Donetzoceras is a genus belonging to the goniatitid family Gonioglyphioceratidae

Gonioglyphioceratidae

Gonioglyphioceratidae is one of three families of the Goniolobocerataceae superfamily. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses, and cuttlefish, and more distantly to the nautiloids....

 ; extinct ammonoids which are shelled cephalopods more closely related to squid , octopus and other coleoids than to the superficially similar Nautilus

Nautilus

Nautilus is the common name of marine creatures of cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in two genera, the type of which is the genus Nautilus...

Donetzoceras has a relatively small, thick-discoidal shell, the inner whorls evolote, later stages involute. Sculpture consists of nodelike riblets and umbilical plications which disappear at maturity.Growth lines form shallow ventral sinus and ventrolateral salients. The ventral lobe pointed with a median saddle about half as high as entire ventral lobe itself.

Donetzoceras is the earliest genus now included in the Gonioglyphioceratidae. Donetzoceras is from the middle and upper Upper Carboniferous

Carboniferous

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

(Pennsylvanian)

References

• Goniat: http://www.goniat.org/index.html
• Saunders et al. 1999; Evolution of Complexity in Paleozoic Ammonoid Sutures, Supplementary Material; Science Mag. http://www.sciencemag.org/feature/data/1043099.dtl

• The Paleobiology Database accessed on 10/01/07