Contribution
Dental paleopathologies in †Pycnodontiformes (Osteichthyes: Actinopterygii)
Capasso, Luigi; Ebert, Martin; Witzmann, Florian
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen Band 311 Heft 3 (2024), p. 299 - 341
68 références bibliographiques
publié: Jul 18, 2024
manuscrit accepté: Apr 8, 2024
manuscrit reçu: Feb 26, 2024
ArtNo. ESP155031103003, Prix: 29.00 €
Abstract
This study provides the first overview of dental pathologies in pycnodonts, a diverse group of fossil actinopterygians that existed from the end of the Middle Triassic to the end of the Eocene. We considered 100 pathological pycnodont specimens, 71 of which were studied by first-hand examination and 29 by consulting published descriptions. Diagnoses were performed based on macroscopic and microscopic observation and, where necessary, also with the help of radiographic and tomographic examinations. The 100 pathological specimens belong to 27 genera and 57 species, which represent 26.5% of all known genera and 10.2% of all known species. The most frequent anomalies are (i) tooth malpositions, (ii) supernumerary teeth and (iii) shape anomalies of single teeth, including microdotia and exceptional cases of macrodontia. Dental pathologies in pycnodonts are unevenly distributed over geological time: they were much more common in the Late Triassic and Jurassic, while they had become much rarer during the Cretaceous. In a single pycnodont population from the Eocene of Mali, 54.5% of the specimens are affected by dental anomalies, probably as the result of pathogenic drift in an isolated population. The uneven distribution of tooth anomalies over the long period of pycnodont evolution suggests that their dentition was initially not ordered into distinct dental rows; this order was acquired only in the most derived forms. To consolidate these hypotheses it will be necessary to expand the paleopathological statistics with more specimens.
Mots-clefs
Congenital malformations • dental anomalies • dental apomorphies • dentition • pycnodont evolution • tooth replacement