A chambered heart is common to all vertebrates, but reptiles show unparalleled variation in ventricular septation, ranging from almost absent in tuataras to full in crocodilians. Because mammals and birds evolved independently from reptile lineages, studies on reptile development may yield insight into the evolution and development of the full ventricular septum. Compared with reptiles, mammals and birds have evolved several other adaptations, including compact chamber walls and a specialized conduction system. These adaptations appear to have evolved from precursor structures that can be studied in present-day reptiles. The increase in the number of studies on reptile heart development has been greatly facilitated by sequencing of several genomes and the availability of good staging systems. Here, we place reptiles in their phylogenetic context with a focus on features that are primitive when compared with the homologous features of mammals. Further, an outline of major developmental events is given, and variation between reptile species is discussed.

中文翻译：

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爬行动物作为研究心脏发育的模型系统。

所有脊椎动物都有一个有腔的心脏，但爬行动物的心室间隔表现出无与伦比的变化，从大蜥蜴几乎不存在到鳄鱼的完整。由于哺乳动物和鸟类独立于爬行动物谱系进化，因此对爬行动物发育的研究可能会深入了解整个心室间隔的进化和发育。与爬行动物相比，哺乳动物和鸟类已经进化出其他几种适应性，包括紧凑的室壁和专门的传导系统。这些适应似乎是从可以在当今爬行动物中研究的前体结构演变而来的。几个基因组的测序和良好分期系统的可用性极大地促进了爬行动物心脏发育研究数量的增加。这里，我们将爬行动物置于其系统发育背景中，重点关注与哺乳动物的同源特征相比的原始特征。此外，还给出了主要发育事件的概要，并讨论了爬行动物物种之间的差异。