Chamberland Lisa, Salgado-Roa Fabian C, Basco Alma, Crastz-Flores Amanda, Binford Greta J, Agnarsson Ingi
Department of Biology, University of Vermont, Burlington, VT, USA.
Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogota, Colombia.
PeerJ. 2020 Apr 30;8:e8976. doi: 10.7717/peerj.8976. eCollection 2020.
Modern molecular analyses are often inconsistent with pre-cladistic taxonomic hypotheses, frequently indicating higher richness than morphological taxonomy estimates. Among Caribbean spiders, widespread species are relatively few compared to the prevalence of single island endemics. The taxonomic hypothesis circumscribes a species with profuse variation in size, color and body form. Distributed throughout the Neotropics, is the only morphological species of in the New World in this globally distributed genus.
We inferred phylogenetic relationships across Neotropical populations of using three target genes. Within the Caribbean, we estimated genetic diversity, population structure, and gene flow among island populations.
Our findings revealed a single widespread species of throughout the Caribbean, , while suggesting two recently divergent mainland populations that may represent separate species, diverging linages, or geographically isolated demes. The concatenated and (Cytochrome c oxidase subunit 1) phylogeny supported a Caribbean clade nested within the New World. Genetic variability was high between island populations for our dataset; however, gene flow was also high, especially between large, adjacent islands. We found structured genetic and morphological variation within island populations; however, this variation does not reflect genealogical relationships. Rather, isolation by distance and local morphological adaptation may explain the observed variation.
现代分子分析结果常常与分支分类学之前的分类假设不一致，常常显示出比形态分类学估计更高的丰富度。在加勒比地区的蜘蛛中，与单岛特有物种的普遍程度相比，广泛分布的物种相对较少。分类假设界定了一个在大小、颜色和体型上有大量变异的物种。该物种分布于整个新热带区，是这个全球分布属在新世界唯一的形态物种。
我们使用三个目标基因推断了新热带区种群的系统发育关系。在加勒比地区内部，我们估计了岛屿种群之间的遗传多样性、种群结构和基因流。
我们的研究结果揭示了整个加勒比地区存在一个单一的广泛分布物种，即 ，同时表明最近有两个分化的大陆种群，它们可能代表不同的物种、分化的谱系或地理隔离的群落。串联的和 （细胞色素 c 氧化酶亚基 1）系统发育支持一个嵌套在新世界内的加勒比分支。对于我们的数据集中的岛屿种群，遗传变异性很高；然而，基因流也很高，特别是在大的相邻岛屿之间。我们在 岛屿种群中发现了结构化的遗传和形态变异；然而，这种变异并不反映谱系关系。相反，距离隔离和局部形态适应可能解释了观察到的变异。
