Feeding biomechanics of Late Triassic Metoposaurids


A new paper has been published in Journal of Anatomy studying the paleoecology of extinct amphibian Temnospondyli. The study aims to expand upon the paleoecological interpretations of these animals using 3D Finite Element Analyses (FEA) because the paleoecology of metoposaurids is controversial; they have been historically considered passive, bottom-dwelling animals, waiting for prey on the bottom of rivers and lakes or they have been suggested to be active mid-water feeders.

Skulls from two taxa, Metoposaurus krasiejowensis, a gigantic taxon from Europe, and Apachesaurus gregorii, a non-gigantic taxon from North America, were analyzed under different biomechanical scenarios. Both 3D models of the skulls were scaled to allow comparisons between them and reveal that the general stress distribution pattern found in both taxa is clearly similar in all scenarios. In light of our results, both previous hypotheses about the paleoecology of these animals can be partly merged: metoposaurids probably were ambush and active predators, but not the top predators of these aquatic environments. To demonstrate that the stress distribution is similar in both scenarios we used the new methodology proposed by Marcé-Nogué et al. 2016 in “Accounting for differences in element size and homogeneity when comparing Finite Element models: Armadillos as a case study” which facilitates the comprehension.

imatge-boxplots-escalats

The FEA results demonstrate that they were particularly efficient at bilateral biting, and together with their characteristically anteropositioned orbits, optimal for an ambush strategy. Nonetheless, the results also show that these animals were capable of lateral strikes of the head, suggesting active hunting of prey.

Regarding the important skull size differences between the taxa analyzed, our results suggest that the size reduction in the North American taxon could be related to drastic environmental changes or the increase of competitors. The size reduction might have helped them expand into new ecological niches, but they likely remained fully aquatic, as are all other metoposaurids.

+ more info: http://onlinelibrary.wiley.com/wol1/doi/10.1111/joa.12605/abstract

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