Meeting Abstract
Typical frog tadpoles are filter feeders and lack a digestively active stomach. Only later, during metamorphosis, do they develop a functional stomach that allows the shift to feeding on larger prey as an adult. The tadpole of Lepidobatrachus laevis, however, is different: it develops an adult-like stomach during embryogenesis and is capable of feeding on larger prey as a tadpole. Consequently, L. laevis does not undergo a significant dietary shift at metamorphosis. Earlier studies of L. laevis lay the foundation for studying how this unusual tadpole stomach morphology develops. However, the complete course of stomach organogenesis has not been described and there is no detailed comparison to typical frog models. This study compares gut development in L. laevis to that in two other frogs, Xenopus tropicalis and Bombina orientalis, whose guts follow a more stereotypical (for anurans) developmental trajectory. Goals are to assess how similar the larval stomach of L. laevis is to a typical adult frog stomach; to determine if its embryonic development parallels stomach metamorphosis in X, tropicalis and B. orientalis; and to document what degree of change it undergoes during metamorphosis. Histological staining is performed with hematoxylin and eosin to characterize general features, Alcian blue-periodic acid Schiff staining to reveal mucins, and Mallory’s trichrome staining to trace development of connective tissues. Additionally, tissues are immunostained to show the onset and amount of pepsin production. This analysis will provide a greater understanding of the evolution of developmental modules, their role in the diversification of amphibian life histories, and how that diversification enables changes in diet and niche.
