Egg snails
| Egg snails | ||||||||||||
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Cyphoma gibbosum with feeding trail on a gorgonian |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Ovulidae | ||||||||||||
| Fleming , 1822 |
The egg snails (Ovulidae) are a family of exclusively marine snails . They feed on sessile animals , especially cnidarians . The first representatives of the ovulids appear in the fossil record in deposits of the Lower Cretaceous .
features
The cases are twisted on the right and convoluted, i. H. the last turn applied almost completely surrounds the previous turn. The mouth is usually narrow and long, and extends over the entire height of the case. In a few forms it can also be widened in the shape of an ear. Very often the top and bottom are greatly elongated by so-called siphon channels. The housing can become spindle-shaped with these shapes. Otherwise, spherical and egg-shaped housings are also known. The shell is usually smooth and shiny. The foot is moderately large with a moderately large propodium . The coat is often colored and bears the color pattern of the case. The viscera is relatively short. The head has a snout and the radula is relatively long. The eyes sit on the thickening of the antennae. With very few exceptions, the representatives of the family are of separate sexes. There is no operculum , but it is created in early ontogenesis and later reduced again. The ontogenetic development takes place via a plankton-eating Veliger larva.
Distribution and way of life
The Ovulidae are typical inhabitants of tropical and subtropical waters. Only a few species are found outside this range. They live from the coast to the deep sea; however, most of the species live in the shallow water areas that are illuminated. The snails are associated with cnidarians, whose polyps they graze on.
The species common in the Atlantic include Simnia spelta and Simnia patula .
Systematics
According to Bouchet & Rocroi (2005), the family is divided into five subfamilies: Ovulinae Fleming, 1822, † Cypraediinae Schilder, 1927, Jenneriinae Thiele, 1929, Pediculariinae Gray, 1853 and Pseudocypraeinae Steadman & Cotton, 1943. This subdivision is made by Fehse (2007 ) declined. He suggests a division into four subfamilies:
- Ovulinae Fleming, 1822
- Prionovolvinae Fehse, 2007
- Aclyvolvinae Fehse, 2007
- Simniinae signs, 1925
The Peduculariinae are interpreted as an independent family; Jenneria and Pseudocypraea are included.
Ovula ovum
literature
- Philippe Bouchet & Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005, ISSN 0076-2997 .
- Dirk Fehse: Contributions to the knowledge of the Ovulidae. XVI. The higher systematics. (Mollusca: Gastropoda). Spixiana, 30 (1): 121-125, Munich 2007 ISSN 0341-8391
- Frank Riedel: Origin and evolution of the "higher" Caenogastropoda . Berliner Geoscientific Abhandlungen, Series E, Volume 32, Berlin 2000, 240 pages, ISBN 3-89582-077-6 .
