Journeys through discrete-character morphospace: synthesising phylogeny, tempo, and disparity

Palaeontologists have long employed discrete categorical data to capture morphological variation in fossil species, using the resulting character-taxon matrices to measure evolutionary tempo, infer phylogenies, and capture morphological disparity. However, to date these have been seen as separate approaches despite a common goal of understanding morphological evolution over deep time. Here I argue that there are clear advantages to considering these three lines of enquiry in a single space: the phylomorphospace. Conceptually these high-dimensional spaces capture how a phylogenetic tree explores morphospace and allow us to consider important process questions around evolutionary rates, constraints, convergence, and directional trends. Currently the literature contains fundamentally different approaches used to generate such spaces, with no direct comparison between them despite the differing evolutionary histories they imply. Here I directly compare five different phylomorphospace approa...古生物学家长期以来一直采用离散分类数据来刻画化石物种的形态变异，并通过所得的特征-分类单元矩阵（character-taxon matrix）来量化演化速率（evolutionary tempo）、推断系统发育关系以及解析形态差异度（morphological disparity）。尽管三者的共同目标均为探究地质历史中的形态演化，但迄今为止，这些研究方向始终被视为相互独立的方法。本文认为，将这三类研究整合至系统发育形态空间（phylomorphospace）这一统一框架中，具备显著优势。从概念层面而言，这类高维空间能够刻画系统发育树如何探索形态空间（morphospace），同时助力我们探讨演化速率、演化约束、趋同演化以及定向演化趋势等关键过程性问题。目前，相关研究领域中存在多种构建此类空间的截然不同的方法，尽管这些方法所隐含的演化历史各不相同，但尚未有研究对其进行直接对比。本文将直接对比五种不同的系统发育形态空间构建方法……