RESUMO
Background: The black-tufted ear marmoset, Callithrix penicillata, is an endemic primate from Brazil, distributed among Cerrado and Atlantic Forest vegetation. Most of the congenital malformations from the spinal cord arises from failures in the neural tube closure. Those failures result in an opened dorsal arch of one or more vertebrae are referred as spina bifida. In the occulta form, the condition is asymptomatic because spinal cord and meninges remain in the normal position. When the meninges become distended with fluid (myelomeningocele), the phenomenon is called spina bifida cystica. In these cases, the spinal cord protrudes into the subarachnoid space and the nerve roots may become displaced, causing neurological defi cits. When this defect allows leakage of cerebrospinal fluid through the skin, it is characterized as the open form. This article reports the findings of the first case of spina bifida occulta in an adult male of Callithrix penicillata collected dead in a brazilian highway. Case: A cadaver of a young-adult, male, black-tufted ear marmoset (Callithrix penicillata) was founded at km 103 of BR-116 highway in the city of Guapimirim, Rio de Janeiro State, Brazil. The cadaver was necropsied at the Laboratory of Animal Anatomy from Universidade Castelo Branco, in the city of Rio de Janeiro, Brazil. During macroscopic evaluation it was possible to identify a normal body score, healthy skin, and the presence of multiple fractures in the skull. Encephalic injury was indicated as the cause of his death. After the necropsy, the body was subjected to maceration technique to prepare his skeleton to the museum of the laboratory. Once soft tissues were removed, the skeleton was placed in the plastic box that contained a colony of necrophagous beetles (Dermestes maculatus), which completed the process of cleaning the bones. At this time, a failure to close the vertebral arches of T2, T3 and T4 was observed which characterized a case of spina bifida oculta. Discussion: As long as spina bifida is one of the most common malformations in humans, it has also been reported in several species of animals. Besides being one of the most common malformations in humans, spina bifida has been reported in several species of animals. However, there is only one report of spina bifida (cystic) of spontaneous occurrence in primates (in a female of Macaca niger with neurological defi cits). According to current literature, this is the first report of spina bifida in Callithrix penicillata, as well as in a wild animal in Brazil. Spina bifida affects most commonly lumbar or sacral vertebrae. In this case, although, malformation occurred at the level of thoracic vertebrae T2, T3 and T4, an uncommon location. The fact that the cause of death of the marmosets have been a traumatic brain injury, coupled with the appearance of changes of the vertebral arches, absence of deformation in the skin and the apparent good body condition, allowed us to deduce that this was a case of spina bifida occulta. It would be unlikely that a wild animal with myelomeningocele could survive until adulthood. The possibility of a coexisting meningocele could be compatible with the survival, despite some degree of motor impairment would make it proned to be hit by cars, falls or predation. It was not possible to determine the cause of malformation in this case, but one can imagine that some factors deficiencies (eg.: folic acid or zinc), genetic factors and effects of teratogenic substances from the environment would be some of the speculated causes for the appearance of spina bifida in this marmoset. Information about congenital malformations from other animals in the same geographic region could eventually reinforce this hypothesis.