Acavoidea
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| Acavoidea | ||||||||||||
| Pilsbry , 1894 |
The Acavoidea are a superfamily from the suborder of the land snails (Stylommatophora). Most of them are mostly relatively large shell snails. The current distribution indicates that their development and radiation took place in the late Mesozoic, before the geological continent Gondwana disintegrated into today's continents.
features
The right-hand winding cases are medium to rather large. The housing shape varies from highly conical to strongly flattened. The embryonic convolutions are also relatively large. In many shapes, the mouths are heavily modified (e.g. heavily lowered, edges bent, greatly enlarged, etc.). However, there are no teeth and very rarely lamellae. The jaws are aulacognath, d. H. thin, smooth or only slightly vertically striped. Occasionally there is also a central protrusion. The hermaphroditic genital apparatus is usually relatively simple with no attachments. Only a few forms form a flagellum , a blind sac on the penis ( caecum ) or a vaginal appendix. The inside of the penis has a complex structure. The group is generally characterized by extremely large egg sizes.
Geographical distribution
The representatives of the Acavoidea are native to South Africa, Madagascar, the Seychelles, Sri Lanka, Australia including Tasmania, New Guinea and South America. The spread suggests that the development and first radiation occurred before the disintegration of the geological continent Gondwana . The disintegration of Gondwana began in the Lower Cretaceous, in the Upper Cretaceous the last land connections with Africa broke off.
Systematics
The superfamily is divided into six families by Bouchet & Rocroi (2005)
- Acavidae Pilsbry, 1895
- Caryodidae Conolly, 1915
- Dorcasiidae Conolly, 1915
- Macrocyclidae Thiele, 1926
- Megomphicidae HB Baker, 1930
- Strophocheilidae Pilsbry, 1902
Schileyko (1998) also divides the superfamily into six families: Acavidae Pilsbry, 1894, Caryodidae Conolly, 1915, Clavatoridae Thiele, 1926, Dorcasiidae Conolly, 1915, Macrocyclidae Thiele, 1926 and Sculptariidae Degner, 1923. The Sculptariidae are from Bouchet & Rocroi ( 2005) placed in the superfamily Plectopyloidea , the Clavatoriidae are treated as a synonym of Acavidae. According to Schileyko (1998), the Strophocheilidae are a separate superfamily with two families.
swell
Individual evidence
- ^ Alan Solem and Adolf Cornelis van Bruggen: World-wide snails: biogeographical studies on non-marine Mollusca. Brill / Backhuys, Leiden 1984 ISBN 90-04-07417-1
literature
- Philippe Bouchet & Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005, ISSN 0076-2997
- Anatolij A. Schileyko: Treatise on Recent terrestrial pulmonate molluscs, Part 4 Draparnaudiidae, Caryodidae, Macrocylcidae, Acavidae, Clavatoridae, Dorcasiidae, Sculptariidae, Corillidae, Plectopylidae, Megalobulimidae, Achatinidaocheilidae. Ruthenica, Supplement 2 (4): 437-564, Moscow 1999, ISSN 0136-0027
