Garra geba, Stiassny & Getahun, 2007

Stiassny, Melanie L. J. & Getahun, Abebe, 2007, An overview of labeonin relationships and the phylogenetic placement of the Afro-Asian genus Garra Hamilton, 1922 (Teleostei: Cyprinidae), with the description of five new species of Garra from Ethiopia, and a key to all African species, Zoological Journal of the Linnean Society 150 (1), pp. 41-83 : 57-59

GARRA GEBA SP. NOV. ( FIG. 13 ; TABLE 4)

Garra geba Getahun, 2000 , nomen nudum (p. 68 unpubl. PhD thesis)

Diagnosis: Distinguished from African congeners by the following combination of features: intermediate disc development; depressed head and gracile body; between five and nine predorsal scales anterior to dorsal fin; asquamate chest, belly, and postpelvic region; posterior chamber of gas bladder small (13.9–16.2% SL); and intestine short (SL 95.0–102.0% Int.L).

Description: Morphometric and meristic data for holotype and seven paratypes given in Table 4. Maximum size: 86.4 mm SL (holotype, AMNH 228485). Currently known only from type series. All specimens extremely gracile (body depth 14.9–16.8, m. 16.0% SL) and elongate, greatest body depth located well anterior to dorsal fin, midway between dorsal-fin origin and snout. Head gracile and depressed, often with small circular tubercles in front of nostrils, becoming tubular beneath eyes. Eyes positioned medially on head. Dorsal head profile rises steeply over snout, dorsum of head more-or-less flattened, dorsal body profile smoothly convex to dorsal-fin origin. Disc variously developed; only weakly so in smaller specimens, becoming quite well-developed (type B) with a narrow free posterior edge and partially free lateral margins in adult specimens, but never broadly papillate (as in type C). Disc in adults markedly wider than deep. Rostral cap well developed, extending ventrally over upper jaw and with invecked ventral margin. Two pairs of barbels: maxillary barbels usually slightly longer than rostral pair. Between 37 and 39 scales along lateral line; between five and nine predorsal scales anterior to dorsal fin; 2.5–3.5 scales from lateral line to origin of pelvic fin; 4.5–5.5 scales from lateral line to dorsal-fin origin. Chest, belly, and postpelvic regions asquamate. Dorsal-fin rays iv, seven, inserted well anterior to pelvic fin, with short subacuminate tip, first and second unbranched rays longest, extending slightly beyond last ray; posterior margin weakly concave, posterior rays extending almost to pelvic-fin tip. Predorsal length 46.9–50.0% SL. Anal-fin rays iv, five, with short subacuminate tip; posterior margin weakly concave. Pectoral rays iv, 11; pectoral length 19.1–22.6% SL, with somewhat pointed tips. Vent located relatively distant from anal fin (vent distance 18.4–29.1, m. 24.6%). Intestine short (SL 95.0–102.0% Int.L). Gas bladder small (posterior chamber 13.9– 16.2% SL).

Colour in preservation: Body dark dorsally, lighter brown below lateral line and ventrally. Head, snout, and most of cheek and opercle: dark brown. Lips, gular region, posterior margin of opercle, and branchiostegal membranes: creamy yellow-brown. Pale coloration extends postero-dorsally around eye. Dorsal-fin membrane pale cream distally, faint submarginal band of black pigment in membrane between rays, and pale cream proximally. Either four or five small black spots between rays in basal membrane of dorsal fin. Anal fin uniformly pale creamy brown. Caudal fin pale dusky brown, with median rays a darker brown. Pelvic and pectoral fins uniformly pale creamy brown.

Distribution and habitat: Currently known only from type locality on Geba River about 2 km south of Hagere Selam town, Tigray, Ethiopia. In this region the Geba River flows through highly degraded farmland with sparse vegetation and little cover. Typeseries was collected some 100 m east of a highway bridge in slowly flowing water over mud and sand, with some fringing grasses along riverbanks.

Etymology: Geba , in reference to the river system in which the type series was collected.

Remarks: In some features (absence of chest, belly, and postpelvic scales, high number of lateral line scales, and median position of the eye) G. geba is similar to G. dembeensis . However, G. geba is readily distinguished from G. dembeensis in having a partially scaled predoral region, a less well-developed disc that lacks prominent papillation, a much shorter intestine (SL 95.0–102.0 vs. 39.0–42.0% Int.L), and a smaller posterior gas bladder chamber (13.9–16.2 vs. 20.9– 21.9% SL).

Material examined – type material: Holotype of G. geba, AMNH 228485, 86.4 mm SL, Geba River , about 2 km south of Hagere Selam town, Tigray, Ethiopia (13°35′N, 39°25′E); paratypes of G. geba, AMNH 223747, seven ex., two ex. C & S, 55.4–69.6 mm SL, same data as holotype.

Figures

Figure 13. Garra geba, holotype, AMNH 228485, 86.4 mm standard length.