Astreptoceras

Astreptoceras is an extinct upper Cretaceous ammonoid cephalopod named by Henderson in 1970. Fossils belonging to this genera have been found in Antarctica and New Zealand.

Astreptoceras
Temporal range:
Scientific classification
Kingdom:
Animalia
Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Ammonoidea
Order:
Ammonitida
Suborder:
Ancyloceratina
Superfamily:
Turrilitoidea
Family:
Diplomoceratidae
Subfamily:
Polyptychoceratinae
Genus:
Astreptoceras

Henderson, 1970

The only described species is Astreptoceras zelandicum (Marshall, 1926). It is a small heteromorph ammonite with almost circular cross-section of the shell. Shell has probably only one straight shaft that is initially without ribs and constrictions. At diameter of about 2 mm there appears first constrictions and at late growth stages, these can be preceded by a collar and shallow secondary constriction. Weak ribs occurs at late growth stages.[2]

References
  1. Sepkoski, Jack (2002). "Sepkoski's Online Genus Database". Retrieved 2014-05-28.
  2. Henderson, R.A. 1970 Ammonoidea from the Mata Series (Santonian-Maastrichtian) of New Zealand. Special papers in palaeontology, 6: 81 p.
  • Nomenclator Zoologicus
  • Sepkoski's list of cephalopod genera


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