Bathycongrus bimaculatus

discussion

Remarks. Newly described in this volume by Smith & Ho (2018 a). This species is only found in southwestern Taiwan off Dong-gang; collected by bottom trawl.

Checklist of eels of Taiwan (orders Anguilliformes and Saccopharyngiformes): An update

description

Description. Proportional measurements and meristic data are provided in Tables 1 – 6. Head length 2.3 (2.3 – 2.5) in PAL, 6.5 (6.5 – 7.0) in TL; preanal length 2.8 (2.7 – 2.8) in TL; predorsal length 2.0 (2.0 – 2.2) in PAL, 5.7 (5.6 – 5.8) in TL; trunk length 1.8 (1.7 – 1.8) in PAL, 5.0 (4.5 – 5.0) in TL; tail length 1.5 (1.5 – 1.6) in TL; depth at head 5.8 (5.5 – 6.7) in PAL, width at head 9.9 (8.4 – 9.9) in PAL. Snout length 4.2 (3.9 – 4.3) in HL; eye diameter 5.8 (4.6 – 5.7); interorbital width 6.6 (6.3 – 7.5); upper jaw 2.8 (2.7 – 2.8); gill opening width 8.4 (7.8 – 9.8); interbranchial width 4.5 (3.9 – 5.1); pectoral-fin length 3.6 (2.7 – 3.6). Body moderately elongate, laterally compressed through the entire length, oval in cross section, becoming more compressed posteriorly; head relatively large, its length 1.3 (1.3 – 1.5) times in trunk length; tip of tail moderately attenuate; anus slightly behind anterior third of total length. Dorsal fin begins over middle of appressed pectoral fin, continuous around tip of tail with caudal and anal fins. Anal fin begins immediately behind anus. Pectoral fin well developed, pointed distally with a narrow base. Gill opening relatively s

The congrid eel genus Bathycongrus of Taiwan, with descriptions of three new species (Anguilliformes: Congridae)

diagnosis

Diagnosis. A small, moderately elongate species of Bathycongrus with head and body compressed; pale color with two black patches on anterior portion of dorsal fin; tail slender, attenuate, though not filiform; trunk length 1.3 – 1.5 times HL; teeth small, conical, in about four rows on jaws, in a short oval patch on vomer; preanal vertebrae 27 – 30, precaudal vertebrae 35 – 37, total vertebrae 109 – 111; and preanal lateral-line pores 27 – 29.

The congrid eel genus Bathycongrus of Taiwan, with descriptions of three new species (Anguilliformes: Congridae)

discussion

Remarks. Bathycongrus bimaculatus belongs to the species group with low vertebral counts (109 – 137), a cluster of small teeth on vomer, and relatively small body size, comprising B. bleekeri, B. unimaculatus, B. trimaculatus and B. parviporus. It differs from above-mentioned species in having relatively few total vertebrae (109 – 111, vs. 113 – 120 or 137 in the other species). Among these species, B. bimaculatus is most similar to B. trimaculatus but can be easily separated by the lack of a black blotch on anal fin (vs. a large black blotch on the fin) and 109 – 111 total vertebrae (vs. 117 – 119). Table 6 shows the selected characters for comparison of these species.

The congrid eel genus Bathycongrus of Taiwan, with descriptions of three new species (Anguilliformes: Congridae)