Evolution of pinniped Carnivora with reference to other aquatic Mammalia - a case study of constructional morphology

Otariidae， Odobenidae和Phocidae的起源和关系，统称为Pinnipedia，仍然是一个未解决的和有争议的话题。虽然免疫学和解剖学上的相似性暗示了鳖属动物的单系起源，但其他解剖学特征，以及它们的古生物地理历史，反而支持双系起源。这种分歧的结果是，如果只采用比较分析方法，包括分类学，Pinnipedia的起源仍然没有解决。虽然这些方法对建立不同分类群之间可能的关系很有用，但重建进化途径是不可能的。相反，我们认为，通过对鳍足动物的运动器官和支撑系统进行结构形态学分析，可以重建鳍足动物的进化路径，这仍然是本研究的主要目标。这种方法是有效的，因为尽管Otariidae， Odobenidae和Phocidae具有相似的整体形态，但它们在水生和陆地运动模式上有所不同。对这些运动选择的分析允许在支撑系统的背景下对解剖差异进行物理力学解释，并因此决定目前在系统发育分析中使用的解剖特征与机械功能不可分割；应该被拒绝。这一分析将进一步为重建所有类群的早期演化提供建构基础。为了更好地理解哺乳动物结构对强制性水生运动的约束框架，我们还计划研究其他水生或半水生哺乳动物的运动模式及其解剖学背景。这将使我们能够建立假设的祖先鳍状结构，这将有助于确定化石食肉动物的祖先到现存鳍状纲。我们的目标不仅是解决Pinnipedia的起源，而且还建立一个基于形态力学分析的方法，除了经典的系统发育分析。

The origins and relationships of the Otariidae, Odobenidae and Phocidae, which are collectively referred to the Pinnipedia, remain an unresolved and controversial subject of debate. While immunological and anatomical similarities are suggestive of a monophyletic origin of the Pinnipedia, other anatomical features, in addition to their palaeobiogeographical history, are instead supportive of a diphyly. The result of this divergence is that the origin of Pinnipedia remains unresolved if only comparative analytical methods, including cladistics, are applied. While these methods are useful for establishing possible relationships between the various taxa, the reconstruction of evolutionary pathways is not possible. It is instead argued that the evolutionary pathways within the Pinnipedia, which remains the primary objective of this proposal, can be reconstructed by applying a constructional morphological analysis to the pinnipedian locomotor apparatus and bracing system. This approach is effective as despite the fact that the Otariidae, Odobenidae and Phocidae share similar overall morphologies, they differ in their aquatic and terrestrial modes of locomotion. An analysis of these locomotory options allows a physicomechanical interpretation of anatomical differences, within the context of the bracing system, and will thusly decide which of the anatomical characters currently used in phylogenetic analyses are inseparable from mechanical functional; and should be rejected. This analysis will furthermore yield the constructional base for the reconstruction of early evolution of all groups. For a better understanding of the framework of the constraints of mammalian constructions on the way to obligatory aquatic locomotion, we also plan to study the locomotion modes and their anatomical backgrounds of other aquatic or semi-aquatic mammals. This will allow us to establish hypothetical ancestral pinniped constructions, which will help to identify fossil carnivores ancestral to extant Pinnipedia. We aim to not only resolve the origin of Pinnipedia but also to establish a methodology based on morphomechanical analysis additional to classical phylogenetic analyses.