Meeting Abstract
The distal glans of the Alligator mississippiensis phallus is an inflatable structure that engorges to form a cup-like shape during copulation to putatively facilitate effective gamete transfer and increase fertilization probability. Previous research has demonstrated the presence of extensive cavernous vascular spaces in the glans tissues that engorge via increased blood flow through paired vessels running the length of the ventral phallus. Here we exploit these blood vessels to artificially inflate the glans tissues and quantitatively measure the shape change during this transition from flaccid to copulatory states. Using dissected necropsy tissues, we inflated the tissues using fluid pressure created through a needle and formalin-filled syringe while impeding back flow out the phallus by ligating the base. 3D wireframes of glans tissues before and after inflation were acquired using 123D Catch (Autodesk). Tissue expansion was measured by assessing distance changes between given tissue landmarks and calculating wireframe volumes. A better understanding of how the alligator phallus achieves a copulatory state lays the foundation for later study of how this morphology interfaces with female cloacal tissues and facilities insemination.
