Meeting Abstract
The general anuran body type, consisting of long hindlimbs, a short inflexible trunk, and short forelimbs is considered a specialization for jumping. However, some frogs primarily use a quadrupedal gait, characterized by limbs moving in diagonal pairs. It is unclear how the morphological specializations associated with jumping constrain the mechanics and kinematics of quadruped locomotion. In this study, we examined four frog species specialized for walking (Kassina senegalensis, Melanophryniscus stelzneri, Phrynomantis bifasciatus, Phyllomedusa hypochondrialis). We aimed to understand how the prominence of this novel quadrupedal gait correlates with a shift in limb morphology. We used 3D high-speed videography to examine whether limb kinematics, limb posture and body posture during walking function to compensate for differences in forelimb and hindlimb length. Our results suggest, frogs specialized for walking accommodate a quadrupedal gait with (1) an increase in relative forelimb length compared to the average anuran body plan and (2) by maintaining greater flexion in the hindlimb compared to the forelimb during walking. These features allow walking frogs to minimize body pitch and maintain a more symmetrical body posture during walking. The results of this study demonstrate how the evolution of novel gaits may lead to conflicts between diverse locomotor modes, and how potential constraints may be overcome through variation in limb morphology and kinematics.
