Anuran forelimb muscle tendinous structures and their relationship with locomotor modes and habitat use

DE OLIVEIRA-LAGÔA, SILVIA; CRUZ, FÉLIX B; AZÓCAR, DÉBORA L MORENO; LAVILLA, ESTEBAN O; ABDALA, VIRGINIA

Current Zoology

Oxford Academic

Año: 2019 vol. 65 p. 599 - 608

1674-5507

The interaction between organisms and their environment is central in functional morphology.Differences in habitat usage may imply divergent morphology of locomotor systems; thus,detecting which morphological traits are conservative across lineages and which ones vary underenvironmental pressure is important in evolutionary studies. We studied internal and externalmorphology in 28 species of Neotropical anurans. Our aim was to determine if internal morphology(muscle and tendons) shows lower phylogenetic signal than external morphology. In addition, wewanted to know if morphology varies in relation to the habitat use and if there are different functionalgroups. We found differences in the degree of phylogenetic signal on the groups of traits.Interestingly, postaxial regions of the forelimb are evolutionarily more labile than the preaxialregions. Phylomorphospace plots show that arboreal (jumpers and graspers) and swimmer frogscluster based on length of fingers and the lack of sesamoid, also reflected by the use of habitat.These functional clusters are also related to phylogeny. Sesamoid and flexor plate dimensions togetherwith digit tendons showed to be important to discriminate functional groups as well as use ofhabitat classification. Our results allow us to identify a ?grasping syndrome? in the hand of thesefrogs, where palmar sesamoid and flexor plate are absent and a third metacarpal with a bony knobare typical. Thus, a lighter skeleton, long fingers and a prensile handmay be key for arboreality.