Titanosaurs and the origin of “wide-gauge” trackways: a biomechanical and systematic perspective on sauropod locomotion
Titanosaurs and the origin of “wide-gauge” trackways: a biomechanical and systematic perspective on sauropod locomotion
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DOI：
10.1017/s0094837300026543
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发表时间：
1999-04
期刊：
影响因子：
2.7
通讯作者：
JEFFREY A. Wilson;M. Carrano
中科院分区：
文献类型：
--
作者：
JEFFREY A. Wilson;M. Carrano
摘要蜥脚类动物的足迹有两种主要的遗迹类型：“窄轨”，指手和足的足迹接近或相交于足迹的中线;“宽轨”，指这些足迹远离中线。这种规格差异可能是由于行为，身体大小或各自的跟踪器之间的形态差异。然而，大型陆生脊椎动物运动的生物力学表明，蜥脚类动物的运动行为可能受到限制，而足迹测量仪之间缺乏系统的大小差异，反对身体大小相关的影响。我们认为，骨骼形态是负责规格的差异和整合数据从运动生物力学和系统学的跟踪记录，以预测后肢形态的宽轨trackmakers。在大型重力门动物中，更广泛的足部站立需要可预测的机械后果和后肢修改。这些可能包括向外成角的股骨、偏置膝关节髁和更偏心的股骨中段横截面。一项对蜥脚类动物后肢形态的调查显示，这些特征是泰坦巨龙的突触，表明它们是宽轨距轨道的制造者。泰坦巨龙的时间和地理分布与这一假设是一致的，因为宽轨距的轨道在白垩纪占主导地位，并在世界各地发现。其他apapapellular synapomorphies的泰坦巨龙被解释在光确定这些动物作为宽轨距trackmakers。我们认为，泰坦巨龙可能比其他蜥脚类恐龙更频繁地使用两足站立。这些遗迹学、生物力学和系统学之间的相关性意味着泰坦巨龙在蜥脚类动物中是独一无二的，因为它有着更多样化的运动习惯。
Abstract Two major ichnotypes of sauropod trackways have been described: “narrow-gauge,” in which both manus and pes prints approach or intersect the trackway midline, and “wide-gauge,” in which these prints are well apart from the midline. This gauge disparity could be the result of differences in behavior, body size, or morphology between the respective trackmakers. However, the biomechanics of locomotion in large terrestrial vertebrates suggest that sauropods were probably restricted in locomotor behavior, and the lack of systematic size differences between footprint gauges argues against body-size-related influences. We argue that skeletal morphology is responsible for gauge differences and integrate data from locomotor biomechanics and systematics with the track record to predict the hindlimb morphology of wide-gauge trackmakers. Broader foot stances in large, graviportal animals entail predictable mechanical consequences and hindlimb modifications. These could include outwardly angled femora, offset knee condyles, and a more eccentric femoral midshaft cross-section. A survey of sauropod hindlimb morphology reveals that these features are synapomorphies of titanosaurs, suggesting that they were the makers of wide-gauge trackways. The temporal and geographic distribution of titanosaurs is consistent with this hypothesis because wide-gauge trackways predominate during the Cretaceous and are found worldwide. Additional appendicular synapomorphies of titanosaurs are interpreted in light of identifying these animals as wide-gauge trackmakers. We suggest that titanosaurs may have used a bipedal stance more frequently than did other sauropods. These correlations between ichnology, biomechanics, and systematics imply that titanosaurs were unique among sauropods in having a more varied repertoire of locomotor habits.