| Grypoceratidae | |
|---|---|
 | |
| Domatoceras umbilicatum | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Nautiloidea |
| Order: | Nautilida |
| Superfamily: | † Trigonoceratoidea |
| Family: | † Grypoceratidae Hyatt in Zittle (1900) |
| Genera | |
| |
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. [1]
The Grypoceratidae are characterized by evolute to involute shells that may have some modification to the venter (the outer rim) varying from flattened to subangular, or bearing a keel. Most are smooth but some have nodes or carinae (auxiliary keels). Sutures generally have distinct ventral and lateral lobes but in some, a ventral saddle. Whorl sections are generally compressed but may be subquadrate to subtrapezoidal or coronate (heart shaped), or slightly depressed dorso-ventrally. [2] [1]
The Grypoceratidae begin with Epidomatodceras from the Lower Carboniferous (Mississippian), an evolute form with a smooth shell, subquadrate whorl section, and a sharp angular ventral lobe in the suture. Epidomatoceras is followed by Domatoceras , Paradomatoceras , Stearoceras , Stenopoceras , and Titanoceras from the Upper Carboniferous (Pennsylvanian) and Lower Permian.
Domatoceras, Paradomatoceras, and Titanoceras are rather similar in that they are somewhat large, evolute with whorls in contact but not deeply impressed along the inner margin of the whorls, and with straight flanks and flattened venters. Whorl sections vary from strongly compressed side to side with height much greater than width in Paradomatoceras to slightly depressed with height less than width in Titanoceras, with Domatoceras subquadrate in between.
Stearoceras is involute with a depressed subtrapizoidal whorl section and slight ventral and lateral lobes. Stenoporceras is subdiscoidal, flattened laterally, and has a suture with broad lateral lobes and a deep ventral saddle as found in syringonautilids.
Permian genera include Parastenopoceras , a smooth, involute form with a semiellptical whorl section and ventral saddle; Plummeroceras , a form similar to Domatoceras but more evolute and with a deep ventral lobe; Pselioceras , a smooth evolute form with a perforate umbilicus, ovoid whorl section, and suture crossing straight over the venter; and Virgaloceras , also similar to Domatoceras but with a row of nodes on the umbilical wall and a ventral saddle instead of the ventral lobe in the suture. Parastenopoceras, Plummeroceras, and Pselioceras are from the Lower Permian; Virgaloceras is from the Upper Permian.
The last three genera are from the Triassic, none having crossed from the Permian. Grypoceras , given simply a Triassic, is like Domatoceras but tending to be more involute and to have more rounded ventral shoulders. Menuthionautilus from the Lower Triassic has a rapidly expanding, smooth involute shell with a deep dorsal impression, broadly convex flanks and rounded venter, suture with a shallow ventral lobe and siphuncle positioned against the venter. Gryponautilus from the Upper Triassic is broadly involute with a narrowly rounded, keel-like venter at maturity and shallow ventral and lateral lobes in the suture.
All members of the Grypoceratidae have a ventral lobe with the exception of Stenoporceras, Parastenopoceras, and Virgaloceras, which have a ventral saddle instead. The derivation of these three within the Grypoceratidae is uncertain. Stenopoceras or Parastenopoceras is the likely ancestor of the Syringonautilidae from the Triassic. [1]
The taxonomy of the Grypoceratidae in the Treatise on Invertebrate Paleontology is straightforward with no attempt to define subdivisions within the family. The taxonomy of the Centroceratina of Shimansky (1962) in Kummel (1964) is more involved. Shimansky first of all divided the Centroceratina into two superfamilies, the Tribolocerataceae with one family and the Centrocerataceae with six families. Among the Centroceratacea the Domatoceratidae and Grypoceratidae (sensu Shimansky) are equivalent to the Gypoceratidae of the Treatise. The Domatoceratidae which include forms with ventral lobes and ventral saddles extends from the Carboniferous barely into the Triassic. The Grypoceratidae of Shimansky contains the Triassic genera of Kummel's larger Grypoceraidae and are derived, probably in the Late Permian, from the more restricted Domatoceratidae. [1]
Psiloceratoidea is a superfamily of Early Jurassic ammonoid cephalopods proposed by Hyatt in 1867, assigned to the order Ammonitida. They were very successful during Hettangian and Sinemurian. Last of them, family Cymbitidae and genera Hypoxynoticeras and Radstockiceras survived into Early Pliensbachian.
Titanoceras is an extinct genus in the nautiloid order Nautilida from the Pennsylvanian and Lower Permian of North America and Western Australia.
Valhallites is an extinct genus in the nautiloid order Nautilida which includes the living Nautilus found in the tropical western Pacifiic. Valhalites belongs to the Koninckioceratidae, a family in the Tainoceratacea, a nautilid superfamily.
Tylonautilus is an extinct genus in the nautiloid order Nautilida from the Lower Carboniferous of Europe and Permian of Japan.
Stearoceras is an extinct genus of prehistoric nautiloids from the Lower Pennsylvanian - Lower Permian with a fair worldwide distribution.(Kümmel 1964)
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.
The Trigonoceratidae is a family of coiled nautiloid cephalopods that lived during the period from the Early Carboniferous (Mississippian) to the Early Permian.
The Centroceratidae is the ancestral family of the Trigonoceratoidea and of the equivalent Centroceratina; extinct shelled cephalopods belonging to the order Nautilida
Tainonautilus is an extinct coiled cephalopod that lived during the Permian and Early Triassic which is included in the nautiloid family Tainoceratidae.
Condraoceras is a genus of liroceratids from the Pennsylvanian of North America and Lower Permian of Europe with a compressed, involute, nautiliconic shell; subcircular whorl section; small umbilicus with a rounded shoulder; suture with shallow ventral and lateral lobes; and narrow subcentral siphuncle.
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.
Holconautilus is a genus of nautiloids from the family Tainoceratidae and order Nautilida, named by Mojsisovics, 1902, and known from Upper Triassic sediments in Europe and E Indies (Timor). Its shell, evolute, discoidal, with simple coarse lateral ribbing; whorl section, subrectagular with a broadly arched venter.
The Rhiphaeoceratidae are a small family of nautilids included in the superfamily Tainocerataceae that comprises four very similar genera. These genera are characterized by a perforate umbilicus and little more than a single evolute coil. Whorl sections are oval, subquadrate, or subtrapezoidal. Sutures bend forward on the outer rim, forming wide shallow ventral saddles and dip strongly to the rear on the inner rim, forming deep dorsal lobes.
Lophoceras is a genus of Nautilids belonging to the tainoceratacean family, Koninckioceratidae, found in Lower Carboniferous sediments in Europe, and named by Hyatt, 1893. The shell of Lophoceras is evolute, large, with a slight impressed zone on the inner rim. In early volutions whorl sections are rounded, but later develop an obtusely angular ventral area and venter that disappears toward the front of the mature body chamber. The suture has an angular ventral saddle, broad shallow lateral lobe, and a dorsal lobe. Except for growth line, the shell is smooth.
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.
Grypoceras is a coiled nautiloid cephalopod from the Triassic of western North America, southern Asia, and Europe that belongs to the nautilid family Grypoceratidae. Named by Alpheus Hyatt in 1883, the shell of Grypoceras is essentially involute with a subtriangular cross section, widest across the umbilical shoulders, with flanks fairing toward a narrow flattened venter. Sutures on flanks are with smooth, deep lobes and with shallow ventral lobes.
Domatoceras is a nautiloid genus and member of the Grypoceratidae from the Pennsylvanian and Permian with a wide spread distribution.