Parambassis bistigmata

description

Description. Biometric data are presented in Table 1. Body laterally compressed, dorsal and abdominal profiles convex, rising steeply from the occiput to base of first dorsal fin, then gently sloping posteriorly becoming almost level at caudal peduncle. Eye large, its margin free. Gill membranes free from isthmus; 6 branchiostegal rays. First branchial arch with 2 – 3 + 12 gill rakers. Holotype Paratypes (N = 6) mean range s. d. Standard length (mm) 39.3 33.13 – 41.16 In % SL Head length 33.8 31.2 27.9 – 34.4 3.6 Predorsal length 40.3 42.1 40.3 – 43.8 3.0 Preanal length 59.6 66.3 59.5 – 73.1 7.2 Body depth 36.4 36.2 34.4 – 37.9 1.7 Depth of caudal peduncle 11.9 11.6 10.7 – 12.4 2.3 Length of caudal peduncle 15.2 15.7 15.1 – 16.3 2.6 Body width 15.0 12.9 10.7 – 15.1 2.1 Snout length 9.8 8.1 6.3 – 9.9 1.6 Eye diameter 10.2 10.3 9.9 – 10.7 3.1 Interorbital width 9.5 10.5 9.4 – 10.7 2.5 Length of dorsal-fin base 49.2 49.7 49.0 – 50.3 1.6 Length of anal-fin base 32.4 32.1 31.4 – 32.8 0.8 Length of pelvic-fin spine 15.1 15.7 15.1 – 16.3 2.6 Length of pectoral fin 21.0 20.3 18.7 – 21.8 6.7 Length of upper caudal-fin lobe 27.7 27.1 22.8 – 31.4 3.6 Length of median caudal-fin rays 10.5 10.5

Parambassis bistigmata, a new species of glassperch from north-eastern India (Teleostei: Ambassidae)

diagnosis

Diagnosis. Parambassis bistigmata is distinguished from all its congeners by presence of two distinct black spots on either side of the anal-fin origin, connected by a narrow black curved line; a well developed pre-orbital edge with prominent, acute spines, partially obscuring the maxilla; dorsal and ventral side of caudal peduncle each with a black longitudinal stripe; and the presence of a vague, faint, vertically-elongate humeral spot.

Parambassis bistigmata, a new species of glassperch from north-eastern India (Teleostei: Ambassidae)

distribution

Distribution. Parambassis bistigmata is known from the type locality, in the Ranga River, Arunachal Pradesh, Brahmaputra drainage and in Umtrao River, Brahmaputra drainage, Meghalaya State, northeast India (Fig. 4).

Parambassis bistigmata, a new species of glassperch from north-eastern India (Teleostei: Ambassidae)

etymology

Etymology. The species name alludes to the two distinct black spots at either side of the anal fin origin; it is formed as a noun.

Parambassis bistigmata, a new species of glassperch from north-eastern India (Teleostei: Ambassidae)