荒漠蜥蜴运动表现和栖息地关系的生态形态适应与进化——以栉缘为例

Lizard toe fringes are composed of laterally projecting elongated scales and have arisen independently at least 26 times in seven families of lizards. Variation in fringe morphology shows a strong association with substrate type. This research was based on “morphology-performance-fitness” framework of ecomorphology. We examined the relationships among sprint speed, morphology and different types of substrate surfaces in species of lizards with fringed toe that exploit different structural habitats. Our objects were several representative lizards with fringed toes living in the desert region of Xinjiang. It is predicted that each lizard will attain its highest sprint speeds on the substrate that is uses most often, that means fringe toed species on sand dune and no fringed species on other habitat; hence, each lizard should exhibit a “home field advantage” (The home field advantage hypothesis). We also predict that fringe toed species should avoid other habitats except sand dune in which their maximal sprinting capabilities are impaired (The habitat constraint hypothesis). By contrast, no fringed species whose sprint speed is less affected by substrate should use a greater variety of habitat in nature (The habitat breadth hypothesis). We measured locomotor performance in laboratory and field environments, and collected morphological characteristics and habitat use data. We measured the kinematics of sprinting and characterized differences in grain size distribution and surface strength of the soil in different habitats, especially the sprint speed sensitivity in different roughness habitat between fringe toed species and no fringed species. Our main goals were to assess which processes drive variability in morphology in order to understand how substrate structure affects sprint speed in species with fringed toe in different habitats and to determine the relationship between morphology and performance. Our study will be the first of its kind in lizard with fringed toe, providing a significant contribution to our understanding of evolutionary processes of desert lizard morphology, locomotor performance and habitat use.

趋同进化是生物进化过程中的基本形式之一，即类似的性状特征在多个支系中独立发展，这会影响生物体的表型（形态）的许多方面。蜥蜴栉缘是由伸长的鳞片侧面突出组成，在7个蜥蜴科中独立出现至少26次。栉缘形态变化与运动基质类型表现出强烈的相关性。然而栉缘对蜥蜴在不同栖息地基质条件下运动表现的影响尚未见研究报道。本研究依据“形态——表现——适合度”这一生态形态学的研究框架，以栖息于新疆荒漠地区不同类群具栉缘的几种代表性蜥蜴为对象, 分别在实验室和野外环境下测定其运动表现，测定有栉缘物种和无栉缘物种在不同粗糙度基质之间的冲刺速度敏感度，并和形态特征及栖息地利用数据的相关性进行统计分析。我们的研究是对栉缘影响蜥蜴运动机制研究的首次，其结果对于理解荒漠蜥蜴形态、运动表现和栖息地利用机制的适应性进化有重要意义。

趋同进化是生物进化过程中的基本形式之一，即类似的性状特征在多个支系中独立发展，这会影响生物体的表型（形态）的许多方面。蜥蜴栉缘是由伸长的鳞片侧面突出组成，在7个蜥蜴科中独立出现至少26次。栉缘形态变化与运动基质类型表现出强烈的相关性。然而栉缘对蜥蜴在不同生境基质条件下运动表现的影响尚未见研究报道。本研究依据“形态-表现-适合度”这一生态形态学的研究框架，以栖息于新疆荒漠地区不同类群具栉缘的几种代表性蜥蜴为对象, 分别在实验室和野外环境下测定其运动表现，测定有栉缘物种和无栉缘物种在不同粗糙度基质之间的冲刺速度敏感度，并和形态特征及生境利用数据的相关性进行统计 分析，旨在分析蜥蜴栉缘这一特化的形态特征与运动能力的关系及其对生境利用影响等生态学意义。我们的研究是对栉缘影响蜥蜴运动机制研究的首次，其结果对于理解荒漠蜥蜴形态、运动表现和生境利用机制的适应性进化有重要意义。具体而言，我们共测定了鬣蜥科三种沙蜥，即栉缘双侧发达的大耳沙蜥(Phrynocephalus mystaceus)、单侧发达的变色沙蜥(P. versicolor)及两侧均不发达的旱地沙蜥(P. helioscopus)的形态和运动表现，此外还测定了蜥蜴科的栉缘双侧发达的网纹麻蜥(Eeremias grammica)、单侧发达的快步麻蜥(E. velox)和两侧均不发达的敏麻蜥（E. auguta）的运动表现。整体而言，栉缘不发达的的旱地沙蜥成体在不同基质上的速度敏感度均无显著性差异，即“万金油”策略。单侧发达的变色沙蜥在不同基质上的运动表现介于“主场优势”和“万金油假说”的中间过渡类型。大耳沙蜥的外侧栉缘的存在更利于冲刺，而在埋沙方面双侧栉缘状态下表现更好，并且栉缘相对面积能促进了大耳沙蜥的埋沙表现。网纹麻蜥发达的双侧栉缘和较大的腹部面积增加运动时与基质的接触面积，利于获得更快的冲刺速度和加速度；头部形态大小与两种麻蜥的冲刺速度存在显著正相关关系，与耐力呈负相关。麻蜥属种内及种间形态和功能之间的关系由于面临不同的选择压力而表现出可塑性并有利于物种共存。