Garra tana, 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 : 59-61

GARRA TANA SP. NOV. ( FIG. 14 ; TABLE 5)

Garra tana Getahun, 2000 , nomen nudum, (p. 108, unpublished PhD thesis)

Diagnosis: Distinguished from African congeners by the following combination of features: very weakly developed disc; between three and five predorsal scales anterior to dorsal fin; chest, belly, and postpelvic region asquamate; elongate, narrow caudal peduncle (length 20.4–22.3%, m. 20.2% SL; depth 7.2– 10.0, m. 8.4% SL); and short intestine (SL 62.0–79.0% Int.L).

Description: Morphometric and meristic data for holotype and 30 paratypes given in Table 5. Maximum size: 108.3 mm SL (holotype, AMNH 223824). Currently known only from type series. All specimens are slender and gracile (body depth 13.4–18.8, m. 16.6% SL), greatest body depth located well anterior to dorsal-fin origin, at level of pectoral-fin tip. Caudal peduncle: elongate and narrow. Head short (18.9– 25.6%, m. 21.5% SL), snout prominent, with no tubercles, mouth wide. Eyes positioned medially on head, and relatively large (diameter 15.3–27.9% HL, m. 21.5%). Dorsal head profile rises steeply over snout, then more-or-less smoothly convex to dorsal-fin origin. Type-A disc: very weakly developed and inconspicuous without free posterior margin. Rostral cap well-developed, ventrally expanded covering upper jaw and with clearly invecked ventral margin. Two pairs of small barbels: rostral pair frequently conspicuous and often longest. Either 39 or 40 scales along lateral line; between three and five predorsal scales anterior to dorsal fin; either three or four scales from lateral line to origin of pelvic fin; 4–4.5 scales from lateral line to dorsal-fin origin. Chest, belly, and postpelvic regions asquamate. Dorsal-fin rays iii, seven, inserted well anterior to pelvic fin, with subacuminate tip, third branched ray longest, extending well beyond last ray; posterior margin concave. Predorsal length: 39.8– 50.0% SL. Anal-fin rays iii, five, with subacuminate tip; posterior margin concave. Pectoral-fin rays iv, 11; pectoral length 16.6–20.2% SL, with somewhat pointed tips. Vent located distant from anal fin (vent distance 17.9–53.0, m. 27.8%). Intestine short (SL 62.0–79.0% Int.L). Gas bladder well developed and large (posterior chamber 22.1–25.4% 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 opercle, and branchiostegal membranes: pale yellow-brown. Dorsal fin membrane with pale cream tip, faint submarginal band of black pigment in membrane between rays, and pale cream proximally. Some specimens with faint trace of either five or six very small black spots between rays in basal membrane of dorsal fin, but in most specimens dorsalfin spots absent. Anal fin uniformly pale creamy yellow. Caudal fin pale creamy brown, with median rays a contrasting darker brown. Pelvic and pectoral fins uniformly pale creamy brown.

Distribution and habitat: Currently known only from south of Lake Tana, Ethiopia. All specimens were collected by trawl close to shore (25–2000 m) in water ranging from 2 to 14 m in depth, over mud, sand, and rocks.

Remarks: G. tana occurs in sympatry with G. regressus and G. dembeensis . It is readily distinguished from G. regressus by the possession of a well-developed rostral cap with invecked ventral margin that covers the upper jaw (vs. regressed rostral cap with smooth margin and upper jaw exposed in G. regressus ), and from G. dembeensis by a weakly developed, type-A mental disc that lacks a free posterior margin (vs. well-developed disc with free posterior and lateral margins in G. dembeensis ). G. tana is further differentiated from both species by an elongate caudal peduncle (length 20.4–22.3% SL vs. 18.2–18.8% SL and 12.7–19.4% SL, respectively).

Etymology: Tana , in reference to the lake in which the type series was collected.

Material examined – type material: Holotype of G. tana, AMNH 223824, 108.3 mm SL, Kenbefami, Lake Tana , Ethiopia (11°40′N, 37°20′E); paratypes, AMNH 227687 , eight ex., two ex. C & S, 26.4–102 mm SL, north-west of Dek Island , Lake Tana , Ethiopia (11°56′N, 37°11′E); paratypes, AMNH 227688 , three ex., 88.1–94.6 mm SL, Kibran shore, Lake Tana , Ethiopia (11°39′N, 37°23′E); paratype, AMNH 227689 , one ex., 104.4 mm SL, Entos Island, Lake Tana, Ethiopia

Figures

Figure 14. Garra tana, holotype, AMNH 223824, 108.3 mm standard length.