at the Lake Biwa Museum, Japan

Robin James Smith

  home    about ostracods    ostracod facts    checklists    key    gallery    publications   

Genus Candonopsis Vavra, 1891

Superfamily: Cypridoidea Baird, 1845
Family: Candonidae Kaufmann, 1900
Subfamily: Candoninae Kaufmann, 1900

Two species have been reported from Japan:

1. Candonopsis kingsleii (Brady & Robertson, 1870)

Figures in: Meisch 2000 (carapace and appendages), Okubo 2004 (carapace).
Habitat: In Japan reported from irrigation ponds and rice fields. Elsewhere known from littoral zones of lakes, ponds and temporary water bodies (Meisch 2000).
Mode of life: Benthic.
Reproduction mode: Sexual.
Known distribution: None given by Okubo (2004) for Japan. Elsewhere known from Europe, Asia and north America (Meisch 2000).

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

2. Candonopsis tenuis (Brady, 1886)

External view of male right valve of Candonopsis tenuis, length 1005 microns.

External view of female right valve of Candonopsis tenuis, length 875 microns. Females are noticeably smaller than males.

The male sexual organ of Candonopsis tenuis, length 244 microns.

Additional figures in: Sars 1896 (carapace and caudal ramus), Karanovic & Marmonier 2002 (carapace and appendages), Smith & Janz 2008 (carapace and appendages).
Habitat: In Japan found along the shores of Lake Biwa (Smith & Janz 2008). Elsewhere reported from a river (Brady 1886), waterholes, a swamp (Sars 1896), a well (Karanovic & Marmonier 2002), and crab holes, tree holes and tin cans (Victor & Fernando 1978).
Mode of Life: Benthic.
Reproduction Mode: Sexual, males common.
Distribution: Lake Biwa, Shiga Prefecture. Elsewhere, Australia (Brady 1886, as Candona tenuis; Sars 1896; Karanovic & Marmonier 2002), Indonesia (Klie 1932), Samoa and Tonga (Victor & Fernando 1978; Hartmann 1984).

Brady, G. S. 1886. Notes on freshwater Entomostraca from South Australia. Proceedings of the Zoological Society of London, 82-93.

Hartmann, G., 1984. Zur Kenntnis der Ostracoden der polynesischen Inseln Huahiné (Gesellschaftsinseln) und Rangiroa (Tuamotu-Inseln). Mitteilungen aus dem hamburgischen zoologischen Museum und Institut 81: 117-169.

Karanovic, I. & Marmonier, P. 2002. On the genus Candonopsis (Crustacea: Ostracoda: Candoninae) in Australia, with a key to the world recent species. Annales de Limnologie, 38, 199-240.

Klie, W. 1932. Die Ostracoden der Deutschen Limnologischen Sunda Expedition. In A. Thienemann (ed.) Tropische Binnengewasser. Arch. Hydrobiol., suppl. v. 11, p. 447-502.

Sars, G. O. 1896. On fresh-water Entomostraca from the neighbourhood of Sydney, partly raised from dried mud. Archiv for Mathematik og Naturvidenskab, 18, 1-81.

Smith, R. J. & Janz, H. 2008. Recent species of the Family Candonidae (Ostracoda, Crustacea) from the ancient Lake Biwa, Central Japan. Journal of Natural History, 42, 2865-2922.

Victor, R. & Fernando, C. H. 1978. Systematics and ecological notes on Ostracda from container habitats of some South Pacific islands. Canadian Journal of Zoology, 56, 414-422.

Key characters Candonopsis tenuis & Candonopsis kingsleii
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 - sulcusNo sulcus
Carapace - ornamentation - surfaceSurface smooth
Carapace - width/length ratio (w/l)Less than 0.4 (slender species)
Antennule - segmentsSeven moveable segments
Antennule - Rome organNo Rome organ
Antenna - exopoditeExopodite reduced to small segment
Antenna - swimming setaeNo swimming setae present
Fifth limb - morphologyMaxilliped; Male palps one fused mass
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 three setae at end
Seventh Limb - segmentsFive segments
Seventh Limb - first segmentThree setae
Caudal ramusElongate ramus with two claws and one seta
Caudal ramus - attachmentWith no loops