OSTRACOD RESEARCH

at the Lake Biwa Museum, Japan


Robin James Smith

  home    about ostracods    ostracod facts    checklists    key    gallery    publications   

Genus Cyprinotus Brady, 1866

Superfamily: Cypridoidea Baird, 1845
Family: Cyprididae Baird, 1845
Subfamily: Cyprinotinae Bronshtein, 1947

Two species have been reported from Japan:

1. Cyprinotus kimberleyensis McKenzie, 1966

Figures in: McKenzie 1966 (carapace and appendages); Okubo 1974 (carapace and appendages); Okubo 2004 (carapace).
Habitat: Rice fields (Okubo 1974; 1990; 2004), swamp (Okubo 1974); muddy field (Broodbakker 1988).
Mode of life: Nektobenthic (swimmer).
Reproduction mode: Asexual. Males unknown.
Known distribution: Okayama Prefecture (Okubo 1974; Okubo 1990 as Cyprinotus setoensis); Central Shikoku Island (Okubo 2004); Okinawa (Broodbakker 1988; Okubo 2004). Elsewhere, China, Taiwan (Yu et al. 2009, citing grey literature); North-western Australia (McKenzie 1966).

References:
Broodbakker, N. W. 1988. Ecology and distribution of groundwater Crustacea and freshwater Ostracoda in SW Honshu and the Nansei Islands, Japan. Verlagen en Technische Gegevens Institute voor Taxonomische Zoologie, 53, 1-21.

McKenzie, K. G. 1966. Freshwater Ostracoda from North-western Australia. Australian Journal of Marine and Freshwater Research, 17, 259-279.

Okubo, I. 1974 a. Two species of the genus Cyprinotus (Ostracoda, Cyprididae) from Japan. Researches on Crustacea, 6, 58-70.

Okubo, I. 1990a. Seven new species of freshwater Ostracoda from Japan. Researches on Crustacea, 19, 1-12.

Okubo, I. 2004. Nihon tansui san kaimijinko rui ni tsuite. Kabushikigaisha Sanmon Insatsusho, Okayama, Japan, 72pp. [In Japanese, privately published].

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.


2. Cyprinotus uenoi Brehm, 1936


Left side views of a male (top) and female Cyprinotus uenoi, male length 1.5 mm, female length 1.9 mm. Note how the right valve is higher than the left.



External view of female left valve, length 1911 microns.


External view of female right valve, length 1863 microns.



The male sexual organ of Cyprinotus uenoi, length 362 microns.


Additional figures in: Okubo 1974 (carapace and appendages); Victor & Fernando 1981 (carapace and appendages); Okubo 2004 (carapace).
Habitat: Often found in ricefields, especially abundant in the early rice-growing season in Japan. Also found in reservoirs and ponds.
Mode of Life: Nektobenthic (swimmer).
Reproduction mode: Sexual, males common.
Distribution: Okayama Prefecture, Oita Prefecture (Okubo 1974), Gunma Prefecture (Okubo & Ida 1989), and Yamaguchi Prefecture (Broodbakker 1988). Elsewhere, it has been reported from China (Brehm 1936), the Philippines (Victor & Fernando 1981) and Korea (Kim & Min 1991; Chang et al. 2012).

References:
Brehm, V. 1936. Ostrakoden aus Mandschuko. Annotationes Zoologicae Japonensis, 15, 374-377.

Broodbakker, N. W. 1988. Ecology and distribution of groundwater Crustacea and freshwater Ostracoda in SW Honshu and the Nansei Islands, Japan. Verlagen en Technische Gegevens Institute voor Taxonomische Zoologie, 53, 1-21.

Chang, C. Y., Lee, J. & Smith, R. J. 2012. Nonmarine ostracods (Crustacea) from South Korea, including a description of a new species of Tanycypris Triebel (Cyprididae, Cypricercinae). Zootaxa, 3161, 1 - 19.

Kim, W. & Min, G.S. 1991. Redescription of recent freshwater ostracods (Crustacea: Ostracoda) from Korea: A systematic study of four species of family Cyprididae. The Korean Journal of Systematic Zoology, 7, 81-100.

Okubo, I. 1974. Two species of the genus Cyprinotus (Ostracoda, Cyprididae) from Japan. Researches on Crustacea, 6, 58-70.

Okubo, I. and Ida, K. 1989. Freshwater Ostracoda from Gunma Prefecture, Japan. Bulletin of the Biogeographical Society of Japan, 44, 105-107. [In Japanese.]

Okubo, I. 2004. Nihon tansui san kaimijinko rui ni tsuite. Kabushikigaisha Sanmon Insatsusho, Okayama, Japan, 72pp. [In Japanese, privately published].

Victor, R. & Fernando, C. H. 1981. Freshwater ostracods (Crustacea: Ostracoda) of the subfamily Cyprinotinae Bronstein, 1947 from Malaysia, Indonesia and the Philippines. Hydrobiologia, 83, 11-27.


Key characters Cyprinotus uenoi & Cyprinotus kimberleyensis
Carapace - ventral valve overlapLeft valve overlaps right along ventral margin
Carapace - margin structure - septaNo septa present
Carapace - margin structure - ridges on inner calcified lamellaOn right valve
Carapace - dorsal view - female with brood pouchBrood pouch not visible
Carapace - lateral view - ventral marginVentral margin approximately straight to concave
Carapace - lateral view - valve heightRight valve noticeably higher than left
Carapace - internal viewAnterior calcified inner lamella about as wide as posterior one
Carapace - ornamentation - denticlesSmall denticles near ventral margin of valves
Carapace - ornamentation - sulcusNo sulcus
Carapace - ornamentation - surfaceSurface smooth
Carapace - width/length ratio (w/l)Between 0.4 and 0.7 (medium species)
Antennule - segmentsSeven moveable segments
Antennule - Rome organRome organ present
Antenna - exopoditeExopodite reduced to small segment
Antenna - swimming setaeSwimming setae long, reaching to about end of claws
Fifth limb - morphologyMaxilliped
Sixth limb - segmentsFive segments
Sixth limb - setae on first segmentOne seta
Sixth limb - h3 seta on final segmentH3 seta short; much shorter than half length of claw
Seventh LimbCleaning limb, with a pincer at end
Seventh Limb - segmentsThree segments
Seventh Limb - first segmentThree setae
Caudal ramusElongate ramus with two claws and two setae
Caudal ramus - attachmentWith no loops