91.3 Saturday, Jan. 7 Force production by the forelimbs of salamanders and pectoral fins of mudskippers during terrestrial locomotion KAWANO, S.M.*; BLOB, R.W.; Clemson Univ.; Clemson Univ. email@example.com
Salamanders are often used to model the locomotor capacities of early tetrapods due to postural and morphological similarities. The fossil record provides evidence that terrestrial adaptations began in the anterior region of the body in tetrapodomorphs, but little data on salamander forelimb function is available to provide insights in this context. Three-dimensional ground reaction force (GRF) and kinematic data of isolated footfalls of the tiger salamander (Ambystoma tigrinum) forelimb were compared to similar data from the hindlimb to evaluate mechanical differences between these appendicular systems. Similar to reptiles, salamander forelimb and hindlimb force production exhibit both similarities and differences. For instance, the mean magnitude and orientation of the GRF is similar between the forelimb and hindlimb in salamanders, which may be due to the similar size and proportions of these limbs in the group. However, peak net GRF occurred much later in stance for the forelimb than the hindlimb. Comparison of salamander forelimb forces to preliminary GRF data from the pectoral fins of amphibious Periophthalmus mudskipper fish during terrestrial crutching suggest numerous similarities in mechanical performance between the pectoral appendages in these taxa, despite their drastically different morphologies. Further work on the locomotor biomechanics of the pectoral fin vs. limb for terrestrial locomotion of extant, amphibious fishes and salamanders will contribute towards our understanding of the locomotor capacities of tetrapodomorphs during the water-to-land transition in tetrapod evolution.