Ostracod Research at the Lake Biwa Museum, Japan

Robin James Smith

Genus Ilyocypris Brady & Norman, 1889

Superfamily: Cypridoidea Baird, 1845
Family: Ilyocyprididae Kaufmann, 1900
Subfamily: Ilyocypridinae Kaufmann, 1900

Seven species have been reported from Korea:

1. Ilyocypris bradyi Sars, 1890

Figures in: Meisch 2000, Karanovic & Lee 2013.
Habitat: Stream with sand and gravel substate (Karanovic & Lee 2013). Elsewhere, reported from springs, the slow-flowing runoff of springs, and ponds fed by springs, as well as ponds, gravel pits, rivers, swamps and lakes (Meisch 2000).
Mode of life: Benthic.
Reproduction mode: Sexual in Korea, asexual elsewhere.
Known distribution: North Gyeongsang Province (Karanovic & Lee 2013). Generally, Holarctic (Meisch 2000).
Notes: Only two adult males have been reported from Korea (other specimens were juveniles) (Karanovic & Lee 2013). Elsewhere, only females are known.
References:
⚬ Karanovic I., & Lee, W. 2013. On the ostracod genus Ilyocypris, with description of one new species from Korea and the first report of males of I. bradyi (Crustacea: Ostracoda: Podocopida). Proceedings of the Biological Society of Washington, 126, 39-71.
⚬ 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.


2. Ilyocypris dentifera Sars, 1903

Figures in: Sars 1903; Victor & Fernando 1981; Smith et al. 2019.
Habitat: Often found in ricefields, but also in temporary pools.
Mode of life: Nektobenthic (swimmer).
Reproduction mode: Sexual.
Known distribution: Gyeongsangbuk-do, Korea (Smith et al. 2019). Elsewhere Japan, China, and the Philippines (see Smith et al. 2019).
References:
⚬ Sars, G.O. 1903. Fresh-water Entomostraca from China and Sumatra. Archiv for Mathematik og Naturvidenskab, 25, 3-44.
⚬ Smith, R. J., Zhai, D. & Chang, C. Y. 2019. Ilyocypris (Crustacea: Ostracoda) species in North East Asian rice fields; description of one new species, and redescriptions of Ilyocypris dentifera Sars, 1903 and Ilyocypris japonica Okubo, 1990. Zootaxa, 4652, 56-92.


3. Ilyocypris hanguk Karanovic & Lee, 2013

Figures in: Karanovic & Lee 2013
Habitat: Stream with clay substrate and submerged water plants.
Mode of life: Nektobenthic (swimmer).
Reproduction mode: Sexual.
Known distribution: South Jeolla Province (Karanovic & Lee 2013). Currently only known from South Korea.
References:
⚬ Karanovic I., & Lee, W. 2013. On the ostracod genus Ilyocypris, with description of one new species from Korea and the first report of males of I. bradyi (Crustacea: Ostracoda: Podocopida). Proceedings of the Biological Society of Washington, 126, 39-71.


4. Ilyocypris incus Smith et al., 2019

Figures in: Smith et al. 2019
Habitat: Rice fields
Mode of life: Nektobenthic (swimmer).
Reproduction mode: Sexual.
Known distribution: Gyeongsangbuk-do, Korea. Elsewhere, Japan (Smith et al. 2019).
References:
⚬ Smith, R. J., Zhai, D. & Chang, C. Y. 2019. Ilyocypris (Crustacea: Ostracoda) species in North East Asian rice fields; description of one new species, and redescriptions of Ilyocypris dentifera Sars, 1903 and Ilyocypris japonica Okubo, 1990. Zootaxa, 4652, 56-92.


5. Ilyocypris japonica Okubo, 1990

External view of male left valve of Ilyocypris japonica, length 784 microns.

External view of male right valve of Ilyocypris japonica, length 769 microns.

The male sexual organ of Ilyocypris japonica, length 204 microns.

Additional figures in: Okubo 1990; 2004; Smith et al. 2019.
Habitat: Rice fields.
Mode of life: Nektobenthic (swimmer).
Reproduction mode: Sexual.
Known distribution: Gyeongsangbuk-do, Gyeongsangnam-do, Korea. Elsewhere, Japan (Smith et al. 2019).
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, 72 pp. [In Japanese, privately published]
⚬ Smith, R. J., Zhai, D. & Chang, C. Y. 2019. Ilyocypris (Crustacea: Ostracoda) species in North East Asian rice fields; description of one new species, and redescriptions of Ilyocypris dentifera Sars, 1903 and Ilyocypris japonica Okubo, 1990. Zootaxa, 4652, 56-92.


6. Ilyocypris salebrosa Stepanaitys, 1960

Right side view of a female Ilyocypris salebrosa, length about 0.95 mm.

External view of female left valve of Ilyocypris salebrosa, length 964 microns.

External view of female right valve of Ilyocypris salebrosa, length 962 microns.

The male sexual organ of Ilyocypris salebrosa, length 209 microns.

Additional figures in: Smith et al. 2011
Habitat: Lakes
Mode of life: Nektobenthic (swimmer).
Reproduction mode: Sexual in Japan (Smith et al. 2011). Males have not be reported from other areas.
Known distribution: East coast of South Korea (Lee et al. 2000). Outside of Korea reported from Japan (Smith et al. 2011; Schornikov 2004), China (Mischke 2001), Turkey (Özulug 2005), Italy (Rossetti 2006), and Canada (Delorme 1970 as Pelocypris alatobulbosa).
References:
⚬ Delorme, L.D. 1970. Freshwater ostracodes of Canada. Part IV. Families Ilyocyprididae, Notodromadidae, Darwinulidae, Cytherideidae, and Entocytheridae. Canadian Journal of Zoology, 48, 1251-1259.
⚬ Lee, E., Huh, M. & Schornikov, E. I. 2000. Ostracod fauna from the East Sea coast of Korea and their distribution - preliminary study on Ostracoda as an indicator of water pollution. Journal of the Geological Society of Korea, 36, 435-472. [In Korean with English abstract.]
⚬ Mischke, S. 2001. Mid and Late Holocene palaeoenvironment of the lakes Eastern Juyanze and Sogo Nur in NW China, based on ostracod species assemblages and shell chemistry. Berliner Geowissenschaftliche Abhandlungen E 35, 1-131.
⚬ Özulug, O. 2005. Living specimens of Ilyocypris salebrosa Stepanaitys, 1959 (Crustacea: Ostaracoda) from Thrace, Turkey. Zoology in the Middle East, 34, 114-116.
⚬ Rossetti, G., Martens, K., Meisch, C., Tavernelli, S. & Pieri, V. 2006. Small is beautiful: diversity of freshwater ostracods (Crustacea, Ostracoda) in marginal habitats of the province of Parma (Northern Italy). Journal of Limnology, 65, 121-131.
⚬ Schornikov, E. 2004. Crustacea: Ostracoda. In: Tyurin, A.N. & Drozdov, A.L. (Eds), Far-Eastern Marine Biospherical Reserve. Biota. V. 2, Vladivostok, pp. 458-465. [In Russian].
⚬ 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.


7. Ilyocypris subpulchra Yang, 1982

Figures in: Yang 1982
Habitat: Unknown.
Mode of life: Unknown.
Reproduction mode: Unknown.
Known distribution: East Coast of South Korea (Lee et al. 2000). Elsewhere, China (Yang 1982).
References:
⚬ Lee, E., Huh, M. & Schornikov, E. I. 2000. Ostracod fauna from the East Sea coast of Korea and their distribution - preliminary study on Ostracoda as an indicator of water pollution. Journal of the Geological Society of Korea, 36, 435-472. [In Korean with English abstract.]
⚬ Yang, 1982. Cretaceous-Quaternary ostracode fauna from Jiangsu. Geological Publishing House, Peking, 1-386. [In Chinese]