Radiographic anatomy of the vertebral column and pelvic limb of Subulo gouazoubira (Fischer, 1814), the brown brocket deer from southern Brazil

The study aims to check the use of standard positioning to take radiographs in small cervids, to provide radiographic anatomy images of the vertebral spine and pelvic limbs from Subulo gouazoubira and, compare the radiographic anatomy of this species with that of domestic sheep (Ovis aries) and other cervids documented in the literature. A total of 11 deceased specimens from Southern Rio Grande do Sul state, Brazil, were analyzed: 9 individuals (6 females and 3 males) without fractures underwent radiographic examination. One adult female underwent computed tomography (CT) with multiplanar and 3D reconstructions. Two adult females had skeletal preparations by biological maceration. Radiographic positioning followed protocols established for small domestic animals. The vertebral formula consistent across specimens: C7–T13–L6–S5–Co10. Coccygeal vertebrae counts were confirmed via CT imaging. Notable presence of phalanges in vestigial digits II and V. Long bones exhibit a more slender and elongated morphology relative to body size when compared to the domestic sheep. The middle phalanx is proportionally longer when compared to domestic sheep and marsh deer (Blastocerus dichotomus), suggesting an adaptation for enhanced support on forested substrates. Observations indicate a thinner cortical layer, contributing to a more delicate skeletal structure. Some specimens, despite falling within the expected size range for adults, displayed signs of incomplete skeletal maturity in the pelvic limbs. This underscores the necessity for comprehensive radiographic assessments in long bone epiphyses evaluations to accurately determine age structures within populations from Southern Brazil. The study provides detailed radiographic and osteological insights into S. gouazoubira, highlighting both similarities and distinct differences when compared to domestic sheep and other cervids. The findings emphasize the importance of species-specific diagnostic imaging protocols to inform clinical practices and conservation strategies.