at the Lake Biwa Museum, Japan
Robin James Smith
Genus Cypretta Varva, 1895
Superfamily: Cypridoidea Baird, 1845
Family: Cyprididae Baird, 1845
Subfamily: Cyprettinae Hartmann, 1971
One species has been reported from Japan:
1. Cypretta seurati Gauthier, 1929
Dorsal views of two female Cypretta seurati, length 0.68 mm. This species is very globular. In this species, like most of the genus Cypretta, the right valve overlaps the left (a handful of species in the genus have the opposite overlap).
External view of a left valve of a female Cypretta seurati. Length 673 microns. The septa can be clearly seen along the anterior margin.
External view of a right valve of a female Cypretta seurati. Length 686 microns. The surface is covered in small, shallow pits (punctate).
Additional figures in: Okubo 1973 (carapace and appendages); Okubo 2004 (carapace); Smith & Kamiya 2006 (carapace); Meisch et al. 2007 (carapace); Smith et al. 2011 (carapace).
Habitat: Rice fields, ponds (Okubo 1973), freshwater rockpools (Smith & Kamiya 2006), and Lake Biwa (Smith et al. 2011).
Mode of life: Nektobenthic (swimmer).
Reproduction mode: Asexual, males unknown.
Known distribution: Shiga, Okayama, Fukuoka, Miyazaki, Gunma, Kagoshima, and Shizuoka Prefectures (Okubo 1973; Okubo & Ida 1989; Smith & Kamiya 2006; Smith et al. 2011; Tanaka et al. 2015). Outside Japan widespread in lower latitudes (Meisch et al. 2007). References:
Meisch, C., Mary-Sasal, N., Colin, J-P., & Wouters, K. 2007. Freshwater Ostracoda (Crustacea) collected from the islands of Futuna and Wallis, Pacific Ocean, with a checklist of the non-marine Ostracoda of the Pacific Islands. Bulletin de la Société des naturalistes luxembourgeois, 108, 89-103.
Okubo, I. 1973. Cypretta seurati Gauthier, 1929, from Japan (Ostracoda, Cyprididae). Proceedings of the Japanese Society of Systematic Zoology, 9, 1-6.
Smith, R. J., Janz, H. & Okubo, I. 2011. Recent Cyprididae and Ilyocyprididae (Crustacea: Ostracoda) from Lake Biwa, Japan, including a summary of the lake's ostracod fauna. Zootaxa, 2874, 1-37.
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.]
|Key characters||Cypretta seurati|
|Carapace - ventral valve overlap||Right valve overlaps left along ventral margin|
|Carapace - margin structure - septa||Septa present only along anterior margin|
|Carapace - margin structure - ridges on inner calcified lamella||No ridges|
|Carapace - dorsal view - female with brood pouch||Brood pouch not visible|
|Carapace - lateral view - ventral margin||Ventral margin approximately straight to concave|
|Carapace - lateral view - valve height||Left and right valves similar height|
|Carapace - internal view||Anterior calcified inner lamella wider than posterior one|
|Carapace - ornamentation - denticles||No denticles near ventral margin|
|Carapace - ornamentation - sulcus||No sulcus|
|Carapace - ornamentation - surface||Surface pitted|
|Carapace - width/length ratio (w/l)||Greater than 0.7 (rounded species)|
|Antennule - segments||Seven moveable segments|
|Antennule - Rome organ||Rome organ present|
|Antenna - exopodite||Exopodite reduced to small segment|
|Antenna - swimming setae||Swimming setae long, reaching to about end of claws|
|Fifth limb - morphology||Maxilliped|
|Sixth limb - segments||Five segments|
|Sixth limb - setae on first segment||One seta|
|Sixth limb - h3 seta on final segment||H3 seta short; much shorter than half length of claw|
|Seventh Limb||Cleaning limb, with a pincer at end|
|Seventh Limb - segments||Three segments|
|Seventh Limb - first segment||Three setae|
|Caudal ramus||Elongate ramus with two claws and two setae*|
|Caudal ramus - attachment||With no loops|
* Although the ramus is elongate, it is small and delicate.