Candonopsis tenuis (Brady, 1886)

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 : 2906-2907

Candonopsis tenuis (Brady, 1886)

( Figures 26C,D and 24 )

Candona tenuis: Brady, 1886

Candonopsis tenuis comb. nov.: Sars, 1896

Remarks

The Japanese specimens very closely match the redescription of C. tenuis from Australia provided by Karanovic and Marmonier (2002). Two small differences include the absence of a spine on the Ga claw of the UR (present in the Australian specimens) and a slightly more projecting b lobe on the Hp (not so prominent in the Australian specimens). Candonopsis sumatrana Klie, 1932 has a reduced spine on the Ga claw, and so in this respect is most similar to the Japanese specimens. However, although the taxonomy of the genus Candonopsis has relied heavily on the presence or absence of the spines on the UR claws, Karanovic and Marmonier (2002) highlighted that the spines are not a stable feature and can vary within a species. Furthermore, C. tenuis has a more elongate female carapace with a less strongly arched dorsal margin than C. sumatrana , although in the latter the curvature of the dorsal margin seems variable.

Previously, one representative of this genus was reported in Japan, Candonopsis kingsleii (Brady and Robertson, 1870) by Okubo (2004) in ponds and rice fields. Candonopsis kingsleii has a very similar carapace shape in lateral view to C. tenuis , but in dorsal view the former is more pointed towards the anterior. Other differences include a shorter L7 h2 seta in C. kingsleii and slight differences in the appearances of the male L5 and Hp as well as a UR lacking spines on both claws.

In Lake Biwa C. tenuis was found in the littoral zone of the Karasuma Hanto, especially in very shallow, muddy habitats along the lakeshore down to a depth of 0.5 m. Localities 81 and 84 in Figure 1 .

Figures

Figure 1. Location of Lake Biwa and sampling localities.

Figure 24. (A–I) Candonopsis tenuis. (A) Male left valve, internal view (LBM 1430003336); (B) female left valve, internal view (LBM 1430003337); (C) distal section of male An2 (LBM 1430003336); (D) distal section of female An2 (LBM 1430003337); (E) right male L5 palp (LBM 1430003336); (F) left male L5 palp (LBM 1430003336); (G) L7 (LBM 1430003336); (H) UR (LBM 1430003336); (I) Hp (LBM 1430003336).

Figure 26. (A, B) Pseudocandona abei sp. nov. (A) Female, whole carapace, right lateral view (LBM 1430003331); (B) female, whole carapace, dorsal view, anterior to right (LBM 1430003331). (C, D) Candonopsis tenuis. (C) Male, whole carapace, right lateral view (LBM 1430003334); (D) female, whole carapace, right lateral view (LBM 1430003335). (E–G) Cypria matzkeae sp. nov. (E) Whole carapace, right lateral view (LBM 1430003338); (F) whole