Dysomma polycatodon

diagnosis

Diagnosis. Pectoral fin present; dorsal-fin origin anterior tolevel of pectoral fin base, predorsal length 10.0 – 12.9 % TL; anus anterior, just below pectoral fin, preanal length 15.5 – 18.2 % TL; trunk very short, trunk length 2.4 – 3.9 % TL; 2 intermaxillary teeth; 3 compound teeth on vomer; 3 or 4 rows of small sharp teeth on upper jaw; single row of 2 large anterior teeth followed by 22 – 31 small sharp teeth on lower jaw; head pores: IO 4, SO 3, M 6, POP 0 (1 with 1), AD 1 (1 with 0); lateral-line pores: predorsal 3 – 5, prepectoral 5 – 7, preanal 8 – 11, and total 65 – 78, the last at about anterior two-thirds of total length; MVF 8 - 13 - 130, total vertebrae 128 – 133 (1 with 120). Body light grayish to brown dorsally, paler ventrally; posterior half of anal-fin base deep brown, and dorsal and anal fins with white margins.

Review of the arrowtooth eel genera Dysomma and Dysommina in Taiwan, with the description of a new species (Anguilliformes: Synaphobranchidae: Ilyophinae)

discussion

Remarks. The holotype of this species, collected off Madagascar, has 140 vertebrae (Karrer, 1983), significantly more than the specimens from Taiwan (128 – 133). One of two specimens in NMMB-P 18040 has only 120 total vertebrae. However, no other difference can be observed and the vertebrae appear to be complete. This specimen may represent a different species when more specimens are available.

Review of the arrowtooth eel genera Dysomma and Dysommina in Taiwan, with the description of a new species (Anguilliformes: Synaphobranchidae: Ilyophinae)

discussion

Remarks. A common species collected by bottom trawl from northeastern and southwestern Taiwan, but not as abundant as D. anguillare.

Annotated checklist of eels (orders Anguilliformes and Saccopharyngiformes) from Taiwan

Dysomma polycatodon Karrer 1983

Dysomma polycatodon Karrer, 1983 Dysomma polycatodon Karrer 1983: 89, Figs. 27A–B. Holotype: MNHN 1979-0003. Type locality: Indian Ocean off NW Madagascar, 15° 21’ S, 46° 11’ E, 170–175 m.

Redescription of the eel Ilyophis arx Robins, 1976 (Anguilliformes: Synaphobranchidae: Ilyophinae) with a description of a new species of Ilyophis, and a taxonomic synopsis of the Ilyophinae