Leal Francisca, Tarazona Oscar A, Ramírez-Pinilla Martha Patricia
Laboratorio de Biología Reproductiva de Vertebrados, Grupo de Estudios en Biodiversidad, Escuela de Biología, Universidad Industrial de Santander, Bucaramanga, Colombia.
J Morphol. 2010 Nov;271(11):1328-41. doi: 10.1002/jmor.10875.
Despite the attention squamate lizards have received in the study of digit and limb loss, little is known about limb morphogenesis in pentadactyl lizards. Recent developmental studies have provided a basis for understanding lizard autopodial element homology based on developmental and comparative anatomy. In addition, the composition and identity of some carpal and tarsal elements of lizard limbs, and reptiles in general, have been the theme of discussions about their homology compared to non-squamate Lepidosauromorpha and basal Amniota. The study of additional embryonic material from different lizard families may improve our understanding of squamate limb evolution. Here, we analyze limb morphogenesis in the gekkonid lizard Gonatodes albogularis describing patterns of chondrogenesis and ossification from early stages of embryonic development to hatchlings. Our results are in general agreement with previous developmental studies, but we also show that limb development in squamates probably involves more chondrogenic elements for carpal and tarsal morphogenesis, as previously recognized on the grounds of comparative anatomy. We provide evidence for the transitory presence of distal carpale 1 and intermedium in the carpus and tibiale, intermedium, distal centralia, and distal tarsale 2 in the tarsus. Hence, we demonstrate that some elements that were believed to be lost in squamate evolution are conserved as transitory elements during limb development. However, these elements do not represent just phylogenetic burden but may be important for the morphogenesis of the lizard autopodium.
尽管有鳞目蜥蜴在指（趾）和肢体缺失的研究中受到了关注，但对于五指蜥蜴的肢体形态发生却知之甚少。最近的发育研究为基于发育和比较解剖学来理解蜥蜴 autopodial 元素同源性提供了基础。此外，蜥蜴肢体以及一般爬行动物的一些腕骨和跗骨元素的组成和身份，一直是与非有鳞目鳞龙形下纲和基干羊膜动物相比其同源性讨论的主题。对来自不同蜥蜴科的更多胚胎材料的研究可能会增进我们对有鳞目肢体进化的理解。在这里，我们分析了睑虎科蜥蜴白喉睑虎（Gonatodes albogularis）的肢体形态发生，描述了从胚胎发育早期到幼体阶段的软骨形成和骨化模式。我们的结果总体上与之前的发育研究一致，但我们也表明，有鳞目动物的肢体发育可能涉及更多用于腕骨和跗骨形态发生的软骨形成元素，正如之前基于比较解剖学所认识到的那样。我们提供了证据表明腕骨中的远端腕骨 1 和间介骨以及跗骨中的胫跗骨、间介骨、远端中央骨和远端跗骨 2 会短暂存在。因此，我们证明了一些被认为在有鳞目进化中丢失的元素在肢体发育过程中作为短暂元素被保留了下来。然而，这些元素不仅仅代表系统发育负担，可能对蜥蜴 autopodium 的形态发生很重要。
