The Phylogenetic Relationships and Ecomorphological Diversification of Early Crocodylomorphs

地球上生物的多样性在时间和生命之树上分布不均。理解支持这一观察的动力和过程是进化生物学领域的中心问题之一。鳄鱼形目动物是一群假脊椎动物，包括鳄鱼及其已灭绝的近亲，在今天表现出有限的分类学和形态多样性；然而，现存的形式只代表了该物种在其约2.3亿年历史中所取得的多样性的一小部分。鳄形动物占据了各种生态环境，进化了一系列不同的形态，并在两次大规模灭绝事件中幸存下来。这使得它们成为研究宏观进化过程的一个很好的系统；然而，为了能够有效地做到这一点，一个良好的系统发展史是必要的。在鳄鱼形目中，“早期鳄形目”(“神州纲”+原生纲)的进化关系鲜为人知，而海鞘亚纲的位置也是如此。因此，该项目将设法通过建立和分析一个新的系统发育数据集，包括编制一份图文并茂的字符清单来解决这一问题。该项目将结合对广泛分类群的第一手观察数据，并利用CT扫描技术来研究和表征标本的内部解剖结构。由此产生的系统发育将被应用，进行颅骨和颅后差异分析，以更好地了解该群体跨越三叠系/侏罗系边界的生态辐射。这样做将允许确定物种灭绝的选择性和对大规模物种灭绝事件的恢复能力，这对当今的保护工作具有潜在的影响。

The diversity of organisms on Earth is unevenly distributed across time and the tree of life. An understanding of the dynamics and processes underpinning this observation is one of the central questions in the field of evolutionary biology. Crocodylomorphs, a group of pseudosuchian archosaurs that includes crocodilians and their extinct relatives, exhibit limited taxonomic and morphological diversity in the present day; however, extant forms represent only a fraction of the diversity achieved by the group throughout their around 230-million-year history. Crocodylomorphs have occupied a variety of ecologies, evolved a disparate range of morphologies, and survived two mass extinction events. This makes them an excellent system through which to study macroevolutionary processes; however, a well-resolved phylogeny is necessary to be able to effectively do so. Within Crocodylomorpha, the evolutionary relationships of 'early crocodylomorphs' ("Shenosuchia" + Protosuchia) are poorly known, as is the position of the thalattosuchians. As such, this project will seek to address this issue through the construction and analysis of a new phylogenetic dataset, including the development of an illustrated character list. This project will incorporate data from first-hand observation of a wide range of taxa and utilise CT scanning technology to study and characterize the internal anatomy of specimens. The resultant phylogeny will be applied, conducting cranial and post-cranial disparity analyses to better understand the group's ecomorphological radiation across the Triassic/Jurassic boundary. Doing so will allow for extinction selectivity and resilience to mass extinction events to be determined, with potential implications for present-day conservation efforts.