Beyrichoceras

Beyrichoceras is a genus belonging to the Goniatitid family, Maxigoniatitidae [1] that lived during the Mississippian Period (Early Carboniferous)

Beyrichoceras
Temporal range: L Carboniferous – M Mississippian 345.3–336 Ma [1]
Fossil shells of Beyrichoceras from Visean of Madagascar (Erfoud)
Scientific classification
Kingdom:
Animalia
Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Ammonoidea
Order:
Goniatitida
Suborder:
Goniatitina
Superfamily:
Pericyclaceae
Family:
Maxigoniatitidae
Genus:
Beyrichoceras

Foord 1903

Description

Beyrichoceras can be recognized by its small, thickly discoidal shell with small umbilicus, deep dorsal impression, arched flanks and rounded venter [2] The ventral lobe of the suture is bifurcated, wide at its base, narrowing apically, ending in a pair of outwardly turned prongs separated by a low median saddle. The first lateral lobe is similar in size to the ventral lobe; broad, V-shaped, and more or less symmetrical. The umbilical lobe, like the first lateral lobe, is broad, V-shaped, and fairly symmetrical, only much shallower. The dorsal lobe is long and narrow, closely flanked by narrow internal lobes.

Taxonomic position

Beyrichoceras is assigned to the Maximitidae,[1][3] although some authors have assigned it to the Muensteroceratidae or Anthracoceratidae.[4] Miller and Furnish [2] included Beyrichoceras in the subfamily Goniatitinae, family Goniatitidae, and superfamily Goniatitaceae. The Maxigoniatitidae, established by Korn, Klug & Mapes, 1999, is based on Goniatites maximus var. saourensis Pareyn, 1961, renamed Maxigoniatites

Distribution and range

Beyrichoceras is found in middle Lower Carboniferous ( Mississippian upper Osagean-Meremacian equivalent) strata [4] in North America, Europe, and North Africa.[2][3]

Paleoecology

Beyrichoceras has been described as a "fast-moving nektonic carnivore".[1] Its small, involutely coiled form nevertheless suggest a floating nektonic or nekto-benthic stalker capable to sudden swift maneuvering. As with all known cephalopods, Beyrichoceras was undoubtedly carnivorous.

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References
  1. Paleobioloby-Beyrichoceras 12/08/09
  2. Miller, Furnish, and Schindewolf, 1957, Paleozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L, Mollusca 4.
  3. GONIAT-online 12/08/09
  4. W. B. Saunders, D. M. Work, S. V. NikolaevaEvolution of Complexity in Paleozoic Ammonoid Sutures, Supplementary Material Science magazine
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