Pelvic Cutaneous Musculature in Toads of the Genus Bufo

Abstract

which we have named the abdominal crenator. The gracilis minor muscle attaches posteriorly to the distal end of the femur and anteriorly to the pelvic abdominal skin by anterior and posterior fiber bundle groups. The anterior muscle fiber bundle group spreads out under, and attaches to, the pelvic skin on a curved line that approximates the anterior margin of an area of pelvic skin specialized for absorbing water from moist substrates. The posterior muscle fiber bundle group runs medially along the thigh and attaches to the posterior portion of the abdominal crenator muscle anteriorly and ventrally to the cloaca. Fibers from the gracilis minor interweave in a complex manner with anteriorly projecting fibers of the abdominal crenator forming a latticework-like arrangement beneath the pelvic skin. Interspecific comparisons show that the muscle complex is variable among species. We suggest that this muscle complex is part of a functional system that facilitates water absorption by the pelvic skin.