Beyrichoceras

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Beyrichoceras
Temporal range: L Carboniferous – M Mississippian 345.3–336  Ma
Maxigoniatitidae - Beyrichoceras.JPG
Fossil shells of Beyrichoceras from Visean of Madagascar (Erfoud)
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Beyrichoceras

Foord 1903

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

Contents

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.

Related Research Articles

Goniatite Extinct order of molluscs

Goniatids, informally goniatites, are ammonoid cephalopods that form the order Goniatitida, derived from the more primitive Agoniatitida during the Middle Devonian some 390 million years ago. Goniatites (goniatitids) survived the Late Devonian extinction to flourish during the Carboniferous and Permian only to become extinct at the end of the Permian some 139 million years later.

<i>Goniatites</i> Extinct genus of molluscs

Goniatites is a genus of extinct cephalopods belonging to the family Goniatitidae, included in the superfamily Goniatitaceae. Hibernicoceras and Hypergoniatites are among related genera.

Beyrichoceras is a genus belonging to the Goniatitid family, Muensteroceratidae, a group of ammonoids, extinct shelled cephalopods related to belemnites and recent coleoids and more distantly to the nautiloids

Pseudohaloritidae is the larger of two families that form the goniatitid superfamily Pseudohaloritoidea, the other being the monogenerc Maximitidae. They are part of the vast array of shelled cephalopods known as ammonoids that are more closely related to squids, belemnites, octopuses, and cuttlefish, than to the superficially similar Nautilus.

The Posttornoceratidae are Late Devonian goniatites (Ammonoidea) included in the superfamily Tornoceratoidea. The family, Posttornoceratidae, named by Bogoslovsky in 1962, is based on the genus Posttornoceras, named by Wedekind in 1910, originally included in the Tornoceratidae.

Gastrioceratoidea Extinct superfamily of molluscs

Gastrioceratoidea is one of seventeen superfamilies in the suborder Goniatitina, ammonoid cephalopods from the Late Paleozoic.

The Ammonellipsitinae is a subfamily within the Pericyclidae, a family within the goniatitid superfamily Pericycloidea from the Lower Carboniferous (Mississippian) characterized by having a suture in which the sides of the ventral lobe diverge and the first lateral saddle is acute or subacute, and in which the immature and juvenile shell has a wide umbilicus.

Prolecanitida is an order of extinct ammonoid cephalopods with discoidal to thinly lenticular shells with goniatitic or ceratitic sutures and which retained the simple retrochoanitic siphuncle with backward extending septal necks. As typical for ammonoids the siphuncle is along the ventral margin. Prolecanitids form a relatively small and stable order within the Ammonoidea with 43 named genera and about 1250 species, but with a long-ranging lineage of about 108 m.y. stretching from the Lower Carboniferous to the Triassic. Although not as diverse as their goniatitid contemporaries, the Prolecanatida provided the stock from which all later Mesozoic ammonoids were derived.

The Clydonautiloidea are a superfamily within the nautiloid order Nautilida characterized by smooth, generally globular, shells with nearly straight sutures, in early forms, but developing highly differentiated sutures in some later forms. Where known, the siphuncle tends to be central to subcentral.

Grypoceratidae Extinct family of molluscs

Grypoceratidae is the longest-lived family of the Trigonoceratoidea, or of the near equivalent Centroceratina; members of the Nautilida from the Upper Paleozoic and Triassic.

The Centroceratidae is the ancestral family of the Trigonoceratoidea and of the equivalent Centroceratina; extinct shelled cephalopods belonging to the order Nautilida

Aphelaeceras is an extinct genus from the nautilid family Trigonoceratidae which is part of the Trigonocerataceae, that lived during the Mississippian Period in the late Paleozoic.

Peripetoceras is a genus in the Clydonautilacean family, Liroceratidae. It can be recognized by its smooth, involute shell with a deep small umbilicus with rounded shoulders and steep convex wall; whorl section with flattened venter, rounded ventral shoulders and convergent slightly convex flanks; suture with slight ventral and lateral lobes; and small siphuncle located dorsally of the center.

Edaphoceras is a genus of koninckioceratid nautilids from the Mississippian of North America, named by Hyatt, 1884, with depressed whorls just in contact. The shell, as typical for the family, is evolute; whorl section is fusiform with broadly rounded venter and dorsum meeting at a narrow angle on either side. Its suture has a distinct ventral and dorsal lobe and an angular lateral saddle. The siphuncle is small and near central.

Pseudonautilidae is a family of Jurassic and Lower Cretaceous nautilid cephalopods belonging to the same superfamily as modern Nautilus, Nautilaceae, but forming a different branch from the family Nautilidae. Pseudonautilids, together with other nautilids, were contemporary with the ammonoids, which comprise an entirely different set of shelled cephalopod stocks more closely related to octopus and squid.

Neoaganides is a small, 1–2 cm diameter subdiscoidal to subglobular goniatitid belonging to the family Pseudohaloritidae that lived from the Late Pennsylvanian to the Late Permian, existing for some 56 million years.

The Uddenitinae a subfamily of the Medlicottiidae, a family of ammonoid cephalopods included in the Prolecanitida. The Uddenitinae, proposed by Miller and Furnish, and known from the Pennsylvanian and Lower Permian, are transitional between the ancestral Pronoritidae and the more traditional medlicottiids

Neoglaphyrites is a gonititid ammonite that lived during the latest Pennsylvanian and early Permian. Its shell is ellipsoidal and moderately involute; the umbilicus deep and typically less than 15 per cent of the shell diameter but in some species closer to 20 per cent. Delicate growth lines forming ventral and lateral sinuses and ventrolateral and dorsolateral salients have been found on Canadian Arctic specimens. The suture is characterized by the ventral lobe split into two broad prongs that are separated by a high median ventral saddle; prongs closely approximate the width of the first lateral lobe. The first lateral saddle is evenly rounded and is nearly symmetrical. The umbilical lobe is V-shaped and internal lobes are deep and narrow.

Pronorites is a prolecanitid genus from the middle and upper Carboniferous, upper Mississippian and Pennsylvanian. Distribution is wide spread.

Masonoceras is a genus of Karagondoceratids from Lower Mississippian strata, the shell of which is thinly subdiscoidal to discoidal with an acute ventral margin in late ontogeny. Whorls are strongly embracing, umbilicus narrow to occluded. The mature external suture contains a wide trifid ventral lobe, the flanking prongs longer that the medial, an asymmetrically rounded lateral saddle and a deeper asymmetric pointed lateral lobe. Internal molds of the type, Mesoceras Kentuckiense show presence of a broad hyponomic sinus flanked by high rounded vantrolateral salients.

References

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