Using micro-ct scanning to study the morphology and evolution of the spine-shaped prepollex in anura (Chordata: Lissamphibia)

Abstract

The prepollex is a carpal element of anurans that exhibits extensive morphological diversity. Among this variety, it is developed into a conspicuous spine in clades nested in five distantly related families. Because it is used in male-male combats, this spine has an important role during reproductive period of territorial species. Its anatomy encompasses several muscles connected to distinct forearm skeletal elements. However, how hand muscles and prepollical elements are associated to each other and how this varies across clades is not well known. The character state transformation series leading to this convergent anatomy is also poorly understood. The functional morphology of these muscles and the role of the prepollex in social interactions make compelling an integrative and evolutionary study of the anuran prepollex. This project aims to study the comparative anatomy of the spine-shaped prepollex of Anura using microcomputed tomographic(microCT) scanning. This non-destructive procedure allows for detailed study of internal anatomy, even of species that are scarce in scientific collections. The project will focus on the morpho-anatomical differences of the spine-shaped prepollex, aiming to clarify its functional significance and evolutionary history in the clades where this important structure is present. (AU)