''Somalinautilus'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
nautiloids that is found in the Middle to Upper Jurassic of England, France, and
Somaliland
Somaliland,; ar, صوماليلاند ', ' officially the Republic of Somaliland,, ar, جمهورية صوماليلاند, link=no ''Jumhūrīyat Ṣūmālīlānd'' is a ''de facto'' sovereign state in the Horn of Africa, still conside ...
. The genus contains three species, ''S. antiquus'', first assigned to ''Nautilus'' by Dacque in 1910, ''S. fuscus'', first assigned to ''Nautilus'' in 1898, and ''S. clausus'', first used under ''Nautilus'' in 1890. Another species of ''Nautilus'' was named in 1905, ''N. bisculatus'', which is now a synonym of ''S. antiquus''.
Two features that differentiate ''Somalinautilus'' are that the venter is arched and low, and its ventral shoulders are subangular. This distinguishes ''Somalinautilus'' from its close relatives ''
Paracenoceras'', ''
Tithonoceras'', and ''
Aulaconautilus''. ''Tithonoceras'' is closest related to ''Paracenoceras'' within the group, and the three other genera are all descended from the groups sister taxa. In 1927 the family
Paracenoceratidae
The Paracenoceratidae are an extinct family of prehistoric nautiloids. The cephalopods lived during the Jurassic and Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the thi ...
was named to house these four genera, and in 1956, the family was then downgraded to a subfamily within
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 in t ...
.
However, the group is now considered to be a family again.
References
{{paleo-nautiloidea-stub