Compliant Substrates Disrupt Elastic Energy Storage in Jumping Tree Frogs.

Arboreal frogs navigate complex environments and face diverse mechanical properties within their physical environment. Such frogs may encounter substrates that are damped and absorb energy or are elastic and can store and release energy as the animal pushes off during take-off. When dealing with a compliant substrate, a well-coordinated jump would allow for the recovery of elastic energy stored in the substrate to amplify mechanical power, effectively adding an in-series spring to the hindlimbs.

Morphological and kinematic specializations of walking frogs.

The anuran body plan is defined by morphological features associated with saltatory locomotion, but these specializations may have functional consequences for other modes of locomotion. Several frog species use a quadrupedal walking gait as their primary mode of locomotion, characterized by limbs that move in diagonal pairs. Here, we examine how walking species may deviate from the ancestral body plan and how the kinematics of a quadrupedal gait are modified to accommodate the anuran body plan.

A revised metric for quantifying body shape in vertebrates.

Vertebrates exhibit tremendous diversity in body shape, though quantifying this variation has been challenging. In the past, researchers have used simplified metrics that either describe overall shape but reveal little about its anatomical basis or that characterize only a subset of the morphological features that contribute to shape variation. Here, we present a revised metric of body shape, the vertebrate shape index (VSI), which combines the four primary morphological components that lead to shape diversity in vertebrates: head shape, length of the second major body axis (depth or width), and shape of the precaudal and caudal regions of the vertebral column.