Downsizing a giant: re-evaluating Dreadnoughtus body mass
Downsizing a giant: re-evaluating Dreadnoughtus body mass
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DOI：
10.1098/rsbl.2015.0215
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发表时间：
2015-06-01
期刊：
影响因子：
3.3
通讯作者：
Maidment, Susannah C. R.
中科院分区：
文献类型：
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作者：
Bates, Karl T.;Falkingham, Peter L.;Maidment, Susannah C. R.
对身体质量的估计通常代表了生物力学和宏观进化假说的基础假设。最近，一个缩放方程被应用到一个新发现的泰坦龙类蜥脚类恐龙（Dreadnoughtus），产生了59 300公斤的体重估计这种动物。在这里，我们使用一个建模方法来检查这个质量估计Dreadnoughtus的可验证性。我们发现，59 300公斤的Dreadnoughtus是非常不可信的，并表明，群众超过40 000公斤需要高的身体密度和膨胀的软组织体积外的骨骼几倍以上，发现在生活四足哺乳动物。从其他一个小样本的祖龙类似的结果表明，低端的质量估计来自缩放方程是最合理的无畏，根据现有的体积和密度数据从现存的动物。虽然体积模型似乎更严格地限制了恐龙的体重，但仍然需要进一步用来自活体动物的更详尽的数据来支持这些模型。体积模型和比例方程之间的质量预测的相对和绝对差异也表明需要系统地比较广泛的大小和分类范围内的预测，以更好地为恐龙体型的研究提供信息。
Estimates of body mass often represent the founding assumption on which biomechanical and macroevolutionary hypotheses are based. Recently, a scaling equation was applied to a newly discovered titanosaurian sauropod dinosaur (Dreadnoughtus), yielding a 59 300 kg body mass estimate for this animal. Herein, we use a modelling approach to examine the plausibility of this mass estimate for Dreadnoughtus. We find that 59 300 kg for Dreadnoughtus is highly implausible and demonstrate that masses above 40 000 kg require high body densities and expansions of soft tissue volume outside the skeleton several times greater than found in living quadrupedal mammals. Similar results from a small sample of other archosaurs suggests that lower-end mass estimates derived from scaling equations are most plausible for Dreadnoughtus, based on existing volumetric and density data from extant animals. Although volumetric models appear to more tightly constrain dinosaur body mass, there remains a clear need to further support these models with more exhaustive data from living animals. The relative and absolute discrepancies in mass predictions between volumetric models and scaling equations also indicate a need to systematically compare predictions across a wide size and taxonomic range to better inform studies of dinosaur body size.