Titel
Njoerdichthys dyckerhoffi gen. et sp. nov. (Pycnodontiformes, lower Turonian) northward migration caused by the Cretaceous Thermal Maximum
Autor*in
Frank Wiese
Georg-August-Universität Göttingen, Department of Geobiology, Geoscience Centre
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Abstract
A new pycnodont taxon, Njoerdichthys dyckerhoffi gen. et sp. nov., from the Turonian of the Lower Saxony Basin of Germany is described and its systematic positions is established based on phylogenetic analyses of three specimens using slightly altered data matrices. All analyses display some differences to previous analyses but show very similar results to each other apart from the interpretation of the position of several taxa such as, e.g., Palaeobalistum. The new pycnodontiform specimens from northwestern Germany are unambiguously identified as a derived member of Pycnodontidae with close relationships to Abdobalistum and Nursallia? goedeli because of the unique combination of characters. One of the three specimens represents a juvenile form. Its morphological characters are limited, but it shares some characters with Njoerdichthys dyckerhoffi gen. et sp. nov. and is consequently allocated to the new taxon. The systematic placement of the new taxon, Njoerdichthys gen. nov., within Pycnodontidae is surprising since it does not display the one autapomorphic character (postparietal brush-like extension for muscle attachment) previously proposed to define this clade, but rather displays a combination of derived and homoplastic characters indicating that the definition of supra-generic taxa needs to be re-evaluated in the future by including more and new taxa. The distribution of pycnodontiform fishes in the Cretaceous appears to concur with changes in global climatic conditions, where high upper-ocean temperatures and high sea levels allow these fishes to migrate into higher latitudes as evidenced by the occurrence of the new taxon and Anomoeodus subclavatus in the Campanian of Sweden.
Stichwort
ActinopterygiiPycnodontidaePhylogenyClimateTuronianPalaeobiogeogeography
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
Erschienen in
Titel
Cretaceous Research
Band
116
ISSN
0195-6671
Erscheinungsdatum
2020
Publication
Elsevier BV
Projekt
Kod / Identifikator
P29796-B29
Erscheinungsdatum
2020
Zugänglichkeit
Rechteangabe
© 2020 The Author(s)
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