Phylogeography of the widespread Caribbean spiny orb weaver Gasteracantha cancriformis

Background. 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 Gasteracantha cancriformis circumscribes a species with profuse variation in size, color, and body form. Distributed throughout the Neotropics, G. cancriformis is the only morphological species of Gasteracantha in the New World in this globally distributed genus. Methods. We inferred phylogenetic relationships across Neotropical populations of Gasteracantha using three target genes. Within the Caribbean, we estimated genetic diversity, population structure, and gene flow among island populations. Results. Our findings revealed a single widespread species of Gasteracantha throughout the Caribbean, G. cancriformis, while suggesting two recently divergent mainland popu...背景：现代分子分析结果往往与支序分类学诞生前的分类假说相悖，且常显示出比形态分类学评估更高的物种丰富度。在加勒比蜘蛛类群中，广布物种相对稀少，而单岛特有种则较为普遍。分类学假说认为，驼背棘腹蛛（Gasteracantha cancriformis）是一个体型、体色及躯体形态均存在丰富变异的物种。该属（棘腹蛛属Gasteracantha）在全球广泛分布，驼背棘腹蛛的分布范围覆盖整个新热带区（Neotropics），同时也是新大陆（New World）地区该属中唯一以形态学物种概念界定的物种。 方法：本研究选取3个靶标基因，对新热带区棘腹蛛属种群的系统发育关系（phylogenetic relationships）进行推断；在加勒比海区域内，我们还估算了岛屿种群间的遗传多样性（genetic diversity）、种群结构（population structure）以及基因流（gene flow）水平。 结果：本研究结果显示，加勒比海地区广泛分布的棘腹蛛属物种仅为驼背棘腹蛛（G. cancriformis），同时表明存在两个近期分化的大陆种群……