Gymnites
Encyclopedia
Gymnites is a genus of ammonoid cephalopod from the Middle Triassic belonging to the ceratitid
family Gymnitidae
.
along with Ophiceras, Flemingites, and Xenaspis, genera since assigned elsewhere, and included the Gymnitidae in the suborder Ceratitoidea (now the superfamily Ceratitaceae
). Smith (1932, p.30) shows Gymenites derived from Xenaspis and giving rise to the Pinacoceratidae.
The American Treatise (Part L, 1957) also includes Gymnites in the Gymnitidae, along with mainly descendant forms such as Buddhaites, Japonites, and variations on Gymnites itself, but instead included the Gymnitidae in the Pinacocerataceae
which is consistent with Smith's derivation of the Pinacoceratidae from Gymnites.
Ceratitida
The 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....
family Gymnitidae
Gymnitidae
The Gymnitidae is a family of Lower to Middle Triassic ammonoid cephalopods with evolute, discoidal shells.Hyatt and Smith included the Gymnitidae in the suborder Ceratitoidea, which later became the superfamily Ceratitaceae and included in it genera more primitive than Gymnites as well as the...
.
Description
The shell of Gymnites is evolute, generally smooth, with a wide umbilicus. Whorls are moderately embracing, whorl section oval and somewhat compressed. The outer whorl may be costate or have rows of nodes, or both. The suture is ammonitic with a wide bifurcated ventral lobe and two lateral lobes on either side.Taxonomic relation
Hyatt and Smith (1905, p.115)included Gymnites in the GymnitidaeGymnitidae
The Gymnitidae is a family of Lower to Middle Triassic ammonoid cephalopods with evolute, discoidal shells.Hyatt and Smith included the Gymnitidae in the suborder Ceratitoidea, which later became the superfamily Ceratitaceae and included in it genera more primitive than Gymnites as well as the...
along with Ophiceras, Flemingites, and Xenaspis, genera since assigned elsewhere, and included the Gymnitidae in the suborder Ceratitoidea (now the superfamily Ceratitaceae
Ceratitaceae
The Ceratitaceae is a superfamily in the ammonoid cephalopod order Ceratitida characterised in general by highly ornamented or tuberculate shells with ceratitic sutures that may become goniatitic or ammonitic s some offshoots....
). Smith (1932, p.30) shows Gymenites derived from Xenaspis and giving rise to the Pinacoceratidae.
The American Treatise (Part L, 1957) also includes Gymnites in the Gymnitidae, along with mainly descendant forms such as Buddhaites, Japonites, and variations on Gymnites itself, but instead included the Gymnitidae in the Pinacocerataceae
Pinacocerataceae
The Pinacocerataceae are generally smooth, compressed, evolute to involute ammonoids from the Triassic, belonging to the Ceratitida, in which the suture is ammonitic, with adventitious and auxiliary elements....
which is consistent with Smith's derivation of the Pinacoceratidae from Gymnites.
References
- Alpheus Hyatt and James Perrin Smith, 1905. The Triassic Cephalopod General of America. United States Geological Survey Professional Paper no. 40.
- James Perrin Smith, 1932. Lower Triassic Ammonoids of North America. U.S. Geological Survey PP 167.
- Treatise on Invertebrate Paleontology, Part L, Ammonoidea. Geol Soc. of America and Univ. Kansas Press, 1957. p.L184.