|
Camaenidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Helicoidea, the typical snails and their allies. This is one of the most diverse families in the clade Stylommatophora. These snails occur in a wide variety of habitats in the tropics of Eastern Asia and Australasia.〔Cuezzo M. G. (2003). "Phylogenetic analysis of the Camaenidae (Mollusca: Stylommatophora) with special emphasis on the American taxa". ''Zoological Journal of the Linnean Society'' 138(4): 449-476. .〕 A large American group, which is mainly represented by species from the Caribbean, has until recently also be subsumed under the Camaenidae. However, latest molecular phylogenetic studies showed that these species represent a different family, the Pleurodontidae.〔Wade, C.M., Hudelot, C., Davison, A., Naggs, F., Mordan, P.B. Molecular phylogeny of the helicoid land snails (Pulmonata: Stylommatophora: Helicoidea), with special emphasis on the Camaenidae. ''Journal of Molluscan Studies'' 73: 411-415.〕〔Bouchet, P., Rocroi, J.P. Classification and Nomenclator of gastropod families. ''Malacologia'' 47: 1-397.〕 This molecular study also implies that the Bradybaenidae, currently being treated as a distinct family within the Helicoidea, is a junior synonym of the Camaenidae. == Anatomy == Camaenid shells are often quite large (25–50 mm), but a number of species also have small shells (<5 mm). Shells reveal a remarkable diversity in shape and colour, which is partly linked with their life style. For instance, arboral species tend to have large and conical shells, whereas terrestrial species often have rather flat shells. The shells of some taxa can be vividly coloured, showing banding or other conspicuous patterns, but others are plain and uniform. This family is defined by a missing diverticulum and a missing stimulatory organ. It is suggested that the family Camaenidae as currently delimited is a polyphyletic taxon. There are no synapomorphies uniting this diverse family. The American group is closely related to the families Helicidae and Helminthoglyptidae, while the Australasian group is a closely related to the Bradybaenidae.〔Scott B. 1996. ''Phylogenetic relationships of the Camaenidae (Pulmonata: Stylommatophora: Helicoidea)''. Journal of Molluscan Studies, 62: 65-73. (Abstract )〕 In order to retain the Camaenidae as a monophyletic clade, the Neotropical Pleurodontidae will need to be removed as an independent family, and the Bradybaenidae will need to be included. This taxonomic decision is currently pending a formal suggestion and wider acceptance among systematists, however. In this family, the number of haploid chromosomes lies between 26 and 30 (according to the values in this table).〔Barker G. M.: Gastropods on Land: ''Phylogeny, Diversity and Adaptive Morphology''. in Barker G. M. (ed.): ''(The biology of terrestrial molluscs )''. CABI Publishing, Oxon, UK, 2001, ISBN 0-85199-318-4. 1-146, cited pages: 139 and 142.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Camaenidae」の詳細全文を読む スポンサード リンク
|