Beyrichoceras

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

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 adapically, 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 midde 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.

References