Morphological disparity and ontogeny of the endemic heteromorph ammonite genus Aegocrioceras (Early Cretaceous, Hauterivian, NW-Germany)

Journal article
(Original article)


Publication Details

Author(s): Hoffmann R, Weinkauf M, Wiedenroth K, Goeddertz P, de Baets K
Journal: Palaeogeography, Palaeoclimatology, Palaeoecology
Publication year: 2019
ISSN: 0031-0182


Abstract

Despite the fact that heteromorph ammonites often show a large range of intraspecific variation, that variation has rarely been quantified. Here, we quantify the intraspecific variation and ontogeny of 85 newly collected specimens of the Hauterivian endemic ammonite genus Aegocrioceras. All specimens were collected from concretions in the recently exposed bed 82 in the clay pit Resse in NW Germany (Lower Saxony Basin). Data for the conch morphology (diameter, whorl height, whorl interspace, rib spacing) were collected in 45° steps using the new software CONCH©. The CONCH© software will be made officially available with this publication. All ammonites were a priori identified as A. bicarinatum or A. semicinctum. An assessment of the intra- and interspecific variation as well as the ontogeny of this assemblage demonstrates the presence of just one species, i.e., A. bicarinatum. Comparison with the type material of A. bicarinatum and A. semicinctum reveals a large morphological overlap of different conch parameters and does not support a separation of both forms as distinct species. The analyzed assemblage of A. bicarinatum has a high variation in conch morphology including whorl interspace, umbilical width, and whorl expansion. Furthermore, the changes in intraspecific variation through ontogeny were quantified and the presence or absence of sexual dimorphism within the assemblage is discussed.


FAU Authors / FAU Editors

de Baets, Kenneth PD Dr.
Lehrstuhl für Paläoumwelt


External institutions
Rheinische Friedrich-Wilhelms-Universität Bonn
Ruhr-Universität Bochum (RUB)
Université de Genève (UNIGE) / University of Geneva


How to cite

APA:
Hoffmann, R., Weinkauf, M., Wiedenroth, K., Goeddertz, P., & de Baets, K. (2019). Morphological disparity and ontogeny of the endemic heteromorph ammonite genus Aegocrioceras (Early Cretaceous, Hauterivian, NW-Germany). Palaeogeography, Palaeoclimatology, Palaeoecology. https://dx.doi.org/10.1016/j.palaeo.2019.01.020

MLA:
Hoffmann, René, et al. "Morphological disparity and ontogeny of the endemic heteromorph ammonite genus Aegocrioceras (Early Cretaceous, Hauterivian, NW-Germany)." Palaeogeography, Palaeoclimatology, Palaeoecology (2019).

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Last updated on 2019-19-01 at 13:50

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