''Algerites'' is middle Cretaceous (

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

) anisoceratid ammonoid with a close-coiled adult shell in which the whorls at that stage are in close contact, after starting off with openly coiled whorls, and in which every rib (a character of the family) has a pair of sharp ventral tubercles. ''Algerites'', which is found in North Africa, named for the country of Algeria, is thought to be derived from ''Idiohammites'', also an anisoceratid. It (''Algerites'') differs from '' Allocrioceras'' in that the later whorls come together in close contact where as in the latter they remain apart. The

Anisoceratidae Anisoceratidae is an extinct Family (biology), family of heteromorph ammonites which belong to the Ancyloceratina superfamily Turrilitoidea. Members of the family range is from the lower Albian to the upper Turonian. The family is possibly deriv ...

to which this genus is assigned is included in the diverse

heteromorph The Ancyloceratina were a diverse suborder of ammonite most closely related to the ammonites of order Lytoceratina. They evolved during the Late Jurassic but were not very common until the Cretaceous period, when they rapidly diversified and bec ...

ic superfamily

Turrilitoidea Turrilitoidea is a diverse superfamily of Cretaceous ammonites generally considered as heteromorphic and commonly included in the suborder Ancyloceratina. Shells of this diverse group do not coil planospirally, as typical for most ammonitida, am ...

References

* Arkell ''et al.'', 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L, Ammonoidea. Geol. Soc. of America and Univ. Kansas Press. Ammonitida genera Late Cretaceous animals of Africa Fossils of Algeria Turrilitoidea {{ammonitida-stub