RESUMEN
BACKGROUND: The classification of Saguinus ursulus as a new taxon and the vulnerability of this species highlighted the need for data on its specific morphophysiological attributes. This study used ultrasound to determine the typical characteristics of pelvic-abdominal structures and organs. METHODS: Nine healthy primates of the species S. ursulus were evaluated, through ultrasound tests, to determine the morphometry of the organs of the pelvic-abdominal cavity and the levels of ovarian activity. RESULTS: Topography, morphology, and biometrics of the organs were described. It was observed that organs of S. ursulus are similar to those of other Neotropical primate species. However, the kidney morphology is different,the left is triangular and the right is elliptical, while the gallbladder is bilobed. CONCLUSION: Ultrasonography has proven to be efficient and effective for organ evaluation. The ultrasound findings are a first step toward understanding the physiology of a less-known species.