- Ophidioceras
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Ophidioceras
Temporal range: U SilurianScientific classification Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Tarphycerida Family: Ophidioceratidae Genus: Ophidioceras
Barrande, 1867Ophidioceras is an alternate name for the Tarphycerid genus Ophioceras, which is known from the Upper Silurian of Europe and North America.[1]
Ophioceras, as this genus is more properly known, has a narrow, evolutly wound, closely coiled shell that diverges in the adult stage. The shell is more or less circular in cross section, strongly annulate with close spaced, rounded, transverse ribs. The venter is bicarinate, with keels along either side separated by a flattened surface. The siphuncle is tubular and thin walled, and may be slightely ventral or dorsal of the center. The adult aperture has deep hypononic and occular sinuses, not too dissimilar from the Ordovican Lituites, to which this genus is possibly allied. [1][2]
Some 12 species have been described which have been reduced to two, Ophioceras rudens Barrande, 1865 and O. simplex Barrande, 1865 with two subspecies, O. simplex simplex and O. s. proximum. Minor evolutionary changes can be observed within both species, which In spite of their widespread distribution do not demonstrate any major geographical variations.[3]
References
- ^ a b W.M Furnish and Brian F Glenister 1964. Nautiloidea-Tarphyhceria. Treatise on Inverterbrate Paleontology Part K. Geological Soc of America and Univ Kansas Press.
- ^ Charles Hepworth Holland 2010. Coiled nautiloid cephalopods from the British Silurian. Proceedings of the Geologists’ Association 121 (2010) 13–23 [1]
- ^ Stridsberg, S. & Turek, V., 1997: A revision of the Silurian nautiloid genus Ophioceras Barrande. GFF, Vol. 119 (Pt. 1, March), pp. 21–36. Stockholm. ISSN 1103–5897; Abstract.[2]
Categories:- Cephalopods
- Silurian animals
- Silurian extinctions
- Prehistoric animals of Europe
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