Evolution of tendon shape in Diphyabatrachia is influenced by size, phylogeny and locomotion

FRATANI, JÉSSICA; PONSSA MARIA LAURA; ABDALA VIRGINIA

Praga

Congreso; The 12th International Congress of Vertebrate Morphology; 2019

International Society of Vertebrate Morphologists (ISVM)

Tendonsare viscoelastic elements with unique mechanical properties. With aclose relation to movement, tendons function is mainly related to thetransmission, amplification and recycling of energy. In Anura,jumping is the principal locomotor challenge, and most relatedanatomical specializations have been observed in pelvic girdle andhindlimbs. Despite of a greatly specialized body plan, locomotorvariation in anurans goes beyond jumping, including specializationsfor swimming, burrowing, and climbing. On this study we applyGeometric Morphometrics method to test for morphological adaptationin three tendinous elements associated with the urostyle and hindlimbjoints. The variation of 99 species of Diphyabatrachia clade wasanalyzed as a study case, taking in consideration functional andecological aspects of species and their phylogenetic history.Diphyabatrachia includes jumping and climbing species of arborealhabitats (Centrolenidae) and jumpingspecies of long and short distances with terrestrial and aquatichabitats (Leptodactylidae). We found significant differences betweenlocomotor modes and habitat use regarding tendon shape, especially inthe patellar tendon of jumping-arborealspecies when compared to others. In all analyzed tendons, locomotormodes and habitat use showed interaction with size. Optimization andreconstruction of tendon shape revealed two putative synapomophies, abroad tendon of the longissimus dorsi for Leptodactylinae and anelongated patellar tendon for Centrolenidae. In addition, there wassignificant covariation of shape between the knee and the heel tendonshapes, which led us to propose a functional analogy between thesetwo structures. Allevidence points to an adaptive significance of tendon variation, yetthe results also showed a great influence of phylogeny. Therefore, itis possible to conclude that a combination of factors, rather thanone determinant variable, is influencing tendon evolution inDyphiabatrachia.