Knoll Fabien, Chiappe Luis M, Sanchez Sophie, Garwood Russell J, Edwards Nicholas P, Wogelius Roy A, Sellers William I, Manning Phillip L, Ortega Francisco, Serrano Francisco J, Marugán-Lobón Jesús, Cuesta Elena, Escaso Fernando, Sanz Jose Luis
ARAID-Fundación Conjunto Paleontológico de Teruel-Dinopolis, 44002, Teruel, Spain.
School of Earth and Environmental Sciences, University of Manchester, Manchester, M13 9PL, UK.
Nat Commun. 2018 Mar 5;9(1):937. doi: 10.1038/s41467-018-03295-9.
Fossils of juvenile Mesozoic birds provide insight into the early evolution of avian development, however such fossils are rare. The analysis of the ossification sequence in these early-branching birds has the potential to address important questions about their comparative developmental biology and to help understand their morphological evolution and ecological differentiation. Here we report on an early juvenile enantiornithine specimen from the Early Cretaceous of Europe, which sheds new light on the osteogenesis in this most species-rich clade of Mesozoic birds. Consisting of a nearly complete skeleton, it is amongst the smallest known Mesozoic avian fossils representing post-hatching stages of development. Comparisons between this new specimen and other known early juvenile enantiornithines support a clade-wide asynchronous pattern of osteogenesis in the sternum and the vertebral column, and strongly indicate that the hatchlings of these phylogenetically basal birds varied greatly in size and tempo of skeletal maturation.
中生代幼鸟化石有助于深入了解鸟类早期发育的演化过程，然而这类化石十分稀少。对这些早期分支鸟类骨化序列的分析，有可能解答有关其比较发育生物学的重要问题，并有助于理解它们的形态演化和生态分化。在此，我们报告了一件来自欧洲早白垩世的早期幼年反鸟亚纲标本，它为这一最为多样化的中生代鸟类类群的骨发生提供了新的线索。该标本由一具近乎完整的骨骼组成，是已知最小的中生代鸟类化石之一，代表了孵化后的发育阶段。将这件新标本与其他已知的早期幼年反鸟亚纲进行比较，支持了胸骨和脊柱在整个类群中骨化的异步模式，并有力地表明，这些系统发育基部鸟类的雏鸟在骨骼成熟的大小和速度上差异很大。
