Taxonomic and morphometric revision of Alopiidae (Lamniformes) shark family: a qualitative holistic approach based on dental characters

While only three extant species are recognised, the fossil record suggests greater diversity, though classification remains contentious due to a reliance on isolated and interpreted dental fossils. To address this, the research combines quantitative geometric morphometric analysis of tooth shape with qualitative assessments of diagnostic features across both extant and putative fossil alopiid genera.

Analysis of a comprehensive dataset of fossil tooth images reveals that the current taxonomic framework lacks strong morphometric support. Notably, the fossil genus †‘Anotodus’ retroflexus exhibits strong morphometric similarity to the lamnid shark <i>Isurus oxyrhinicus</i>, yet retains key qualitative features that support its placement within Alopiidae, suggesting convergent evolution. Conversely, the Cretaceous genus †Paranomotodon aligns with Alopiidae in both morphometric and qualitative analyses, affirming its familial inclusion.