Meeting Abstract

120.5  Tuesday, Jan. 7 11:30  Histological Investigation of the Adult Male American Alligator Phallus MOORE, BC*; GUILLETTE, LJ; Louisiana Tech University, Ruston; Medical University of South Carolina, Charleston

Alligators are seasonal breeders with a courtship and breeding period occurring in April and May concurrent with a peak in circulating testosterone. However, the specific mechanics of the reproductive act are not fully understood. To address this question, we collected adult male phalli from animals captured at Merritt Island National Wildlife Refuge, Florida in April 2010 for paraffin histology analysis. Investigation of the collagen fiber architecture of the phalli using picrosirius red staining with circularly polarized light revealed pronounced structural differences in fiber thickness distribution and orientation between the shaft, cuff/glans, and distal tip. The morphology of the semen-conducting sulcus spermaticus displayed greater elaboration and convolution of its secretory epithelium, as compared to a previous investigation of the sulcus of immature male phalli. Further, pronounced muscle bundles lining the length of the sulcus speak to an ejaculatory function. Histochemical staining revealed a complex, mucin-rich glandular epithelium covering various regions of the phallus with numerous, differing adjacent cell types. The cuff and proximal tip of the phallus show evidence of an inflation function with an elaborate sinus defined by vascularized connective tissues. These and other morphological observations will be discussed in the context of a more comprehensive understanding of functional intromission and insemination.