| Frechites Temporal range: early Triassic | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | † Ammonoidea |
| Order: | † Ceratitida |
| Family: | † Beyrichitidae |
| Genus: | † Frechites Smith, 1932 |
Frechites is an early Triassic ammonite, a kind of cephalopod with an external shell, included in the ceratitid family Beyrichitidae.
J.P. Smith, 1932, put Frechites in the Ceratididae where it remained included in the Treatise Part L. It was later removed to the Beyrichitidae, established by Spath, 1934.
The shell of Frechites is robust, involute, and strongly ribbed. The outer whorl embraces most of the inner, leaving a small umbilicus. Short, strong ribs appear along the umbilical shoulder that split in twos and threes in the middle of the sides, which continue to the outer, or ventrolateral, shoulder but do not cross the venter, or outer rim, which is left smooth.
The suture of Frechites is partly ammonitic, with a slightly serrate first lateral saddle. The other saddles in the suture are rounded and smooth. As such this is intermediate between common Ceratitidae with entirely ceratite sutures -smooth saddles, serrate lobes, and the normal Beyrichideae with sutures that tend to be ammonitic or subammonitid, with deep serrated lobes and high serrated saddles.
Ammonoids are extinct spiral shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living coleoids than they are to shelled nautiloids. The earliest ammonoids appeared during the Devonian, with the last species vanishing during or soon after the Cretaceous–Paleogene extinction event. They are often called ammonites, which is most frequently used for members of the order Ammonitida, the only remaining group of ammonoids from the Jurassic up until their extinction.
Albanites is a genus of extinct cephalopods belonging to the ammonoid order Ceratitida that lived during the Early Triassic epoch.
Beyrichites is an extinct genus in the ammonoids cephalopod, order Ceratitida from the Lower and Middle Triassic of southern Europe, Asia, and western North America.
Ussuria is a genus of Lower Triassic ammonites with a smooth, involute discoidal shell with submonophyllic sutures, belonging to the ceratitid family Ussuriidae.
Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post-Triassic ammonites.
Thalassoceratidae a family of late Paleozoic ammonites included in the goniatitid superfamily Thalassoceratoidea along with the Bisatoceratidae. Some eight genera are included, although the specific number and exactly which depends on the particular classification.
Ammonitina comprises a diverse suborder of ammonite cephalopods that lived during the Jurassic and Cretaceous periods of the Mesozoic Era. They are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific geological time periods.
Medlicottiidae is a family of ammonoid cephalopods belonging to the Prolecanitida, known from the Upper Carboniferous (Pennsylvanian) to the Early Triassic.
Ussurites is an extinct ammonoid cephalopod genus belonging to the suborder Phylloceratina and is included in the family Ussuritidae. Its range is restricted to the early Middle Triassic, (Anisian)
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.
Tissotiidae is a family of ammonites (Ammonitina) belonging to the Acanthoceratoidea.
Gymnites is a genus of ammonoid cephalopod from the Middle Triassic belonging to the ceratitid family Gymnitidae. These nektonic carnivores lived during the Triassic period, the Anisian age.
Episageceratinae is a subfamily of the Medlicottiidae, a family of prolecanitid ammonites. The Episageceratinae, proposed by Ruzhencev, 1956, is based on the genus Episageceras previously included in the subfamily Medlicottiinae and lived during Late Permian and Early Triassic times. So far only three confirmed genera are included: Episageceras, Latisageceras, and Nodosageceras.
Inyoites is an ammonoid genus from the Lower Triassic, included in the ceratitid family Inyoitidae.
Flemingites is an extinct genus of evolute ammonoid from the Smithian with spiral ridges on the shell.
Ophiceras is an extinct genus of smooth, evolute ceratitid ammonites from the Griesbachian, with a rounded venter. Fossils of the genus have been found in Armenia, Azerbaijan, China, Greenland, and India.
Meekoceras is an extinct genus of ceratitid ammonites with a discoidal shell that lived during the Early Triassic Epoch.
Clypeoceras is a genus of ammonites with an involute discoidal shell from the Lower Triassic.
Sturia is a genus of ceratitid ammonoids from the Lower Triassic with an ammonitic suture.
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