OSTRACOD RESEARCH

at the Lake Biwa Museum, Japan


Robin James Smith

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Genus Limnocythere Brady, 1868

Superfamily: Cytheroidea Baird, 1845
Family: Limnocytheridae Klie, 1938
Subfamily: Limnocytherinae Klie, 1938

Five species have been reported from Japan:

1. Limnocythere cyphoma Smith & Janz, 2009


Lateral left view of a female (left) and male Limnocythere cyphoma. Length about 0.4 mm.



The male sexual organ of Limnocythere cyphoma, length 136 microns.


Additional figures in: Smith & Janz 2009 (carapace).
Habitat: Lake Biwa.
Mode of life: Benthic.
Reproductive mode: Sexual.
Known distribution: Currently only known from Lake Biwa (Smith & Janz 2009).

References:
Smith, R. J. & Janz, H. 2009. Recent ostracods of the superfamilies Cytheroidea and Darwinuloidea (Crustacea) from Lake Biwa, a Japanese ancient lake. Species Diversity, 14, 217-241.


2. Limnocythere fude Smith & Janz, 2009

Figures in: Smith & Janz 2009 (carapace).
Habitat: Lake Biwa.
Mode of life: Benthic.
Reproductive mode: Sexual.
Known distribution: Currently only known from Lake Biwa (Smith & Janz 2009).

References:
Smith, R. J. & Janz, H. 2009. Recent ostracods of the superfamilies Cytheroidea and Darwinuloidea (Crustacea) from Lake Biwa, a Japanese ancient lake. Species Diversity, 14, 217-241.


3. Limnocythere kamiyai Smith & Janz, 2009


Lateral left view and ventral view of a female Limnocythere kamiyai. Length about 0.4 mm.


Additional figures in: Smith & Janz 2009 (carapace).
Habitat: Lake Biwa.
Mode of life: Benthic.
Reproductive mode: Sexual.
Known distribution: Currently only known from Lake Biwa (Smith & Janz 2009).

References:
Smith, R. J. & Janz, H. 2009. Recent ostracods of the superfamilies Cytheroidea and Darwinuloidea (Crustacea) from Lake Biwa, a Japanese ancient lake. Species Diversity, 14, 217-241.


4. Limnocythere levigatus Smith & Janz, 2009


The male sexual organ of Limnocythere levigatus, length 147 microns.


Additional figures in: Smith & Janz 2009 (carapace).
Habitat: Lake Biwa.
Mode of life: Benthic.
Reproductive mode: Sexual.
Known distribution: Currently only known from Lake Biwa (Smith & Janz 2009).

References:
Smith, R. J. & Janz, H. 2009. Recent ostracods of the superfamilies Cytheroidea and Darwinuloidea (Crustacea) from Lake Biwa, a Japanese ancient lake. Species Diversity, 14, 217-241.


5. Limnocythere stationis Vavra, 1891

Figures in: Meisch 2000 (carapace and appendages); Smith & Janz 2009 (carapace and appendages).
Habitat: Lake Biwa (Smith & Janz 2009); rice fields, small and large lakes, ponds, beds of rivers, bogs (Schornikov and Trebukhova 2001); shallow well, pools and flowing water (Martens 1984);
Mode of life: Benthic.
Reproductive mode: Sexual.
Known distribution: Shiga Prefecture (Smith & Janz 2009). Elsewhere, Western Europe (Meisch 2000); Sudan (Martens 1984); Uzbekistan (Schornikov and Trebukhova 2001), the Far-East of Russia (Schornikov 2004; Schornikov and Trebukhova 2001); Korea (Lee et al. 2000; Schornikov and Trebukhova 2001); China (Schornikov and Trebukhova 2001; Yu et al. 2005; Zhai & Zhao 2014).

References:
Lee, E-H, 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 [Korean 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.

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.

Schornikov, E. I. 2004. Crustacea: Ostracoda. 458-465. In: Tyurin, A. N. & Drozdov, A. L. (eds), Far-Eastern Marine Biospherical Reserve. Biota V. 2. Vladivostok: Dalnauka [in Russian].

Schornikov, E. I. and Trebukhova, Y. A. 2001. Ostracods of brackish and fresh waters of southwestern coast of Peter the Great Bay. Pp. 5685. In: Kasyanov, V. L., Vaschenko, M. A. and Pitruk, D. L. (Eds) The State of Environment and Biota of the Southwestern Part of Peter the Great Bay and the Tumen River Mouth. Dalnauka, Vladivostok.

Smith, R. J. & Janz, H. 2009. Recent ostracods of the superfamilies Cytheroidea and Darwinuloidea (Crustacea) from Lake Biwa, a Japanese ancient lake. Species Diversity, 14, 217-241.

Yu, N., Zhao, Q., Schornikov, E.L., & Chen, L. 2005. Recent Ostracods from the Taihu Lake. Acta Micropalaeontologica Sinica, 22, 143-151. [Chinese with English abstract].

Zhai, D. & Zhao, W. 2014. On some recent non-marine ostracods from northern China, with description of one new species. Crustaceana, 87, 985-1026.


Key characters Limnocythere
cyphoma
Limnocythere
fude
Limnocythere
kamiyai
Limnocythere
levigatus
Limnocythere
stationis
Carapace - ventral valve overlapLeft valve overlaps right along ventral margin
Carapace - margin structure - septaNo septa present
Carapace - margin structure - ridges on inner calcified lamellaNo ridges
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 wider than posterior one
Carapace - ornamentation - denticlesNo denticles near ventral margin
Carapace - ornamentation - sulcusSulcus present near dorsal margin
Carapace - ornamentation - surfaceSurface smooth Surface pitted Surface pitted Surface Smooth Surface pitted
Carapace - width/length ratio (w/l)Between 0.4 and 0.7 (medium species)
Antennule - segmentsFive moveable segments
Antennule - Rome organRome organ absent
Antenna - exopoditeExopodite a spinneret seta
Antenna - swimming setaeNo swimming setae present
Fifth limb - morphologyWalking leg
Sixth limb - segmentsFour segments
Sixth limb - setae on first segmentFour setae
Sixth limb - h3 seta on final segmentNo h3 seta
Seventh LimbWalking leg, smaller than sixth limb
Seventh Limb - segmentsFour segments
Seventh Limb - first segmentFour setae
Caudal ramusReduced to only one or two setae or absent
Caudal ramus - attachmentWith no caudal ramus attachment