Banca de DEFESA: THAIS MATTOS ESTRUC

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : THAIS MATTOS ESTRUC
DATE: 17/04/2025
TIME: 15:00
LOCAL: on-line
TITLE:

Morphological Characterization of the Penis of Three Species of Leontopithecus Lesson, 1840 (Primates: Callitrichidae)

KEY WORDS:

copulatory organ, lion tamarin, primates, histology, stereology

PAGES: 87
BIG AREA: Ciências Biológicas
AREA: Zoologia
SUBÁREA: Zoologia Aplicada
SUMMARY:

The genus Leontopithecus includes primates endemic to the Atlantic Forest, with four described species, all threatened by habitat fragmentation and diseases such as yellow fever. This study aimed to characterize and quantify, both macroscopically and using histochemical, immunohistochemical, scanning electron microscopy (SEM), and stereological techniques, the penile elements of the species L. rosalia, L. chrysomelas, and L. chrysopygus, establishing morphometric parameters and inter- and intraspecific variations. Thirty penises
collected from formalin-fixed cadavers from the Centro de Primatologia do Rio de Janeiro (CPRJ) were analyzed. Macroscopic analyses were performed at the Laboratório de Ensino e Pesquisa em Morfologia de Animais Domésticos e Selvagens at the Universidade Federal Rural do Rio de Janeiro (UFRRJ); histological analyses were performed at the Laboratório de Histologia Integrativa at the Universidade Federal do Rio de Janeiro (UFRJ); scanning electron microscopy (SEM) was conducted at the Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO-UFRJ); and stereological analyses were carried out at the Laboratório de Biomorfologia Celular e Extracelular at the Universidade Federal Fluminense (UFF). Macroscopic analysis revealed that the penis of the three species had three parts: root, body, and glans. The average penis length was 3.27 ± 0.43 cm in L. rosalia, 3.37 ± 0.50 cm in L. chrysomelas, and 3.12 ± 0.53 cm in L. chrysopygus. No significant differences in length were found between the species. The root of the penis showed variations in length and diameter among the species: L. rosalia had a length of 0.78 ± 0.17 cm and diameter of 0.64 ± 0.29 cm; L. chrysomelas had 0.90 ± 0.16 cm in length and 0.63 ± 0.24 cm in diameter; and L. chrysopygus had 0.72 ± 0.18 cm in length and 0.45 ± 0.10 cm in diameter. In the root of the penis, the cavernous bodies were dorsal, with collagen fibers arranged irregularly and surrounded by a tunica albuginea that formed a median septum. In L. rosalia and L. chrysomelas, smooth muscle fibers were present. The body of the penis also showed variations in length and diameter: L. rosalia had 2.44 ± 0.41 cm in length and 0.24 ± 0.06 cm in diameter; L. chrysomelas had 2.20 ± 0.42 cm in
length and 0.33 ± 0.10 cm in diameter; and L. chrysopygus had 2.01 ± 0.41 cm in length and 0.30 ± 0.05 cm in diameter. The glans was covered by keratinized stratified squamous epithelium with spicules, with dermal papillae observed in L. chrysomelas. Distinct forms and sizes were observed in the glans between species. In L. rosalia, the length was 0.23 ± 0.02 cm and the diameter was 0.23 ± 0.03 cm; in L. chrysomelas, it was 0.27 ± 0.05 cm in length and 0.31 ± 0.06 cm in diameter; and in L. chrysopygus, it was 0.27 ± 0.04 cm in length and 0.28 ± 0.04 cm in diameter. The glans had a triangular shape in L. rosalia and L. chrysopygus, and a mushroom cap shape in L. chrysomelas. The penile bone was located in the dorsal region of the glans in L. rosalia and L. chrysopygus, while in L. chrysomelas, it was located in the cavernous body to the right of the median septum. SEM analysis revealed differences in the spicules of the glans, which were conical and directed toward the proximal region. The spicules in L. rosalia were short and horizontal, while in L. chrysomelas, they were arranged in a crescent shape. This study investigated the morphology and structure of the penis in three Leontopithecus species, revealing anatomical, histological, and morphometric differences among them, such as variations in length, diameter of the glans, and morphology of the penile bone. The analyses showed that the species exhibited distinct characteristics, such as a smaller urethral and cavernous body area in L. rosalia and a larger penile body diameter in L. chrysomelas. The results provide new insights into the evolution of penile morphology in primates and pave the way for future investigations on sexual selection, reproductive strategies, and sperm competition. 

COMMITTEE MEMBERS:
Externo à Instituição - ALCIDES PISSINATTI - CPRJ
Externo à Instituição - CARLOS AUGUSTO DOS SANTOS SOUSA - UFVJM
Externo ao Programa - 1281417 - LUCIANO DA SILVA ALONSO - nullInterno - 2181722 - MARCELO ABIDU FIGUEIREDO
Externo à Instituição - MAURICIO ALVES CHAGAS - UFF
Externo à Instituição - PAULO DE SOUZA JUNIOR - Unipampa
Externo à Instituição - YURI KARACCAS DE CARVALHO - UFF