Spitidiscus

Spitidiscus Temporal range: Hauterivian-Barremian ~130–125 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Fossil shell of Spitidiscus species from Alpes-de-Haute-Provence, on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Family:	†Holcodiscidae
Genus:	†Spitidiscus Kilian, 1910

Spitidiscus seunesi (Kilian) Barremian, Brestak, Cr1 426X1 (Coll. St. Breskovski) at the Sofia University Museum of Paleontology and Historical Geology

Spitidiscus is a genus of ammonites placed in the family Holcodiscidae.[1][2]

Species

List of species within Spitidiscus:[3]

• Spitidiscus hugii^[citation needed]
• Spitidiscus kilapiae Rawson and Aguirre-Urreta, 2012 - Argentina
• Spitidiscus oregonensis Imlay, 1960 - Oregon
• Spitidiscus riccardii Leanza, and Wiedmann, 1992 - Argentina
• Spitidiscus rotulia - England^[citation needed]
• Spitidiscus simitiensis Haas, 1960 - Colombia
• Spitidiscus vandeckii (d'Orbigny, 1847)

Description

Member species have a rather evolute shell in which the whorl section is more or less circular, venter broadly rounded and dorsum fairly deeply impressed. Close, fine low, single or rarely branching ribs are interspersed by frequent straight or slightly sinuous, moderately deep but wide constrictions. The type species S. rotulia is from the Hauterivian of England.^[citation needed]

Biostratigraphic significance

The first appearance of the species Spitidiscus hugii or Spitidiscus vandeckii are proposed to be the marker for the beginning of the Barremian.[4]

Distribution

Spitidiscus has been found in:[3]

• Agrio Formation, Argentina
• Magdalena Valley, Simití and Cáqueza, Colombia
• Kaliste Formation, Czech Republic
• France
• Gagra, Georgia, Caucasus
• Maiolica Formation, Italy
• Subbetics, Spain
• Foggy Creek, Oregon
• Bulgaria^[citation needed]
• Portugal^[citation needed]
• Russia^[citation needed]
• Morocco^[citation needed]
• Mexico^[citation needed]

References

1. Wright, C. W. with Callomon, J.H. and Howarth, M.K. (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, at 69.
2. "Spitidiscus". Sepkoski's Online Genus Database – Cephalopoda.
3. "Spitidiscus". Fossilworks.
4. "GSSP Table - Mesozoic Era". Geologic Time Scale Foundation. Retrieved 15 January 2014.

Bibliography

• "Spidiscus". Paleobiology Database. Retrieved 30 December 2021.
• "Spidiscus". Encyclopedia of Life (EOL). Retrieved 30 December 2021.
• Wright, Claud William; with John Hannes Callomon and M.K. Howarth (1996). Roger L. Kaesler (ed.). Mollusca 4 Revised, Cretaceous Ammonoidea in Treatise on Invertebrate Paleontology Part L. Boulder, Colorado and Lawrence, Kansas: The Geological Society of America & University of Kansas Press. p. 69.
• Arkell, W. J.; Furnish, W. M.; Kummel, Bernhard; Miller, A.K.; Moore, R.C.; Schindewolf, O.H. (1957). "Part L, Mollusca 4: Cephalopoda, Ammonoidea". In Raymond C. Moore (ed.). Treatise on Invertebrate Paleontology. Geological Society of America and University of Kansas Press. p. L371. ISBN 978-0-8137-3012-7 – via Internet Archive.