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Neritimorpha
Neritimorpha is a clade of gastropod molluscs that contains around 2,000 extant species of sea snails, limpets, freshwater snails, land snails and slugs. This clade used to be known as the superorder Neritopsina. Etymology The clade’s name, Neritimorpha, is from the Ancient Greek νηρίτης (nērī́tēs 'Nerite') and μορφή (morphḗ 'form'). Description Despite their relatively low diversity, with only around 2,000 species, neritomorphs have achieved a remarkable diversity of forms, resembling a smaller-scale version of the diversity achieved by Gastropoda as a whole. Terrestrial lifestyles have evolved at least three separate occasions in neritimorphs: the extinct Dawsonellidae and the extant taxon, extant Helicinidae and Hydrocenidae. Neritimorphs also include the shellless, slug-like ''Titiscania''. In all modern neritomorphs except neritopsids, the inner walls of the protoconch are resorbed. Unlike most other gastropods, neritomorphs typically have calcifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycloneritimorpha
Cycloneritida (nerites and false-limpets) is an order of land snails, freshwater snails, and sea snails.MolluscaBase eds. (2020). MolluscaBase. Cycloneritida. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=1054475 on 2020-08-21 These are gastropod molluscs within the subclass Neritimorpha. 14 of the families in the order are extant, and eight of the families are extinct. It was previously categorized as the clade Cycloneritimorpha. According to the Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), as well as the Cycloneritida, the subclass Neritimorpha also contains the (entirely fossil) clade Cyrtoneritimorpha, plus a number of other fossil families that are currently unassigned. The earliest evolutionary forms of Cycloneritimorpha show double visceral organs, double gills, and normally a double-chambered heart. Taxonomy The taxonomy of Cycloneritida is based on work by Kano et al. (2002) that recognizes 4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
