Phylogenetic Relationships Within the Australian Sphenomorphus Group (Squamata: Scincidae) and the Study of Limb Reduction

9707428尖吻蜥蜴类包括至少210000种公认物种，是澳大利亚爬行动物(两栖和爬行动物)区系的主要组成部分。这些蜥蜴的特征是肢体的缩小程度差异很大：在所描述的14个属中，有8个属包含表现出肢体缩小的物种，范围从失去单个指骨(手指或脚趾中的骨元素)到完全丧失肢体。圣地亚哥大学的Tod Reeder将利用线粒体编码的12S和16S核糖体(R)RNA基因的DNA序列来评估70多种ShenMorus物种及其同类的系谱关系。他还将研究一系列形态特征，这些特征主要来自骨科结构和鳞片。这些数据将被用来生成物种的系谱，部分原因是为了生成自然分类。这些物种的截肢模式将在系谱的背景下进行评估，以确定截肢的次数和轨迹，并确定与这些形态变化相关的生活史特征。还将评估前肢和后肢之间的相对肢体缩短率。该项目的结果将加深对蜥蜴系统发育的理解，为还原特征在蜥蜴系统发育和生物学中的应用提供经验信息，并为其他生物学和生态属性的研究提供必要的框架。

9707428 Reeder The scincid lizards of the Sphenomorphus group include at least 210 recognized species and represent a dominant component of the Australian herpetological (amphibian and reptile) fauna. These lizards are characterized by extensive variation in reduction of limbs: eight of the fourteen described genera contain species that exhibit limb reduction, ranging from loss of a single phalange (a bony element in a finger or toe) to complete limblessness. Tod Reeder of the University of San Diego will employ DNA sequences from the mitochondrially-encoded 12S and 16S ribosomal (r)RNA genes to assess genealogical relationships among over 70 Sphenomorphus species and allies. He also will examine a suite of morphological characters, derived primarily from osteological structures and scales. These data will be used to generate a genealogy of the species, in part to generate a natural classification. The patterns of limb reduction in these species will be assessed from within the context of the genealogy in order to determine the number of times and trajectories of limb reduction and to determine the life-history traits associated with these morphological changes. Relative rates of limb reduction between fore- and hind-limbs also will be assessed. Results from this project will improve understanding of lizard phylogeny, provide empirical information on the utility of reductive characters in lizard phylogeny and biology, and contribute a necessary framework for the investigation of other biological and ecological attributes.