Cretaceous bird from Brazil informs the evolution of the avian skull and brain

• 成果类型: Article
• 署名作者: Chiappe, Luis M.; Navalon, Guillermo; Martinelli, Agustin G.; Carvalho, Ismar de Souza; Miloni Santucci, Rodrigo; Wu, Yun-Hsin; Field, Daniel J.
• 署名单位: University of Cambridge; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET); Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN); Universidade Federal do Rio de Janeiro; Universidade de Coimbra; Universidade de Brasilia; University of Cambridge
• 刊物名称: Nature
• ISSN/ISSBN: 0028-4667
• DOI: 10.1038/s41586-024-08114-4
• 发表日期: 2024-11-14
• 关键词: enantiornithine aves ornithothoraces; inner-ear; SYSTEM; size

摘要

A dearth of Mesozoic-aged, three-dimensional fossils hinders understanding of the origin of the distinctive skull and brain of modern (crown) birds1. Here we report Navaornis hestiae gen. et sp. nov., an exquisitely preserved fossil species from the Late Cretaceous of Brazil. The skull of Navaornis is toothless and large-eyed, with a vaulted cranium closely resembling the condition in crown birds; however, phylogenetic analyses recover Navaornis in Enantiornithes, a highly diverse clade of Mesozoic stem birds. Despite an overall geometry quantitatively indistinguishable from crown birds, the skull of Navaornis retains numerous plesiomorphies including a maxilla-dominated rostrum, an akinetic palate, a diapsid temporal configuration, a small cerebellum and a weakly expanded telencephalon. These archaic neurocranial traits are combined with a crown bird-like degree of brain flexion and a bony labyrinth comparable in shape to those of many crown birds but substantially larger. Altogether, the emergent cranial geometry of Navaornis shows an unprecedented degree of similarity between crown birds and enantiornithines, groups last sharing a common ancestor more than 130 million years ago2. Navaornis provides long-sought insight into the detailed cranial and endocranial morphology of stem birds phylogenetically crownward of Archaeopteryx, clarifying the pattern and timing by which the distinctive neuroanatomy of living birds was assembled. The exceptionally preserved skull of a starling-sized fossil bird from 80 million years ago allows reconstruction of the brain, enabling detailed endocranial description of an archaic bird that is evolutionarily intermediate between Archaeopteryx and living birds.