| Centroceratidae | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Nautiloidea |
| Order: | Nautilida |
| Superfamily: | † Trigonoceratoidea |
| Family: | † Centroceratidae Hyatt in Zittel, 1900 |
| Genera | |
See text | |
The Centroceratidae is the ancestral family of the Trigonoceratoidea and of the equivalent Centroceratina; extinct shelled cephalopods belonging to the order Nautilida
The Centroceratidae, which range from the Middle Devonian to the Lower Permian, are characterized by gyroconic, evolute tarphyceraconic, and involute nautiliconic shells with compressed whorls, typically with a quadrangular whorl section in which the flanks converge on venter that is much narrower than the dorsum and ventral and umbilical shoulders are sharply angular, or rarely rounded. In some, e.g. Centroceras, the flanks are divided by a ridge that runs along the middle. Sutures have ventral and lateral lobes but are transverse dorsally. The siphuncle is tubular and close to but not on in contact with the venter (Kummel 1964).
The Centroceratidae are thought probably to be derived from the rutoceratid stock (Flower 1950, 1988, Kummel 1964) Earliest are Centroceras, Homaloceras , and Strophiceras from the Middle Devonian; Centroceras and Homaloceras from North America, Strophiceras from Europe. Next is Carlloceras from the Upper Devonian of North America, followed by Diorugoceras from the Lower Carboniferous of Europe. Last is Phacoceras, found in the Lower Carboniferous of Europe and Lower Permian of Australia. (Kummel 1964)
Homaloceras is the most primitive, with a laterally compressed, cyrtoconic to gyroconic shell with a narrow, concave venter, broadly convex flanks, and rounded dorsum, The suture is only slightly sinuous, the siphuncle tubular and near the venter.
Centroceras , the type genus, is evolute with only a few, rapidly expanding whorls and wide, perforate umbilicus. The cross section may be faintly hexagonal from the effect of a median ridge on either flank, otherwise is tetragonal. Flanks converge from a broad dorsum to a narrow, barely convex venter. Ventral and umblical shoulders are sharp. The suture is with a shallow ventral lobe and broad lateral lobes with subacute saddles on the shoulders; the siphuncle is tubular, near the venter; the living chamber half a volution in length. The surface is covered with alternating striae and lirae; fine, parallel "scratches" and "wires"
Strophiceras has a probably gyroconic shell with a higher than wide, compressed, subrectangular whorl section with slightly arched dorsum and venter and flattened flanks. The venter has a median ridge aligned with diagonally elongated nodes. The suture is with ventral and dorsal lobes, the siphuncle very close to the venter.
Carlloceras has a moderately involute shell with a compressed trapezoidal whorl section, nearly flat ventral and lateral areas, and slight dorsal impression. The suture has a ventral saddle and broad lateral lobe and the siphuncle is small and near the venter.
Diorugoceras is very involute and smooth, with a compressed whorl section with broad, slightly convex flanks that converge toward a concave venter. Ventral shoulders are angular, umbilical shoulders broadly rounded. The suture is with broad, deep lateral lobes, the nature of the ventral and lateral lobes is unknown, as is the position of the siphuncle.
Phacoceras as a moderately involute, highly compressed, smooth, lenticular shell with an acute venter and widest at the umbilical shoulder; suture with ventral saddle and broad shallow lobes on flanks; siphuncle slightly ventral from center.
Genera in ascending stratigraphic order, descriptions from Kummel 1964. p K432 in the Treatise Part K .
Aturia is an extinct genus of Paleocene to Miocene nautilids within Aturiidae, a monotypic family, established by Campman in 1857 for Aturia Bronn, 1838, and is included in the superfamily Nautilaceae in Kümmel 1964.
Cooperoceras is a genus of Tainoceratid nautiloid cephalopod molluscs within the superfamily Tainocerataceae, characterized by and evolute shell with an open, perforate, umbilicus, sinuous ribs at maturity, and recurved hollow spines along the ventro-lateral shoulders. The flanks and venter are flattened, the flanks converge on the dorsum, the venter has a shallow median groove. The suture is with rounded ventral and lateral lobes. The siphuncle is small, tubular, and subcentral.
Tetragonoceras is an extinct prehistoric nautiloid genus from the nautilid family Tetragonoceratidae that lived during the Middle Devonian, found in Canada.
Homaloceras is an extinct nautiloid cephalopod from the Middle Devonian with a strongly curved shell, included in the nautilid family Centroceratidae.
Tithonoceras is a genus of nautiloid cephalopod from the Upper Jurassic found in the Crimea, belonging to the nautilacean family Paracenoceratidae.
Heminautilus is an extinct genus of nautiloids from the nautilacean family Cenoceratidae that lived during the Early Cretaceous. Fossils of Heminautilus have been registered in rocks of Barremian and Aptian age. Nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.
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.
The Trigonoceratoidea are a superfamily within the Nautilida that ranged from the Devonian to the Triassic, thought to have contained the source for the Nautilaceae in which Nautilus is found.
Syringonautilidae is a family of Nautiloidea from the middle to late Triassic. Syringonautilidae comprise the last of the Trigonoceratoidea and are the source for the Nautilaceae which continued the Nautiloidea through the Mesozoic and into the Cenozoic right down to the recent. Syringonautilidae is a strictly Triassic family, derived early in the Triassic from the Grypoceratidae.
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.
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.
Metacoceras is a nautilitoid cephalopod from the Upper Carboniferous (Pennsylvanian) and Permian, the shell of which is moderately evolute with a subquadrate whorl section, bearing nodes on the ventral or umbilical shoulders or both, but otherwise smooth. The siphuncle is small, subcentral and orthochoanitic. The suture has shallow ventral and lateral lobes but no dorsal or annular lobe.
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.
Nassauoceras is a tetragonoceratid nautiloid from the Middle Devonian of Europe, the shell of which is evolute with a wide, deep umbilicus, slight dorsal impression, low arched venter, rounded ventral shoulders, and flanks that converge dorsally so as to produce a subtrigonal whorl section. Nodes are present on the ventral shoulders. Sutures have shallow ventral and lateral lobes. The siphuncle is near the ventral margin.
Wellsoceras is a tetragonoceratid that starts off with an evolute shell in which whorls are in contact, but has a mature living chamber that diverges and becomes free. The whorl section is slightly wider than high and is faintly subquadrangular. Flanks are slightly convex and tend to converge very slightly toward the center. All shoulders are strongly rounded. The suture is straight ventrally or with a slight ventral lobe, well developed lateral lobes, and a broad, low dorsal saddle. The siphuncle is located half way between the center and the ventral margin.
Halloceras is a gyroconic rotoceratid from the Lower Devonian of North America, with a subtriangular whorl section, narrow dorsum, divergent flanks, and broad, rounded venter, frills at various growth points, suture with shallow ventral and lateral lobes, and a small siphuncle near the venter.
Germanonautilus is a cephalopod genus included in the nautilid family Tainoceratidae, found widespread in the Triassic of North America, Europe, Asia, and north Africa. The shell is a moderately involute nautilicone ; whorl section subquadrate to trapezoidal, widest across the umbilical shoulders, flanks flattened and ventrally convergent, venter flat and wide, dorsum narrowly and deeply impressed. The suture is with broad and deep lateral lobes and a shallow ventral lobe. The siphuncle is central and nummuloidal, composed of expanded segments that give a beaded appearance. Its color is usually brown-grey.
Domatoceras is a nautiloid genus and member of the Grypoceratidae from the Pennsylvanian and Permian with a wide spread distribution.