| Titanoceras Temporal range: Pennsylvanian - Permian | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Nautiloidea |
| Order: | Nautilida |
| Family: | † Grypoceratidae |
| Genus: | †Titanoceras Hyatt (1884) |
Titanoceras is an extinct genus in the nautiloid order Nautilida from the Pennsylvanian and Lower Permian of North America and Western Australia.
The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, Nautilus and Allonautilus, with six species. All told, between 22 and 34 families and 165 to 184 genera have been recognised, making this the largest order of the subclass Nautiloidea.
The Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods of the Carboniferous Period. It lasted from roughly 323.2 million years ago to 298.9 million years ago Ma. As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain by a few hundred thousand years. The Pennsylvanian is named after the U.S. state of Pennsylvania, where the coal-productive beds of this age are widespread.
The Permian is a geologic period and system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago (Mya), to the beginning of the Triassic period 251.902 Mya. It is the last period of the Paleozoic era; the following Triassic period belongs to the Mesozoic era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the city of Perm.
Titanoceras grew to be fairly large, with a tightly spiraled shell that reached a diameter of about 8 in (20 cm +) with about three volutions. The inner coils are partially enveloped by the next outer, resulting in a channel or impression along the inner rim, the dorsum. Otherwise all whorls are visible. (The descriptive term is evolute). Whorls have a somewhat rectangular cross section that is wider than high; in contrast with the otherwise similar and contemporary Domatoceras . The venter, which forms the outer rim, may be broadly arched. Septa are close spaced making chambers broad but short. Sutures have shallow lobes along the sides and across the venter and short saddles in between, along the ventro-lateral shoulders, but go straight across the dorsum.
Domatoceras is a nautiloid genus and member of the Grypoceratidae from the Pennsylvanian and Permian with a wide spread distribution.
Titanoceras is found is limestone, indicating it lived in shallow-water carbonate banks. It could no doubt swim, but probably was not an active swimmer unlike fish and squid. It most likely spent its time crawling over or just above the sea floor. Titanoceras probably preyed upon crustaceans, bottom fish, and perhaps other cephalopods.
Titanoceras is placed in the Grypoceratidae, a family of similar genera within the Nautilida. Nautilid families that are more similar and have a common ancestor are combined in superfamilies. The Grypoceratidae are part of the Trigonocerataceae.
Grypoceratidae is the longest-lived family of the Trigonocerataceae, or of the near equivalent Centroceratina; members of the Nautilida from the Upper Paleozoic and Triassic.
The Trigonocerataceae 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.
