Bathynomus sp.

Huang, Ming-Chih, Kawai, Tadashi & Bruce, Niel L., 2022, A new species of Bathynomus Milne-Edwards, 1879 (Isopoda: Cirolanidae) from the southern Gulf of Mexico with a redescription of Bathynomus jamesi Kou, Chen and Li, 2017 from off Pratas Island, Taiwan, Journal of Natural History 56 (13 - 16), pp. 885-921 : 902-903

Bathynomus sp.

Material

TMCD 003326 and TMCD 003334

One ovigerous female, collected by bottom trawl in the northern South China Sea between North Vereker Bank (221.061°N, 116.109°E) and Pratas Island (20.717°N, 116.700°E) by the crew of Keelung-based fishing vessel Jin Ruiyi 37 on 17 June 2019 ( Figure 1 ) voucher numbers TMCD003326 . One male, captured in waters of the South China Sea (19.084°N, 115.250°E) by the crew of Keelung-based fishing vessel Jing yang on 12 May 2020; the water depth was about 420–550 m, TMCD003334 . TL 309 and 356 mm, CL 150 and 173 mm, wet weight 1100 and 1600 g, respectively ( Table 1 ).

Remarks

Two apparently sympatric species of Bathynomus are present in the material examined. Both of these had been identified as Bathynomus jamesi (Kou, Chen and Li, 2017) ; that identification was confirmed by COI data (NCBI Acc. No. MW575424 and MW577652 ).

The second apparent species, while having the same clypeus and pleonite characters as B. jamesi , differs from B. jamesi s. str. in a number of significant characters (state of B. jamesi in parentheses): the body is slender, with the pereon lateral margins relatively straight (vs convex); the pleotelson is 0.70 times as long as wide (vs 0.42–0.56); the pleotelson spines are flat and proximally broad (vs round, proximally narrow). These morphological character differences would be considered indicative of a separate species, but at present we are unable to discern further differentiating characters. Furthermore, COI data indicates that this material is conspecific with the South China Sea material identified as B. jamesi . At present we regard the identity of these specimens as inconclusive, and prefer to exclude the material from B. jamesi until further specimens are available to either evaluate variation within B. jamesi or confirm that the material represents a distinct species.

Figures

Figure 1. Map of Taiwan, Pratas Island and Hainan. The sampling site of Bathynomus kensleyi of Lowry and Dempey (2006) is between North Vereker bank and Pratas Island, indicated by an open square (□), and the Bathynomus kensleyi of Lowry and Dempey (2006) sampling site is indicated by a black square (■) (Lowry and Dempsey 2006). The black triangle (▲) indicates the sampling site of Bathynomus jamesi from Kou et al. 2017.