Department of Biology, Adelphi University, Garden City, New York.
Anatomical Sciences Department, Health Sciences Center, Stony Brook University, Stony Brook, New York.
Anat Rec (Hoboken). 2020 Apr;303(4):732-758. doi: 10.1002/ar.24198. Epub 2019 Jun 28.
Like many long-standing dinosaur taxa, Brachiosaurus altithorax from the Upper Jurassic Morrison Formation of North America suffers from taxonomic issues stemming from a relatively incomplete holotype. Lack of anatomical overlap has precluded definitive referral of important specimens, including a mostly complete skull discovered in 1883. We redescribe this skull and some other significant brachiosaurid specimens based on new preparation and computed tomographic (CT) data. We argue that these elements are most parsimoniously referred to B. altithorax. Including these tentatively referred elements in a phylogenetic analysis does not alter the hypothesized relationships of B. altithorax, congruent with the presence of a single brachiosaurid taxon across western North America in the Late Jurassic. Based on CT data, we estimate that B. altithorax had a slower tooth replacement rate than Camarasaurus or the diplodocoids it shared Morrison Formation landscapes with, which suggests a difference in diet and/or feeding strategy. Anat Rec, 303:732-758, 2020. © 2019 Wiley Periodicals, Inc.
与许多历史悠久的恐龙分类群一样，来自北美上侏罗统莫里森组的腕龙科腕龙（Brachiosaurus altithorax）因其相对不完整的正型标本而存在分类问题。由于缺乏解剖重叠，一些重要的标本无法被明确归入其中，包括 1883 年发现的一个大部分完整的头骨。我们根据新的准备和计算机断层扫描（CT）数据重新描述了这个头骨和其他一些重要的腕龙类标本。我们认为这些元素最合理的归属是腕龙（Brachiosaurus altithorax）。在系统发育分析中包括这些暂定归属的元素并没有改变腕龙（Brachiosaurus altithorax）的假设关系，这与在晚侏罗世北美西部存在单一的腕龙类分类群是一致的。基于 CT 数据，我们估计腕龙（Brachiosaurus altithorax）的牙齿更换率比圆顶龙（Camarasaurus）或与其共享莫里森组景观的梁龙科（Diplodocoids）慢，这表明其饮食和/或觅食策略存在差异。解剖学记录，303：732-758，2020. © 2019 Wiley Periodicals，Inc.
