Astreptoceras

Astreptoceras; Temporal range: Campanian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Ammonoidea
Order:	Ammonitida
Suborder:	Ancyloceratina
Superfamily:	Turrilitoidea
Family:	Diplomoceratidae
Subfamily:	Polyptychoceratinae
Genus:	Astreptoceras; Henderson, 1970

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.

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

^ Sepkoski, Jack (2002). "Sepkoski's Online Genus Database". Retrieved 2014-05-28. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
^ Henderson, R.A. 1970 Ammonoidea from the Mata Series (Santonian-Maastrichtian) of New Zealand. Special papers in palaeontology, 6: 81 p.

Nomenclator Zoologicus [1]
Sepkoski's list of cephalopod genera [2]

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[Sepkoski_Ceph-1] Sepkoski, Jack (2002). "Sepkoski's Online Genus Database". Retrieved 2014-05-28. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)

[2] Henderson, R.A. 1970 Ammonoidea from the Mata Series (Santonian-Maastrichtian) of New Zealand. Special papers in palaeontology, 6: 81 p.

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