Geometric morphometrics dismiss the polymorphic Hydrocotyle quinqueloba (Araliaceae) from the neotropics

Hydrocotyle taxonomy is poorly resolved due the traditional assessment of leaf morphology that has imposed difficulties to species delimitation and prompted the recognition of several infraspecific taxa. Hydrocotyle quinqueloba comprises ten infraspecific taxa that differ mainly by the shape of their leaf blade. The species occurs in montane forests of the Andes and eastern Brazil, along the Atlantic forest and Cerrado domains. However, the geographic distribution of the taxa under H. quinqueloba is poorly known, and their supposedly continuous morphological variation remains unverified. Here we analyze the morphological variation and documented correlated differences in geographic distribution of H. quinqueloba to assess whether they support the delimitation of distinct species or the recognition of infraspecific taxa. For this task, we applied landmark-based geometric morphometrics (GM) to leaves and traditional morphometrics to other structures of specimens of
H. quinqueloba. Procru...

天胡荽属（Hydrocotyle）的分类学问题长期未能得到妥善解决：传统基于叶形态的评估方法为物种界定带来了极大困难，同时催生了诸多种下类群的认定。五裂天胡荽（Hydrocotyle quinqueloba）包含10个种下类群，类群间的核心差异集中于叶片形态。该物种分布于安第斯山脉与巴西东部的山地森林生境，涵盖大西洋森林与塞拉多（Cerrado）生物群落域。然而，五裂天胡荽属下各类群的地理分布范围仍鲜为人知，其被推测存在的连续形态变异也尚未得到验证。本研究针对五裂天胡荽的形态变异与已记录的地理分布关联差异展开分析，以评估这些特征是否支持将其划分为独立物种，抑或仅需认定为种下类群。为此，我们对五裂天胡荽标本的叶片采用基于地标点的几何形态测量学（landmark-based geometric morphometrics, GM）分析，并对标本其余结构采用传统形态测量学方法。Procru...