| 词条 | Beyrichoceras |
| 释义 |
| fossil_range = L Carboniferous – M Mississippian {{fossilrange|345.3|336}}[1] | image = Maxigoniatitidae - Beyrichoceras.JPG | image_caption = Fossil shells of Beyrichoceras from Visean of Madagascar (Erfoud) | regnum = Animalia | phylum = Mollusca | classis = Cephalopoda | subclassis = Ammonoidea | ordo = Goniatitida | subordo = Goniatitina | superfamilia = Pericyclaceae | familia = Maxigoniatitidae | genus = Beyrichoceras | genus_authority = Foord 1903 | subdivision_ranks = | subdivision = }} Beyrichoceras is a genus belonging to the Goniatitid family, Maxigoniatitidae [1] that lived during the Mississippian Period (Early Carboniferous) DescriptionBeyrichoceras 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 positionBeyrichoceras 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 MaxigoniatitesDistribution and rangeBeyrichoceras is found in middle Lower Carboniferous ( Mississippian upper Osagean-Meremacian equivalent) strata [4] in North America, Europe, and North Africa.[2][3]PaleoecologyBeyrichoceras 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. References1. ^1 2 3 Paleobioloby-Beyrichoceras 12/08/09 {{Taxonbar|from=Q4900233}}2. ^1 2 Miller, Furnish, and Schindewolf, 1957, Paleozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L, Mollusca 4. 3. ^1 GONIAT-online 12/08/09 4. ^1 W. B. Saunders, D. M. Work, S. V. NikolaevaEvolution of Complexity in Paleozoic Ammonoid Sutures, Supplementary Material Science magazine 4 : Goniatitida genera|Ammonites of Europe|Mississippian ammonites|Pericyclaceae |
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