翼龙是最早的动力飞行脊椎动物,化石记录可以追溯到现在之前的大约2.3亿年。大多数物种只有一到三个标本,通常是零碎的。然而,从许多优秀的标本中可以看出,包括多个软组织保存标本。因此,Rhumphorhynchusmuensteri是唯一适合分析种内变异的翼龙之一。以前已经预测,直接参与飞行装置的元件,比如前肢,与骨架的其他部分相比,它们的比例将受到更大的约束。我们调查了在Rhamphorhynchus的元素和身体部位中看到的变异程度,这代表了翼龙中用于测试这些对种内变异的期望的最佳模型系统。我们恢复了整个阑尾和轴向元件高度约束的证据(头部,脖子,躯干,尾巴,前肢,后肢),这表明一切对飞行都很重要。我们进一步发现,在最大的标本中,尾部变异增加,建议在更成熟的个体中减少对尾巴的约束和/或更强的性选择。
Pterosaurs were the first powered flying vertebrates, with a fossil record that stretches back to about 230 million years before present. Most species are only known from one to three specimens, which are most often fragmentary. However, Rhamphorhynchus muensteri is known from numerous excellent specimens, including multiple specimens with soft tissue preservation. As such, Rhamphorhynchus muensteri is one of the only pterosaurs amenable to analysis for intraspecific variation. It has been previously predicted that elements directly involved in the flight apparatus, such as those of the forelimb, will be more highly constrained in their proportions than other parts of the skeleton. We investigated the degree of variation seen in elements and body parts of Rhamphorhynchus, which represents the best model system among pterosaurs for testing these expectations of intraspecific variation. We recover evidence for high levels of constraint throughout the appendicular and axial elements (head, neck, torso, tail, forelimbs, hindlimbs), suggesting that all were important for flight. We further find that tail variation increases among the largest specimens, suggesting reduced constraint and/or stronger sexual selection on the tail in more mature individuals.