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

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

Current Zoology

Oxford University Press

Año: 2018 vol. 00 p. 1 - 19

1674-5507

The interaction between organisms and their environment is central in functional morphology. Differences in habitat usage mayimply divergent morphology of locomotor systems; thus, detecting which morphological traits are conservative across lineages andwhich ones vary under environmental pressure is important in evolutionary studies. We studied internal and external morphology in28 species of Neotropical anurans. Our aim was to determine if internal morphology (muscle and tendons) shows lower phylogeneticsignal than external morphology. Additionally, we wanted to know if morphology varies in relation to the habitat use and if there aredifferent functional groups. We found differences in the degree of phylogenetic signal on the groups of traits. Interestingly, postaxialregions of the forelimb are evolutionarily more labile than the preaxial regions. Phylomorphospace plots show that arboreal (jumpersand graspers) and swimmer frogs cluster 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 together with digit tendons showed tobe important to discriminate functional groups as well as use of habitat classification. Our results allow us to identify a ?graspingsyndrome? in the hand of these frogs, where palmar sesamoid and flexor plate are absent and a third metacarpal with a bony knob aretypical. Thus, a lighter skeleton, long fingers and a prensile hand may be key for arboreality.