Ontogenia de cingulados juvenis do quaternário da Bahia, Brasil: morfologia e paleobiologia

Abstract

Members of the Order Cingulata are placental mammals with articulated bony armor covering their bodies. They represent the most diverse group within the superorder Xenarthra, among which the glyptodonts (Glyptodontinae) comprise the most peculiar armored herbivores. This is a clade whose oldest specimens originate from tropical areas of South America during the Middle to Late Miocene. Their fossil record is mainly represented by disarticulated osteoderms and skull fragments. Juvenile specimens of cingulates are relatively frequent in fossil collections; however, knowledge about their juvenile stages is still incipient. The morphological variations seen in different developmental stages of taxa are important for understanding their life history, especially concerning fossil material due to biases presented by the record. In this research, we describe two juvenile specimens of Cingulata Glyptodontinae, attributed to the genus Glyptotherium Osborn, 1903, collected at Gruta da Lapinha, Iramaia, BA. Detailed morphological evidence of juvenile individuals is described, including an almost complete hemimandible, dental morphology, postcranial bones, and the ornamentation pattern of osteoderms, as well as information regarding their diet and feeding habits derived from mesowear and microwear (texture analysis) dental studies. Additionally, the development of methodologies using tools that would be applied to teeth still attached to the mandible and extremely fragile is proposed. Finally, the protocol's applicability developed for the above purpose is demonstrated in samples reported at the end of this research.