Li Pi-Peng, Gao Ke-Qin, Hou Lian-Hai, Xu Xing
Shenyang Normal University, Shenyang 110034, People's Republic of China.
Proc Natl Acad Sci U S A. 2007 Mar 27;104(13):5507-9. doi: 10.1073/pnas.0609552104. Epub 2007 Mar 21.
Gliding is an energetically efficient mode of locomotion that has evolved independently, and in different ways, in several tetrapod groups. Here, we report on an acrodontan lizard from the Early Cretaceous Jehol Group of China showing an array of morphological traits associated with gliding. It represents the only known occurrence of this specialization in a fossil lizard and provides evidence of an Early Cretaceous ecological diversification into an aerial niche by crown-group squamates. The lizard has a dorsal-rib-supported patagium, a structure independently evolved in the Late Triassic basal lepidosauromorph kuehneosaurs and the extant agamid lizard Draco, revealing a surprising case of convergent evolution among lepidosauromorphans. A patagial character combination of much longer bilaterally than anteroposteriorly, significantly thicker along the leading edge than along the trailing edge, tapered laterally to form a wing tip, and secondarily supported by an array of linear collagen fibers is not common in gliders and enriches our knowledge of gliding adaptations among tetrapods.
滑翔是一种能量高效的运动方式，它在几个四足动物类群中独立且以不同方式进化而来。在此，我们报道了一种来自中国早白垩世热河群的端生齿蜥蜴，它展现出一系列与滑翔相关的形态特征。它代表了化石蜥蜴中这种特化现象的唯一已知实例，并为冠群有鳞类动物在早白垩世向空中生态位的生态多样化提供了证据。这种蜥蜴具有由背肋支撑的翼膜，这种结构在晚三叠世的基干鳞龙形类动物克内龙和现存的鬣蜥科蜥蜴飞蜥中独立进化而来，揭示了鳞龙形类动物之间一个惊人的趋同进化案例。翼膜的特征组合为：两侧比前后长得多，前缘比后缘明显更厚，向侧面逐渐变细形成翼尖，并由一系列线性胶原纤维提供次生支撑，这种特征组合在滑翔动物中并不常见，丰富了我们对四足动物滑翔适应性的认识。
