Coordinated dispersal and pre-Isthmian assembly of the Central American ichthyofauna

We document patterns of coordinated dispersal over evolutionary time frames in heroine cichlids and poeciliine live-bearers, the two most species-rich clades of freshwater fishes in the Caribbean basin. Observed dispersal rate (DO) values were estimated from time-calibrated molecular phylogenies in Lagrange+, a modified version of the ML-based parametric biogeographic program Lagrange. DO is measured in units of ‘wallaces’ (wa) as the number of biogeographic range-expansion events per million years. DO estimates were generated on a dynamic paleogeographic landscape of five areas over three time intervals from Upper Cretaceous to Recent. Expected dispersal rate (DE) values were generated from alternative paleogeographic models, with dispersal rates proportional to target area and source-river discharge volume, and inversely proportional to paleogeographic distance. Correlations between DO and DE were used to assess the relative contributions of these three biogeographic parameters. DO es...

本研究记录了加勒比盆地中物种多样性最高的两个淡水鱼类支系——丽体鱼慈鲷（Heroine cichlids）与花鳉科胎生鱼类（Poeciliine live-bearers）在演化时间尺度下的协同扩散模式。观测扩散率（Observed dispersal rate, DO）通过基于最大似然（Maximum Likelihood, ML）的参数化生物地理学程序Lagrange的改进版本拉格朗日+（Lagrange+），从时间校准分子系统发育树中估算得到。DO以‘华莱士单位（wallaces, wa）’为单位进行计量，定义为每百万年发生的生物地理分布区扩张事件数量。DO的估算基于从白垩纪晚期（Upper Cretaceous）至现代（Recent）的三个时间间隔内、涵盖五个区域的动态古地理景观完成。预期扩散率（Expected dispersal rate, DE）通过不同古地理模型生成，该类模型设定扩散速率与目标区域面积、源河径流量呈正相关，与古地理距离呈负相关。通过DO与DE之间的相关性，可评估上述三类生物地理学参数的相对贡献程度。DO……