Hamulina Explained

Hamulina is an extinct ammonoid cephalopod genus belonging to the family Hamulinidae.^[1] These cephalopod were fast-moving nektonic carnivores. They lived during the Cretaceous period, Barremian age. The type species is Hamulina astieriana.

Description

It may be large. The whorl section generally is increasing rapidly. The short final shaft is generally straight or curved. The main shaft is with dense, fine, prorsiradiate minor ribs and distant, periodic, weakly trituberculate major ribs. The minor ribs are weakened or disappearing on hook and final shaft. The major ribs are strengthened and approximating. The ammonitic suture is finely divided.

Distribution

Fossils of these cephalopods have been found in rocks of Cretaceous of Bulgaria, Colombia (Santa Rosa de Viterbo, Boyacá), Hungary, Italy, Mexico, Spain, Trinidad and Tobago.^[2]

Further reading

• Web site: Hamulina . mindat.org . 2 May 2022.
• Book: [[Claud William Wright |Wright C.W.]] with J.H. Callomon and M.K. Howarth . 1996 . Mollusca 4 Revised: Cretaceous Ammonoidea . 4 . Treatise on Invertebrate Paleontology Part L . Roger L. Kaesler . Boulder, Colorado and Lawrence, Kansas . The Geological Society of America & University of Kansas Press . registration . 231-232 . Internet Archive.
• Book: . Furnish, W. M. . Kummel, Bernhard . Miller, A.K. . Moore, R.C. . Schindewolf, O.H. . 1957 . Part L, Mollusca 4: Cephalopoda, Ammonoidea . Treatise on Invertebrate Paleontology . Geological Society of America and University of Kansas Press . Raymond C. Moore . Raymond Cecil Moore . registration . L215 . Internet Archive.
• Sepkoski, Jack Online Genus Database – Cephalopodes

Notes and References

1. with and (1996), Mollusca 4 Revised, Cretaceous Ammonoidea, vol. 4, in Treatise on Invertebrate Paleontology, Part L (Roger L. Kaesler ed.), Boulder, Colorado: The Geological Society of America & Lawrence, Kansas: University of Kansas Press, pp. 231, 232.
2. Web site: Hamulina . Fossilworks . 2 May 2022.