Holcodiscidae is an

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 cuttle ...

family placed in the superfamily

Desmoceratoidea Desmoceratoidea, formerly Desmocerataceae, is a superfamily of Cretaceous ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonit ...

. Wright, C. W. with J.H. Callomon and M.K. Howarth (1996), ''Mollusca 4 Revised, Cretaceous Ammonoidea'', vol. 4
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 (Roger L. Kaesler et el. eds.), Boulder, Colorado: The Geological Society of America & Lawrence, Kansas: University of Kansas Press, p.48.

Description

Moderately involute with rounded, rectangular, or depressed whorl section; straight or sinuous, fine, dense ribs typically continuing over venter and may be periodically truncated by oblique, enlarged ribs, with or without umbilical, lateral and ventrolateral tubercles. Suture rather simple.Tzankov, V. & Breskovski, S. (1982), "Volume et contenu de la famille Holcodiscidae Spath, 1924," ''C.R. Acad. bulg. Sci.'', 35, 4, 491-93.

Genera

* ''

Astieridiscus ''Astieridiscus'' is an extinct lower Cretaceous ammonite. Its shell evolute, covered by dense, simple or branching, slightly flexuous ribs. The sides are slightly flattened, the venter rounded. No umbilical or other tubercles except on innermost ...

'' * ''

Holcodiscus ''Holcodiscus'' is an extinct ammonite genus placed in the family Holcodiscidae. Species in this genus were fast-moving nektonic carnivores. The type species of the genus is ''Ammonites caillaudianus''. Description Circular to rectangular who ...

'' * '' Jeanthieuloyites'' * '' Parasaynoceras'' * ''

Spitidiscus ''Spitidiscus'' is a genus of ammonites placed in the family Holcodiscidae. with and (1996), ''Mollusca 4 Revised , Cretaceous Ammonoidea'', vol. 4, in ''Treatise on Invertebrate Paleontology'', Part L (Roger L. Kaesler et el. eds.), Boulde ...

Distribution

Fossils of species within this family have been found 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 ...

sediments in Argentina, Austria, Bulgaria, Chile, Colombia, the Czech Republic, Czechoslovakia, France, Hungary, Italy, Mexico, Morocco, Portugal, Romania, Slovakia, Spain and Russia.

References

External links

* * * Arkell, W. J. ''et al.'', (1957). Mesozoic Ammonoidea in Treatise on Invertebrate Paleontology, Part L, Ammonoidea. Geological Society of America and Univ Kansas Press. Cretaceous ammonites Early Cretaceous first appearances Santonian extinctions Ammonitida families Desmoceratoidea {{Ammonitina-stub