Xenocephalites

Xenocephalites
Temporal range: Middle Jurassic
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida
Suborder: Ammonitina
Superfamily: Stephanoceratoidea
Family: Macrocephalitidae
Genus: Xenocephalites
Spath, 1928

Xenocephalites is an extinct ammonoid cephalopod genus from the late Middle Jurassic belonging to the stephanoceratoid family Macrocephalitidae. It is known from southern Alaska, Greenland, Mexico, and Argentina.

Xenocephalites can be recognized by its coarsly ribbed, prominently umbilicate, involute shell where in ribs are widely splayed, tending to bifurcate high on the flanks. Macrocephalites is similar except that its ribbing is finer and more dense. In both the ribbing crosses uninterrupted over the venter.

References

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