Estudo anatômico do cerebelo de Bradypus variegatus, Schinz 1825 (Mammalia: Pilosa)

Abstract

The common sloth (Bradypus variegatus, Schinz 1825) is an arboreal quadruped species belonging to the Class Mammalia, Superorder Xenarthra and Family Bradypodidae. In South America, it inhabits from northern Colombia to southwestern Venezuela, southern Ecuador, eastern Peru and Bolivia, in addition to being present in Brazil. In the case of organic systems, bradypodids have certain anatomical peculiarities such as double posterior vena cava, six to nine cervical vertebrae depending on the species; common duct for the urinary and genital tracts in females and internal testes in males. However, there are few studies concerning the central nervous system, especially when comparing them to domestic animals. Therefore, the present work aims to analyze, describe and morphologically characterize the cerebellar structures of the Bradypus variegatus sloth. 10 animals were used for the analyses, obtained after natural death from the Wild Animal Screening Center, and fixed in 20% formaldehyde. Reserved in numbered tanks in 30% saline solution, the animals also received individual identifications. The skullcap and brain were removed to gain access to the cerebellum. The organ was separated from the brain stem by a cross section and preserved in a 20% formaldehyde solution in glass reservoirs. The cerebellar structure of common sloths, in both males and females, was, on average, 1.21 cm long by 1.62 cm wide. From the analysis carried out, it is concluded that the B. variegatus cerebellum has an ovoid morphology, slightly flattened in the cranial and caudal lateral portions, presenting the worm in the central region, right and left hemispheres with lobes and fissures, which corroborate with descriptive studies performed on humans and domestic animals.