Garra magnacavus, Shangningam & Kosygin & Sinha, 2019

Shangningam, Bungdon, Kosygin, Laishram & Sinha, Bikramjit, 2019, A new species of rheophilic cyprinid fish (Teleostei: Cyprinidae) from the Brahmaputra Basin, northeast India, Zootaxa 4695 (2), pp. 148-158 : 149-152

Garra magnacavus , new species

( Fig. 1 & 2 )

Holotype. ZSI FF 6010, 68.0 mm SL; India: Arunachal Pradesh: Lower Subansiri District, Ranga River, Brahmaputra River Basin , 27°20’ N 93°48’ E, 547 m above sea level, Bikramjit Sinha, 16 March 2013.

Paratypes. ZSI/V/ APRC /P−783, 3 ex., 58.2−82.0 mm SL, same data as holotype .

Diagnosis. The new species belongs to the genus Garra in having the width of the crescentic anteromedian fold of the lower lip slightly wider than the width of the callous pad, the lateral end of the anteromedian fold of the lower lip reaching the anterolateral lobe of the mental adhesive disc and the presence of three rows of pharyngeal teeth. Garra magnacavus is distinguished from congeners in having the following combination of characters: body elongate with 42 lateral-line scales, 14−16 predorsal scales, an incipient proboscis with a transverse lobe, 15−19 rounded large pits on the snout and a weakly developed non-fleshy central callous pad.

Description. Morphometric characters of type specimens presented in Table 1 . Body elongate; compressed laterally, more so on caudal peduncle. Dorsal profile smoothly arched to supraoccipital process, slightly straight to dorsal-fin origin then gently sloping towards caudal peduncle. Ventral profile flattened from head to chest, more or less rounded up to pelvic-fin origin, straight from pelvic to caudal-fin base. Head moderately large; depressed, with slightly convex interorbital space; height less than length; width greater than height. Eyes small, dorso-laterally located, closer to posterior margin of opercle than to snout tip. Snout with 15−19 large rounded hollow pits, 4−6 located on anterior lateral side of nostrils, another pair in between nostrils, 6−9 on the dorso-anteriormost portion of transverse lobe; incipient proboscis appearing like a notch in ethmoid region, visible in dorsal view as groove anterior to nostrils. Transverse groove thinly demarcated. Sublachrymal groove deep, connected to lateral groove of rostral cap. Rostral lobe absent.

Barbels in two pairs; rostral barbel anteroventrally located, shorter than eye diameter; maxillary barbel at corner of mouth, shorter than rostral barbel. Rostral cap slightly extended, highly fimbriate, papillate ventral surface moderately wide; separated from upper jaw by deep groove and laterally continuous with lower lip. Upper lip appearing as thin band of weakly developed papillae in single ridge. Upper jaw not entirely covered by rostral cap. Disc elliptical, shorter than wide, narrower than head width through base of maxillary barbel; anterolateral lobe of lower lip reduced, one slight notch on lateral region of lateroposterior flap present; papillae on posteriormedian region of anteromedian fold large, coarsely arranged appearing as flat lobes; groove between posterior anteromedian fold and central callous pad deep and wide; papillae on inner half of whole length of lateroposterior flap coarsely arranged. Central callous pad rhomboidal shaped, weakly developed, non-fleshy, posteriormost margin of lateroposterior flap extending much beyond vertically to posterior margin of eye.

Dorsal fin with 3 simple and 8½ (4) branched rays, distal margin concave, origin slightly closer to snout tip than to caudal-fin base, inserted anterior to vertical through pelvic-fin origin; first branched ray longest, last branched ray extending to vertical of longest pelvic-fin ray. Pectoral fin with 1 simple and 12 (2) or 13 (2) branched rays, reaching beyond midway to pelvic-fin origin, margin subacuminate. Pelvic fin with 1 simple and 8 (4) branched rays, reaching well beyond midway to anal-fin origin, surpassing anus; second branched ray longest, not extending to base of anal fin; origin closer to anal-fin origin than to pectoral-fin origin, inserted vertically below base of second branched dorsal-fin ray; distal margin slightly convex. Anal fin short with 2 simple and 5½ (4) branched rays, first branched ray longest, not reaching base of caudal fin, distal posterior margin slightly concave, origin midway between pel- vic-fin origin and caudal-fin base. Vent midway between anal- and pelvic-fin origins. Caudal fin forked, upper lobe slightly longer, tip of lobes pointed, 10 (upper lobe) + 9 (lower lobe) principal rays.

Lateral line complete with 42 (4) scales. Transverse scale rows above lateral-line scales 4; between lateral line and pelvic-fin origin 3 (4); between lateral line to anal-fin origin 3 (4). Circumpeduncular scales 16 (4). Predorsal scales 14 (2), 15 (1), or 16 (1); scales regularly arranged, same size as flank scales. Chest and belly scaled. One long axillary scale at base of pelvic fin, its tip reaching posterior end of pelvic-fin origin. Dorsal-fin base scales 7 (2) or 8 (2), of which last 8 connected to base of dorsal fin. Anal-fin base scales 3(2) or 2(2), of which last 2–3 connected to base of anal fin. Scales between anus and anal-fin origin 6 (2) or 7(2).

Osteology. Total vertebrae 40 (1), consisting of 26 abdominal and 14 caudal vertebrae. Predorsal vertebrae 14. Pharyngeal teeth triserial, tooth pattern 4,3,2, each tooth mostly pointed at top, first row widely separated ( Fig. 3 ).

Coloration (in alcohol). Head, dorsum, and lateral side light gray. Mouth, chest, and abdomen yellowish white. Dorsal-fin rays spotted with black from base to tip of rays except last unbranched ray hyaline. Pectoral and pelvic fins with thin melanophores. Anal fin immaculate. Caudal fin black, more concentrated on median rays. Caudal-fin rays hyaline.

Distribution. Garra magnacavus is known only from the type locality, the Ranga River, in the Brahmaputra basin of Lower Subansiri District in Arunachal Pradesh, India ( Fig. 4 & 5 ).

Etymology. The species epithet magnacavus is derived from Latin magna meaning large, cavus meaning pit or hollow, referring to the large pits present in the snout. It is here used as a noun in apposition.

Figures

FIGURE 1. Garra magnacavus, ZSI FF 6010, holotype, 68.0 mm SL. India: Arunachal Pradesh, lower Subansiri District, Ranga River. a, dorsal view; b, lateral view; c, ventral view.

FIGURE 2. Garra magnacavus, ZSI FF 6010, holotype, 68.0 mm SL, India, Arunachal Pradesh, Ranga River, lower Subansiri District, a, dorsal view of head; b, ventral view of head: afll, anteromedian fold of lower lip; alll, anterolateral lobe of lower lip; ccll, central callous pad of lower lip; lfll, lateroposterior flap of lower lip; lj, lower jaw; uj, upper jaw; rc, rostral cap.

FIGURE 3. Pharnygeal teeth of Garra magnacavus.

FIGURE 4. Map showing collection locality of Garra magnacavus.

FIGURE 5. Ranga River, type locality of Garra magnacavus.