''Tainoceras'' is an extinct coiled cephalopod that live during the later part of the

Paleozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

and

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

, that belongs to the

nautiloid Nautiloids are a group of cephalopods (Mollusca) which originated in the Late Cambrian and are represented today by the living ''Nautilus'' and ''Allonautilus''. Fossil nautiloids are diverse and species rich, with over 2,500 recorded species. Th ...

family

Tainoceratidae Tainoceratidae is a family of late Paleozoic and Triassic nautiloids that are a part of the order Nautilida, characterized by large, generally evolute shells with quadrate to rectangular whorl sections. Shells may bear ribs or nodes, or both. ...

.Kummel 1964, Nautiloidea—Nautilida. Treatise on Invertebrate Paleontology Part K Mollusca 3. Geol Soc of America and Univ Kansas Press Teichert and Moore (eds) ''Tainoceras'' has an evolude shell with a subquadrate whorl section that bears a double row of nodes on either side of its broad outer rim (venter). '' Metacoceras'' is similar except for lacking the double rows of nodes. '' Tainionautilus'' is similar, except that instead of nodes it has thick slanting lateral ribs

References

Nautiloids Pennsylvanian first appearances Triassic extinctions Fossil taxa described in 1883 Prehistoric nautiloid genera {{Paleo-nautiloid-stub