Wedel Mathew J, Taylor Michael P
College of Osteopathic Medicine of the Pacific and College of Podiatric Medicine, Western University of Health Sciences, Pomona, California, United States of America.
PLoS One. 2013 Oct 30;8(10):e78213. doi: 10.1371/journal.pone.0078213. eCollection 2013.
Skeletal pneumaticity is found in the presacral vertebrae of most sauropod dinosaurs, but pneumaticity is much less common in the vertebrae of the tail. We describe previously unrecognized pneumatic fossae in the mid-caudal vertebrae of specimens of Giraffatitan and Apatosaurus. In both taxa, the most distal pneumatic vertebrae are separated from other pneumatic vertebrae by sequences of three to seven apneumatic vertebrae. Caudal pneumaticity is not prominent in most individuals of either of these taxa, and its unpredictable development means that it may be more widespread than previously recognised within Sauropoda and elsewhere in Saurischia. The erratic patterns of caudal pneumatization in Giraffatitan and Apatosaurus, including the pneumatic hiatuses, show that pneumatic diverticula were more broadly distributed in the bodies of the living animals than are their traces in the skeleton. Together with recently published evidence of cryptic diverticula--those that leave few or no skeletal traces--in basal sauropodomorphs and in pterosaurs, this is further evidence that pneumatic diverticula were widespread in ornithodirans, both across phylogeny and throughout anatomy.
在大多数蜥脚类恐龙的骶前椎骨中发现了骨骼气腔，但气腔在尾椎骨中则要少见得多。我们描述了在长颈巨龙和梁龙标本的中部尾椎骨中以前未被识别的气腔窝。在这两个类群中，最远端的气腔椎骨与其他气腔椎骨之间由三到七个无气腔椎骨序列隔开。在这两个类群的大多数个体中，尾气腔并不显著，其不可预测的发育意味着它在蜥脚类动物以及蜥臀目的其他地方可能比以前认为的更为普遍。长颈巨龙和梁龙尾气腔化的不规则模式，包括气腔间隙，表明气腔憩室在活体动物体内的分布比在骨骼中的痕迹更为广泛。与最近发表的关于基础蜥脚形亚目恐龙和翼龙中隐性憩室（即几乎没有或没有骨骼痕迹的憩室）的证据一起，这进一步证明了气腔憩室在鸟颈类主龙中广泛存在，贯穿系统发育和整个解剖结构。
