Ostracod Research at the Lake Biwa Museum, Japan

Robin James Smith

Genus Bradleytriebella Savatenalinton & Martens, 2009

Superfamily: Cypridoidea Baird, 1845
Family: Cyprididae Baird, 1845
Subfamily: Cypricercinae McKenzie, 1971

Two species have been reported from Japan:

1. Bradleytriebella lineata (Victor & Fernando, 1981)

Dorsal view of a female Bradleytriebella lineata, anterior to the right. Length about 0.6 mm.

External view of a female left valve of Bradleytriebella lineata, length 619 microns. The surface of the valves are covered in striations, reminiscent of a fingerprint.

External view of a female right valve of Bradleytriebella lineata, length 601 microns.

Additional figures in: Victor & Fernando 1981; Okubo 2004 (as Strandesia biwaensis sp. nov.); Savatenalinton & Martens 2010; Smith et al. 2011; Ishii et al. 2017.
Habitat: Shallow areas of Lake Biwa, especially on sandy substrates near water plants. Outside of Japan known from reservoirs, rice fields, canals, swamps, springs, ponds and ditches.
Mode of life: Nektobenthic (swimmer).
Reproductive mode: Asexual, males unknown.
Known distribution: Lake Biwa, Shiga Prefecture (Okubo 2004; Smith et al. 2011), Akita Prefecture (Ishii et al. 2017). Elsewhere, Philippines (Victor & Fernando 1981 as Strandesia lineata), Sudan (Martens 1984, as Paracypretta amati) and Thailand (Savatenalinton and Martens 2010).
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]
⚬ Martens, K. 1984. On the freshwater ostracods (Crustacea, Ostracoda) of the Sudan, with special reference to the Red Sea Hills, including a description of a new species. Hydrobiologia, 110, 137-161.
⚬ Okubo, I. 2004. Nihon tansui san kaimijinko rui ni tsuite. Kabushikigaisha Sanmon Insatsusho, Okayama, Japan, 72pp. [In Japanese, privately published].
⚬ Savatenalinton, S. & Martens, K. 2010. On the subfamily Cypricercinae McKenzie, 1971 (Crustacea, Ostracoda) from Thailand, with the description of six new species. Zootaxa, 2379, 1-77.
⚬ 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.
⚬ Victor, R. & Fernando, C.H. 1981. Freshwater ostracods (Crustacea: Ostracoda) of the genus Strandesia Vavra, 1895 from Malaysia, Indonesia and the Philippines. Archiv für Hydrobiologie, Supplementband, 58, 469-522.


2. Bradleytriebella tuberculata (Hartmann, 1964)

Dorsal view of a female Bradleytriebella tuberculata, anterior to the right. Length about 0.7 mm. This species typically has two tubercles (bumps) on the carapace in the areas marked with white triangles, giving an angular appearance in dorsal view. However, in some populations these tubercles are weakly expressed or absent (as with this specimen).

External view of a female left valve of Bradleytriebella tuberculata, length 740 microns. The surface of the valves are covered in striations.

External view of a female right valve of Bradleytriebella tuberculata, length 710 microns.

Additional figures in: Okubo 1990; Okubo 2004; Savatenalinton & Martens 2009.
Habitat: Seep next to a stream (Smith et al. 2014). Elsewhere, known from rice fields (Okubo 1990; Savatenalinton & Martens 2009).
Mode of life: Nektobenthic (swimmer).
Reproductive mode: Asexual, males unknown.
Known distribution: Jeju Island (Smith et al. 2014). Elsewhere reported from Japan (Okubo 1990), India (Hartmann 1964), Thailand (Savatenalinton & Martens 2009), and Taiwan (Yu et al. 2009).
References:
⚬ Hartmann, G. 1964. Asiatische Ostracoden, systematische und zoogeographische Untersuchungen. Internationale Revue der Gesamten Hydrobiologie, Systematische Beihefte, 3, 1-155.
⚬ 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].
⚬ Savatenalinton, S. & Martens, K. 2009a. Generic revision of Cypricercinae McKenzie, 1971 (Crustacea, Ostracoda), with the description of three new genera and one new species and a phylogenetic analysis of the subfamily. Hydrobiologia, 632, 1-48.
⚬ Smith, R. J., Lee, J., & Chang, C. Y. 2014. Nonmarine Ostracoda (Crustacea) from Jeju Island, South Korea, including descriptions of two new species. Journal of Natural History, http://dx.doi.org/10.1080/00222933.2014.946110, 1-40.
⚬ Yu, N., Zhao, Q., Li, E., Chen, S. & Chen, L. 2009. An updated and annotated checklist of recent nonmarine ostracods from China. Zootaxa, 2067, 29-50.