at the Lake Biwa Museum, Japan

Robin James Smith

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Genus Cavernocypris Hartmann, 1964

Superfamily: Cypridoidea
Family: Cyprididae
Subfamily: Cypridopsinae

One species has been reported from Japan:

Cavernocypris cavernosa Smith, 2011

2011 Cavernocypris cavernosa n. sp. - Smith: 16-20, figs 1A-H, 2.

Left side view of a female Cavernocypris cavernosa, length about 0.6 mm.

External view of a female left valve of Cavernocypris cavernosa, length 590 microns. The surface of the carapace is covered in numerous small pits.

External view of a female right valve of Cavernocypris cavernosa, length 573 microns.

Additional figures in: Smith 2011 (carapace and appendages).
Habitat: Poorly sorted gravels of springs and rivers.
Mode of life: Interstitial.
Reproductive mode: Asexual, males unknown.
Known distribution: Shiga and Shizuoka Prefectures, Japan.

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.

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.]

Key characters Cavernocypris cavernosa
Carapace - ventral valve overlapLeft valve overlaps right along ventral margin
Carapace - margin structure - septaNo septa present
Carapace - margin structure - ridges on inner calcified lamellaOn left valve. !Bit difficult to see!
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 pitted
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 reduced, not reaching to 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 ramusReduced ramus with two setae
Caudal ramus - attachmentWith no caudal ramus attachment