Английская Википедия:Arionoceras

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Шаблон:Short description Шаблон:Italic title Шаблон:Taxobox

Arionoceras is an extinct orthocerid genus from the Middle and Upper Silurian, of Europe that is estimated to have lived from 422.9 to 418.1 mya, existing for approximately Шаблон:Mya.[1]

Taxonomy

Arionoceras was named by Barskov (1966) [2] and originally assigned to the Michelinoceratidae, but attributed by Serpagli and Gnoli (1977) -ibid to the Geisonoceratidae Zhuravleva (1959) "on the basis of the (admittedly irregular) occurrence of a lining-like endosiphucular deposit." Dzik (1984) assigned Arionoceras to the newly proposed Arionoceratidae as the type genus. Sepkoski (2002)[3] follows previous authors in putting Arionoceras in the Orthoceratida.

Morphology

Arionoceras has a straight or slightly curved shell with a circular or depressed cross section, smooth or transversely sculptured surface, and large apically pointed protoconch.[2] The siphuncle is central with very short suborthochoanitic septal necks and cylindrical connecting rings. Apical chambers in adults have cameral deposits.

References

Шаблон:Reflist Шаблон:Portal Шаблон:Taxonbar

  1. PaleoBiology Database: Arionoceras, basic info
  2. 2,0 2,1 ; Some Remarks and Emendaation of the Family Arionoceratidae Dzik 1984 (Cephalopoda, Nautiloidea).[1]
  3. J. J. Sepkoski. 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363:1-560