New Age of Fishes initiated by the Cretaceous−Paleogene mass extinction
New Age of Fishes initiated by the Cretaceous−Paleogene mass extinction
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白垩纪-古近纪大规模灭绝引发的鱼类新时代
DOI：
10.1073/pnas.1504985112
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
R. Norris
中科院分区：
文献类型：
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作者：
E. Sibert;R. Norris
射线鳍鱼类是地球上最具多样性和生态优势的脊椎动物群。以往的分子生物学和古生物学研究表明，现代冠鳍鱼（冠硬骨鱼）辐射在晚白垩世或早第三纪的某个时候。我们的数据表明，在6600万年前白垩纪-古近纪大灭绝之后，冠硬骨鱼立即在远洋生态系统中发挥了目前的主导生态作用，填补了新空出的生态位，标志着“鳍鱼时代”的开始。据我们所知，我们的研究是第一个地理上全面的，高分辨率的海洋脊椎动物群落研究。辐鳍鱼（Actinoptusi）包括近一半的现代脊椎动物的多样性，是一个生态和数量上占主导地位的巨型动物在大多数水生环境。冠硬骨鱼多样化相对较近，在晚白垩世和早古近纪，虽然确切的时间和原因，他们的辐射和上升到生态优势是不受约束。本文利用保存在深海沉积物中的微化石牙齿和鲨鱼皮鳞（鱼化石），研究了白垩纪末和古近纪早期中上层鱼类群落的变化。我们发现，白垩纪-古近纪（K/Pg）灭绝事件标志着地球仪周围的鱼化石群落结构发生了深刻的变化：尽管在世界各地的白垩纪深海沉积物中，鲨鱼的牙齿数量超过了鳍状鱼类的牙齿，但在古新世，鳍状鱼类牙齿与鲨鱼牙齿的比例急剧增加。在边界处，鳍鱼牙齿的大小和数量也有所增加。这些变化至少持续了新生代的前2400万年。这种新的鱼类群落结构始于K/Pg大灭绝，表明灭绝事件在启动现代“鱼类时代”方面发挥了重要作用。
Significance Ray-finned fishes are the most diverse and ecologically dominant group of vertebrates on the planet. Previous molecular phylogenies and paleontological studies have shown that modern ray-finned fishes (crown teleosts) radiated sometime in the Late Cretaceous or early Paleogene. Our data suggest that crown teleosts came into their current dominant ecological role in pelagic ecosystems immediately following the Cretaceous−Paleogene mass extinction 66 million years ago by filling newly vacated ecological niches and marking the beginning of an “age of ray-finned fishes.” Our study is, to our knowledge, the first geographically comprehensive, high-resolution study of marine vertebrate communities across the extinction. Ray-finned fishes (Actinopterygii) comprise nearly half of all modern vertebrate diversity, and are an ecologically and numerically dominant megafauna in most aquatic environments. Crown teleost fishes diversified relatively recently, during the Late Cretaceous and early Paleogene, although the exact timing and cause of their radiation and rise to ecological dominance is poorly constrained. Here we use microfossil teeth and shark dermal scales (ichthyoliths) preserved in deep-sea sediments to study the changes in the pelagic fish community in the latest Cretaceous and early Paleogene. We find that the Cretaceous−Paleogene (K/Pg) extinction event marked a profound change in the structure of ichthyolith communities around the globe: Whereas shark denticles outnumber ray-finned fish teeth in Cretaceous deep-sea sediments around the world, there is a dramatic increase in the proportion of ray-finned fish teeth to shark denticles in the Paleocene. There is also an increase in size and numerical abundance of ray-finned fish teeth at the boundary. These changes are sustained through at least the first 24 million years of the Cenozoic. This new fish community structure began at the K/Pg mass extinction, suggesting the extinction event played an important role in initiating the modern “age of fishes.”