Kuhlia rupestris: Boulenger, 1915

LOISELLE, PAUL V. & STIASSNY, MELANIE L. J., 2007, Rehabilitation of the Malagasy Endemic Kuhlia sauvagii Regan, 1913 (Teleostei: Perciformes), with the Designation of a Neotype for Centropomus rupestris Lacépéde, 1802, American Museum Novitates 3561 (1), pp. 1-16 : 9-12

Kuhlia rupestris: Boulenger, 1915 ; Arnoult, 1959; Mauge´,

1986; Sparks and Stiassny, 2003.

Kuhlia rupestris sauvagii: Pellegrin, 1933 , fig. 48.

Kuhlia rupestris var.: Kiener, 1963.

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

ADDITIONAL MATERIAL EXAMINED: MAD- AGASCAR: 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 ° 59925 S, 48 ° 12970 E], Tosmasina Province . AMNH 215492 , 2 ex., 55.7– 102.7 mm SL, Lokoho River downstream of Belaoke [14 ° 33990 S, 49 ° 45900 E], Antsiranana Province, Madagascar . AMNH 237598 , 1 ex., 60.1 mm SL, Andranobe Creek near the village of Ambodiatafana, Nosy Boraha [16 ° 43930 S, 50 ° 00978 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 ° 55957 S, 49 ° 54974 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 ° 59945 S, 50 ° 11925 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 ° 26905 S, 49 ° 49924 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 ° 40954 S, 49 ° 57925 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 ° 42970 S, 49 ° 58900 E], Antsiranana Province . UMMZ 234821 , 11 ex., 27.0–68.0 mm SL, Ambanizana River [15 ° 35935 S, 49 ° 28940 E], Antsiranana Province . UMMZ 234860 , 5 ex., 56.0–83.0 mm SL, Onive River , Masoala Peninsula [15 ° 17902 S, 50 ° 17905 E], Antsiranana Province . UMMZ 235285 , 2 ex., 82.0– 102.0 mm SL, Andrianbondro Creek at Mahavelo Village [22 ° 21947 S, 47 ° 22905 E], Fianarantsoa Province . UMMZ 239921 , 5 ex., 27.0–51.0 mm SL, Manombo National Park

[23 ° 01915 S, 47 ° 43975 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 reddishbrown 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 reddishbrown 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 crescentshaped 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

TABLE 3

Loadings of Morphometric Variables in Sheared Principal Components Analysis for Kuhlia sauvagii and Kuhlia rupestris samples from Réunion and Madagascar (see fig. 3 )

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.

Figures

Fig. 1. Verified ranges of Kuhlia rupestris (shaded stars) and Kuhlia sauvagii (shaded circles) on Madagascar.

Fig. 3. Scatterplot of sheared second and third PC scores of 17 log-transformed morphometric variables for Kuhlia sauvagii (open stars) and Kuhlia rupestris samples from Réunion (black circles) and Madagascar (open squares).