Ostracod Research at the Lake Biwa Museum, Japan

Robin James Smith

Genus Cypridopsis Brady, 1867

Superfamily: Cypridoidea Baird, 1845
Family: Cyprididae Baird, 1845
Subfamily: Cypridopsinae Kaufmann, 1900

Three species have been reported from Japan:

1. Cypridopsis nigrovittata Okubo, 1990

Figures in: Okubo 1990; Okubo 2004.
Habitat: Irrigations ponds and rice fields (Okubo 2004).
Mode of life: Nektobenthic (swimmer).
Reproductive mode: Asexual.
Known distribution: Okayama Prefecture (Okubo 1990), Okinawa Prefecture (Okubo & Terauchi 1992). Elsewhere reported from China (Yu et al. 2005; 2008; 2010)
References:
⚬ Okubo, I. 1990. Sixteen species of freshwater Ostracoda from Japan. Bulletin of the Biogeographical Society of Japan, 45, 39-50.
⚬ Okubo, I. 2004. Nihon tansui san kaimijinko rui ni tsuite. Kabushikigaisha Sanmon Insatsusho, Okayama, Japan, 72pp. [In Japanese, privately published].
⚬ Okubo, I. & Terauchi, M. 1992. Freshwater Ostracoda from the Southwestern Islands of Japan. Proceedings of the Japanese Society for Systematic Zoology, 46, 101-108.
⚬ Yu, N., Chen, L. & Zhao, Q. 2008. On abundance and biomass of ostracods in Tai Lake. Resources and Environment in the Yangtze Basin, 17 (4), 546–550. [In Chinese with English abstract]
⚬ Yu, N., Zhao, Q. & Chen, X. 2010. New records of freshwater Ostracoda from Dianchi Lake, Yunnan Province, SW China. Acta Micropalaeontologica Sinica, 27 (4), 344–350. [In Chinese with English abstract]
⚬ Yu, N., Zhao, Q., Schornikov, E. L. & Chen, L. 2005. Recent ostracods from Taihu Lake. Acta Micropalaeontologia Sinica, 22 (2), 143–151. [In Chinese with English abstract]

2. Cypridopsis uenoi Brehm, 1933

Figures in: Ueno 1965.
Habitat: Pools and rice fields.
Mode of Life: Nektobenthic (swimmer).
Reproductive Mode: Asexual?
Distribution: Nagano Prefecture (Brehm 1933), throughout Honshu (Ueno 1965).
Remarks: This species was last reported by Ueno (in Ueno & Hanai 1965), who stated it was found in rice fields and pools throughout Honshu, the main island of Japan. The type specimens are lost (McKenzie, 1972).
References:
⚬ Brehm, V. 1933. Einige japanische Ostracoden. Transactions of the Natural History Society of Formosa, 23, 297-298.
⚬ McKenzie, K. G. 1972. Results of the speleological survey in South Korea 1966. XXII. Subterranean Ostracoda from South Korea. Bulletin of the National Science Museum, Tokyo, 15, 155-166.
⚬ Ueno, M. & T. Hanai. 1965. Ostracoda. In K. Okada et al. New illustrated encyclopedia of the fauna of Japan (Vol. 11). Hokuryukan, Tokyo, p. 453-456, figs. 416-427 (in Japanese).

3. Cypridopsis vidua (O. F. Müller, 1776)

Dorsal view of a female Cypridopsis vidua, length 0.6 mm. Anterior to the right. The patches of colouration are very variable, ranging from dark purple/black through to light green. Specimens with no colouration are also known.

External view of female left valve of Cypridopsis vidua, length 645 microns. The surface of the valves are often pitted (punctate) and covered with stiff setae.

External view of female right valve of Cypridopsis vidua, length 640 microns.

Additional figures in: Meisch 2000; Okubo 2004; Smith et al. 2011; Ishii et al. 2017.
Habitat: Found in a wide variety of habitats. In Japan found in lakes, ponds, and rice fields.
Mode of Life: Nektobenthic (swimmer).
Reproductive Mode: Asexual, males unknown (although see Meisch 2000, p. 377).
Distribution: Shiga Prefecture (Smith et al. 2011), Shizuoka Prefecture (Tanaka et al. 2015), Akita Prefecture (Ishii et al. 2017). Elsewhere found globally, a cosmopolitan species (Meisch 2000).
References:
⚬ Ishii, T., Suzuki, A. & Tanaka, H. 2017. First report of distribution and occurrence of freshwater Ostracoda from Lake Hachiro in Akita Prefecture. Memoirs of the Faculty of Education and Human Studies Akita University (Natural Science), 72, 1-7. [In Japanese with English abstract]
⚬ Meisch, C. 2000. Freshwater Ostracoda of Western and Central Europe. In: Schwoerbel, J., Zwick, P., (Eds.), Süßwasserfauna von Mitteleuropa 8/3. Spektrum Akademischer Verlag, Heidelberg, Berlin 522 pp.
⚬ Okubo, I. 2004. Nihon tansui san kaimijinko rui ni tsuite. Kabushikigaisha Sanmon Insatsusho, Okayama, Japan, 72pp. [In Japanese, privately published].
⚬ Smith, R. J., Janz, H. & Okubo, I. 2011. Recent Cyprididae and Ilyocyprididae (Crustacea: Ostracoda) from Lake Biwa, Japan, including a summary of the lake's ostracod fauna. Zootaxa, 2874, 1-37.
⚬ Tanaka, H., Kotorii, H., Yokozawa, K., Wakabayashi, F., Kimoto, K. & Sano, K. 2015. Distribution and occurrence of freshwater Ostracoda (Crustacea) from southwest region of Mt. Fuji. TAXA, Proceedings of the Japanese Society of Systematic Zoology, 38, 26-41. [In Japanese with English abstract.]