ABSTRACT

The neck posture and function in sauropods have been widely studied during the last decades. The cartilaginous neutral pose (CNP) method is commonly used in biomechanical reconstructions by positioning the vertebrae with the joint surfaces aligned to obtain the ‘neutral pose’. However, few studies have analysed the posture and function of the tail of sauropods. The published data suggest that most sauropods maintained their tails in a horizontal position. We test the neutral pose hypothesis in the anterior caudal vertebrae (C4 to C9) of Aeolosaurus maximus (Titanosauria, Sauropoda), a member of Aeolosaurini endemic of South America, by using the following methodologies: CNP, and range of movement (RoM). The results show that the tail of A. maximus possibly presented in a sigmoidal format which differs from the horizontal position commonly inferred to other sauropods. A. maximus is the first sauropod with caudal vertebrae presenting in situ protonic posture, which corroborates the neutral pose hypothesis and demonstrates that this characteristic is possibly a feature of the Aeolosaurini clade.

摘要

在过去的几十年里，蜥脚类恐龙的颈部姿势和功能得到了广泛的研究。软骨中性姿势 (CNP) 方法通常用于生物力学重建，方法是将椎骨与关节面对齐以获得“中性姿势”。然而，很少有研究分析蜥脚类动物尾巴的姿势和功能。公布的数据表明，大多数蜥脚类恐龙将尾巴保持在水平位置。我们通过使用以下方法学：CNP 和运动范围 (RoM)，测试了南美洲特有风龙科动物巨型风龙(Titanosauria, Sauropoda)的前尾椎骨 (C4 至 C9) 的中性姿势假设。结果表明，A. maximus的尾部可能以 sigmoidal 格式呈现，这与通常推断到其他蜥脚类恐龙的水平位置不同。A. maximus是第一个尾椎呈原位质子姿势的蜥脚类恐龙，这证实了中性姿势假说，并证明这一特征可能是风龙进化枝的一个特征。