A new species of Stygiopontius (Copepoda, Siphonostomatoida, Dirivultidae) from a deep-sea cold seep in the South China Sea

A new species of the copepod genus Stygiopontius is described based on samples from a cold seep in northeastern South China Sea southwest to Taiwan, which were collected by the ROV Faxian with its mother vessel R/V Kexue in September 2017. The copepods were obtained by washing Shinkaia crosnieri Baba & Williams, 1998 (Decapoda: Munidopsidae) caught at a depth of 1124 m. The new species can be distinguished from its congeners by the combination of the following characteristics: caudal rami about 3.5 times as long as wide; basis of maxilliped with plumose seta, endopodal claw of maxilliped stout, with a row of fine spinules on inner margin; coxa of leg 1 with one inner seta; basis of leg 1 with stout spine exceeding to end of first endopodal segment; second endopodal segment of female leg 4 with pointed process; third exopodal segment of leg 4 with three outer spines. This is the first record of a Stygiopontius species from a cold seep.