Genital morphology of the male South American fur seal (Arctocephalus australis) and biological implications

Male capacity for spreading genes to a great number of descendents and to determine population dynamics depend directly on the genital organs. Morphological studies in pinnipeds are scarce and the functional meaning of some characteristics has never been discussed. We hypothesized that Arctocephalus australis (A. australis) shows morphophysiological adaptations in order to guarantee the perpetuation of the species in the unique annual mating season. Seven males, dead from natural causes, had their genital organs collected and fixed for morphological description. Some features differ from other described mammalian males and are closely related to the biology and reproductive cycle of this species, as the scrotal epidermis, absence of glandular portion in the ductus deferens and spermatogenic epithelium suggest a recrudescent testis period. The corona glandis exhibits a singular arrangement: its erectile border looks like a formation of petals and its association with the os penis gives a "lily-flower" form to this region. We propose the name margo petaliformis to this particular erectile border of the corona glandis because of its similarity to a flower corola. The male genital organs of A. australis show morphological features compatible with adaptation to environment requirements and reproductive efficiency.

Morphology of accessory genital glands of spotted paca(Agouti paca Linnaeus, 1766)

The spotted paca is the second largest rodent in Brazil, where it is of great economic interestin impoverished regions in view of its prominence as a low-cost source of protein. Littleis known about the morphology of the accessory genital glands of this species. Thus, westudied the position and morphology of the genitals in ten adult male spotted pacas. Theanimals were divided into two groups, five animals were used for fixing of samples in 10%aqueous formaldehyde for macroscopic studies and the other five animals were designatedfor microscopic analysis. These were arranged in pairs and had the vesicular, prostate,coagulating and bulbourethral glands identified, being structured as mucous glands, whichlead into the pelvic urethra. It was concluded that the accessory genital glands found in thepaca are the same as those found in most rodents, showing similar histological aspects