The Italian record of the Cretaceous shark, Ptychodus latissimus Agassiz, 1835 (Chondrichthyes; Elasmobranchii)

PeerJ

article

Manuel Amadori¹  Jacopo Amalfitano²  Luca Giusberti²  Eliana Fornaciari²  Giorgio Carnevale³  Juergen Kriwet¹ 

[1] University of Vienna, Department of Paleontology;Dipartimento di Geoscienze, Università degli Studi di Padova;Dipartimento di Scienze della Terra, Università degli Studi di Torino

关键词: Fossil sharks;    Taxonomy;    Heterodonty;    Durophagy;    Upper Cretaceous;    Veneto region;   

DOI  :  10.7717/peerj.10167

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Associated and isolated teeth of the extinct elasmobranch Ptychodus latissimus Agassiz, 1835 from the Upper Cretaceous Scaglia Rossa pelagic limestone of northern Italy are described and discussed here in detail for the first time. The dentition of this widely distributed species consists of low-crowned molariform teeth that exhibit marked and strong occlusal ornamentations suitable for crushing hard-shelled prey. The associated tooth sets and isolated teeth analyzed here are heterogeneous in size and crown outline, but unambiguously belong to a single species. Re-examination of this Italian material consisting of ca. 30 specimens mostly coming from historical collections allows for a rigorous assessment of the intraspecific variability of P. latissimus, including the identification of three different tooth “morphotypes” based on their positions within the jaws. The relatively flat crowns and occlusal sharp and thick ridges indicate a high adaptation for crushing hard-shelled prey in P. latissimus indicating that the durophagous adaptations of this species were certainly more pronounced than in all other species of Ptychodus. We hypothesize that P. latissimus was a third-level predator occupying habitats with abundant thick-shelled prey, such as inoceramid bivalves and ammonites.

【 授权许可】

CC BY