| Tornoceratidae | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | †Ammonoidea |
| Order: | †Goniatitida |
| Superfamily: | †Tornoceratoidea |
| Family: | †Tornoceratidae |
| Subfamilies | |
Tornoceratidae is a family of goniatitid ammonoinds from the middle and upper Devonian The family is included in the suborder Tornoceratina and the superfamily Tornoceratoidea.
Tornoceratids are subdiscoidal goniatitids with biconvex growth lines and sutures that form 6 to 10 lobes, the ventral one undivided, the lateral ones originating as subdivisions of external and internal lateral saddle.[1] They are derived from the Anarcestida.
Tornoceratidae as now understood[2] are essentially the Tornoceratidae of Arthaber (1911) described in the Treatise on Invertebrate Paleontology, Vol L[3], revised to include three subfamilies, the Tornnoceratinae, Aulatornoceratinae, and Falcitornoceratinae.
As previously understood in Miller et al. (1964) Tornoceratidae was included in the Cheilocerataceae, a superfaminily in the Goniatitida which also includes Cheiloceratidae. Tornoceratidae in the sense of Miller et al. is not divided into subfamilies.
Tornnoceratinae is based on the genus Tornoceras described by Hyatt in 1884.[4] Included in the subfamily as well are Epitornoceras and Lobotornoceras, both placed in the Tornoceratidae in the Treatise, along with the genera Crassotornoceras, Oxytornoceras, and Simicheiloceras which have been added since. Tornoceratinae are the root stock of the tornoceratids and are derived from Anarcestida. Tornoceratinae in turn gave rise to Aulatornoceratinae and Falcitornoceratinae.
Aulatornoceratinae and Falcitornoceratinae were erected by Becker in 1993. Aulatornoceratinae comes from Aulatornoceras, named by Schindewolf in 1922 while Falcitornoceratinae comes from Falcitornoceras named by House and Price in 1985.
Tornoceras is a tornoceratid genus widespread from the Middle and Upper Devonian of North America, Eurasia, North Aftrica, and Western Australia with a closed umbilucus and moderate sutural flextures. Sutures form six lobe, the lateral ones are rounded.[5]
Epitornoceras is a variety of Tornoceras, perhaps a synonym.[6] Saunders et al. in 2004 however derives Epitornoceras from Tornoceras as a separate genus. Epitornoceras was first described by Frech in 1902.
Lobotornoceras is an Upper Devonian tornoceratid from Europe, North Aftrica, and Western Australia. It is like Tornoceras however the internal suture form an additional pair of lobes.[7] The genus is derived from Tornoceras in Saunders (2004). Lobotornoceras was described by Schindewolf in 1936.
Protornoceras is a tornoceratid from the Upper Devonian of Europe with an open umbilcus and sutures that have little relief, described by Dybczynski in 1913. Protornoceras is shown as a subgenus of Tornoceras in Miller et al., but as a separate genus derived from Tornoceras in Saunders (2004).
Tornoceras, Epitornoceras, Lobotornoceras. and Protornoceras, along with Crassotornoceras, Linguatornoceras, Domanikoceras, Simcheiloceras, Tornia, and Oxytornoceras comprise the subfamily, Tornoceratinae.
Aulatornoceras, type for the Aulatornoceratinae was previously considered a subgenus of Tornoceras[8]. The genus is known from the Upper Devonian of North America and Europe with a ventrolateral grove running along the out part of the flanks on either side.
Aulatornoceras gave rise to Truyolsoceras and Polonoceras, which gave rise to Armatites , Kirsoceras, and Pernoceras, which gave rise to Pseudoclymenia[9], makng up the Aulotornoceratidae.
Polonoceras is an Upper Devonian tornoceriatid from Europe, described by Dybczynski in 1913. It is characterized by a ventrolaterally angular shell and sutures with prominent ventrolateral saddles. Polonoceras is treated as a subgenus of Tornoceras in Miller et at, but as a separate genus in Saunders 2004, where it is derived from Aulatornoceras.
Pseudoclymenia is a Tornoceratid described by Frech in 1897, from the Upper Devonian of Europe, North Africa, and Western Australia. It is similar to Tornoceras but with a characteristically narrower shell and wider umbilicus. Pseudoclymenia is derived from Pernoceras[10] and indicated as a synonym of Protornoceras.
Genera making up the Falcitornoceratinae form an evolutionary series, Phoenixites, Falcitornoceras, Gundolficeras, Exolornoceras, leading up to Posttornoceras, type genus of the Posttornoceratidae.
Falcitornoceras type genus of the Falcitornoceratinae, was named by House and Price in 1985, Phoenixites and Exotornoceras by Becker in 1993, and Gundolficeras by Becker in 1995.
The Tornoceratidae probably gave rise to the Cheiloceratidae (Miller et al. 1964, fig 12, L27) but though which genus is unspecifed (Saunders et al. 2004) . The Tornoceratidae may also have given rise, though Tornoceras to the Clymeniida