Temporal and phylogenetic evolution of the sauropod dinosaur body plan.
Temporal and phylogenetic evolution of the sauropod dinosaur body plan.
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DOI：
10.1098/rsos.150636
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发表时间：
2016-03
影响因子：
3.5
通讯作者：
Allen V
中科院分区：
文献类型：
--
作者：
Bates KT;Mannion PD;Falkingham PL;Brusatte SL;Hutchinson JR;Otero A;Sellers WI;Sullivan C;Stevens KA;Allen V
蜥脚类恐龙庞大的体型和身体结构在陆地脊椎动物中是无与伦比的。然而，到目前为止，只有有限的尝试，研究时间和系统发育模式的蜥脚类bauplan。在这里，我们结合联合收割机三维计算模型与系统发育重建量化整个蜥脚类辐射的全身形状和身体部分的属性的演变。与化石中缺乏软组织保存相关的限制导致关于平均绝对体型预测的误差条很大。然而，应用任何一致的骨骼：身体体积比的所有类群产生的身体形状的变化，同时出现在蜥脚类动物历史上的主要宏观进化事件。中三叠世蜥尾类动物的重心（CoM）发生了尾向移动，这与各种恐龙谱系中两足动物的进化有关，但在晚三叠世蜥脚类动物中发生了逆转。颅向CoM的转变与晚三叠世四足动物的进化相吻合，随后在晚侏罗世-白垩纪的泰坦龙形类中，包括最大的蜥脚类动物，出现了更惊人的颅向转变。这些头部CoM的变化与颈部扩大密切相关，颈部扩大是蜥脚类恐龙进化的关键创新，也是它们进化的关键。通过创造一个更大的进食信封，颈部伸长被认为增加了进食效率，并打开了其他食草动物无法进入的营养生态位。然而，我们发现，相对颈部大小和CoM的位置并不强烈相关推断的摄食习惯。相反，泰坦龙形类的颅侧CoM位置似乎与运动和环境分布密切相关，可能有助于这个群体的持续成功，直到白垩纪末，所有其他蜥脚类动物都在晚白垩纪早期灭绝。
The colossal size and body plan of sauropod dinosaurs are unparalleled in terrestrial vertebrates. However, to date, there have been only limited attempts to examine temporal and phylogenetic patterns in the sauropod bauplan. Here, we combine three-dimensional computational models with phylogenetic reconstructions to quantify the evolution of whole-body shape and body segment properties across the sauropod radiation. Limitations associated with the absence of soft tissue preservation in fossils result in large error bars about mean absolute body shape predictions. However, applying any consistent skeleton : body volume ratio to all taxa does yield changes in body shape that appear concurrent with major macroevolutionary events in sauropod history. A caudad shift in centre-of-mass (CoM) in Middle Triassic Saurischia, associated with the evolution of bipedalism in various dinosaur lineages, was reversed in Late Triassic sauropodomorphs. A craniad CoM shift coincided with the evolution of quadrupedalism in the Late Triassic, followed by a more striking craniad shift in Late Jurassic–Cretaceous titanosauriforms, which included the largest sauropods. These craniad CoM shifts are strongly correlated with neck enlargement, a key innovation in sauropod evolution and pivotal to their gigantism. By creating a much larger feeding envelope, neck elongation is thought to have increased feeding efficiency and opened up trophic niches that were inaccessible to other herbivores. However, we find that relative neck size and CoM position are not strongly correlated with inferred feeding habits. Instead the craniad CoM positions of titanosauriforms appear closely linked with locomotion and environmental distributions, potentially contributing to the continued success of this group until the end-Cretaceous, with all other sauropods having gone extinct by the early Late Cretaceous.