Psiloceratidae is an extinct family of

cephalopod A cephalopod is any member of the molluscan class Cephalopoda ( Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...

s belonging to the

ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefis ...

subclass.

Description

The Psiloceratidae are evolute, smooth or with blunt primary ribbing. The venter is rounded and generally smooth, in some feebly keeled. Sutures are simple with phylloid saddle endings in some. The aptychus is single, found in sutu in Psiloceras

Genera

* '' Badouxia'' Guex and Taylor, 1976 * '' Caloceras'' * '' Discamphiceras'' * '' Euphyllites'' Wahner, 1898 * '' Franziceras'' Buckman, 1923 * '' Kammerkaroceras'' * '' Laqueoceras'' * '' Murihikuites'' Stevens, 2004 * '' Paradiscamphiceras'' Taylor, 1988 * '' Paraphylloceras'' Salfeld, 1919 * '' Psiloceras'' * '' Psilophyllites''

Distribution

Fossils of species within this genus have been found in the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest per ...

rocks of Canada, in the

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

rocks of Argentina, Austria, Canada, China, France, Germany, Hungary, Mexico, New Zealand, Spain), United Kingdom, United States, as well as in the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

of Australia and Russia.

References

* Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press. Ammonitida families Psiloceratoidea Rhaetian first appearances Maastrichtian extinctions {{Ammonitina-stub