Yirrkala altiusculodorsalis sp. nov., a New Species from South China Sea

Abstract

A rare Indo-pacific snake-eel genus, Yirrkala, of tribe Sphagebranchini, subfamily Ophichthinae, family Ophichthidae, has 16 former species and 1 new species described in this article. Albeit it has such a great number of species, it is still known as “lack-description genus”, given that many species provisionally belong to this genus is still remain in opaque in status, whether belongingness or validity. The new species is under this genus according to its absent pectoral fins and dorsal fin, very elongated body, fragile dorsal fin and anal fin, dorsal fin origin posterior to rictus, posterior nares within mouth, short tubular anterior nares, and two preopercular pores, intermaxillary teeth present out of restriction of mandible. And it is unique in dorsal-fin length greater than half of maximum body height, dorsal-fin origin anterior to gill opening, body not patterned, median groove exceeding anterior-naris base. The difference between Yirrkala misolensis and Yirrkala maculata is reviewed. An overview of this genus is provided, and a key for distinguishing the species in this genus is also given.