OSTRACOD RESEARCH

at the Lake Biwa Museum, Japan


Robin James Smith

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Genus Candonocypris Sars, 1896

Superfamily: Cypridoidea Baird, 1845
Family: Cyprididae Baird, 1845
Subfamily: Herpetocypridinae Kaufmann, 1900

Two species have been reported from Japan:

1. Candonocypris caledonica (Méhes, 1939)


External view of a left valve of a female Candonocypris caledonica. Length 1647 microns.


External view of a right valve of a female Candonocypris caledonica. Length 1726 microns.

Additional figures in: Méhes 1939 (carapace and appendages, as Herpetocypris caledonica); Okubo 2004 (carapace).
Habitat: Rice fields and ditches (Okubo 2004).
Mode of life: Benthic.
Reproduction mode: Asexual, males unknown.
Known distribution: None given by Okubo (2004). Shizuoka Prefecture (Kaji 2010). Outside of Japan known from New Caledonia (Méhes 1939, as Herpetocypris caledonica; Maddocks 2005, as Herpetocypris caledonica).
Notes: It needs to be confirmed that the Japanese specimens are C. caledonica. Unfortunately, the type specimens of this species are lost (De Deckker 1981), which hinders comparisons.

References:
De Deckker, P. 1981. Ostracoda from Australian inland waters - notes on taxonomy and ecology. Proceedings of the Royal Society of Victoria, 93, 43-85.

Kaji, T. 2010. Ontogeny and function of the fifth limb in cypridocopain ostracods. Zoological Science, 27, 673-677.

Maddocks, R.F. 2005. New thalassocypridine Ostracoda from anchialine caves of the Loyalty Islands, New Caledonia (Podocopida, Paracypridinae). Micropaleontology 51, 169-216.

Méhes, G. 1939. Ostracodes de la Nouvelle-Caledonie. Revue Suisse Zoologie, 46, 549-565.

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


2. Candonocypris novaezelandiae (Baird, 1843)


External view of a left valve of a female Candonocypris novaezelandiae. Length 1577 microns.


External view of a right valve of a female Candonocypris novaezelandiae. Length 1625 microns.

Additional figures in: Okubo 1975 (carapace and appendages, as Candonocypris assimilis); De Deckker 1981 (carapace and appendages); Okubo 2004 (carapace, as Candonocypris assimilis); Valls et al. 2013 (carapace); Escrivá et al. 2014 (carapace); Scharf et al. 2014 (carapace and appendages).
Habitat: Eel culture ponds (Okubo 1975; Ikeya & Hanai 1982), rice fields (Okubo 2004), an esturary (Ikeya & Hanai 1982). Elsewhere, large reservoirs, lakes (including brackish lakes), farm dams, ponds, rivers, flood plains of rivers, streams, a brackish channel (De Deckker 1983; Escrivá et al. 2014; Valls et al. 2013; Yousef 2010; Scharf et al. 2014).
Mode of life: Benthic (juveniles swim, but adults apparently do not).
Reproduction mode: Asexual in Japan. Elsewhere, generally asexual, but sexual populations reported from Australia (De Deckker 1983).
Known distribution: Chiba Prefecture (Okubo 1975) and Shizuoka Prefecture (Okubo 1975; 2000; Ikeya & Hanai 1982, as Candonocypris assimilis). Elsewhere, China (Yu et al. 2010), New Zealand (Sars 1894), Australia (Sars 1894; De Deckker 1981; 1983), New Caledonia (De Deckker 1983); South Africa (Martens et al. 1996), Egypt (Yousef 2010; Yousif et al. 2013), Tunisia, Germany, Belgium, England (Scharf et al. 2014), and Spain (Valls et al. 2013; Escrivá et al. 2014).
Notes: Candonocypris novaezelandiae and Candonocypris assimilis were synonymised by De Deckker (1981), although some authors continue to use the name Candonocypris assimilis. Scharf et al. (2014) remarked that the natural range of this species is most probably Australasia, and populations outside of this area, including those in Japan, are likely invasive.

References:
De Deckker, P. 1981. Ostracoda from Australian inalnd waters - notes on taxonomy and ecology. Proceedings of the Royal Society of Victoria, 93, 43-85.

De Deckker, P. 1983. Notes on the ecology and distribution of non-marine ostracods in Australia. Hydrobiologia, 106, 223-234.

Escrivá A., Rueda, J., Armengol, X. & Mesquita-Joanes, F. 2014. Artificial dam lakes as suitable habitats for exotic invertebrates: Ostracoda ecology and distribution in reservoirs of the eastern Iberian Peninsula. Knowledge and Management of Aquatic Ecosystems, 412. doi: 10.1051/kmae/2013091.

Ikeya, N. & Hanai, T. 1982. Ecology of Recent ostracods in the Hamana-ko region, the Pacific coast of Japan. University Museum of the University of Tokyo, Bulletin 20, 15-59.

Martens, K., Davies, B. R., Baxter, A. J. & Meadows, M. E. 1996. A contribution to the taxonomy and ecology of the Ostracoda (Crustacea) from Verlorenvlei (Western Cape, South Africa). South African Journal of Zoology, 31, 23-36.

Okubo, I. 1975. Studies on Ostracoda in fishponds - I. Two species in fishponds of the Chiba Prefectural Freshwater Fisheries Experimental Station. Bulletin of the Japanese Society of Scientific Fisheries, 41, 155-165.

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

Sars, G. O. 1894. Contributions to the knowledge of the fresh-water Entomostraca of New Zealand as shown by artificial hatching from dried mud. Videnskabs-Selskabets Skrifter. I. Mathem.-naturv., 5, 1-62.

Scharf, B., Meisch, C., Schön, I. & Martens, K. 2014. New records of Candonocypris novaezelandiae (Crustacea, Ostracoda) from Germany, Belgium,England and Tunisia. Abhandlungen des Naturwissenschaftlichen Vereins zu Bremen, 47, 337-344.

Valls, L., Rueda, J. & Mesquita-Joanes, F. 2013. Dynamics of Ostracoda (Crustacea) assemblages in a Mediterranean pond system (Racó de l'Olla, Albufera Nat. Park) with focus on the exotic species Candonocypris novaezelandiae (Baird, 1843). Annales de Limnolologie - International Journal of Limnology 49, 237-247.

Yousef, E. A. 2010. Taxonomy and description of the female Candonocypris novaezelandiae (Baird, 1843) (Crustacea: Ostracoda) from River Nile, Sohag Governorate, Egypt. Egyptian Academic Journal of Biological Sciences, 2, 61-69.

Yousif, F., Hafez, S., Bardicy, S. E., Tadros, M., Taleb, H. A. 2013. Experimental evaluation of Candonocypris novaezelandiae (Crustacea: Ostracoda) in the biocontrol of Schistosomiasis mansoni transmission. Asian Pacific Journal of Tropical Biomedicine, 3, 267-272.

Yu, N., Zhao, Q & Chen, X. 2010. New records of freshwater Ostracoda from the Dianchi Lake, Yunnan Province, SW China. Acta Micropalaeontologica Sinica 27, 344-350.


Key characters Candonocypris caledonica and Candonocypris novaezelandiae
Carapace - ventral valve overlapLeft valve overlaps right along ventral margin
Carapace - margin structure - septaNo septa present
Carapace - margin structure - ridges on inner calcified lamellaOn 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 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)Between 0.4 and 0.7 (medium 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 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 - attachmentTriangular loop at ventral end