A Devonian predatory fish provides insights into the early evolution of modern sarcopterygians.
一种泥盆纪捕食性鱼类揭示现代肉鳍鱼类的早期演化

Authors / 作者: Lu J, Zhu M, Ahlberg PE, Qiao T, Zhu Y, Zhao W, Jia L.
Journal / 期刊: Science advances
Year / 年份: 2016
DOI: 10.1126/sciadv.1600154
Publisher / 出版社: https://www.science.org/doi/10.1126/sciadv.1600154
Abstract source / 摘要来源: https://europepmc.org/article/MED/27386576

Author abstract / 作者原文摘要
Crown or modern sarcopterygians (coelacanths, lungfishes, and tetrapods) differ substantially from stem sarcopterygians, such as Guiyu and Psarolepis, and a lack of transitional fossil taxa limits our understanding of the origin of the crown group. The Onychodontiformes, an enigmatic Devonian predatory fish group, seems to have characteristics of both stem and crown sarcopterygians but is difficult to place because of insufficient anatomical information. We describe the new skull material of Qingmenodus, a Pragian (~409-million-year-old) onychodont from China, using high-resolution computed tomography to image internal structures of the braincase. In addition to its remarkable similarities with stem sarcopterygians in the ethmosphenoid portion, Qingmenodus exhibits coelacanth-like neurocranial features in the otic region. A phylogenetic analysis based on a revised data set unambiguously assigns onychodonts to crown sarcopterygians as stem coelacanths. Qingmenodus thus bridges the morphological gap between stem sarcopterygians and coelacanths and helps to illuminate the early evolution and diversification of crown sarcopterygians.

Summary basis / 解读依据
摘要解读依据已查看的索引作者摘要；如已保存全文，可用于进一步阅读。
Summary based on the inspected indexed author abstract; archived full text, when available, is provided for further reading.

Key findings / 主要发现
对箐门齿鱼头骨材料的 CT 分析发现，其兼具肉鳍鱼干群特征与耳区类似空棘鱼的解剖结构。修订后的系统发育分析将爪齿鱼类置于肉鳍鱼冠群中的空棘鱼干群位置。
CT analysis of Qingmenodus skull material revealed a combination of stem-sarcopterygian features and coelacanth-like anatomy in the otic region. A revised phylogenetic analysis placed onychodonts within crown sarcopterygians as stem coelacanths.

Conclusions / 结论
箐门齿鱼填补肉鳍鱼干群与空棘鱼之间的部分形态间隙；它为鬼鱼和斑鳞鱼提供比较背景，并非对这些清单类群的新描述。
Qingmenodus helps bridge a morphological gap between stem sarcopterygians and coelacanths. It provides comparative context for Guiyu and Psarolepis, not new descriptions of those listed taxa.

Relevance / 关联说明
主要研究对象为箐门齿鱼，鬼鱼作为肉鳍鱼干群的比较对象。
Main study organism is Qingmenodus; Guiyu is an explicit stem-sarcopterygian comparator.