Pyramidellidae
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| JE Gray , 1840 |
The Pyramidellidae are a species-rich family mostly very small to small, exclusively marine snails within the Heterobranchia , which are distributed worldwide. They live as ectoparasites on a large number of host animals. More than 6000 species and 350 genera are described.
features
The Pyramidellidae have tall conical shells into which the whole body of the snail can be withdrawn. The protoconch is left-handed and the rest of the case is right-handed. The case mouth, the shape of which varies depending on the type, can be closed with an operculum .
A fold of the foot, the mentum, slightly notched at the midline, protrudes in front between the head and propodium . The antennae between which the eyes sit have a concave surface.
The snails have a telescopic trunk with stiletto-like jaws, with which host animals can be drilled. There is no radula .
The animals are hermaphrodites that produce sperm and egg cells at the same time. They mate each other with their penises . The fertilized egg cells are deposited in gelatinous clutches within which the Veliger larvae feed on yolk or leave the capsule as free-swimming larvae after a few days in order to live as plankton until metamorphosis , often only for a few days.
The Pyramidellidae are usually very small with a housing length of a few millimeters, only in exceptional cases up to 5 centimeters.
The animals live as ectoparasites on various host animals, especially polychaetes and molluscs , but also splashworms , crabs , sponges and sea squirts . Only a few species of the Pyramidellidae are host-specific. Most species are not picky about the choice of host.
Systematics
According to Bouchet and Rocroi (2005) the family Pyramidellidae forms with the family Amathinidae Ponder, in 1987 the superfamily Pyramidelloidea . The family Pyramidellidae has over 6000 species in about 350 genera.
- Family Pyramidellidae
- Subfamily Chrysallidinae
- Genus Babella
- Genus Boonea
- Genus Chrysallida
- Genus Egilina
- Genus Parthenina
- Genus Spiralinella
- Subfamily Cingulininae
- Genus Cingulina
- Subfamily Cyclostremellinae
- Genus Cyclostremella
- Subfamily Eulimellinae
- Genus Eulimella
- Subfamily Odostomellinae
- Genus Odostomella
- Genus Heviera
- Subfamily Odostomiinae
- Genus Brachystomia
- Genus Jordaniella
- Genus Linopyrga
- Genus Liostomia
- Genus Megastomia
- Genus Noemiamea
- Genus Odostomia
- Genus Ondina
- Subfamily Pyramidellinae
- Genus Longchaeus
- Genus Milda (snail)
- Genus Otopleura
- Genus Pyramidella
- Subfamily Sayellinae
- Genus Sayella
- Subfamily Syrnolininae
- Genus Syrnola
- Subfamily Tiberiinae
- Genus Tiberia
- Subfamily Turbonillinae
- Genus Bartschella (snail)
- Genus Careliopsis
- Genus Chemnitzia
- Genus Cylindriturbonilla
- Genus Dunkeria
- Genus Pyrgiscus
- Genus Ptycheulimella
- Genus Turbonilla
- Subfamily Chrysallidinae
literature
- Pyramidellidae. In: John W. Tunnell, Jean Andrews, Noe C. Barrera, Fabio Moretzsohn: Encyclopedia of Texas Seashells: Identification, Ecology, Distribution, and History. Texas A&M University Press, College Station (Texas) 2010, pp. 260f.
- V. Fretter, A. Graham: The structure and mode of life of the pyramidellidae, parasitic opisthobranchs (PDF; 15.1 MB). Journal of the Marine Biological Association of the United Kingdom. Vol. 28, No. 2, 1949, pp. 493-532.
- Alfred Kaestner : Textbook of special zoology. Volume I, part 3 . Jena 1993, ISBN 3-334-60412-8 .
Web links
- Marine Species Identification Portal: Pyramidellidae Gray JE, 1840
- Fischhaus Zepkow: Family Pyramidellidae - pyramid snails
- ITIS report
- Animal Diversity Web