Dissertation Research: Growth and Evolution of the Shell in Turtles: Patterns, Processes, and Consequences of Morphological Variation

拉巴贝拉9701119作者将研究海龟真皮外壳的生长、功能和进化模式。龟壳代表了一种独特的骨骼系统，特别适合于生长研究，因为大多数骨化和发育发生在孵化后。龟甲是除颅骨外少数几个已缝合的脊椎动物骨骼系统之一，是探索已缝合结构生长的有用比较模型。生长模式的功能后果将在形态整合、机械完整性和相对外壳质量的背景下进行评估。将描述不同种类的隐甲鱼的壳生长模式，并在系统发育的背景下进行比较。将使用基于地标的形态测量方法对增长轨迹进行量化和比较。缝合线在贝壳生长中所起的作用，以及这种作用与贝壳几何形状的关系，将在一项使用荧光骨标记量化骨骼生长的研究中进行评估。形态整合、壳体强度和相对壳体质量的功能假设将使用统计模型和力学测试相结合的方法进行评估。这项研究有助于理解个体发育变化和形态进化之间的关系，检查有助于形态总体发展的组织水平过程，并将这些发现置于功能背景下。

LaBarbera 9701119 The authors will study patterns of dermal shell growth, function and evolution in turtles. The turtle shell represents a unique skeletal system which is particularly amenable to growth studies because most ossification and development occurs post-hatching. As one of few sutured vertebrate skeletal systems other than the skull, the turtle shell is a useful comparative model for exploring the growth of sutured structures. The functional consequences of growth patterns will be evaluated in the context of morphological integration, mechanical integrity and relative shell mass. Patterns of shell growth will be characterized for various species of cryptodiran turtles and compared in a phylogenetic context. Growth trajectories will be quantified and compared using landmark-based morphometric methods. The role that sutures play in shell growth, and the relationship of that role to shell geometry, will be assessed in a study using fluorochrome bone markers to quantify skeletal growth. Functional hypotheses of morphological integration, shell strength, and relative shell mass will be evaluated using a combination of statistical models and mechanical testing. This study contributes to an understanding of the relationship between ontogenetic change and morphological evolution, examines tissue level processes which contribute to the gross development of form, and places these findings in a functional context.