DINOSAUR BIOGEOGRAPHY AND THE IMPLICATIONS OF FOSSIL RECORD BIAS

边缘头（即，有角和圆顶头的恐龙）代表了晚白垩世的双足和四足鸟臀目恐龙的辐射，广泛分布在北美西部和亚洲，并以其广泛的颅面轮廓而闻名。边缘头类化石记录的丰富性，包括许多多个体的骨床，关节骨骼和孤立的大型化石遗骸，是必不可少的正在进行的晚白垩世北美西部的恐龙动物群的特征。例如，marginocephalians是最丰富的可识别的鸟臀目分类群之一，构成了加拿大阿尔伯塔南部恐龙公园（76.9-74.4 Ma）和马蹄峡谷（73.1-67.95 Ma）地层的恐龙为主的宏体化石组合。这些分类群的宏体化石遗骸的狭窄地层分布和低的同时代多样性（<3种）促使了对离散的“亚地层”动物群组合带的认识。对于专注于恐龙进化和古生物地理学的研究，这些模式是理解选择压力的关键，这些压力影响了更广泛的恐龙组合中特定类群的进化，这些组合最好在系统发育背景下进行处理，以提供对该组的最广泛的理解。本研究的目的是测试现有的系统发育假说与marginocephalian多样性，并利用多种基于遗传学的化石记录方法，以确定在哪些地区的采样差的化石记录偏见我们的理解这些恐龙的多样性和动物区系营业额。

The Marginocephalia (i.e., the horned and dome-headed dinosaurs) represent a Late Cretaceous radiation of bipedal and quadrupedal ornithischian dinosaurs that were widespread throughout western North America and Asia and remarkable for their extensive craniofacial ornamentation. The richness of the marginocephalian fossil record which includes numerous multi-individual bonebeds, articulated skeletons and isolated macrofossil remains, is essential to the ongoing characterisation of the Late Cretaceous dinosaur fauna of western North America. For example, marginocephalians are among the most abundant identifiable ornithischian taxa that constitute the dinosaur dominated macrofossil assemblages of the Dinosaur Park (76.9-74.4 Ma) and Horseshoe Canyon (73.1-67.95 Ma) formations of southern Alberta, Canada. The narrow stratigraphic distribution of the macrofossil remains of these taxa and the low contemporaneous diversity (<3 species) has prompted the recognition of discrete 'sub-formational' faunal assemblage zones. For studies focused on dinosaur evolution and palaeobiogeography, these patterns are key to understanding the selection pressures influencing the evolution of specific taxa in the wider dinosaur assemblage which are best approached in a phylogenetic context to provide the broadest understanding of the group. This study aims to test existing phylogenetic hypotheses associated with marginocephalian diversity and to utilise multiple phylogenetic-based biogeographic methods to identify areas where poor sampling of the fossil record biases our understanding of diversity and faunal turnover of these dinosaurs.