Comparative morphology of modern and fossil coleoid jaw apparatuses
Abstract:Current knowledge about the jaw apparatuses (i.e. beaks or mandibles) of modern and fossil cephalopods is reviewed with special reference to those of coleoids. In modern cephalopods, the jaw apparatus is housed in the buccal mass and consists of articulated upper and lower jaws, which have a special function to bite and cut up a prey with the aid of the surrounding jaw muscles. Both the upper and lower jaws are composed mainly of a darkly tinted chitin-protein complex. The jaw apparatuses of extant coleoids are characterised by a posteroventrally elongated inner lamella in the lower jaw and the absence of a calcareous jaw element. These features are clearly distinguishable from those of nautilid jaws, which possess a substantially reduced inner lamella of the lower jaw and calcareous tips in both the upper and lower jaws. Recent discoveries of well-preserved jaws referable to vampyropod and possibly teuthid coleoids from the Late Cretaceous of the North Pacific fill the gap in the relatively poor fossil record of the Coleoidea; they clearly demonstrate that large non-belemnoid coleoids existed in this bioprovince together with ammonoids and nautilids.
Document Type: Research Article
Publication date: 2012-10-01
More about this publication?
- Neues Jahrbuch für Geologie und Paläontologie continuously publishes current original contributions from all fields of geology, ever since its foundation in 1807. All published contributions are in the English language.
- Editorial Board
- Information for Authors
- Subscribe to this Title
- Ingenta Connect is not responsible for the content or availability of external websites