With more than 30,000 species, teleosts comprise about half of today’s living vertebrates, enriched with a wide set of adaptations to all aquatic systems. Their evolution was marked by modifications of their tail, that involved major rearrangements of the metameric organization of the axial skeleton. The most posterior or ural caudal skeleton, primitively included more than 10 vertebrae and, through a series of fusions and losses, became reduced to a single vertebra in modern ostariophysans, one of the largest clades of teleosts. The ontogeny of the ostariophysan Danio rerio recapitulates this process by forming two or three separate vertebrae that become a single vertebra in adults. We characterize the developmental sequence of this change by describing the processes of patterning, fusion and differential growth on each of the constitutive elements that sculpt the adult terminal vertebra. The ontogenetic changes of the terminal vertebra were characterized, highlighting their shared and derived characters in comparison with other teleosts. In zebrafish, there is: i) a loss of the preural centrum 1, ii) the formation of an hourglass-shaped autocentrum only in the anterior but not the posterior border of the compound centrum, iii) the formation of a vestigial posterior centrum that does not form an autocentrum and becomes incorporated beneath the compound centrum during development, and iv) the elongated dorso-posterior process of the compound centrum or pleurostyle appears as an independent element posterior to the compound centrum, before fusing to the ural neural arches and the anterior portion of the compound centrum. The unique features of the formation of the terminal vertebra in Danio rerio reflect the remarkable changes that occurred during the evolution of teleosts, with potential shared derived characteristics for some of the major lineages of modern teleosts. A new ontogenetic model is proposed to illustrate the development of the terminal vertebra, and the phylogenetic implications for the evolution of caudal skeleton consolidation in ostariophysans are discussed.

中文翻译：

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从 Devo 到 Evo：斑马鱼末端椎骨的模式、融合和进化。

硬骨鱼拥有 30,000 多种物种，约占当今现存脊椎动物的一半，并具有对所有水生系统的广泛适应性。它们的进化以尾巴的改变为标志，其中涉及轴向骨骼的同色异谱组织的主要重排。最近的尾骨或尾骨，最初包括 10 多块椎骨，经过一系列融合和损失，在现代 ostariophysans（最大的硬骨鱼分支之一）中变成了单个椎骨。斑鳢鱼的个体发育通过形成两个或三个独立的椎骨来概括这一过程，这些椎骨在成年人中变成一个单独的椎骨。我们通过描述图案化的过程来描述这种变化的发展顺序，塑造成人终末椎骨的每个组成元素的融合和差异生长。末端椎骨的个体发育变化进行了表征，与其他硬骨鱼相比，突出了它们的共同特征和衍生特征。在斑马鱼中，有：i) 前中枢的丧失 1，ii) 仅在复合中枢的前缘而不是后缘形成沙漏形自中枢，iii) 形成残留的后中枢，不形成自中心，并在发育过程中并入复合中心下方，并且 iv) 复合中心或胸膜柱的拉长的背-后突在复合中心后部作为一个独立的元素出现，然后融合到 ural 神经弓和复合中心的前部。斑马尾椎骨形成的独特特征反映了硬骨鱼进化过程中发生的显着变化，现代硬骨鱼的一些主要谱系具有潜在的共同衍生特征。提出了一种新的个体发育模型来说明终末椎骨的发育，并讨论了骨骺尾骨整合进化的系统发育意义。