Blind snakes represent the most basal group of extant snakes and include fossorial species with unusual skeletal traits. Despite their known phylogenetic position, little is known about their ontogeny and what it might reveal about the origin of their skull anatomy. Here we describe for the first time the ontogenetic transformations of the skull of a blind snake, the typhlopid Amerotyphlops brongersmianus, including embryos and postnatal individuals. Furthermore, we provide data on the size changes relative to skull growth of the main elements of the gnathic complex. We observed that the skull of this blind snake undergoes considerable morphological change during late ontogeny. Additionally, we detected delayed development of some traits (closure of the skull roof, opisthotic-exoccipital suture, ossification of the posterior trabeculae) simultaneously with clearly peramorphic traits (development of the crista circumfenestralis, growth of the pterygoid bar). Our analysis suggests that the unique skull anatomy of blind snakes displays plesiomorphic and highly autapomorphic features, as an outcome of heterochronic processes and miniaturization, and is shaped by functional constraints related to a highly specialized feeding mechanism under the selective pressures of a fossorial lifestyle.

中文翻译：

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盲蛇 Amerotyphlops brongersmianus (Serpentes: Typhlopidae) 头骨的个体发育为蛇的颅骨进化带来了新的见解

盲蛇代表了现存蛇类中最基本的群体，包括具有不寻常骨骼特征的化石物种。尽管它们已知的系统发育位置，但对它们的个体发育以及它可能揭示的关于它们头骨解剖学起源的信息知之甚少。在这里，我们首次描述了盲蛇头骨的个体发生转化，伤寒 Amerotyphlops brongersmianus，包括胚胎和出生后的个体。此外，我们提供了与颌骨复合体主要元素的颅骨生长相关的大小变化数据。我们观察到这条盲蛇的头骨在个体发育晚期经历了相当大的形态变化。此外，我们检测到一些特征的延迟发展（颅顶闭合、后枕骨缝合、后小梁骨化）同时具有明显的变形特征（环腹嵴的发育，翼状骨的生长）。我们的分析表明，盲蛇独特的头骨解剖结构显示出同形性和高度自形性特征，这是异时过程和小型化的结果，并且受到与在化石生活方式的选择压力下高度专业化的摄食机制相关的功能限制的影响。