Garra substrictorostris, Roni & Vishwanath, 2018

Roni, Narengbam & Vishwanath, Waikhom, 2018, A new species of the genus Garra (Teleostei: Cyprinidae) from the Barak River drainage, Manipur, India, Zootaxa 4374 (2), pp. 263-272 : 264-269

Garra substrictorostris , new species

( Figure 1 )

Holotype: MUMF 22034 , 173 mm SL; India: Manipur: Churachandpur District: Leimatak River ( Barak River drainage); 24°34'33'' N, 93°40'01'' E, 513 m above sea level, Nebeshwar et al., 9 August 1999.

Paratypes: MUMF 22029–22033 , 5 specimens, 23–137mm SL; same data as holotype.

Diagnosis. A large, robust-bodied Garra , reaching 173 mm SL, distinguished from its congeners in the Barak and Chindwin River drainages in possessing the following combination of characters: a prominent transverse lobe on the snout with 14–20 multicuspid tubercles; a narrow antrorse unilobed proboscis on the snout, with 3–5 medium to large multicuspid tubercles on its anterior margin and 4–6 multicuspid tubercles on its anteroventral margin; lateral surface of the snout slightly elevated, lobular with 7–11 small tubercles; 5½ transverse scales rows above the lateral line, 3½ or 4½ rows between the lateral line and anal-fin origin. Distance between anus and analfin origin 15–27% of that between pelvic-fin origin and anal-fin origin.

Description. General body shape as shown in Figure 1 . Morphometric data are in Table 1. Body elongate, compressed laterally, more so towards caudal peduncle. Dorsal profile smoothly arched to dorsal- fin origin, then gently sloping towards caudal peduncle. Ventral profile slightly curved from chest to abdomen, then more or less round up to pelvic-fin origin, straight from pelvic- to caudal-fin base. Head large depressed, with a slightly convex interorbital space. Eyes, dorso-laterally located, closer to posterior margin of opercle than to snout tip. Snout rounded, with a prominent transverse lobe covered with 14–20 multi-cuspid tubercles, demarcated posteriorly by a deep transverse groove; depressed rostral surface slightly concave; a prominent unilobed proboscis which slightly extends forward up to the transverse groove but not reaching the transverse lobe, with 3–5 medium to large multicuspid tubercles on the anterior margin and 4–6 multi-cuspid tubercles on anteroventral margin ( Fig. 2a ). Proboscis moderately elevated, sharply separated from the depressed rostral surface by a deep transverse groove; a prominent transverse lobe on the snout with 14–20 multi-cuspid tubercles; lateral surface of snout slightly elevated, lobular with 7–11 small tubercles. Depressed rostral surface slightly concave. Sublachrymal groove long, connected to groove on rostral cap. Rostral lobe absent.

Barbels in two pairs; rostral barbels anteroventrally located, slightly shorter than eye diameter; maxillary barbels at corner of mouth, shorter than rostral barbels. Rostral cap well- developed, slightly fimbriate, papillate ventral surface moderately wide; separated from upper jaw by deep groove and laterally continuous with lower lip ( Fig. 2b ). Upper jaw entirely covered by rostral cap. Disc elliptical; papillae on posteromedian region of anteromedian fold medium; groove between anteromedian fold and central callous pad shallow; anterolateral lobe of lower lip present; papillae on inner half of whole length of lateroposterior flap medium, regularly arranged; anterior marginal surface of central callous pad with small randomly arranged papillae; posteriormost margin of lateroposterior flap extending vertically to posterior margin of the eye.

Dorsal fin with 3 (6) simple and 8½ (6) branched rays, first branched ray longest, last not extending to vertical from anal-fin origin; distal margin concave; origin nearer to snout tip than to caudal-fin base, anterior to vertical from pelvic-fin origin. Pectoral fin with 1(6) simple and 15 (6) branched rays, margin subacuminate, fifth branched ray longest, not extending to pelvic-fin base. Pelvic fin with 1(6) simple and 7 (3) or 8(3) branched rays, second branched ray longest, not extending to anal- fin base; origin closer to anal-fin origin than to pectoral-fin origin origin vertically below base of second branched dorsal-fin ray; distal margin truncate. Anal fin with 3(6) simple and 5½ (6) branched rays, first branched ray longest; distal margin slightly concave, origin closer to caudal-fin base than to pelvic-fin origin. Anus closer to anal fin than to pelvic-fin origin (15–27% of that between pelvic-fin origin and anal-fin origin). Caudal fin forked; lower lobe slightly longer than upper lobe; 10+9 principal rays.

Lateral line complete, with 33(4) or 34 (2) scales; 5½ (6) transverse scales rows above lateral line; 3½ (6) rows between lateral line and pelvic- fin origin: 3½ (2) or 4½ (4) rows between lateral line and anal- fin origin. Circumpeduncular scales 16 (6). Predorsal scales 10 (6); arranged regularly. Chest and belly scaled. Long axillary scale at base of pelvic fin, its tip reaching posterior end of pelvic-fin origin. Six (6) scales along the dorsal-fin base, 5 (6) along the anal-fin base and 3 (6) scales between anus and anal-fin origin.

Colour. In formalin, body dark gray dorsally; light brownish or yellowish ventrally and below lateral line. Dorsum of head, snout and opercles dark brown. Mouth, chest and abdomen yellowish white or light gray. Pectoral fin darker gray than pelvic and anal fins. Base of branched dorsal-fin rays spotted with black. Lower lobe of the caudal fin darker brown than upper lobe. A black spot at upper angle of the gill opening.

Distribution. Garra substrictorostris is known from the Leimatak River in Churachandpur district (Barak River drainage) Manipur, India ( Fig. 3). It inhabits clean, swift- flowing freshwater streams over a substrate of gravel and boulders ( Fig. 4 ).

Etymology. The species name refers to its narrow proboscis; from the Latin ‘ substrictus ’ meaning ‘narrow’, and ‘ rostrum ’ meaning ‘beak’, a compound word, used as an adjective.

Discussion. Of the 31 species recognized from the drainages of northeastern India, 14 species, viz., G. arunachalensis , G. birostris , G. bimaculacauda , G. clavirostris , G. cornigera , G. elongata , G. gotyla , G. kalpangi , G. koladynensis , G. litanensis , G. nasuta , G. parastenorhynchus , G. quadratirostris and G. trilobata have a proboscis on the snout ( Fig. 5 ). Garra substrictorostris possesses a prominent proboscis on the snout and is hence easily distinguished from the 17 species that lack this character.

From those species possessing a proboscis, G. substrictorostris is distinguished from G. arunachalensis in having 33−34 (vs. 35) lateral-line scales, presence (vs. absence) of an anterolateral lobe of the lower lip and the absence (vs. presence) of narrow faint black stripes on the caudal peduncle; from G. birostris in having a unilobed (vs. bilobed) proboscis, 5½ (vs. 4½) transverse scale rows above the lateral line and sublachrymal groove connected to rostral cap groove (vs. not connected); from G. bimaculacauda in the absence (vs. presence) of two distinct black spots on the lobes of the caudal fin, prominent (vs. weakly developed) proboscis and 16 (vs. 12) circumpeduncular- scale rows; from G. clavirostris in possessing a narrow (vs. club-shaped) proboscis, absence (vs. presence) of narrow black stripes on the caudal peduncle; from G. elongata in having a prominent (vs. weakly developed) proboscis, 33–34 (vs. 39–40) lateral-line scales, in the absence (vs. presence) of a transverse black bar on the dorsal fin and the absence (vs. presence) of a longitudinal black band on the middle of the caudal fin; from G. gotyla in the presence (vs. absence) of multicuspid tubercles, more transverse scale rows above lateral line 5½ (vs. 4½), and 5 (vs. 3−4) scales on the anal-fin base; from G. kalpangi in having a well-developed (vs. weakly developed) proboscis, 5½ (vs. 3½) transverse scale rows above the lateral line and 15 (vs. 10–12) branched pectoral-fin rays; from G. koladynensis in having unilobed (vs. trilobed) proboscis, slightly concave (vs. flat) depressed rostral surface; from G. litanensis in having 33–34 (vs. 32) lateral- line scales and presence (vs. absence) of scales on the chest; from G. parastenorhynchus in having 33–34 (vs. 31–32) lateral line scale, absence (vs. presence) of a conspicuous dark spot at the caudal base; from G. quadratirostris in having 33−34 (vs. 37) lateralline scales, 3–4 (vs. 5–6) preanal scales and slightly concave (vs. creased and convex) depressed rostral surface; from G. trilobata in having unilobed (vs. trilobed) proboscis, 16 (vs. 14) circumpeduncular scales and presence (vs. absence) of an anterolateral lobe of the lower lip.

M’Clelland (1838) described Platycara nasuta (now Garra ) as: “Snout abruptly depressed between the eye with a large pit between the nostrils, …”. His figure 2a shows a crescentic mark in between the nares which may be the pit he mentioned (part of head of his figure reproduced and labelled here as Fig. 5j ). Garra substrictorostris neither has a depression between eyes nor a pit between the nares.

Garra species with a proboscis presently recognized from China and Southeast Asia include G. bispinosa , G. cyrano , G. fuliginosa , G. gravelyi , G. longchuanensis , G. orientalis , G. qiaojiensis , G. salweenica , and G. rotundinasus ( Nebeshwar & Vishwanath 2013; Yu et al. 2016). Garra substrictorostris can be differentiated from G. fuliginosa , G. orientalis and G. salweenica in having unilobed (vs. trilobed) proboscis.

The holotype of Garra gravelyi in ZSI is reported to be damaged and not suitable for comparison (L. Kosygin & B.D. Shangningam, ZSI, pers. comm.). Four specimens of Garra collected from the Lokchao stream at Moreh, Indo-Myanmar border, Chindwin River drainage, in addition to having similar morphometric and meristic characters to G gravelyi , are consistent with the description of the species by Annandale (1919) in having a transverse groove on the snout and the descriptions of Hora (1921) and Menon (1964) in having a squarish incipient proboscis. The MUMF specimens are tentatively identified as G. gravelyi , pending redescription of the species. The images of the proboscis and mental disc in Annandale (1919) and those of the specimens from Lokchao are compared in Figure 6 . Garra substrictorostris is distinct from G. gravelyi in having a prominent, narrow, antrorse unilobed proboscis, i.e., raised and slightly extending forward from the posterior margin of the depressed rostral surface on snout vs. an incipient proboscis ( Fig. 7 )

The new species can be further differentiated from G. fuliginosa and G. orientalis in having (vs. lacking) black spots at the base of the dorsal-fin rays; and from G. salweenica in lacking (vs. having) a dark blotch on the caudal peduncle, and in lacking (vs. having) a black mark at the tip of the upper caudal-fin lobe. Garra substrictorostris differs from G. bispinosa in possesing a unilobed (vs. bilobed) proboscis, the presence (vs. absence) of multicuspid tubercles and 15 (vs. 13−14) branched pectoral-fin rays; from G. cyrano in the absence (vs. presence) of blackish longitudinal stripes along the posterior portion of the body and absence (vs. presence) of black median rays on the caudal fin; from G. longchaunensis in possessing 16 (vs. 12) circumpenduncular scales and absence (vs. presence) of a black mark at the tip of upper caudal-fin lobe; from G. qiaojiensis in possessing 3 (vs. 4) unbranched dorsalfin rays and 16 (vs. 12) circumpenduncular scales; and from G. rotundinasus in having 33−34 (vs. 36−37) lateralline scales, 5½ (vs. 2½−3) transverse scale rows above the lateral line and 16 (vs. 12) circumpenduncular scales.

Figures

FIGURE 1. Garra substrictorostris, sp. nov., holotype, MUMF 22034, 173 mm SL; a. dorsal, b. lateral and c. ventral views. India:Manipur: Churchandpur District:Leimatak River (Barak River drainage).

FIGURE 2. Snout of Garra substrictorostris, a. morphology of snout showing transverse lobe, proboscis, depressed rostral surface and lateral surfaces of holotype; b. oromandibular structure of holotype.

FIGURE 4. Leimatak River,Manipur, India; typelocality and habitat of Garra substrictorostris.

FIGURE 5. Snout characters of: a. Garra arunachalensis (MUMF 4304, 121 mm SL); b. G.birostris (MUMF 4302, 102 mm SL); c. G.clavirostris (MUMF 22004, 117 mm SL); d. G.cornigera (MUMF 12061, 76 mm SL); e. G.elongata (MUMF 2311, 94 mm SL); f. G. gotyla (MUMF 4300, 104 mm SL); g. G. koladynensis (MUMF 4313, 130 mm SL); h. G. kalpangi (MUMF 22035, 76 mm SL); i. G. litanensis (MUMF 69, 72 mm SL); j. G. nasuta [redrawn after……..]; k. G. quadratirostris (MUMF 4306, 104 mm SL); l. G. trilobata (MUMF 12051, 118 mm SL); m.G.substrictorostris (MUMF 22034, 173 mm SL)

FIGURE 6. Comparison of snouts and mental discs: a. side view of snout of Garra gravelyi redrawn from Annadale (1919: Plate II, fig. 3) and b. of a specimen from Lokchao (MUMF 22046, 90mm SL); mental disc of G. gravelyi reproduced from Annandale (1919: Plate II, fig.3a) and of MUMF 22046, 90 mm SL.

FIGURE 7. Comparison of side view of snout: a. side view of snout of Garra gravelyi (showing incipient proboscis, redrawn from Annadale 1919: Plate II, fig. 3), b. specimen of G. gravelyi from Lokchao, MUMF 22046 (showing incipient proboscis) and c. side view of snout of G. substrictorostris, MUMF 22034 (showing antrorse unilobed proboscis).