafemur unmodified, without ventral dentition in T. macroceps); metatibia at apex ventrally with strong, apically-truncate, dentiform process (such a process absent in T. macroceps); metabasitarsus slender basally, strongly expanded apically (metabasitarsus slender, parallel-sided through its entire length in T. macroceps); metatarsomeres II and III elongate, weakly pubescent (metatarsomeres II and III distinctly not elongate, similar in length to metatarsomere IV, with abundant pubescence as on surrounding tarsomeres in T. macroceps).
The female differs from T. fumida (Cockerell), known only in the female sex, by the divergent compound eyes (parallel in T. fumida); the supraclypeal area with exclusively white setae (strongly intermingled with black setae in T. fumida); the vertex with white setae, a few with slight infuscation (nearly all setae black on vertex in T. fumida); the wing membrane hyaline (strongly infuscated in T. fumida); and the tomentose bands strong and wide on the second through fifth metasomal terga (tomentose bands of metasoma weak on second through fourth metasomal terga, nearly absent on fifth metasomal tergum in T. fumida).
Tetralonia (Thygatina) wickwari
(Bingham), new combination
Podalirius wickwari Bingham In Wickwar, 1908: 122.
Eucara wickwari (Bingham): Brooks, 1988: 575.
Lectotype
A male labeled “Columbo / Ceylon / 3·06 [March 1906] / O. Wickwar” and “Podalirius / wickwari ♂ / Bingh Type” in the Natural History Museum, London (B.M. Type Hym 17b641) (here designated).
Paralectotype
A male with identical labels as that of the lectotype (here designated). The paralectotype had been crudely dissected and is much broken (the labrum, mouthparts, and anterior legs are glued on a piece of card).
Tetralonia (Thygatina) fumida (Cockerell)
Thygatina fumida Cockerell, 1911: 237.
Tetralonia (Thygatina) fumida (Cockerell):
Michener, 2000: 716 (although Michener did not explicitly propose the new combination of the epithet fumida with Tetralonia, he can be considered as having done so automatically in his placement of Thygatina as a subgenus of Tetralonia given that T. fumida is the type species for the former).
Lectotype
A female labeled “Kandy / Ceylon / February [19]10 / E. Comber” in the Natural History Museum, London (here designated).
Paralectotype
A female labeled “Ceylon. / Kandy. / B.1. [19]08 / O.S. Wickwar” in the Natural History Museum, London (here designated). The paralectotype has the mouthparts removed and is accompanied by a note reading, “I found these tunneling in a bank and storing their nest with pollen. The tunnel went into the bank about 8–10 inches. Kandy. Ceylon. Jan: 08. O.S.W. [O.S. Wickwar].”
Discussion
There is at least one additional species in the Oriental fauna that we have chosen not to describe. The dilemma rests on the fact that there are two undescribed males in this region—one from southern India, the other from Sri Lanka—and either could be the yet unknown male for T. fumida. Tetralonia fumida is known only from females occurring in southern India and Sri Lanka (table 1). The Sri Lankan species T. wickwari, known only from males (table 1), and an undescribed male from this same island agree well with T. fumida, yet each form of male is specifically distinct. Either T. wickwari is the male and thereby a senior synonym of T. fumida (leaving the other Sri Lankan male as an undescribed species), or the undescribed male is the unrecognized mate of T. fumida. The matter is further complicated in that a third, specifically distinct male is known from the mainland in southern India. Since T. fumida is known to occur in both Sri Lanka and southern India, this third form could alternatively be the long-lost male for the species. Should this scenario prove to be true, the female of T. wickwari would remain undiscovered and the second Sri Lankan male would represent an undescribed species. Regardless, there is either a new species in southern India or in Sri Lanka. That T. wickwari and T. fumida are synonyms and that both unassociated males are new is a remote possibility. Until males and females are captured together (ideally in copula), thereby revealing which is the new species and which is the male for T. fumida, it is prudent to hesitate naming these forms. More intensified collecting in the region is required to resolve this issue.
A specimen of the potentially new southern Indian male is in the Donald and Madge Baker Collection, Division of Entomology, University of Kansas Natural History Museum. The specimen is labeled “South India: Nilgri Hills, Cherangode, 3500 ft, xi 1950, P.S. Nathan”. A specimen of the potentially new Sri Lankan male is in the Natural History Museum, London, labeled “Colombo, Ceylon, O.S.W. 6.08” // “Ceylon, O.S.W. 6.08. O.S. Wickwar. 1912–189”. The Ceylonese male is similar to the peninsular male but differs by the inner orbits of the compound eyes being conspicuously divergent, the metatarsi less elongate and slender, and metatarsomeres II and III short and conspicuously pubescent, especially apically and dorsally. Additionally, the Ceylonese male has the metabasitarsus parallel-sided, the clypeus dark, the labrum testaceous, the second flagellomere half as long as the third flagellomere, and the fifth metsasomal sternum between the lateral tufts of setae being glossy and devoid of macrosculpture.
Acknowledgments
We are grateful to Prof. Dr. Holger H. Dathe and Prof. Dr. Dorothea Brückner for careful commentary on an earlier version of the manuscript. This is contribution No. 3442 of the Division of Entomology, University of Kansas Natural History Museum. Partial support was provided by National Science Foundation grant EF-0341724 (to M.S.E.).
