鸟类骨盆的发育与恐龙祖先相似，这一成果由美国耶鲁大学Bhart-Anjan S. Bhullar课题组经过不懈努力而取得。2022年7月27日出版的《自然》杂志发表了这项成果。
研究人员使用胚胎成像技术在三个维度上重现了鸟类盆腔组织的形态发生，从而可以与化石记录进行直接比较。许多祖先恐龙的特征（例如，前向耻骨、短髂骨和耻骨“靴子”）在鸟类早期形态发生中短暂存在，并通过性状获得的系统发育序列显示。研究定量地证明禽类骨盆个体发育与非禽类恐龙向鸟类的转变相似，并为骨盆内的表型协方差提供证据，这种协方差在Archosauria中是保守的。鸟类胚胎中祖先状态的存在可能源于这种保守的协变关系。
总之，尽管鸟类骨盆的早期发育很少被研究，该研究提供的证据表明它是通过末端添加机制进化而来，即新的非形变状态被添加到发育序列的末端，导致该序列在较早的祖先性状中表达。该研究检测到的表型整合表明了一种以前未被识别的末端添加机制，并暗示在进化过渡期间保留祖先状态是常见的。
据悉，活鸟(Aves)的身体从其爬行动物祖先开始得到了很大的改变。尤其是鸟类的骨盆从早期恐龙类到现生鸟类的过渡过程中经历了重大变化。高质量的化石记录充分证明了这种转变的发生过程；然而，它背后的个体变化却鲜为人知。
附：英文原文
Title: The developing bird pelvis passes through ancestral dinosaurian conditions
Author: Griffin, Christopher T., Botelho, Joo F., Hanson, Michael, Fabbri, Matteo, Smith-Paredes, Daniel, Carney, Ryan M., Norell, Mark A., Egawa, Shiro, Gatesy, Stephen M., Rowe, Timothy B., Elsey, Ruth M., Nesbitt, Sterling J., Bhullar, Bhart-Anjan S.
Issue&Volume: 2022-07-27
Abstract: Living birds (Aves) have bodies substantially modified from the ancestral reptilian condition. The avian pelvis in particular experienced major changes during the transition from early archosaurs to living birds1,2. This stepwise transformation is well documented by an excellent fossil record2,3,4; however, the ontogenetic alterations that underly it are less well understood. We used embryological imaging techniques to examine the morphogenesis of avian pelvic tissues in three dimensions, allowing direct comparison with the fossil record. Many ancestral dinosaurian features2 (for example, a forward-facing pubis, short ilium and pubic ‘boot’) are transiently present in the early morphogenesis of birds and arrive at their typical ‘avian’ form after transitioning through a prenatal developmental sequence that mirrors the phylogenetic sequence of character acquisition. We demonstrate quantitatively that avian pelvic ontogeny parallels the non-avian dinosaur-to-bird transition and provide evidence for phenotypic covariance within the pelvis that is conserved across Archosauria. The presence of ancestral states in avian embryos may stem from this conserved covariant relationship. In sum, our data provide evidence that the avian pelvis, whose early development has been little studied5,6,7, evolved through terminal addition—a mechanism8,9,10 whereby new apomorphic states are added to the end of a developmental sequence, resulting in expression8,11 of ancestral character states earlier in that sequence. The phenotypic integration we detected suggests a previously unrecognized mechanism for terminal addition and hints that retention of ancestral states in development is common during evolutionary transitions.
DOI: 10.1038/s41586-022-04982-w
Source: https://www.nature.com/articles/s41586-022-04982-w
Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html
本期文章：《自然》：Online/在线发表
