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- Title
The black layer in cephalopods from the German Muschelkalk (Triassic).
- Authors
Klug, Christian; Korn, Dieter; Richter, Ute; Urlichs, Max
- Abstract
Thin, dark, probably phosphatic coatings were found on the dorsum in front of and sometimes behind the aperture of 50 specimens ofParaceratitesandCeratites(Ammonoidea) belonging to 14 species and subspecies and in three specimens ofGermanonautilus, all from the Middle Triassic of Germany. The proportions, occurrences, position, outline, and preservation in fossil Nautiloidea and Ammonoidea (originally organic matter) of this structure support the hypothesis that it is homologous with the black layer in RecentNautilusandAllonautilus. It is not yet possible to test whether these cephalopods show homologous styles of the development of these structures or whether the black layer can be identified in a common ancestor. In contrast to many ammonoids,CeratitesandParaceratites, most Palaeozoic ammonoids, and some Mesozoic ammonoids probably did not have lower mandibles that were suitable for the closure of the aperture. They probably possessed a dorsally extending mantle (supracephalic mantle fold) and a hood, as in RecentNautilusandAllonautilus, that was attached to the black layer. This interpretation is corroborated by a similar morphology of the black layer in an adult specimen of the nautilidCenocerasfrom the South German Middle Jurassic and three specimens ofGermanonautilusfrom the South German Middle Triassic (both Nautiloidea).
- Subjects
MUSCHELKALK (Germany); MOLLUSKS; SQUIDS; PHOSPHATE fertilizers; TRIASSIC paleopedology
- Publication
Palaeontology, 2004, Vol 47, Issue 6, p1407
- ISSN
0031-0239
- Publication type
Article
- DOI
10.1111/j.0031-0239.2004.00422.x