Department of Earth Sciences, University of Oxford, Oxford OX1 3PR, UK.
Proc Biol Sci. 2010 Jun 7;277(1688):1675-83. doi: 10.1098/rspb.2009.2177. Epub 2010 Feb 4.
The spiny-finned teleost fishes (Acanthomorpha) include nearly one-third of all living vertebrate species and assume a bewildering array of bodyplans, but the macroevolutionary assembly of modern acanthomorph biodiversity remains largely unexplored. Here, I reconstruct the trajectory of morphological diversification in this major radiation from its first appearance in the Late Cretaceous to the Miocene using a geometric morphometric database comprising more than 600 extinct species known from complete body fossils. The anatomical diversity (disparity) of acanthomorphs is low throughout the Cretaceous, increases sharply and significantly in the wake of the Cretaceous-Palaeogene (K-P) extinction, and shows little change throughout subsequent Cenozoic intervals. This pattern of morphological diversification appears robust to two potential biasing factors: the 'Lagerstätten effect', and the non-random segregation of rare and common taxa along phenotypic axes. Dissecting the trajectory of acanthomorph radiation along phylogenetic lines reveals that the abrupt post-extinction increase in disparity is driven largely by the proliferation of trophically diverse modern groups within Percomorpha, a spiny-fin subclade containing more than 15 000 living species and identified as showing a substantially elevated diversification rate relative to background vertebrate levels. A major component of the Palaeogene acanthomorph radiation reflects colonization of morphospace previously occupied by non-acanthomorph victims of the K-P. However, other aspects of morphological diversification cannot be explained by this simple ecological release model, suggesting that multiple factors contributed to the prolific anatomical radiation of acanthomorphs.
硬骨鱼类（棘鳍鱼类）包括了现存所有脊椎动物物种的近三分之一，其身体形态呈现出令人眼花缭乱的多样性，但现代棘鳍鱼类生物多样性的宏观进化组合在很大程度上仍未被探索。在这里，我利用一个包含超过 600 种已灭绝物种的完整身体化石的几何形态计量数据库，从白垩纪晚期到中新世重建了这一主要辐射的形态多样化轨迹。棘鳍鱼类的解剖多样性（歧异度）在整个白垩纪都很低，在白垩纪-古近纪（K-P）灭绝之后急剧而显著地增加，并在随后的新生代间隔中几乎没有变化。这种形态多样化模式似乎对两个潜在的偏倚因素具有稳健性：“Lagerstätten 效应”，以及稀有和常见分类群沿着表型轴的非随机分离。沿着进化谱系剖析棘鳍鱼类辐射的轨迹，发现歧异度在灭绝后突然增加的主要原因是多食性现代群体在 Percomorpha 中的大量繁殖，Percomorpha 是一个棘鳍亚群，包含超过 15000 个现存物种，并且被确定为相对于背景脊椎动物水平表现出显著升高的多样化率。古近纪棘鳍鱼类辐射的一个主要组成部分反映了对 K-P 非棘鳍鱼类受害者所占据的形态空间的殖民化。然而，形态多样化的其他方面不能用这种简单的生态释放模型来解释，这表明多种因素促成了棘鳍鱼类的丰富解剖辐射。
