Bergqvist Lílian P, Pereira Paulo Victor Luiz G C, Machado Alessandra S, Castro Mariela C DE, Melki Luiza B, Lopes Ricardo T
Departamento de Geologia, Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos 274, Bl. G, Sala G1053, Ilha do Fundão, 21941-611 Rio de Janeiro, RJ, Brazil.
Programa de Pós-graduação em Geologia, Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos 274, Bl. G, sala G1053, Ilha do Fundão, 21941-611 Rio de Janeiro, RJ, Brazil.
An Acad Bras Cienc. 2019 Sep 2;91(suppl 2):e20181290. doi: 10.1590/0001-3765201920181290.
Abstract: Riostegotherium yanei from the Itaboraí Basin, Brazil, is the oldest known Xenarthra. This paper aims to describe the internal morphology of the osteoderms of Riostegotherium yanei from the perspective of histology and micro-CT approaches, expanding the available data on cingulate osteoderm microstructure. Seven osteoderms of R. yanei were used for the internal microstructure description and eight of Dasypus novemcinctus for comparison. The osteoderms of Riostegotherium yanei lacks the diploë-like structure typical of glyptodonts but has a three-layered structure composed of two layers of non-Haversian compact bone enclosing a central layer of primary and secondary osteons. This internal organization is distinct from other Astegotheriini of comparable age, but similar to Dasypus. The 3D reconstruction of Riostegotherium yanei revealed two patterns of internal organization. Pattern 1 of movable osteoderm is composed of large remodeled areas at the base and a more compact bone at the tongue; in Pattern 2 (both movable and buckler), the internal cavities are much smaller, more numerous, and more interconnected to each other. In one buckler osteoderm, the cavities are organized somewhat radially with a compact central region (Pattern 1). Pattern 1 of both movable and buckler osteoderms resemble that of Dasypus.
来自巴西伊塔博拉伊盆地的雅内氏里约热内卢贫齿兽是已知最古老的异关节总目动物。本文旨在从组织学和显微CT方法的角度描述雅内氏里约热内卢贫齿兽骨板的内部形态，扩充关于有甲目骨板微观结构的现有数据。使用了7块雅内氏里约热内卢贫齿兽的骨板来描述其内部微观结构，并使用8块九带犰狳的骨板进行比较。雅内氏里约热内卢贫齿兽的骨板缺乏雕齿兽典型的板障状结构，但具有三层结构，由两层非哈弗斯系统致密骨包围着一层中央的初级和次级骨单位。这种内部结构与其他年龄相当的阿斯泰戈兽亚科动物不同，但与犰狳属相似。雅内氏里约热内卢贫齿兽的三维重建揭示了两种内部结构模式。可移动骨板的模式1在基部由大的重塑区域组成，在舌状部分有更致密的骨；在模式2（可移动和盾牌状骨板）中，内部腔隙更小、更多，且彼此之间连接更紧密。在一块盾牌状骨板中，腔隙呈放射状排列，中央区域致密（模式1）。可移动和盾牌状骨板的模式1与犰狳属的相似。
