Garra biloborostris , a new labeonine species from north-eastern India ( Teleostei : Cyprinidae )

Garra biloborostris, a new labeonine species is described from the Kanamakra River of the Brahmaputra River basin in Assam. It can be distinguished from its congeners of northeast India in having a unique combination of the following characters: a proboscis represented by two separate and slightly elevated arch-shaped lobes, each lobe with three acanthoid tubercles on its anterodorsal marginal aspect; bulgy lateral surface of the snout giving a lobe like appearance; a prominent knob-like transverse lobe with 10 – 16 smallto medium-sized acanthoid tubercles; 30 + 3 lateral line scales; 81⁄2 branched dorsal fin rays; and 51⁄2 branched anal fin rays.


Introduction
Cyprinid genus Garra Hamilton, 1822 includes elongate, small-to medium-sized, bottom dwelling fish species which are distributed from Borneo and southern China to Sub-Saharan Africa through Middle East Asia and Arabian Peninsula (ZHang & CHen, 2002) and are usually found in the fast flowing rivers and streams where they adhere themselves against swift current by clinging to substratum, mainly by means of their suctorial disc but also by the horizontally placed paired fins, especially the pectorals (menon, 1964).The genus is characteristic in having a modified lower lip forming a mental adhesive disc whose posterior margin is discontinuous with the mental region.The crescentic anteromedian fold of the mental adhesive disc is similar to or wider than the width of the central callous pad and the lateral end of the anteromedian fold on each side usually reaches the anterolateral lobe of the mental adhesive disc.
Currently, the genus consists of 25 valid species in different river drainages of northeast India of which Garra annandalei Hora, 1921;G. arunachalensis  A collection of fishes from the Kanamakra River of the Bhramaputra River basin in Assam, India, included an unnamed species of Garra, which has a peculiar proboscis on the snout, is herein described as Garra bilob orostris, new species.

Material and Methods
All descriptions are based on formalin preserved specimens.Measurements were made on left hand side of the specimens with digital calipers to the nearest 0.1 mm.Fin rays and scales were counted under stereo-zoom transmitted light microscope.The number of specimens exhibiting a given count is indicated in parentheses.Counts, measurements and terminology follow nebesHwar & VisHwanatH (2013).Lateral line scales (scales on the body + scales on the caudal fin) are counted from the anteriormost pored scale in contact with the shoulder girdle to the posteriormost pored scale on the caudal fin.Dorsal and anal fin ray counts follow Kottelat (2001), that is, indicating the last deeply branched ray as "1 ½".
Two specimens were dissected and stained with alizarin red S to observe the vertebral column.The total number of vertebrae is presented as the sum of abdominal and caudal vertebrae following roberts (1989).Abdominal vertebrae were counted from the vertebrae of the Weberian apparatus to the vertebra with its haemal spine anterior to the first anal-fin pterygiophore.The Weberian apparatus is counted as four vertebrae.Caudal vertebrae were counted from the vertebra with its haemal spine immediately posterior to the first anal fin pterygiophore to the vertebra bearing hypural plate.Predorsal vertebrae were counted from the vertebrae of the Weberian apparatus to the vertebra with its neural spine immediately anterior to the first dorsal fin pterygiophore.The examined specimens are deposited in Manipur University Museum of Fishes (MUMF).

Results
Garra biloborostris sp.nov.Fig. 1  transverse lobe covered with 10 -16 small-or mediumsized tubercles; proboscis represented by two separate arch-shaped lobes, each lobe slightly elevated, demarcated from depressed rostral surface by shallow groove; each lobe with three acanthoid tubercles on anterodorsal marginal aspect (medial one prominent, large-sized, directed anterodorsally and lateral ones medium-sized, directed laterodorsally) and with 1-4 small-sized tubercles may be present on dorsal surface; lateral surface of snout bulgy giving lobe like appearance with 3 -10 small-sized tubercles (Fig. 2); and depressed rostral surface slightly convex with 1 -4 small tubercles immediately posterior to transverse groove.Sublachrymal groove shallow and connected to rostral cap groove.Eyes placed dorsolaterally in posterior half of head (Fig. 3).Barbels in two pairs; rostral barbles anterolaterally located, shorter than eye diameter; maxillary barbels at corner of mouth, shorter than rostral barbles.Rostral cap well developed, moderately or slightly fimbriate, about one sixth of length of its distal margin on each lateral extremity smooth; papillate ventral surface moderately wide.Upper lip appearing as a thin band of weakly developed papillae.Upper jaw entirely covered by rostral cap.Mental adhesive disc elliptical, shorter than width, narrower than head width through roots of maxillary barbels; anteromedian fold of mental adhesive disc entirely or slightly covered by rostral cap; papillae on anteromedian fold small and regularly arranged; groove between anteromedian fold and central callous pad deep; papillae on inner half of whole length of lateroposterior flap coarsely arranged; anterior marginal surface of central callous pad with or without small papillae; posterior most margin of lateroposterior flap extending vertically to posterior margin of eye (Fig. 4).
Dorsal fin with 3 (12) simple and 8½ (12) branched rays; last simple ray shorter than head length; distal margin slightly concave; origin closer to snout tip than to caudal fin base, inserted anterior to vertical from pelvic fin origin; first branched ray longest, last branched ray not extending vertically to anal fin origin.Pectoral fin with 1 (12) simple and 12 (6) or 13 (6) branched rays; fourth branched ray longest, shorter than head length; margin subacuminate.Pelvic fin with 2 (12) simple and 7 branched rays; second branched ray longest, surpassing anus; origin closer to anal fin origin than to pectoral fin origin, inserted under base of fifth branched dorsalfin ray.Anal fin short with 3 (12) simple and 5½ (12) branched rays; first branched ray longest, not reaching   base of caudal fin; posterior margin straight; origin at midway between caudal-fin base and pelvic-fin origin.Anus closer to anal fin origin than to pelvic-fin origin (distance from anus to anal fin 17.8 -26.2 % of pelvicanal distance).Caudal fin forked; lower lobe slightly longer, tenth ray counting from upper lobe shortest.

Osteological features. Total vertebrae 31 (2), consisting of 20 + 11 (2) abdominal + caudal vertebrae. Predorsal vertebrae 9(2).
Colouration in preservative (Fig. 1).body light gray dorsally, light brown ventrally.Mouth and chest light gray.Dorsal and pectoral more dark than pelvic and anal fin.Yellowish white ventrally at origin of pectoral and pelvic fins.Branched dorsal-fin rays with black dots.Six narrow dark black stripes on caudal peduncle.A black spot at upper angle of the gill opening.
Etymology.The specific epithet is derived from Latin bi, meaning two, lobus meaning lobe, and rostris meaning beak or bill, referring to the two beak-like lobes on the proboscis.An adjective.

Remarks
nebesHwar & VisHwanatH (2013) described the oromandibular structures and snout morphology including tuberculation patterns of Garra Hamilton.nebesHwar & VisHwanatH (2015) also stated the genus to have one of the following snout characters: a smooth surface, a transverse lobe, a proboscis with a transverse lobe, and a pair of rostral lobes with or without a transverse lobe.Thus these characters are very useful in the diagnosis of the species of Garra.
The new species can be further distinguished from Garra arunachalensis in having 33 (vs.35) lateral line scales, in the presence (vs.absence) of anterolateral lobe of lower lip and 16 (vs.12) circumpenducular scales rows; from G. gotyla in the presence (vs.absence) of separate lobe of the proboscis on the snout, depressed rostral surface not bulgy (vs.highly bulgy); from G. kalpangi in having a larger disc , in the presence (vs.absence) of transverse groove at tip of the snout and presence (vs.absence) of six narrow dark black stripes on caudal peduncle.
The new species differs from Garra litanensis in the presence (vs.absence) of scales on the chest, 33 (vs.32) lateral line scales and the absence (vs.presence) of black spots at the base of the dorsal fin; from G. trilobata in the presence (vs.absence) of anterolateral lobe of the lower lip, 33 (vs.31 -32) lateral line scales and 16 (vs.14) circumpeducular scales.
Garra biloborostris further differ from G. bimacula cauda in the absence (vs.presence of two distinct black spots on the caudal fin, one each on the tips of the dorsal and ventral lobes), presence (vs.absence of dark band along the length of the body); from G. parastenorhyn chus absence (vs.presence of a conspicuous dark spot at the caudal fin base), absence (vs.presence of multicuspid tubercles), absence (vs.presence of overhanging proboscis).