Anomphalidae
Introduction The '''Anomphalidae''' is an extinct family of fossil sea snails, marine gastropod mollusks. These are archaeogastropods which are included in the suborder Trochina. The Anomphalidae lived during the Paleozoic, from the Silurian to the Middle Permian. According to some authorities these snails belong instead to the Euomphalacea.
Morphologic diagnosis Shells of the Anomphalidae are rounded, almost discoidal, low-spired trochospiral inform, possibly with a globular body whorl. The aperture is oval, without exhalent slit or crease. The umbilicus is narrow, open or closed. The inner shell layer is seemingly nacreous. The shell surface is generally smooth, ornamentation consisting of fine transverse lyrae or growth lines parallel to the aperture lip.The Anomphalidae differ from the Euomphalcea to which they have been reassigned  in being more trochoidal, in lacking the angulation on the upper whorl surface characteristic of Euomphalacea, and in having the inner shell layer seemingly nacreous. (The inner shell layers of the Euomphalacea may be of laminar aragonite, but are never nacreous.) The Anomphalidea differ from the Pleurotomariacea in lacking the often deep slit or selenizone, which is characteristic of that taxon.== Taxonomy == J Brooks Knight, ''et al'', in the Treatise, 1960, assigned 10 genera to the Annomphalidae. They are :''Anomphalus'' Meek and Worthen 1866, the type genus:''Cycloscena'' Fletcher 1958:''Eiselia'' Dietz'' 1911:''Isonema'' Meek and Worthen 1866:''Pycnomphalus'' Lindström 1884:''Turbocheilus'' Perner 1907:''Sosiolytes'' Gemmellaro 1889:''Straparella'' Fischer 1885:''Turbinilopsis'' de Koninck 1881:''Tychonia'' de Koninck 1881At present the Anompalideae   has been expanded to include 17 genera in two subfamilies established by Peel, 1984.Added to ''Anomphalus'', ''Cycloscena'', ''Eiselia'', and ''Isonema'' in the Anomphalinae are: ''Antirotiela'' Cossmann 1918, given in the Treatise as a synonym for ''Anomphalus'' :''Frydacosta'' Cook and Nützel 2005:''Delphinuella'' Heidelberger 2001:''Givediscus'' Heidelberger 2001:''Littorella'' Heidelberger 2001:''Nodinella'' Heidelberger 2001 Contained within the Pycnomphalinae in addition to  ''Pycnomphalus'', ''Turbocheilus'', ''Sosiolites'', ''Strapariella'', and ''Tychonia''::''Pycnotrochus'' Perner 1903:''Turbinilopsis'' de Koninck 1881''Pycnotrochus'', from the Upper Silurian of Europe, was removed from the Sinuopeidae (Pleurotomariacea); the lip has a sinus more characteristic of the original family. ''Turbinopsis'', from the Lower Devonian of North America, was removed from the Palaeotrochidae (Palaeotrochacea); has a spiral chord not found on typical Anomphalidae and an aperture with a thicker, wider lip, also atypical.Bouchet & Rocroi, 2005 simply included the Anomphalidae in "basal taxa that are certainly Gastropoda".
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