Department of Geoscience, University of Calgary, Calgary, Alberta, Canada.
Department of Paleontology, Friedrich-Alexander University Erlangen-Nürnberg, GeoZentrum Nordbayern, Erlangen, Germany.
Proc Biol Sci. 2020 Nov 25;287(1939):20201922. doi: 10.1098/rspb.2020.1922. Epub 2020 Nov 18.
The repeated emergence of similar morphologies in the dental elements of Permian conodonts has been a hypothesized example of parallel evolution. To test if morphological parallelisms occur between isolated lineages, this study uses two-dimensional-based geometric morphometrics combined with a revised and expanded phylogeny of Permian conodonts to quantify dental element trait distributions and compare the phenotypic trajectories between lineages. A hierarchical clustering method was used to identify recurrent species pairs based on principal component scores describing their morphological variation, with the further incorporation of widely used ecological metrics such as limiting similarity and morphological overlap. Our research implies that a major contributor to conodont diversity in Palaeozoic marine trophic networks is the emergence of recurrent parallel morphologies via disruptive and directional selection. This study illustrates the mechanisms through which conodonts achieved their status as hyper-diverse predators and scavengers, contributing substantially to the complexity of Palaeozoic marine communities.
二叠纪牙形石牙齿元素中反复出现的相似形态被假设为平行进化的例子。为了检验孤立谱系之间是否存在形态平行，本研究使用基于二维的几何形态计量学，并结合修订和扩展的二叠纪牙形石系统发育，来量化牙齿元素特征的分布，并比较谱系之间的表型轨迹。基于描述其形态变化的主成分得分，我们使用分层聚类方法识别出反复出现的物种对，进一步纳入了广泛使用的生态度量，如限制相似性和形态重叠。我们的研究表明，在古生代海洋营养网络中，牙形石多样性的一个主要贡献因素是通过破坏性和定向选择出现反复出现的平行形态。本研究阐明了牙形石如何成为超多样的捕食者和食腐动物的机制，为古生代海洋群落的复杂性做出了重要贡献。
