Olcostephanus is an extinct ammonoid cephalopod genus belonging to the family Olcostephanidae. These fast-moving nektonic carnivores[1] lived during the Cretaceous, from the upper Valanginian to the lower Hauterivian age.[2][1][3]

Temporal range: Valanginian-Early Cretaceous
~139.8–130.0 Ma
Olcostephanidae - Olcostephanus astierianus.JPG
Fossil of Olcostephanus astierianus from France, on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification e
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida
Family: Olcostephanidae
Genus: Olcostephanus
Neumayr, 1875
  • Astieria Pavlow, 1892
  • Holcostephanus (Astieria) Pavlow, 1892
  • Lemurostephanus Thieuloy, 1977
  • Olcostephanus (Astieria) Pavlow, 1892
  • Rogersites Spath, 1924
  • Satoites Canta-Chapa, 1966


  • Olcostephanus astierianus (d'Orbigny, 1840)
  • Olcostephanus atherstoni Sharpe, 1856
  • Olcostephanus bakeri Imlay, 1937
  • Olcostephanus bosei Riedel, 1938
  • Olcostephanus delicatecostatus Haas, 1960
  • Olcostephanus detonii Rodighiero 1919
  • Olcostephanus filifer Imlay, 1937
  • Olcostephanus laticosta Gerth, 1925
  • Olcostephanus paucicostatus Imlay, 1937
  • Olcostephanus pecki Imlay, 1960
  • Olcostephanus popenoei Imlay, 1960
  • Olcostephanus prorsiradiatus Imlay, 1937
  • Olcostephanus quadriradiatus Imlay, 1938
  • Olcostephanus sanlazarensis Imlay, 1937


Fossils of species within this genus have been found in the Cretaceous sediments of Antarctica, Argentina, Austria, Bulgaria, Chile, Colombia (Macanal Formation, Eastern Ranges),[4] Czech Republic, France, Hungary, Italy, Mexico, Morocco, Poland, Portugal, Romania, Slovakia, South Africa, Spain, Russia, United States, as well as in the Jurassic of Argentina.[1]


  1. ^ a b c d The Paleobiology Database
  2. ^ Sepkoski, Jack Sepkoski's Online Genus Database – Cephalopoda
  3. ^ Wright C. W. with J.H. Callomon and M.K. Howarth (1996), Mollusca 4 Revised, Cretaceous Ammonoidea, vol. 4, in Treatise on Invertebrate Paleontology, Part L (Roger L. Kaesler et al. eds.), Boulder, Colorado: The Geological Society of America & Lawrence, Kansas: University of Kansas Press, p.46.
  4. ^ Piraquive et al., 2011, p.204