About Ovula ovum (Linnaeus, 1758)
Ovula ovum (Linnaeus, 1758) is a fairly common species of cowry. On average, its shells grow to a length of 65–70 millimeters (2.6–2.8 inches), with a minimum recorded length of 50 millimeters (2.0 inches) and a maximum recorded length of 120 millimeters (4.7 inches). Its shells have an egg-shaped form, which is the source of its Latin name ovum, meaning egg. The shell's outer surface is smooth, shiny, and solid snow white. The interior of the shell is dark reddish-purple, and this color is visible through the species' wide, long aperture. The aperture bears teeth along only one of its sides. In living individuals, the cowry's mantle is black; adult cowries have a mantle patterned with small white spots. Juveniles have orange-yellow sensory papillae, which makes them resemble toxic nudibranchs from the genus Phyllidia. The lateral flaps of the mantle usually completely cover the white outer surface of the shell, but the mantle will quickly retract into the shell's opening if the cowry is disturbed. This species is distributed across the Red Sea, the Indian Ocean along the coast of East Africa including Aldabra, Madagascar, Mozambique, Mauritius, Tanzania, Kenya, and Chagos, and the Western and Central Pacific Ocean including New Zealand, Australia, North Sulawesi, Malaysia, Borneo, New Caledonia, the Philippines, French Polynesia, and southern Japan. Ovula ovum inhabits tropical reefs in shallow waters, at depths between 2 and 20 meters (7 to 66 feet). It is typically found growing on algae or soft corals, and feeds primarily on colonies of alcyonarians, including leather corals of the genera Sarcophyton and Sinularia in the family Alcyoniidae.
