The Cymatoceratidae is a family of

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

and early

Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...

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 ...

cephalopods and the most abundant of their kind in the Cretaceous. They are characterized by ribbed, generally involute shells of varied forms - coiled such that the outer whorl envelops the previous one, as with Nautilus, and sutures that are variably sinuous.Kummel 1964. Nautiloidea-Nautilida; Treatise on Invertebrate Paleontology Part K; Teichert and Moore (eds), Geological Society of America and University of Kansas press Cymatoceratids first appear in the Middle Jurassic, derived from the Lower Jurassic ''

Cenoceras ''Cenoceras'' (meaning "recent horn") is an extinct genus within the cephalopod mollusc family Nautilidae, which in turn makes up part of the superfamily Nautilaceae. This genus has been described by Hyatt in 1884. The type species is ''Cenoceras ...

'' (

Nautilidae A nautilus (; ) is any of the various species within the cephalopod family Nautilidae. This is the sole extant family of the superfamily Nautilaceae and the suborder Nautilina. It comprises nine living species in two genera, the type genus, ty ...

) and extend as far as the

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

Taxonomy

Ten cymatoceratid genera are described in the Treatise Part K, 1964. First to appear was the large, tightly involute, rapidly expanding '' Procymatoceras'' from the Middle

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

, followed by the Middle and Upper Jurassic '' Cymatonautilus'' which has a wide umbilicus and subquadrate whorl section. ''Procymatoceras'' and ''Cymatonautilus'' are followed by ''

Cymatoceras ''Cymatoceras'' is a wide-ranging extinct genus from the Nautilaceae, nautilitacean cephalopod family, Cymatoceratidae. They lived from the Late Jurassic to Oligocene, Late Oligocene, roughly from 155 to 23 Ma.Sepkoski, JacSepkoski's Online Genus ...

'' and the similar '' Paracymatoceras''. Six genera are restricted to the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

; '' Eucymatoceras'' and '' Heminautilus'' from the Lower Cretaceous; '' Anglonautilus'' from both the Lower and Upper Cretaceous; '' Deltocymatoceras'', '' Epicymatoceras'', and '' Syrionautilus''. '' Neocymatoceras'' from the Oligocene is synonymous with ''

''. Of the Cymatoceratidae, ''Cymatoceras'' has the longest temporal range, extending from the Late Jurassic to the Tertiary Oligocene. The only other to cross a period boundary is ''Paracymatoceras'' which lived during both the Late Jurassic and Early Cretaceous. The others are restricted to a simple period, sometimes to a single epoch.

References

The Paleobiology Database entry for Cymatoceratidae
{{Taxonbar, from=Q5199383 Prehistoric nautiloid families Mesozoic cephalopods Cenozoic cephalopods Middle Jurassic first appearances Oligocene extinctions