Pinacoceratoidea, formerly Pinacocerataceae, are generally smooth, compressed, evolute to involute

ammonoids 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 cuttle ...

from the Triassic, belonging to the

Ceratitida Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post Triassic ammoni ...

, in which the suture is ammonitic, with adventitious and auxiliary elements. As presently conceived, the Pinacoceratoidea, named by Mojsisovics, 1879, combines six families; the: * Pinacoceratidae * Carnitidae *

Gymnitidae Gymnitidae is a family of Lower to Middle Triassic ammonite cephalopods with evolute, discoidal shells. Hyatt and Smith (1905, p. 114-115) included the Gymnitidae in the suborder Ceratitoidea, which later became the superfamily Ceratitacea ...

* Isculitidae * Klamathitidae * Sagenitidae In ''

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and co ...

'', Part L, the superfamily included only the Pinacoceratidae and Gymnitidae. Of the families more newly included in the Pinacocerataceae, the Carnitidae was removed from the

Ceratitaceae Ceratitoidea, formerly Ceratitaceae, is an ammonite superfamily in order Ceratitida characterized in general by highly ornamented or tuberculate shells with ceratitic sutures that may become goniatitic or ammonitic in some offshoots. (Arkell ...

and the Isculitidae from the

Ptychitaceae Ptychitoidea, formerly Ptychitacheae, is a superfamily of typically involute, subglobular to discoidal Ceratitida in which the shell is smooth with lateral folds or striations, inner whorls are globose, and the suture is commonly ammonitic. Their ...

. ''Klamathites'' was removed from the Carnitidae as type for the Klamathitidae. The Sagenitidae is based on the subfamily Sagenitinae of the tropitacean family

Haloritidae The Haloritidae is a family of subglobular, involute, Triassic ammonoids belonging to the ceratitid superfamily Tropitoidea. Their shells may be smooth or may have ribs that cross or are interrupted on the venter, and may have nodes. Keels and ven ...

. Fossils have been found in Triassic sediments in the United States in California, Nevada, and Alaska; in Canada in British Columbia; in Europe widespread; in China, Russia, Afghanistan, and Vietnam.

References

PinacocerataceaePaleobiology DB
* Treatise on Invertebrate Paleontology, Part L, Ammonoidea. R. C. Moore (ed). Geological Society of America and Univ of Kansas press, 1957 Ceratitida superfamilies Triassic first appearances Triassic extinctions {{Ceratitida-stub