Dining after the dinosaurs? Dietary diversity and niche partitioning in Palaeocene mammals

概述该项目将使用新技术来解决古生物学中一个长期存在的问题：恐龙及其灭绝对哺乳动物进化史的影响。最近的一些研究集中在哺乳动物多样化的时机(例如，Wilson等人)。2012年，Close等人。2015年，格罗斯尼克尔2019)，但更难测试生态多样性的假说。对侏罗纪时期保存完好的关节哺乳动物骨骼的形态分析开始描绘出一幅哺乳动物占据的生态位范围比之前想象的更广泛的图景，但大多数哺乳动物化石只从脱节的遗骸和牙齿中获知，不适合这种类型的功能分析。因此，它们的生态多样性在多大程度上受到K-PG灭绝的影响，以及古新世生态多样性的格局，一直是难以解决的问题。这个项目将采用一种强大的新方法，牙齿微磨损纹理分析(DMT)，其应用于早期哺乳动物是由主管(Purnell等人)首创的。2013年，吉尔等人。2014年)。你将把它与其他饮食替代物(牙齿的同位素数据、中耳和定量形状分析)结合在一起，在系统发育的背景下，对古新世哺乳动物的饮食多样性以及营养生态位占据和分配的模式进行多学科、多代理调查。你将建立现代哺乳动物谱系早期成员所属的饮食行会。DMTA揭示了侏罗纪哺乳动物隐藏的营养多样性，表明哺乳动物进化早期的谱系分裂与生态形态特化和生态位划分有关(Gill等人。2014年)。这个项目将这种方法应用于古新世化石，同样将对哺乳动物的进化史产生新的见解。这个项目非常适合具有地质或生物科学学士学位和定量分析能力的申请者。在莱斯特，你将加入一个由研究人员、博士和硕士学生组成的充满活力的小组，致力于对化石脊椎动物的饮食和营养生态位进行新颖的分析。方法：该项目将专注于新墨西哥州圣胡安盆地的材料--世界上最重要的古新世哺乳动物化石产地之一。这些藏品保存在新墨西哥州自然历史博物馆，包括监督者最近挖掘的新材料，该项目为在新墨西哥州进行实地考察提供了机会。膳食分析将使用Leicester开发的多变量方法使用定量3D牙科微磨损纹理分析(Purnell等人。2013年，吉尔等人。2014年)。将其与牙齿中耳、同位素数据、牙齿地形、功能形态和定量系统发育方法的分析相结合，将允许在不同的时间和空间尺度上对喂养和饮食的作用进行稳健的分析和假设检验。这种方法将允许对饮食假设进行独立测试，并评估更广泛的饮食行业协会中的特定角色，并有可能获得早于并可能推动牙齿适应新功能角色的饮食变化。培训和技能：参加CENTA2提供的自由选择外部培训的学生将获得CENTA2培训学分(CTCs)。一个CTC相当于0.5天的课程，学生必须在他们的三年博士学位中积累100个CTC。专家培训将包括牙齿微磨损纹理分析、牙齿地形分析、系统发育测试和宏观进化模式分析的技术，以及白垩纪-古近纪哺乳动物的解剖分析。重点将放在稳健的量化分析和统计假设检验上。

OverviewThis project will use new techniques to address one of the perennial questions in palaeontology: the impact of dinosaurs and their extinction on mammal evolutionary history. A number of recent studies have focussed on the timing of mammal diversification (e.g. Wilson et al. 2012, Close et al. 2015, Grossnickle 2019), but it is more difficult to test hypotheses of ecological diversity. Morphological analysis of well-preserved articulated mammal skeletons of Jurassic age is starting to paint a picture of mammals occupying a broader range of ecological niches than previously thought, but the majority of fossil mammals are known only from disarticulated remains and teeth, and are not amenable to this type of functional analysis. Consequently, the degree to which their ecological diversity was affected by the K-Pg extinction, and the pattern of ecological diversification during the Palaeocene, have been difficult issues to address. This project will employ a powerful new approach, analysis of Dental Microwear Texture (DMT), the application of which to early mammals was pioneered by the supervisors (Purnell et al. 2013, Gill et al. 2014). You will combine this with other dietary proxies (isotopic data, mesowear and quantitative shape analysis of teeth) in phylogenetic context, to conduct multidisciplinary, multiproxy investigation of the dietary diversity of Palaeocene mammals, and of the patterns of trophic niche occupation and partitioning. You will establish the dietary guilds to which the early members of modern mammal lineages belong. DMTA has revealed hidden trophic diversity in Jurassic mammals, indicating that lineage splitting during the earliest stages of mammalian evolution was associated with ecomorphological specialization and niche partitioning (Gill et al. 2014). This project, applying the approach to Palaeocene fossils, will similarly yield new insights into the evolutionary history of mammals.This project is ideal for applicants with a first degree in geological or biological sciences and an aptitude for quantitative analysis. At Leicester you will join a dynamic group of researchers, PhD and Masters students working on novel analyses of diet and trophic niche in fossil vertebrates.Methodology: The project will focus on material from the San Juan Basin of New Mexico - one of the world's premier localities for Palaeocene mammal fossils. The collections, held in the New Mexico Museum of Natural History, include new material recently excavated by the supervisors, and the project offers opportunities for fieldwork in New Mexico. Dietary analysis will employ quantitative 3D Dental Microwear Texture Analysis using multivariate methods developed at Leicester (Purnell et al. 2013, Gill et al. 2014). Combining this with analysis of tooth mesowear, isotopic data, dental topography, functional morphology, and quantitative phylogenetic methods will allow robust analysis and hypothesis testing of the role of feeding and diet at different temporal and spatial scales. This approach will allow independent testing of dietary hypotheses, and evaluation of specific roles within broader dietary guilds, and has the potential to pick up dietary transtions that predate and potentially drive morphological adaptation of teeth to new functional roles.Training and skills:Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and 'free choice' external training. One CTC equates to 0.5 day session and students must accrue 100 CTCs across the three years of their PhD. Specialist training will include dental microwear texture analysis, dental topographic analysis, techniques for phylogenetic testing and analysis of macroevolutionary patterns, and anatomical analysis of Cretaceous-Paleogene mammals. The emphasis will be on robust quantitative analysis and statistical hypothesis testing.