Danionella priapus

description

Description. Morphometric information, based on 15 specimens, is presented in Table 1. Known maximum size 16.0 mm SL. Head and eye large, mouth supraterminal (Fig. 1). Body laterally compressed, elongate; dorsal fin short, situated opposite posterior half of long anal fin. Caudal fin furcate, with remnants of larval fin fold in front of its dorsal and ventral margins. Remnant of pre-anal larval fin fold present in females only (Fig. 1 b). Anus and genital papilla of adult males located between pelvic fins, in females at normal position in front of anal fin. Genital opening of adult males located at tip of short, conical projection at proximal end of funnel-like structure formed by pelvic fins being fused along their midline (Figs. 1 a, 2). Pseudotypanum present in body musculature at lateral side of anterior gas-bladder chamber, rendering its pigmented surface visible (Fig. 1). Body muscles greatly thinned out at lateral side of posterior gas bladder chamber. Scales absent. Lateral-line canals and pores on head and body absent. Skull, hyopalatine arch, gill arches, and endoskeletal shoulder girdle mostly cartilaginous with perichondral ossifications giving skeleton overall larval a

Danionella priapus, a new species of miniature cyprinid fish from West Bengal, India (Teleostei: Cypriniformes: Cyprinidae)

diagnosis

Diagnosis. Danionella priapus is distinguished from its congeners, D. dracula, D. translucida and D. mirifica, by the presence in adult males of a conical projection of the genital papilla situated between the pelvic fins, which form a funnel-like structure (vs. genital papilla not developed as a conical projection and pelvic fins not funnel-shaped), by possessing 8 pectoral-fin rays (vs. 6 – 7) and 20 – 21 anal – fin rays (vs. 12 – 14 in D. dracula, 12 – 16 in D. translucida, and 17 – 19, rarely 20 in D. mirifica), and by having the last anal-fin pterygiophore inserted in front of haemal spine of vertebra 27 or 28 (vs. 21 or 22 in D. translucida, 23 – 25 in D. mirifica, and 22 – 24 in D. dracula). It differs further from D. translucida and D. mirifica in the presence of a median and two paramedian rows of pigment cells on the dorsal side of the body (vs. pigment rows absent). It is further distinguished from D. dracula and D. mirifica by 7 – 8 dorsal caudal procurrent rays (vs. 5 – 6) and 6 – 8 ventral procurrent rays (vs. 4 – 5). In addition it differs from D. dracula in having two upper jaw bones (vs. one); edges of jaw bones entire, without processes (vs. dorsal face of dentary

Danionella priapus, a new species of miniature cyprinid fish from West Bengal, India (Teleostei: Cypriniformes: Cyprinidae)

distribution

Distribution. The species is known only from the type locality, Jorai River in West Bengal, India (Fig. 5).

Danionella priapus, a new species of miniature cyprinid fish from West Bengal, India (Teleostei: Cypriniformes: Cyprinidae)

etymology

Etymology. The species name priapus is derived from the greek ρίαπος, the god of fertility of Greek mythology. It was inspired by the conical projection of the genital papilla in males, which — at a superficial level — is reminiscent of the penis of mammals. A noun in apposition. Holotype Paratypes Male Males Females Range Mean St. Dev Range Mean St. Dev Standard length (SL) 14.4 12.5 – 14.1 13.7 – 15.0 In % of SL Head length 17.4 17.4 – 20.0 18.3 0.9 19.0 – 20.7 19.8 0.7 Predorsal-fin length 70.1 68.7 – 70.4 69.4 0.7 68.7 – 71.0 70.1 0.8 Prepelvic-fin length 30.6 29.8 – 32.8 30.8 1.1 34.0 – 35.6 34.8 0.5 Preanal-fin length 52.1 51.1 – 52.1 51.5 0.4 53.3 – 54.8 54.2 0.6 Snout to anus 29.9 29.1 – 32.0 30.1 1.0 51.4 – 52.7 51.9 0.4 Body depth at dorsal-fin origin 13.2 13.1 – 15.2 14.1 0.7 14.4 – 16.0 15.4 0.5 Caudal-peduncle depth 7.6 7.5 – 8.5 8.0 0.3 7.5 – 8.9 8.0 0.5 Caudal-peduncle length 18.8 17.9 – 21.6 19.6 1.4 18.1 – 21.3 19.6 1.1 Length of dorsal-fin base 9.7 9.7 – 11.3 10.7 0.5 10.3 – 11.7 10.9 0.5 Length of anal-fin base 30.6 28.4 – 30.7 29.5 0.9 26.0 – 28.3 27.4 0.7 Length of pelvic fin 8.7 7.2 – 8.7 7.4 0.3 6.3 – 8.3 7.0 0.6 In % of HL Eye diameter 44.0 40.0 – 44.0 40.8

Danionella priapus, a new species of miniature cyprinid fish from West Bengal, India (Teleostei: Cypriniformes: Cyprinidae)