OSTRACOD RESEARCH

at the Lake Biwa Museum, Japan


Robin James Smith

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Genus Dolerocypris Kaufmann, 1900

Superfamily: Cypridoidea Baird, 1845
Family: Cyprididae Baird, 1845
Subfamily: Dolerocypridinae Triebel, 1961

Three species have been reported from Japan:

1. Dolerocypris fasciata (O.F. Müller, 1776)

Figures in: Okubo 1972 (carapace and cadual ramus); Meisch 2000 (carapace and appendages); Okubo 2004 (carapace).
Habitat: Rice fields (Okubo 1972; 2004), concrete ditch, a basin, runoff of a spring, slow flowing stream in cave (Broodbakker 1988); reed bed in lake (Hiruta & Smith 2001). Elsewhere, littoral zones of lakes, reed beds, weedy fish ponds and swamps (Meisch 2000).
Mode of life: Nektobenthic (swimmer).
Reproduction mode: Asexual, males unknown.
Known distribution: Okayama Prefecture (Okubo 1972); Gunma Prefecture (Okubo & Ida 1989); Hiroshima Prefecture (Broodbakker 1988); Kagoshima Prefecture (Broodbakker 1988); Okinawa (Broodbakker 1988); Hokkaido (Hiruta & Smith 2001). Elsewhere, Holarctic (Meisch 2000).
Notes: In Japan there is a subspecies, Dolerocypris fasciata nipponensis Okubo, 1972, which differs from Dolerocypris fasciata found elsewhere in that it lacks the dorsal dark green band.

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.

Hiruta, S. & Smith, R. J. 2001. Living Freshwater and Shallow marine Ostracoda in Eastern Hokkaido, Japan (Field excursion E): 107 - 125. In: Guidebook of Excursions of the 14th International Symposium on Ostracoda (ed. Ikeya, N.). Shizuoka, Japan, 147 pp.

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. 1972. Freshwater Ostracoda from Japan, I. Two species of the genus Dolerocypris Kaufmann, 1900. Review of Shujitsu Junior College, Okayama, 1, 41-60.

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

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


2. Dolerocypris ikeyai Smith & Kamiya, 2006


Left side view of a female Dolerocypris ikeyai, length about 1.1 mm. In this genus, the right valve overlaps the left. The colour of the carapace varies from green through to pale green/blue to white.



External view of a female left valve of Dolerocypris ikeyai, length 1066 microns.



External view of a female right valve of Dolerocypris ikeyai, length 1078 microns.


Additional figures in: Smith & Kamiya 2006 (carapace and appendages); Smith 2011 (carapace and caudal ramus); Chang et al. 2012 (carapace).
Habitat: Typically found in the runoff of small springs and seeps (Smith 2011), but has also been reported from rice fields (Tanaka et al. 2015).
Mode of life: Benthic.
Reproduction mode: Sexual populations are known from two small Japanese islands, Yakushima and Tagashima. Elsewhere asexual.
Known distribution: Found throughout most of Japan (not reported from Hokkaido) (Smith 2011; Tanaka et al. 2015), and Korea (Chang et al. 2012).

References:
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.

Smith, R. J. 2011. Groundwater, spring and interstitial Ostracoda (Crustacea) from Shiga Prefecture, Japan, including descriptions of three new species and one new genus. Zootaxa, 3140, 15-37.

Smith, R. J. & Kamiya, T. 2006. Six new species of fresh and brackish water ostracods (Crustacea) from Yakushima, Southern Japan. Hydrobiologia, 559, 331-355.

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.]


3. Dolerocypris sinensis Sars, 1903


Left side view of a female Dolerocypris sinensis, length 1.9 mm. In this genus, the right valve overlaps the left.


External view of a female left valve of Dolerocypris sinensis, length 1815 microns.



External view of a female right valve of Dolerocypris sinensis, length 1877 microns.


Additional figures in: Okubo 1972 (carapace and cadual ramus); Okubo 2004 (carapace).
Habitat: Often found in rice fields (Okubo 1972), but also reported from concrete containers, ditches, ponds, an open well, and a spring/puddle (Broodbakker 1988).
Mode of life: Nektobenthic (swimmer).
Reproduction mode: Asexual, males unknown.
Known distribution: Widespread in Japan (Okayama (Okubo 1972), Gumma (Okubo & Ida 1989), Hiroshima, Yamaguchi and Kagoshima Prefectures and Okinawa (Broodbakker 1988)). Elsewhere, Eurasia (Meisch 2000).

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.

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. 1972. Freshwater Ostracoda from Japan, I. Two species of the genus Dolerocypris Kaufmann, 1900. Review of Shujitsu Junior College, Okayama, 1, 41-60.

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


Key characters Dolerocypris fasciata Dolerocypris ikeyai Dolerocypris sinensis
Carapace - ventral valve overlapRight valve overlaps left along ventral margin
Carapace - margin structure - septaNo septa present
Carapace - margin structure - ridges on inner calcified lamellaOn right and left valvesNo ridgesOn 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 heightLeft and right valves similar height
Carapace - internal viewAnterior calcified inner lamella about as wide as posterior one
Carapace - ornamentation - denticlesNo denticles near ventral margin
Carapace - ornamentation - sulcus No sulcus
Carapace - ornamentation - surfaceSurface smooth
Carapace - width/length ratio (w/l)Less than 0.4 (slender 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 Swimming setae reduced, not reaching to end of claws Swimming setae long, reaching to about end of claws
Fifth limb - morphologyMaxilliped
Sixth limb - segmentsFive segments
Sixth limb - setae on first segmentTwo setae
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