Quantification of ontogenetic change in Triassic ammonoids
Final Report Abstract
Investigations of the conch ontogeny of a large variety of Triassic ammonoids show that many of the developmental patterns of Palaeozoic ammonoids are repeated by their Triassic successors. Similarity does not only regard the general morphology of the adult conch, but also the number and length of growth intervals. The proportions in which the cardinal conch parameters conch width index, umbilical width index, and whorl expansion rate contribute to the total ontogenetic change are also similar in great detail. This is a surprising result because almost all Triassic ammonoids derived from very simple conch forms and simple conch ontogeny, which survived the end-Permian mass extinction event. Conch shapes were computer-simulated to figure out how minor deviations in the growth of ammonoids. These modelled ammonoid conchs were produced by modifications of the three conch parameters whorl height, whorl width, and apertual height. They allow an insight into the various modes of allometric growth; the illustration of the ontogenetic trajectories and their quantification allow for the detection of the mode of allometry.
Publications
- (2010): Quantification of ontogenetic change in Triassic ammonoids. – 8th International Symposium, Cephalopods – Present and Past, August 30 – September 3, 2010, Abstracts: 89
Simon, M.S. & Korn D.
- (2012): Ontogenetic patterns oft he Late Devonian ammonoid Cymaclymenia from Morocco. – Terra Nostra, Centenary Meeting oft he Paläontologische Gesellschaft, Programme, Abstracts, and Field Guides, 24-09.–29.09.2012: 90
Klein, C., Korn, D. & Keupp, H.
- (2012): Quantification of ontogenetic allometry in ammonoids. – Evolution & Development 14(6): 501-514
Korn, D.
