Physocypria biwaensis ( Okubo, 1990 )

Smith, Robin J. & Janz, Horst, 2008, Recent species of the Family Candonidae (Ostracoda, Crustacea) from the ancient Lake Biwa, Central Japan, Journal of Natural History 42 (45 - 46), pp. 2865-2922 : 2916

Physocypria biwaensis ( Okubo, 1990)

( Figures 31 and 32 D–I)

Cypria biwaensis Okubo 1990

Remarks

This was the first species of ostracod to be recorded from Lake Biwa (as Cypria biwaensis ) by Okubo (1990). Physocypria biwaensis is abundant in Lake Biwa, found at depths ranging from 0.1 to 87.4 m. It shows a relatively high variation in the carapace shape, with some specimens notably more elongate than other specimens of the same sex, and variable patterns of colour patches on the carapace. However, it is not possible to confidently divide the specimens into two discrete species by carapace morphology, as there appears to be a range of morphologies from one type to the other. Additionally, examination of the appendages, in particular the male sexual organs and L5 palps, do not show any differences to warrant separation of the two types. Wide intraspecific variation of other Physocypria species, in particular Ph. kraepelini , is well documented (e.g. Meisch 2000), so would not be unusual for Ph. biwaensis , although we cannot rule out at this stage the possibility that there maybe two or more cryptic species in the lake. Localities 1–6, 8, 10–16, 19, 20, 22–35, 37–40, 42–45, 47–49, 51, 54–57, 59, 61–64, 66–74, 83, 85–89, 91 and 92 in Figure 1 .

Figures

Figure 1. Location of Lake Biwa and sampling localities.

Figure 31. Physocypria biwaensis. (A) Whole carapace, right lateral view (LBM 1430003346); (B) whole carapace, left lateral view (LBM 1430003347); (C) whole carapace, dorsal view, anterior to left (LBM 1430003348); (D) whole carapace, right lateral view (LBM 1430003349); (E) whole carapace, left lateral view (LBM 1430003350); (F) whole carapace, dorsal view, anterior to left (LBM 1430003351); (G) whole carapace, right lateral view (LBM 1430003352); (H) whole carapace, left lateral view (LBM 1430003353); (I) whole carapace, dorsal view, anterior to left (LBM 1430003354). Scale bar below H represents 329 Mm.

Figure 32. (A–C) Physocypria nipponica. (A) Hp (LBM 1430003345); (B) male left L5 palp (LBM 1430003345); (C) male right L5 palp (LBM 1430003345); (D–I) Physocypria biwaensis. (D) Hp (LBM 1430003355); (E) male left L5 palp (LBM 1430003355); (F) male right L5 palp (LBM 1430003356); (G) Hp (LBM 1430003356); (H) male left L5 palp (LBM 1430003356); (I) male right L5 palp (LBM 1430003356).