Morphological Characterization of the Penis of Three Species of Leontopithecus (Lesson, 1840)
lion tamarin, morphometry, microscopy, reproductive system
The genus Leontopithecus includes four species of primates endemic to the Atlantic
Forest: L. chrysomelas, L. chrysopygus, L. rosalia, and L. caissara, which face threats
such as habitat fragmentation, hunting, and yellow fever outbreaks, leading to drastic
population declines. This study investigated the male reproductive morphology of L.
chrysomelas, L. chrysopygus, and L. rosalia, using histochemical, immunohistochemical,
and electron microscopy techniques to characterize the penis. Thirty penises from adult
specimens that died in captivity at the Rio de Janeiro Primatology Center were analyzed.
The study identified that the penis of all three species is pendulous and divided into root,
body, and glans, with an internal structure typical of mammals, consisting of cavernous
and spongy bodies. Interspecific morphological differences were found in the diameter of
the body and glans, with L. chrysomelas presenting a mushroom-shaped glans, while the
other two species have triangular glans. Correlations were observed between body length
and penile length in some species. The histological description of the penis and its erectile
tissues contributed to a better understanding of the functions performed by the structures
involved in the complex mechanism of erection and relaxation. The study provided
unprecedented information on the penis morphology of three Leontopithecus species,
expanding knowledge of the reproductive biology of these animals and serving as a basis
for future research on the variability of penile morphology among primates. These findings
are relevant to conservation programs, especially in assisted reproductive management,
contributing to the genetic preservation of these endangered species.