This very large, thick-shelled bivalve is ovate to almost circular in outline; inside of the valves are purplish in colour, and the exterior is purplish with a thick black to olive periostracum. Most have well-developed collabral growth lines on the exterior surface, particularly anteriorly. The hinge teeth are of the heterodont type, very strong, with up to three cardinal teeth (which may be bifid) in each valve. The well-developed lateral teeth are coarsely serrated. There is a strong external ligament posterior to the umbones. There is no lunule and no escutcheon. The pallial line is entire.
The gills are eulamellibranch and the foot is a compressed, tongue shaped foot lacking a byssal groove. There are two relatively short posterior siphons and short papillae on the mantle edge. The mantle margins are not fused ventrally.
Batissa violacea (Lamarck, 1818)
Common name: Violet Batissa
Infraclass Heteroconchia
Cohort Heterodonta
Megaorder Neoheterodontei
Order Venerida
Superfamily Cyrenoidea
Family Cyrenidae
Genus Batissa Gray,1853 (Type species: Cyrena tenebrosa Hinds, 1842 by subsequent designation).
Original name: Cyrena violacea Lamarck,1818. In Lamarck, J. B. P. (1818). Histoire Naturelle des Animaux sans Vertèbres. Paris: Deterville & Verdiere, 5:1-612.
Type locality: Unknown.
Synonyms: Batissa australis Deshayes, 1855; Batissa elegans Prime, 1862; B. sphaericula Prime 1862; and several more.
Lives in lower freshwater sections of rivers and in the freshwater-estuarine interface. In intertidal to shallow water, infaunal, burrowing in sand and mud. Suspension and pedal deposit feeders. Dioecious, non-brooding (oviparous) with free-swimming larvae.
Rivers of tropical north-eastern Australia. An old record from the Richmond River in northern New South Wales needs confirmation, and records from South Austalia are almost certainly erroneous. Also in Andaman Islands, Taiwan, Malaysia, Thailand, Indonesia, Philippines, Papua New Guinea and some SW Pacific Islands (e.g., Fiji, New Caledonia).
Huber (2015) considered Batissa australis Deshayes, 1855 to be the valid name for the Australian species, not B. violacea. However, we do not consider it to differ from B. violacea.
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Benthem Jutting, W. S. S., van (1953). Systematic studies on the non-marine Mollusca of the Indo-Australia Archipelago. IV. Critical revision of the freshwater bivalves of Java. Treubia 22: 19-73.
Bieler, R. & Mikkelsen, P. (2019). Cyrenidae Gray, 1840. Pp. 187-192 in C. Lydeard & Cummings, K. S. Freshwater Mollusks of the World: a Distribution Atlas. Baltimore, John Hopkins University Press.
Hatha, A. A. M., Christi, K. S., Singh, R. & Kumar, S. (2005). Bacteriology of the fresh water bivalve clam Batissa violacea (Kai) sold in the Suva market. The South Pacific Journal of Natural and Applied Sciences 23: 48-50.
Huber, M., Langleit, A. & Kreipl, K. (2015). Compendium of Bivalves 2. A Full-Color Guide to the Remaining Seven Families. A Systematic Listing of 8,500 Bivalve Species and 10,500 Synonyms. Hackenheim, Germany, ConchBooks.
Lamprell, K. & Healy, J. (1998). Bivalves of Australia, volume 2. Leiden, Backhuys Publishers.
Lowery, R. (1997). The biology of Batissa violacea Lamark, 1818 (Bivalvia: Corbiculoidea) in Fiji. The South Pacific Journal of Natural Science 15: 37-52.
Mayor, A. D., Ancog, R. C., Guerrero, R. D. & Camacho, M. V. C. (2016). Environmental factors influencing population density of freshwater clam Batissa violacea (Bivalvia) (Lamarck, 1818) in Cagayan River, Northern Philippines. International Journal of Aquatic Science 7: 63-72.
Morton, B. (1989). The functional morphology of the organs of the mantle cavity of Batissa violacea (Lamarck 1797) (Bivalvia Corbiculacea). American Malacological Bulletin 7: 73-80.
Nurfadillah, N., Praningtyas, I., Karina, S. & Perdana, A. (2018). Analysis of heavy metals content (Pb, Hg and Cd) of Batissa violacea Lamarck in the coastal waters of Calang. IOP Conference Series: Earth and Environmental Science, IOP Publishing.
Thangavelu, A., David, B., Barker, B., Geneste, J. M., Delannoy, J. J., Lamb, L., Araho, N. & Skelly, R. (2011). Morphometric analyses of Batissa violacea shells from Emo (OAC), Gulf Province, Papua New Guinea. Archaeology in Oceania 46: 67-75.
