New species of the eel genera Dysomma and Dysommina from Vietnam, South China Sea (Anguilliformes: Synaphobranchidae).

Two new cutthroat eel species are described from Vietnam. Dysomma intermedium sp. nov. has a relatively long trunk, being about half of head length and anal-fin origin more than twice pectoral-fin length behind the pectoral-fin tip; pectoral fin well developed; dorsal-fin origin over or slightly in front of base of pectoral fin; two intermaxillary teeth; four or five compound teeth on ethmovomer; single row of seven or eight teeth on lower jaw; total lateral-line pores 70-76; and 21 pre-anal and 118-124 total vertebrae. Dysommina brevis sp. nov. differs from congeners by having a trunk shorter than head length, its length 11.1%-11.8% TL; a short pre-anal length 24.6%-25.6% TL, eye diameter 11.8%-12.3% head length; three large and one or two small teeth on ethmovomer; and fewer teeth on the upper and lower jaws. In addition, a specimen representing the first record of Dysommina orientalis in Vietnamese water is documented.