PT  - JOURNAL ARTICLE
AU  - Maren Jansen
AU  - David Marjanović
TI  - The scratch-digging lifestyle of the Permian “microsaur” <em>Batropetes</em> as a model for the exaptative origin of jumping locomotion in frogs
AID  - 10.1101/2021.09.27.460658
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.09.27.460658
4099  - http://biorxiv.org/content/early/2021/09/27/2021.09.27.460658.short
4100  - http://biorxiv.org/content/early/2021/09/27/2021.09.27.460658.full
AB  - Recent studies have shown that the Triassic stem-frog Triadobatrachus lacked the ability to jump off, but nonetheless had the forelimb strength to withstand the impact of landing from a jump. We propose a hypothesis to resolve this pseudoparadox: the strengthened forelimbs are former adaptations to forelimb-based digging that later made jumping possible by exaptation.Micro-CT data from a skeleton of Batropetes palatinus reveal thin cortical bone, confirming Batropetes as terrestrial. Combining adaptations to walking and digging, confirmed by statistical analyses, Batropetes is thought to have searched for food in leaf litter or topsoil. We interpret Batropetes as having used one forelimb at a time to shove leaf litter aside. Batropetes may thus represent an analog or possibly a homolog of the digging stage that preceded the origin of Salientia.We discuss the possibility of homology with the digging lifestyles of other “microsaurs” and other amphibians.Competing Interest StatementThe authors have declared no competing interest.