A unique hybodontiform skeleton provides novel insights into Mesozoic chondrichthyan life

Autor(en)
Sebastian Stumpf, Faviel Alejandro López Romero, R. Kindlimann, Frederic Lacombat, Burkhard Pohl, Jürgen Kriwet
Abstrakt

Asteracanthus was one of the most common Mesozoic hybodontiform chondrichthyans, given that remains traditionally referred to this genus have been reported almost worldwide from Middle Triassic to Late Cretaceous strata so far. Asteracanthus was erected by Louis Agassiz for Late Jurassic fin spines with stellate tubercles. Later, Arthur Smith Woodward synonymized Strophodus, originally introduced by Agassiz for distinctive crushing teeth of Triassic–Cretaceous age, with Asteracanthus based on associated teeth and spines from the English Middle Jurassic. This taxonomic scheme has been accepted for more than 130 years until now, although articulated material has never been found. Here, we present a unique hybodontiform skeleton from the German Late Jurassic, displaying a striking combination of characters: tuberculate dorsal fin spines reminiscent of Asteracanthus, and multicuspid teeth that markedly differ from the crushing teeth previously referred to this genus. Using qualitative and quantitative approaches, we compared its fin spines with those that were found in association with Agassiz’s Strophodus teeth, providing evidence that Asteracanthus and Strophodus in fact represent two valid genera distinct from all other hybodontiforms. Morphological features that distinguish fin spines of Strophodus from those of all other hybodontiforms include a straight anterior border and distally distributed posterior denticles. These observations led us to present an emended diagnosis for Asteracanthus. Dentally, Asteracanthus shows strong resemblance to Hybodus, but it otherwise lacks a palatobasal process on the palatoquadrate. Therefore, and in the absence of any reliable phylogenetic framework, we recommend treating Asteracanthus as incertae familiae until hybodontiform
interrelationships are resolved.

Organisation(en)
Institut für Paläontologie
Externe Organisation(en)
Haimuseum und Sammlung R. Kindlimann, Interprospekt Group AG, Wyoming Dinosaur Center
Journal
Papers in Palaeontology
Band
7
Seiten
1479-1505
Anzahl der Seiten
27
ISSN
2056-2799
DOI
https://doi.org/10.1002/spp2.1350
Publikationsdatum
01-2021
Peer-reviewed
Ja
ÖFOS 2012
105118 Paläontologie
Schlagwörter
ASJC Scopus Sachgebiete
Palaeontology
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/a-unique-hybodontiform-skeleton-provides-novel-insights-into-mesozoic-chondrichthyan-life(d5b14dc8-5479-4744-9267-1b669e55979a).html