Neotype

MNHN 2006-0811 (ex. MNHN 000-0862), syntype of Dules fuscus, Ravine du Gol, Réunion (Île de Bourbon), 81.8 mm SL.

Additional Material Examined

MASCARENES: MNHN 000-0862, 1 ex., 81.5 mm SL, syntype of Dules fuscus, Ravine du Gol, Réunion. MNHN A-3013, 1 ex., 139.0 mm SL, Réunion. MNHN 1982-1009, 1 ex., 54.0 mm SL, St. Denis, Réunion. MNHN 1998-0513, 1 ex. 48.8 mm SL, St. Benoit, Réunion. MNHN 1998-0514, 3 ex., 138.6–170.1 mm SL, no locaty given. MNHN 1999-0551, 1 ex., 131.9 mm SL, Ravine du Gol, Réunion. MNHN 1982-1009, 1 ex., 54.0 mm SL, St. Denis, Réunion. MNHN 000-0832, 1 ex., 155.5 mm SL, Mauritius (Île de France). MNHN 2003-0105, 1 ex., 45.8 mm SL, Mauritius.

MADAGASCAR: MNHN 1935-4, 1 ex., 35.0 mm SL, no locality given. MNHN 1936-29, 161.8 mm SL, Farony River. MNHN A-4193, 3 ex., 59.0–61.5 mm SL, no locality given. AMNH 228094, 1 ex., 63.2 mm SL, Andranobe Creek near Ambodiatafana Village, Nosy Boraha [16°43′30 S, 50°00′78 E], < 1.0 m a.s.l., Toamasina [Tamatave] Province. AMNH 231261, 1 ex., 133.0 mm SL, main channel of the Mahanara River at Antsirabe-Nord [13°58′49 S; 49°57′81 E], 35 m a.s.l., Antsiranana [Diego Suarez] Province. AMNH 232408, 3 ex., 1 cleared and stained, 89.5–101.3 mm SL, lower reaches of Djabala Creek below and above Ampombilava Village, Nosy Be [13°23′11 S, 48°14′22 E]. c. 1.0 m a.s.l., Antsiranana Province. AMNH 233668, 1 ex., 29.5 mm SL, Ankoakoa Creek immediately S. of Antanambe on RN-5. [16°28′50 S, 49°51′00 E], c. 1.0 m a.s.l., Toamasina Province. AMNH 233676, 1 ex., 56.0 mm SL, Maloutrandro River upstream of bridge over RN-5 [16°36′33 S, 49°48′25 E], c. 2.0 m a.s.l., Toamasina Province. AMNH 228080, 2ex., 112.7–170.9 mm SL, Manandriana Creek near of Ankirihisy Village, Nosy Boraha [16°51′39 S, 49°54′99 E], c. 7.0 m a.s.l., Toamasina Province. AMNH 11688, 1 ex., 104.6 mm SL, no locality given. UMMZ 238289, 4 ex., 63.0–76.0 mm SL, Morondava River, Toliara [Tuléar] Province. UMMZ 234812, 3 ex., 67.6–118.4 mm SL, mouth of the Andranobe River, Masoala Peninsula, [15°40′54 S, 49°57′25 E], c. 1.0 m a.s.l., Antsiranana Province. UMMZ 234886, 1 ex., 91.0 mm SL, Manombo National Park, [23°01′10 S, 47°43′75 E], Fianarantsoa Province. UMMZ 239701, 3 ex., 186.3–216.7 mm SL, Ihazofotsy River c. 2 hour's walk from Sakalama Village [22°58′56 S, 46°22′07 E], Toliara Province.

Diagnosis

Differs from congeners, with the exception of K. sauvagii, in the possession in adults of an emarginate (vs. deeply forked) caudal fin. Kuhlia rupestris is distingushed from K. sauvagii in iris coloration (silvery white vs. light brown), the absence of a distinctive wide orange-red cresent-shaped mark covering the upper half of eye (present in K. sauvagii), the persistence into adulthood of a large black blotch on each lobe of the caudal fin, a higher gill-raker count (18–23 [mode 20] vs. 18–20 [mode 19]), and fewer pored lateral line scales (38–41 vs. 42–44).

Description

Morphometric and meristic data for neotype, topotypical, and Malagasy specimens are given in table 1. Largest specimen available is a male, 216.7 mm SL; however, adult lengths of 450 mm SL have been reported (Merrick and Schmida, 1984). Snout relatively short, 21.9–30.5% HL (mean 25.1% SL), dorsal head profile smoothly convex to dorsal fin origin. Jaws more or less isognathous, becoming slightly prognathous in large individuals. Posterior tip of maxilla usually attains, or extends beyond, vertical at mid-orbit, even in juveniles. Preorbital is weakly serrate; preopercle is more strongly so. Preorbital serrae tend to become obsolete in specimens >150.0 mm SL. Two short spines at the angle of the opercle, lower slightly longer than upper. Gill rakers on lower limb of first gill arch elongate and denticulate: 18 (1), 20 (14), 21 (5), or 23 (1).

Both jaws with a single outer row of minute, somewhat recurved unicuspid teeth. An inner band of villiform teeth, 3–4 rows in width, situated rostrally and tapering posteriorly to a single row. Teeth of outer row less than twice as long as those of inner band. Patches of fine conical teeth present on vomer, palatines, endopterygoid sand ectopterygoids.

Head and body covered from mid-orbit to caudal fin with regularly imbricate, ctenoid scales. Those on chest and venter only slightly smaller than those on flanks and dorsum. Cheek scale rows: 3 (5) or 4 (17). Pored scales in lateral line: 38 (2), 39 (15), 40 (7), 41 (1); often with 5–7 small pored scales extending onto base of caudal fin. Lateral line dips downwards to midlateral line at sixth or seventh scale from its origin. Scale rows from origin of anal fin to base of dorsal fin: 14 (1), 15 (1), 16 (18), or 17 (1). Four scale rows between origin of lateral line and mid-dorsal line. Five scale rows between pectoral insertion and anal-fin origin. Circumpeduncular scales: 22 (1), 24 (21). Dorsal and anal scaly sheaths well developed, basal 25–30% of caudal fin heavily scaled.

Dorsal Fin

X, 11 (25). Origin of dorsal fin usually anterior to pelvic insertion. Anal fin: III, 10 (25). Pectoral fin with 13 (4), 14 (19), or 15 (2) rays. Pectoral and pelvic fins short and rounded. Pelvic fins do not extend to urogenital papilla when adducted. Caudal somewhat forked in juveniles and young adults (e.g., plate 1B), becoming moderately emarginate in adults. Vertebral count 25 (10 + 15) in all specimens.

Coloration in Life (Plate 1b)

Snout, top of head, and dorsum light brown. Lips, cheek, opercle, and flanks silvery olive with bluish highlights; venter silvery white. Upper two-thirds of flanks densely speckled with irregular olive-brown spots. Similar spotting variably present on opercle and, more rarely, on cheek. Each scale in the five rows immediately below lateral line marked with a small olive-brown basal dot and a row of somewhat larger brown spots usually present on squamous anal fin sheath. Basal two-thirds of spiny dorsal greyish with a silvery-olive or bluish cast, distal third dusky. Soft dorsal, caudal, and anal fins clear yellow. Diffuse black blotch present distally between first to fifth or sixth dorsal fin soft rays. Specimens <100.0 mm TL typically with distinct pattern of dark inter-radial spots and streaks present medially in caudal fin membranes; reduced to an irregular pattern of darker spots in larger individuals. Large black spot invariably present on middle of each lobe of caudal fin of juveniles and characteristically retained in adults, distal tips of both caudal lobes white or hyaline. Single row of dark brown inter-radial spots variably present along anal fin base. Pelvic fins grayish with silvery-olive or bluish cast basally, hyaline distally. Pectorals hyaline. Iris of eye silvery, with narrow reddish-brown crescent dorsally.

Coloration in Preservative

Snout, top of head, and dorsum light brown. Lips, cheek, opercle, and flank beige; venter dirty white. Pattern of dark spotting on head and body as described for living individuals, but spots are dark brown. Spiny portion of dorsal fin off-white; remaining unpaired fins clear yellow. Dark markings of unpaired fins as described for living individuals. Pelvic fins off-white; pectorals hyaline. Iris of eye silvery-white, with narrow dark crescentic marking in upper quadrant.

Distribution

As currently recognized, the range of Kuhlia rupestris extends from the east coast of Africa to Samoa and from Australia to the Ryukyu Islands (Randall and Randall, 2001). In the western Indian Ocean, its presence has been documented on the Comoros, both coasts of Madagascar (fig. 1), Réunion, and Mauritius, but confirmation of its presence in the Seychelles is lacking (Valade et al., 2004). In this study, we have concentrated on examination of specimens from localities on Madagascar and from islands in the western Indian Ocean, and we can neither confirm nor refute the identity of specimens currently identified as K. rupestris beyond this region.

Figure 1

Verified ranges of Kuhlia rupestris (shaded stars) and Kuhlia sauvagii (shaded circles) on Madagascar.

Natural History

While juveniles are frequently found in estuarine habitats over the species' entire range, on Madagascar subadult and adult K. rupestris are essentially inhabitants of fresh waters. On the eastern versant of Madagascar, K. rupestris is restricted to the lower reaches of rivers. There are no records of this species from elevations much in excess of 30.0 m a.s.l., and upstream of the head of navigation, K. rupestris is typically replaced by K. sauvagii. However, in westward-flowing rivers such as the Onilahy, K. rupestris is routinely found as far as 250 km inland from the coast at altitudes of up to 900 m a.s.l.

Kuhlia rupestris up to 13.0 cm SL are typical inhabitants of clear, well-oxygenated, swiftly flowing waters. Larger individuals are usually found in deep pools where the current is less pronounced. Its Réunionais vernacular designation “doule des rochers” reflects its preference for rocky substrates. Juveniles feed predominantly on aquatic insect larvae and small freshwater shrimp but will take terrestrial insects from the water's surface. Adults are predators of macrocrustaceans and small fishes. Juveniles are at risk from larger predatory fishes, fish-eating birds, and small Nile crocodiles. While its flesh is highly esteemed by the Malagasy, K. rupestris is nowhere sufficiently abundant to support a significant commercial fishery (Kiener, 1963; Kiener and Therezien, 1963).

For a species whose value to recreational fisheries is recognized throughout its extensive range (Keith et al., 1999; Merrick and Schmida,1984), very little is known about the reproductive biology of K. rupestris. Its wide distribution implies the existence of a diadromous life-history pattern and a pelagic larval stage. Its mode of reproduction, however, is unknown, and it remains to be determined whether K. rupestris is a catadromous or an amphidromous spawner as well as to what degree, if any, its reproductive activity is characterized by seasonality.

Conservation Status

Although it has been suggested that its numbers on Réunion have declined due to fishing pressure (Keith et al., 1999), there is no evidence to suggest that this is the case for the Malagasy populations. Following the criteria established by the World Conservation Union, K. rupestris is considered to be a low-risk species (Raminosoa et al., 2002).

Discussion

Lacépéde's Centropomus rupestris is based entirely on Commerson's manuscript description, and no type material was designated at the time of description (Bauchot and Desoutter, 1986; Pruvost personal commun.). Considerable confusion exists in the literature regarding this purportedly widespread taxon and, as an aid for nomenclatural stabilization, the designation of a neotype is herein considered appropriate. Regan (1913) synonymized Dules fuscus Cuvier in Cuvier and Valenciennes,1829, with K. rupestris. The type locality of both Dules fuscus and Centropomus rupestris are the island of Réunion. We have examined the syntypes of D. fuscus, two specimens measuring 81.8 mm and 81.5 mm SL. Following comparison with more recently collected material from Réunion, we can confirm the validity of Regan's decision to synonymize the two species. We thus formally propose the larger of the two specimens of Dules fuscus as the neotype of C. rupestris, a course of action that unambiguously relates this nomen to material collected from the designated type locality of Lacépéde's species, the island of Réunion in the western Indian Ocean.

Table 2

Values in parentheses indicate number of specimens examined with that count

Holotype

BMNH 1895-10-29:91, 122.5 mm SL, Imerina, Madagascar.

Additional Material Examined

MADAGASCAR: MNHN 1998-1512, 1 ex., 181.0 mm SL, Tolanaro (Fort Dauphin). AMNH 237599, 2 ex., 46.3–47.1 mm SL, head of navigation of the Mahavoua River at Antanambe, 2 km upstream of first bridge on RN-5 northbound. AMNH 233671, 1 ex., 51.8 mm SL, Maloko stream at Mavoutano Village, Toamasina Province. AMNH 097085, 5 ex., 90.6–207.2 mm SL, Nosivolo River near Ambatomasina Village, c. 16 km E-NE of Marolambo [19°59′25 S, 48°12′70 E], Tosmasina Province. AMNH 215492, 2 ex., 55.7–102.7 mm SL, Lokoho River downstream of Belaoke [14°33′90 S, 49°45′00 E], Antsiranana Province, Madagascar. AMNH 237598, 1 ex., 60.1 mm SL, Andranobe Creek near the village of Ambodiatafana, Nosy Boraha [16°43′30 S, 50°00′78 E], <1.0 m a.s.l., Toamasina Province. AMNH 228097, 1 ex., 80.9 mm SL, Ambanitsivory Creek near the village of the same name, Nosy Boraha [16°55′57 S, 49°54′74 E], 79 m a.s.l., Toamasina Province. AMNH 231239, 1ex., 40.3 mm SL, Ankavia River at Antsahanandriana Village, on the Antalaha– Maromandia road [14°59′45 S, 50°11′25 E], 9 m a.s.l., Antsiranana Province. AMNH 233664, 1 ex., 78.4 mm SL, Mahavoua River, c. 2 m upstream of the bridge on RN-5 north of Antanambe. [16°26′05 S, 49°49′24 E], c. 2.0 m a.s.l., Toamasina Province. UMMZ 234812, 7ex., 44.3–106.1 mm SL, mouth of the Andranobe River [15°40′54 S, 49°57′25 E], c. 1.0 m a.s.l., Antsiranana Province. UMMZ 234815, 7 ex., 33.7–72.0 mm SL, Lahantozona Creek, c. one hour south of Andranobe camp [15°42′70 S, 49°58′00 E], Antsiranana Province. UMMZ 234821, 11 ex., 27.0–68.0 mm SL, Ambanizana River [15°35′35 S, 49°28′40 E], Antsiranana Province. UMMZ 234860, 5 ex., 56.0–83.0 mm SL, Onive River, Masoala Peninsula [15°17′02 S, 50°17′05 E], Antsiranana Province. UMMZ 235285, 2 ex., 82.0–102.0 mm SL, Andrianbondro Creek at Mahavelo Village [22°21′47 S, 47°22′05 E], Fianarantsoa Province. UMMZ 239921, 5 ex., 27.0–51.0 mm SL, Manombo National Park [23°01′15 S, 47°43′75 E], Fianarantsoa Province.

Diagnosis

Differs from congeners, with the exception of K. rupestris, in the possession of an emarginate (vs. deeply forked) caudal fin. Kuhlia sauvagii is distingushed from K. rupestris in the coloration of the iris (light brown vs. silvery white), the presence of a distinctive wide orange-red cresent-shaped marking covering the upper half of the eye (absent in K. rupestris), the absence of a black blotch on the upper and lower lobe of the caudal fin in specimens >50.0 mm SL, a lower gill-raker count (18–20 [mode 19] vs. 18–23 [mode 20]), and by more pored lateral line scales (42–44 vs. 38–41).

Description

Morphometric and meristic data for holotype and more recently collected specimens given in table 2. Largest specimen is female, 207.2 mm SL, however, this species can grow to 250 mm SL (Loiselle, unpublished data). Snout short, 20.5–27.3% HL (mean 24.5% HL), dorsal head profile straight to dorsal fin origin. Jaws more or less isognathous, becoming slightly prognathous in medium to large individuals. Posterior tip of maxilla barely extending beyond anterior orbital margin. Preorbital weakly serrate; preopercle more strongly so. Two short spines at the angle of the opercle, lower slightly longer than upper. Gill rakers on lower limb of first gill arch: 18 (5), 19 (11), or 20 (3).

Both jaws with a single outer row of minute, somewhat recurved unicuspid teeth. An inner band of villiform teeth, 3–4 rows in width, situated rostrally and tapering posteriorly to a single row. Teeth of outer row only a little longer than those of inner band. Small patches of fine conical teeth present on vomer and palatines. Endopterygoid and ectopterygoid tooth patches lacking or weakly developed.

Head and body covered from mid-orbit to caudal fin with regularly imbricate, ctenoid scales. Scales on chest and venter slightly smaller than those on flanks and dorsum. Scale rows present on cheek: 2 (1), 3 (9) , or 4 (8). Pored scales in lateral line: 42 (8), 43 (5), 44 (4); often with 5–7 small pored scales extending onto base of caudal fin. Lateral line dips downward to midlateral line at tenth scale caudad of origin. Scale rows from origin of anal fin to base of dorsal fin: 15 (9), 16 (2), 17 (3). Five scale rows between origin of lateral line and mid-dorsal line. Five scale rows between pectoral insertion and anal fin origin. Circumpeduncular scales: 22 (2) or 24 (16). Dorsal and anal scaly sheaths well-developed, basal 25–30% of caudal fin heavily scaled.

Dorsal

X, 11 (17). Dorsal-fin origin at, or slightly posterior to, pelvic insertion. Anal: III, 10 (17). Pectoral fin with 14 (11), 15 (4) or 16 (2) rays. Pectoral and pelvic fins short and rounded. Pelvic fins do not extend to urogenital papilla when adducted. Caudal weakly emarginate, and fan-shaped; never strongly forked. Vertebrae. Vertebral count of 25 (10 + 15) in all specimens.

Coloration in Life (Plate 1d)

Snout, top of head, and dorsum pale beige. Lips, cheek, opercle, and flanks silvery beige with golden highlights; venter silvery white. Flanks sparsely speckled with irregular chestnut to maroon spots. Opercle and cheek usually devoid of spotting. A row of somewhat larger reddish-brown spots variably present on squamous sheath of anal fin. Spines and soft rays of dorsal fin grayish olive, with inter-radial membrane golden beige. Spinous dorsal marked with an extensive pattern of chestnut to maroon inter-radial spots and streaks. A less extensive patterning of smaller reddish-brown inter-radial spots present basally in soft dorsal fin. In individuals less than 70.0 mm SL, caudal fin silvery yellow with diffuse black blotch on each lobe and pattern of dark reddish-black inter-radial streaks medially. In larger individuals, black blotches in caudal lobes become diffuse and replaced by series of dusky-brown to black inter-radial streaks. Overall caudal fin coloration of adults is a pattern of alternating silvery-yellow and reddish-brown inter-radial streaks against a grayish background. Anal fin yellow basally, clear gray distally, and marked with a variable pattern of dark reddish-brown inter-radial spots. Pelvic fins clear yellow basally, dusky distally. Pectoral fins hyaline. Iris of eye light brown with wide orange-red crescent-shaped marking covering upper half of eye.

Coloration in Preservative

Snout, top of head, and dorsum brownish beige. Lips, cheek, opercle, and flanks beige; venter dirty white. Pattern of dark spotting on head and body as described for living individuals, but spots light chestnut. Dorsal fin spines pale gray; membrane and all remaining unpaired fins clear yellow. Dark markings of unpaired fins as described for living individuals. Pelvic fins off-white; pectoral fins hyaline. Iris of eye silvery beige, with reddish-brown crescent-shaped marking in upper half.

Distribution

Kuhlia sauvagii is endemic to Madagascar, where it is restricted to rivers draining the eastern coast of the island (fig. 1).

Natural History

Kuhlia sauvagei is found from sea level to 500 m a.s.l. Juveniles are typically found in estuarine habitats and in the lower reaches of rivers, where they often occur syntopically with K. rupestris. When the two species are found together, juveniles of K. sauvagii appear to be less social and associate with the substrate more closely than do those of K. rupestris, rarely rising more than a third of the way up into the water column. Subadult and adult K. sauvagii are most often found above the first significant set of rapids. It is unclear what factors operate to limit the upstream penetration of K. sauvagii in basins such as the Rianila, which lack major physiographic barriers to fish movement. It is worth noting in this context that west of the town of Beforona, the highest point on the Rianila from which K. sauvagii has been reported (Kiener, 1963), the stream gradient increases noticeably, and water temperatures are markedly cooler. This species has essentially the same habitat preferences as does its more widely distributed congener, but large individuals of K. sauvagii appear to frequent areas of strong current to a greater extent than do K. rupestris of the same size. There are no significant differences in diet in the two species, and they are vulnerable to the same suite of predators.

Nothing is known of the reproductive biology of K. sauvagii. Its endemic character and the fact that all specimens <50.0 mm SL were collected from the lowermost reaches of rivers suggests an amphidromous life-history pattern coupled with a very brief planktonic larval stage. Existing holdings of the species are too limited to permit any conclusions to be drawn with regard to reproductive seasonality.

Conservation Status

Unlike many of Madagascar's endemic fishes, Kuhlia sauvagii is widely distributed throughout the eastern versant of the island, and according to local peoples, its numbers do not appear to have diminished significantly over the past few decades. Following the criteria employed by the World Conservation Union, these observations would ordinarily result in its classification as a low-risk species (Raminosoa et al., 2002). However, in view of its habitat preferences, the known impact of deforestation on the water quality of the island's rivers, and the ongoing loss of forest cover east of the hydrographic divide, it would appear more prudent to classify K. sauvagii as a vulnerable species whose status should be monitored on a regular basis.