The phylogenetic structure of 23 populations of Crangonyx hobbsi, a stygobitic amphipod species endemic to the Floridan aquifer, is detailed. Molecular genetic analyses (based on three genes the nuclear 18S rDNA, 28S rDNA, and mitochondrial 16S rDNA) point to the presence of at least two phylogenetic clades within the aquifer. These clades align into two major zoogeographic regions, the Northern Suwannee River Basin and the Coastal and Central Lowlands in the Florida peninsula. Three species delimitation models indicate that the Northern Suwannee River Basin Clade represents a species level differentiation from C. hobbsi sensu stricto. Morphological analyses support the molecular analyses, revealing the presence of several taxonomically significant differences between the two species, including presence/absence of calceoli on the second antennae of males and differences in telson shape in both sexes. Additionally, the molecular diversity of C. hobbsi sensu stricto was shown to be surprisingly variable, suggesting the potential presence of additional diversity within the taxon.

中文翻译：

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一个新物种从佛罗里达州下方崛起：分子系统发育分析揭示了 Crangonyx hobbsi Shoemaker 复合种群之间的神秘多样性，1941（片脚类动物：Crangonyctidae）

详细介绍了 23 个 Crangonyx hobbsi 种群的系统发育结构，这是一种佛罗里达含水层特有的柱足类动物。分子遗传分析（基于三个基因，即核 18S rDNA、28S rDNA 和线粒体 16S rDNA）表明含水层中至少存在两个系统发育进化枝。这些进化枝排列成两个主要的动物地理区域，即北苏旺尼河流域以及佛罗里达半岛的沿海和中部低地。三个物种定界模型表明北苏旺尼河流域分支代表与 C. hobbsi sensu stricto 的物种水平分化。形态学分析支持分子分析，揭示了两个物种之间存在几个分类学上的显着差异，包括雄性第二触角上是否存在 calceoli 以及两性尾节形状的差异。此外，C. hobbsi sensu stricto 的分子多样性显示出惊人的可变性，表明该分类群内可能存在额外的多样性。