Anomphalidae

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Anomphalidae
Temporal range: Silurian–Middle Permian
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Family: Anomphalidae
Wenz, 1938 [1]
Genera

See text

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.

Contents

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. [2]

The Anomphalidae differ from the Euomphalcea to which they have been reassigned [3] 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. [2]

Taxonomy

J Brooks Knight, et al, in the Treatise, 1960, [2] 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 1881

At present the Anompalideae [3] 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".

Related Research Articles

<span class="mw-page-title-main">Euomphalina</span> Suborder of molluscs

The Euomphalina comprise a major suborder of mainly Paleozoic archaeogastropods, shells of which are hyperstophic to depressed orthstrophic, commonly with an angulation at the outer upper whorl surface thought to be coincident with the exhalent channel; shell wall thick, outer layer calcitic, inner layers aragonitic but not nacreous; operculum calcareous and heavy. Their range is from the Upper Cambrian to the Triassic, and possibly as high as the Upper Cretaceous.

<span class="mw-page-title-main">Gastropod shell</span> Part of the body of a gastropod or snail

The gastropod shell is part of the body of a gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less (slugs) but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it (semi-slug). Some snails also possess an operculum that seals the opening of the shell, known as the aperture, which provides further protection. The study of mollusc shells is known as conchology. The biological study of gastropods, and other molluscs in general, is malacology. Shell morphology terms vary by species group.

<span class="mw-page-title-main">Stomatellinae</span> Subfamily of gastropods

Stomatellinae is a subfamily of small sea snails with a brilliantly nacreous interior of the shell, marine gastropod mollusks in the family Trochidae, the top snails.

<span class="mw-page-title-main">Seguenziidae</span> Family of gastropods

Seguenziidae is a family of very small deepwater sea snails, marine gastropod mollusks in the superfamily Seguenzioidea.

Bucaniidae is an extinct family of Paleozoic molluscs of uncertain position possibly being either gastropods or monoplacophorans in the superfamily Bellerophontoidea. The family lived from the Lower Ordovician to the Devonian and have shells in which the apertural margins tend to flare. Most genera have a slit and selenizone, others some modification of this feature.

The †Raphistomatidae is a taxonomic family of fossil sea snails, Paleozoic marine gastropod molluscs. This family was established by Koken in 1896. This family is found in the fossil record from the Upper Cambrian to the Middle Permian.

<span class="mw-page-title-main">Craspedostomatidae</span> Extinct family of gastropods

Craspedostomatidae is an extinct taxonomic family of fossil sea snails, marine, gastropod mollusks in the subclass Gastropoda incertae sedis, unassigned in the class Gastropoda.

<span class="mw-page-title-main">Euomphaloidea</span> Extinct superfamily of gastropods

Euomphaloidea, originally Euomphalacea, is an extinct superfamily of marine molluscs that lived from the Early Ordovician to the Late Cretaceous, included in the Gastropoda but speculated as instead perhaps Monoplacophora.

<i>Anatoma crispata</i> Species of gastropod

Anatoma crispata is a species of minute sea snail, a marine gastropod mollusk or micromollusk in the family Anatomidae.

<i>Carenzia carinata</i> Species of gastropod

Carenzia carinata is a species of sea snail, a marine gastropod mollusk in the family Seguenziidae.

<i>Danilia telebathia</i> Species of gastropod

Danilia telebathia is a species of small sea snail, a marine gastropod mollusk in the family Chilodontidae.

<i>Trochia</i> Genus of gastropods

Trochia is a genus of sea snails, marine gastropod mollusks in the family Muricidae, the murex snails or rock snails.

<i>Callogaza watsoni</i> Species of gastropod

Callogaza watsoni is a species of sea snail, a marine gastropod mollusk in the family Margaritidae.

<i>Gaza superba</i> Species of gastropod

Gaza superba, common name the superb gaza, is a species of deep sea sea snail, a marine gastropod mollusc in the family Margaritidae.

<span class="mw-page-title-main">Lip (gastropod)</span> Mollusc shell

In the shell of gastropod mollusks, the lip is the free margin of the peristome or aperture of the gastropod shell.

Sinutropis is a genus of fossil sea snails, extinct euomphalid archaeogastropods from the Upper Silurian.

<i>Coelotrochus viridis</i> Species of gastropod

Coelotrochus viridis, common name the green top shell, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.

<i>Cataegis finkli</i> Species of gastropod

Cataegis finkli is a species of sea snail, a marine gastropod mollusk in the family Cataegidae.

<i>Seguenzia formosa</i> Species of gastropod

Seguenzia formosa is a species of extremely small deep water sea snail, a marine gastropod mollusk in the family Seguenziidae. The epithet "formosa" means "beautiful".

<i>Trochus kochii</i> Species of gastropod

Trochus kochii is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.

References

  1. (in German) Wenz W. A. (October) 1938. Handbuch der Paläozoologie, 6(1). Page 249.
  2. 1 2 3 J. Brooks Knight et al 1960. Systematic Descriptions (Gastropoda), Treatise on Invertebrate Paleontology, Part I, Mollusca 1, R.C. Moore (ed).
  3. 1 2 Anomphalidea in Paleobio database