Higham Timothy E, Birn-Jeffery Aleksandra V, Collins Clint E, Hulsey C Darrin, Russell Anthony P
Department of Biology, University of California, Riverside, CA 92521;
Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148; and.
Proc Natl Acad Sci U S A. 2015 Jan 20;112(3):809-14. doi: 10.1073/pnas.1418979112. Epub 2014 Dec 29.
Innovations permit the diversification of lineages, but they may also impose functional constraints on behaviors such as locomotion. Thus, it is not surprising that secondary simplification of novel locomotory traits has occurred several times among vertebrates and could potentially lead to exceptional divergence when constraints are relaxed. For example, the gecko adhesive system is a remarkable innovation that permits locomotion on surfaces unavailable to other animals, but has been lost or simplified in species that have reverted to a terrestrial lifestyle. We examined the functional and morphological consequences of this adaptive simplification in the Pachydactylus radiation of geckos, which exhibits multiple unambiguous losses or bouts of simplification of the adhesive system. We found that the rates of morphological and 3D locomotor kinematic evolution are elevated in those species that have simplified or lost adhesive capabilities. This finding suggests that the constraints associated with adhesion have been circumvented, permitting these species to either run faster or burrow. The association between a terrestrial lifestyle and the loss/reduction of adhesion suggests a direct link between morphology, biomechanics, and ecology.
创新使谱系多样化，但也可能对诸如运动等行为施加功能限制。因此，脊椎动物中多次出现新的运动特征的二次简化，并且当限制放宽时可能会导致异常分化，这并不奇怪。例如，壁虎的粘附系统是一项非凡的创新，它使壁虎能够在其他动物无法到达的表面上移动，但在已恢复陆地生活方式的物种中，该系统已经丧失或简化。我们研究了壁虎厚趾虎辐射中这种适应性简化的功能和形态学后果，该辐射显示出粘附系统的多次明确丧失或简化过程。我们发现，在那些已经简化或丧失粘附能力的物种中，形态和三维运动运动学的进化速率有所提高。这一发现表明，与粘附相关的限制已被规避，使这些物种能够跑得更快或打洞。陆地生活方式与粘附丧失/减少之间的关联表明形态学、生物力学和生态学之间存在直接联系。
