Apocrinoceratidae

Apocrinoceratidae is a family of ammonites that existed during the Cretaceous period. This family is part of the superfamily Ancyloceratoidea, which is known for its diverse and often bizarre shell forms. The Apocrinoceratidae are characterized by their highly ornamented, evolute shells.

Taxonomy

The family Apocrinoceratidae was first described by the paleontologist W.J. Arkell in 1957. It belongs to the order Ammonitida, a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. The family includes several genera, such as Apocrinoceras, Emericiceras, and Paracrioceras.

Description

Apocrinoceratidae had a shell that was typically evolute, meaning that all the whorls were visible and not covered by subsequent growth. The shell was highly ornamented with ribs and tubercles. The size of the shell varied among species, with some reaching diameters of up to 30 cm.

Distribution and habitat

Fossils of Apocrinoceratidae have been found in various parts of the world, including Europe, Asia, and North America. They lived in marine environments during the Cretaceous period, approximately 145 to 66 million years ago.

Evolution

The Apocrinoceratidae are thought to have evolved from the Heteromorph ammonites, a group known for their irregularly coiled shells. The exact evolutionary pathway is still a subject of ongoing research.

See also

• List of ammonite genera
• Ammonite
• Cretaceous