Meeting Abstract
Shape and size of the bat baculum (os penis) are established taxonomic characters, but micromorphology of baculum and penis have seldom been studied in bats. This study provides a foundation for further functional research by generating new data on 2D and 3D micromorphology of the Pipistrellus pipistrellus penis. Correlating 3D x-ray microtomography (microCT) imaging with serial, surface stained, undecalcified ground sections enables us to get a precise histomorphological evaluation of a larger number of samples and of other species. Ground sections of the penes of 4 bats (2 subadult) were compared with microCT images of the bacula and some iodine-stained penes of P. pipistrellus (adult n=30, subadult n=22), P. pygmaeus (n=24), P. hanaki (n=9), and P. nathusii (n=11). The baculum in the studied species consists of a proximal bifurcated base, a long, slender shaft, and a small, forked distal tip. The base consists of woven bone and contains a medullary cavity with fatty marrow. The shaft of the baculum consists of lamellar bone around a central vascular canal, surrounded by woven bone in a part of the shaft. Distally the shaft consists of woven bone. The urethra and corpus spongiosum lie ventral of the corpora cavernosa and the baculum. In the subadult bats, the baculum consisted of woven bone completely and its base was not fully developed. The combination with histomorphological techniques enabled a more precise interpretation of the histological structures shown in microCT images from all four Pipistrellus species.
