CONSTRAINT-BASED EXCLUSION OF LIMB POSES FOR RECONSTRUCTING THEROPOD DINOSAUR LOCOMOTION
CONSTRAINT-BASED EXCLUSION OF LIMB POSES FOR RECONSTRUCTING THEROPOD DINOSAUR LOCOMOTION
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DOI：
10.1671/039.029.0213
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发表时间：
2009-06-12
影响因子：
1.4
通讯作者：
Hutchinson, John R.
中科院分区：
文献类型：
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作者：
Gatesy, Stephen M.;Baeker, Martin;Hutchinson, John R.
合理的姿势被确定为后肢的霸王龙雷克斯和其他三个非鸟类兽脚亚目恐龙在中期立场的运动，使用基于约束的排除。这种新的方法，通过分析两种鸟类的验证，涉及应用明显现实的几何和动力学（基于力）的限制，从现存的动物排除，而不是包括，潜在的姿势。从数百万个候选姿势的“配置空间”开始，我们使用了一系列逐步的标准来将体积压缩到一小部分解决方案，这些解决方案可以作为重建完整步幅周期的起点。结果发现，最大相对中期站姿肢体力，以及在较低的力的配置的相对数量，随着身体尺寸的增加而减少。基于约束的排除法将暴龙限制在一个狭窄的区域内，既没有非常圆柱形的姿势，也没有非常弯曲的姿势，这可能允许相对缓慢的奔跑，但没有合理的输入参数和姿势组合产生足够大的力量来高速奔跑。这一分析表明，骨骼信息本身具有有限的价值，辨别中期立场构成。尽管有额外的假设，但要将化石作为功能性动物而不是移动的骨骼来研究，还需要一些未保存的参数，如质量、力和力矩。基于约束的排除是一个透明的，可重复的框架，用于评估恐龙和其他类群的功能假设。
Plausible poses were identified for the hind limb of Tyrannosaurus rex and three other non-avian theropod dinosaurs at mid-stance of locomotion using constraint-based exclusion. This new method, validated by analysis of two species of birds, involves applying demonstrably realistic geometric and kinetic (force-based) constraints from extant animals to exclude, rather than include, potential poses. Starting with a "configuration space" of millions of candidate poses, we used a step-wise series of criteria to constrict the volume to a small subset of solutions, which can serve as starting points for reconstructing complete stride cycles. It was found that the maximum relative mid-stance limb force, as well as the relative number of configurations at lower forces, decreased with increasing body size. Constraint-based exclusion restricted Tyrannosaurus to a narrow region of neither very columnar nor very flexed poses that may have allowed relatively slow running, but no reasonable combinations of input parameters and pose produce forces large enough for high speeds. This analysis shows that skeletal information alone has limited value for discerning mid-stance poses. Despite additional assumptions, unpreserved parameters such as masses, forces, and moments are required to study a fossil as a functioning animal, rather than as a moving set of bones. Constraint-based exclusion is a transparent, reproducible framework for evaluating functional hypotheses in dinosaurs and other taxa.