Ovula ovum

Common egg cowrie
	Living Ovula ovum - adult
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Littorinimorpha
Family:	Ovulidae
Genus:	Ovula
Species:	O. ovum
Binomial name
	Ovula ovum; (Linnaeus, 1758)
Synonyms
	Amphiperas ovum (Linnaeus, 1758); Bulla ovum Linnaeus, 1758; Ovula alba Perry, 1811; Ovula cygnea Röding, 1798; Ovula oviformis Lamarck, 1801; Ovula pygmaea Sowerby, 1828; Ovulum gallinaceum Reeve, 1860; Xandarovula figgisae Cate, 1973;

Ovula ovum, common name the common egg cowrie, is a species of sea snail, a marine gastropod mollusk in the family Ovulidae, the ovulids, cowry allies or false cowries.^[1]

Description

The shells of these quite common cowries reach on average 65–70 millimetres (2.6–2.8 in) of length, with a minimum size of 50 millimetres (2.0 in) and a maximum size of 120 millimetres (4.7 in). They are egg-shaped (hence the Latin name ovum, meaning egg). The surface of the shell is smooth, shiny and completely snow white, with a dark reddish-purple interior, visible through the wide and long aperture, which bears teeth on one side only. In the living cowries the mantle is black, with a pattern of small white spots in adults, while juveniles resemble some toxic nudibranchs of the genus Phyllidia owing to their orange yellow sensorial papillae. The lateral flaps of the mantle usually hide completely the white surface, but the mantle is quickly retracted into the shell opening when the cowry is disturbed.

Ovula ovum with whole body covered by its mantle. This species can be easily found in the nearshore water of northeast coast of Taiwan.
Exemplar from Zanzibar (Tanzania).
Juvenile Ovula ovum with orange yellow papillae looks like a toxic nudibranch Phyllidia sp.
A shell of Ovula ovum.

Distribution

This species is distributed in the Red Sea and in the Indian Ocean along East Africa (Aldabra, Madagascar, Mozambique, Mauritius, Tanzania, Kenya, Chagos) and in Western and Central Pacific Ocean (New Zealand, Australia, North Sulawesi, Malaysia, Borneo, New Caledonia, Philippines, French Polynesia and southern Japan).

Habitat

Ovula ovum lives in tropical reef in shallow waters at 2 to 20 metres (7 to 66 ft) of depth, usually on algae or soft corals, mainly feeding on Alcyonarian colonies (Leather Coral, genus Sarcophyton and Sinularia sp., Alcyoniidae).

Feeding

Ovula ovum eats the sponge Sarcophyton, despite it containing the toxic terpene macrolide sarcophytoxide. O. ovum probably detoxifies sarcophytoxide in the intestines.^[2]

References

^ Ovula ovum (Linnaeus, 1758). WoRMS (2010). Ovula ovum (Linnaeus, 1758). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=216904 on 5 June 2010 .
^ Spiteller, D. (2008). "Defense Strategies of Marine and Aquatic Organisms". Encyclopedia of Ecology. pp. 844–852. doi:10.1016/B978-008045405-4.00903-4.

Morton B. & Morton JE. (1983). The sea shore ecology of Hong Kong. Hong Kong: Hong Kong University Press.
Lorenz F. & Fehse D. (2009). The Living Ovulidae - A manual of the families of Allied Cowries: * Ovulidae, Pediculariidae and Eocypraeidae. Conchbooks, Hackenheim, Germany
Jean-François Hamel & Annie Mercier - Observations on the biology of the common egg shell Ovula ovum in Majuro, Marshall Islands - SPC Trochus Information Bulletin #12 – June 2006
Liu, J.Y. [Ruiyu] (ed.). (2008). Checklist of marine biota of China seas. China Science Press. 1267 pp.
Spencer, H.G., Marshall, B.A. & Willan, R.C. (2009). Checklist of New Zealand living Mollusca. Pp 196–219. in: Gordon, D.P. (ed.) New Zealand inventory of biodiversity. Volume one. Kingdom Animalia: Radiata, Lophotrochozoa, Deuterostomia. Canterbury University Press, Christchurch

External links

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[WoRMS-1] Ovula ovum (Linnaeus, 1758). WoRMS (2010). Ovula ovum (Linnaeus, 1758). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=216904 on 5 June 2010 .

[2] Spiteller, D. (2008). "Defense Strategies of Marine and Aquatic Organisms". Encyclopedia of Ecology. pp. 844–852. doi:10.1016/B978-008045405-4.00903-4.

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