ammonoid

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ammonoid

(ăm′ə-noid′)
n.
An extinct cephalopod mollusk of the subclass Ammonoidea of the Devonian to Cretaceous Periods, having a straight or coiled chambered shell characterized by more or less intricate suture patterns where the septa between individual chambers join the outer shell wall.
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References in periodicals archive ?
(4) Ammonoids were devastated by the largest extinction in Earth's history, at the end of the Permian Period, as well as Late Cretaceous mass extinction.
For several more years, Tim, focusing increasingly on the marine Triassic and its ammonoid fauna, divided his field time between the Arctic Islands and northeastern British Columbia, where the upper part of the Triassic stratigraphic column is particularly well developed.
Septal complexity in ammonoid cephalopods increased mechanical risk and limited depth.
The mean complexity of a substructure increased in ammonoids over the first part of their history, but declined after that.
The ammonoids studied were deposited in museums (Museu de Valltorta: MV, Valencia; Conjunto Paleontologico de Teruel: CPT, Aragon) or in university collections (Colleccions de Paleontologia de la Universitat Autonoma de Barcelona: PUAB, Bellaterra, Catalunya).
The surveys in the present study indicate that more than 800 ammonoids and 300 belemnoids are present in the tile of the shopping complex.
Of particular interest among our discoveries were several hundred specimens of cephalopod ammonoids, including many that had never been found anywhere in the world before.
Geometric analysis of shell coiling: Coiling in ammonoids. Journal of Paleontology 41:43-65.
However, over the crinoidal tract a set of red, ferruginous detritic limestones appear, fol lowed by an alternation of yellowish marls and marly/ silty limestones levels with brachiopods, some ammonoids and trace-fossils of Thalassinoides type.