Phylogenetic and Biological Studies of Dinosaur Bone Histology

骨组织是一种复杂的生物学现象。骨骼的性质反映了系统发育、个体发育和个体生活史中的事件。恐龙骨组织学研究的真正进展源于对同源骨的个体发生系列的有纪律的研究。这些研究为对恐龙的生理推断提供了最好的基础。活的和化石的变温动物典型的骨骼结构被称为片层-地带性，宽带与窄环交替，分别反映了骨沉积的快速和缓慢的年度周期。活体恒温动物的纤维板层骨生长迅速，通常没有季节性中断。恐龙骨骼具有恒温动物和变温动物的双重特征。现在很明显，无向纤维板层骨不是基生恐龙的特征，而是衍生的特征状态，在恐龙的不同谱系中独立进化了几次。组织学保证了对恐龙生物学的独特而有力的洞察。在考虑恐龙的古生物学时，我们将根据这些动物自身的独特优点来评估它们，而不是强迫它们基于现存的恒温动物和变温动物的刻板印象。特别值得注意的四个方面是：同一物种个体发生系列的标准化研究；骨组织类型变异的系统发育研究骨类型的地层分布；以及对现存恒温动物和变温动物骨骼生物学的研究。在拟开展的研究中，恐龙生长系列的系统发育范围将扩大到包括基础恐龙、thyreophhorans和边际头类，以及更多的衍生形式，如hypsilophodontids、maniraptorans和基础鸟类。因此，骨骼类型的进化和分布将比以前更清晰地集中在系统发育上。拟议的研究跨越了恐龙的整个地层分布，从晚三叠纪到晚白垩纪。本研究的一个特别有价值的方面是包含了中国恐龙陆凤龙、剑龙和原角龙的生长系列。同样重要的是，这些研究将包括各种现存的变温动物和恒温动物。对已知环境和生物历史的现存动物的研究将阐明影响骨骼结构的因素。这些研究的结果将更深入地了解化石骨的组织学结构的系统发育和古生物学意义。

Dodson 9506694 Bone histology is a complex biological phenomenon. The nature of bone reflects phylogeny, ontogeny and events that punctuate the life history of the individual. Genuine progress in the study of dinosaur bone histology has resulted from disciplined studies of ontogenetic series of homologous bones. Such studies offer the best possible basis for physiological inferences about dinosaurs. Living and fossil ectotherms typically show bone structure termed lamellar-zonal, having wide zones alternating with narrow annuli, reflecting annual periods of rapid and slow bone deposition respectively. In living endotherms fibro-lamellar bone records rapid growth, typically without seasonal interruptions. Dinosaurs bone shows features characteristic of both endotherms and ectotherms. It is now evident that azonal fibrolamellar bone is not a character of basal dinosaurs, but is a derived character state that evolved independently several times in different lineages within the Dinosauria. Histology promises a privileged and powerful insight into dinosaur biology. In considering the paleobiology of dinosaurs, we will assess these animals on their own unique merits, without forcing them into stereotypes based on living endotherms and ectotherms. Four aspects of the proposed research are especially noteworthy: the standardized study of ontogenetic series of the same species; the phylogenetic study of the variation of bone tissue types; the stratigraphic distribution of bone types; and the investigation of the bone biology of living endotherms and ectotherms. In the proposed research the phylogenetic scope of growth series of dinosaurs will be extended to include basal dinosaurs , thyreophorans, and marginocephalians, as well as more derived forms such as hypsilophodontids, maniraptorans and basal birds. As a result, the evolution and distribution of bone types will be drawn into sharper phylogenetic focus than was previously possible. The proposed studies span the entire stratigrap hic distribution of dinosaurs, from the Late Triassic to the Late Cretaceous. A particularly valuable aspect of this study is the inclusion of growth series of the Chinese dinosaurs Lufengosaurus, Shunosaurus, and Protoceratops. Equally important, these studies will encompass a diverse array of extant ectotherms and endotherms. Studies of living animals of known environmental and biological history will elucidate factors that influence the structure of bone. The result of these investigations will be deeper insight into the phylogenetic and paleobiological significance of the histological structures of fossil bone.