Garra magnarostrum, Singh & Tudu & Gurumayum, 2024

Singh, Pratima, Tudu, Asha Kiran & Gurumayum, Shantabala Devi, 2024, Garra magnarostrum, a new species of cyprinid fish (Teleostei: Cyprinidae) from the Brahmaputra River drainage, Northeastern India, Records of the Zoological Survey of India 124 (3), pp. 219-227 : 220-224

Garra magnarostrum sp. nov.

( Figure 1 )

Material examined: Holotype: ZSI FF 8210, 136.0 mm SL, India: Papum Pare District: Ranga River near Lichi Village , Arunachal Pradesh, (Brahmaputra basin), 27 ᵒ 22 ´ 20 ″ N; 93 ᵒ 52 ´ 18 ″ E, 28 December 2018, coll. S.D. Gurumayum.

Diagnosis: Garra magnarostrum is distinguished from congeners in the Indian sub-continent, Myanmar and China in having (vs. lacking) many small and budding tubercles on the ventral side of the transverse lobe of the snout ( Figure 2 ). It further differs from congeners in having a combination of the following characters: a multilobed proboscis on the snout, a long head (27.9% SL), a long snout (63% HL), small eye (13% HL), deep caudal peduncle (14.7% SL), short gular disc (34% HL), 14½ branched pectoral-fin rays, 33 lateral line scales, 11 predorsal scales, 13 circumpeduncular scales and presence of multicuspid tubercles on the snout.

Description: Morphometric data of the holotype is presented in Table 1. Body elongate, laterally compressed, compressed more towards caudal peduncle. The dorsal profile smoothly arched to dorsal-fin origin, then slanting down towards the caudal peduncle. Ventral profile flattened from head to chest, slightly rounded up to pelvic-fin origin then almost straight towards caudal-fin base.

Head large, depressed with somewhat convex inter orbital area, head depth less than head length. Eyes are small, situated dorsolaterally in the posterior half of the head( Figure 3).The snout is slightly rounded,its transverse lobe covered with 28 large-sized multicuspid acanthoid tubercles on its dorsal side, 23 small-sized tubercles and numerous buddings on its ventral side ( Figure 2 ); demarcated posteriorly by a deep, transverse groove. The lateral surface of the snout is slightly elevated with 15 multicuspid tubercles, and 3-6 small to medium-sized tubercles between nostrils and eyes. Proboscis prominent, thick, multilobed, protruding downward above the transverse groove, with 26 medium to large uni- to multicuspid tubercles, differentiated from the depressed rostral surface by a distinct transverse groove; width smaller than internarial space ( Figure 4 ). Multicuspid acanthoid tubercles usually hexa- to octa-cuspids ( Figure 5 ). The sublachrymal groove is deep, horizontally curved, and connected to the rostral-cap groove.

Barbels in two pairs: rostral barbels anteroventrally located, shorter than eye diameter; maxillary barbels at Garra magnarostrum , a new species of cyprinid fish (Teleostei: Cyprinidae ) from the Brahmaputra River... the corner of mouth, much shorter than rostral barbels. The upper jaw is completely covered by a well-developed rostral cap. The rostral cap is well-developed and highly fimbriate; separated from the upper jaw by a deep groove, laterally continuous with the lower lip. Gular disc elliptical, wider than long, narrower than head width through roots of maxillary barbels; labellum of lower lip poorly developed, entirely covered with papillae; torus with numerous papillae, almost covered by the rostral cap; toral groove present.

a

Dorsal fin with one simple and 8½ branched rays, last simple rays almost equal to head length, origin much closer to snout tip than caudal-fin base. Pectoral fin with one simple and 14½ branched rays, its length less than head length. Pelvic fin with one simple and 7½ branched ray, not reaching anus, its origin midway between anal-fin origin and pectoral-fin origin, inserted vertically below the base of second branched dorsal-fin ray. Anal fin with one simple and 5½ branched rays, anus opening closer to anal-fin origin than to pelvic-fin origin. Caudal fin forked, lower lobe slightly longer, 9+8 branched rays.

One long axillary scale at the base of the pelvic fin, its tip extending posteriorly beyond the pelvic fin base. Dorsal-fin base scales 9. Anal fin base scales 6. Prepelvic scales 17. Scales between anus and anal-fin origin 3. Lateral line complete with 33 scales. Transverse scale rows between dorsal-fin origin to lateral line 4½; between lateral line and pelvic-fin origin 3½. Predorsal scales 11, scales regularly arranged. Chest and belly scaled. Circumpeduncular scales 13.

Colouration: In alcohol, the head, dorsum and lateral sides are yellowish-grey. Mouth, chest and abdomen brownish to yellowish-white. Ventral surface from rostral cap to anal-fin origin yellowish-grey. Dorsal and pectoral fins are darker and pelvic and anal fins are yellowish brown. Posterior margins of pelvic and anal fins are hyaline; 3-6 median principal branched caudal-fin rays and distal margins of caudal-fin lobes are dark grey.

Distribution: Garra magnarostrum is known only from the Ranga River in Arunachal Pradesh (Brahmaputra River drainage) ( Figures 6 and 7 ).

Etymology: The species epithet magnarostrum is derived from the Latin magna, meaning large, and rostrum, meaning snout, referring to the large snout. The species epithet is a noun in apposition to the generic name.

Figures

Figure 1. Garra magnarostrum, ZSI FF 8210, holotype, 136.0 mm SL: a. dorsal; b. lateral; and c. ventral aspects. Scale bar: 10 mm.

Figure 2. Ventral view of head showing oromandibular structure and tuberculation on ventral surface of transverse lobe of Garra magnarostrum, ZSI FF 8126, holotype, 136.0 mm SL.

Figure 4. Dorsal view of head of Garra magnarostrum, ZSI FF 8126, holotype, 136.0 mm SL.

Figure 5. Multicuspid acanthoid tubercles of Garra magnarostrum: a. Tubercles on snout and b. a single multicuspid tubercle of transverse lobe.

Figure 6. Ranga River, the type locality of Garra magnarostrum.

Figure 7. Map showing type locality of Garra magnarostrum.