Palaeohistological evidence for ancestral high metabolic rate in archosaurs

Metabolic heat production in archosaurs has played an important role in their evolutionary radiation during the Mesozoic, and their ancestral metabolic condition has long been a matter of debate in systematics and palaeontology. The study of fossil bone histology provides crucial information on bone growth rate, which has been used to indirectly investigate the evolution of thermometabolism in archosaurs. However, no quantitative estimation of metabolic rate has ever been performed on fossils using bone histological features. Moreover, to date, no inference model has included phylogenetic information in the form of predictive variables. Here we performed statistical predictive modelling using the new method of phylogenetic eigenvector maps on a set of bone histological features for a sample of extant and extinct vertebrates, in order to estimate metabolic rates of fossil archosauromorphs. This modelling procedure serves as a case study for eigenvector-based predictive modelling in a phy...初龙类（archosaurs）的代谢产热在中生代时期的演化辐射进程中发挥了关键作用，其祖先的代谢状态长期以来一直是分类学与古生物学领域争论的核心议题。对化石骨组织学（bone histology）的研究可为骨生长速率提供关键信息，而骨生长速率曾被用于间接探究初龙类的热代谢演化历程。然而，此前尚无研究借助骨组织学特征对化石物种的代谢率开展定量估算。此外，截至目前，尚无任何推断模型将系统发育信息以预测变量的形式纳入建模范畴。本研究针对现生与已灭绝脊椎动物样本的一系列骨组织学特征，采用系统发育特征向量映射（phylogenetic eigenvector maps）这一新方法开展统计预测建模，以估算化石初龙形类（archosauromorphs）的代谢率。本建模流程可作为基于特征向量的预测建模在系统发育[原文未完整表述]领域的案例研究。