''Cenoceras'' is an extinct genus within the
cephalopod mollusc family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Nautilidae
The nautilus (, ) is a pelagic marine mollusc of the cephalopod family Nautilidae. The nautilus is the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina.
It comprises six living species ...
, which in turn makes up part of the superfamily
Nautilaceae
The Nautilaceae form one of five superfamilies that make up the Nautilida according to Bernard Kummel (1964), and the only one that survived past the Triassic. The Nautilaceae comprise six families: Nautilidae, Paracenoceratidae, Pseudonautilidae ...
. This genus has been described by Hyatt in 1884. The
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...
is ''Cenoceras intermedium'' (Sowerby).
Species
*''
Cenoceras boreale'' †
Dagys and Sobolev 1988
*''
Cenoceras trechmanni'' †
Kummel 1953
[
]
Description
Shells of these nektonic carnivores are variable in form, depending on species; ranges from evolute to involute, compressed lenticular to globose with rounded to flattened venter and flanks. The suture generally has shallow ventral and lateral lobes. The location of the siphuncle is variable, but never at an extreme ventral or dorsal position (Kümmel 1964, K449).
Fossil range
''Cenoceras'' has a fossil range from the Upper Triassic
The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. ...
, Carnian
The Carnian (less commonly, Karnian) is the lowermost stage (stratigraphy), stage of the Upper Triassic series (stratigraphy), Series (or earliest age (geology), age of the Late Triassic Epoch (reference date), Epoch). It lasted from 237 to 227 m ...
age to the Middle Jurassic, Callovian
In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 166.1 ± 4.0 Ma (million years ago) and 163.5 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...
age (from 235.0 to 163.5 Ma).[The Paleobiology Database]
/ref>[Sepkoski, Jac]
Sepkoski's Online Genus Database – Cephalopoda
/ref>
References
* Kümmel, B. 1964, Nauiloidea-Nautilida, in The Treatise on Invertebrate Paleontology, Part K, Nautiloidea; Geological Society of America and University of Kansas Press.
* Cyril Walker & David Ward (1993) - Fossielen: Sesam Natuur Handboeken, Bosch & Keuning, Baarn.
External links
Prehistoric nautiloid genera
Late Triassic first appearances
Middle Jurassic extinctions
Prehistoric cephalopods of Europe
{{paleo-Nautiloidea-stub