Evolutionary Divergence of Geographic Subspecies within the Scalloped Spiny Lobster Panulirus homarus (Linnaeus 1758)

Panulirus homarus is an economically important spiny lobster that is widespread through the Indo-West Pacific Region, but has an uncertain taxonomic status, with three or four geographic subspecies having been described. This study used mitochondrial (16S, COI and control region) and nuclear (18S, ITS-1) DNA sequences to examine specimens of all putative subspecies and forms from throughout their range, in order to determine their genetic validity, and understand the evolutionary history of this species. Despite the range of diversity present in the loci examined, the results were consistent across genes. P. h. rubellus from the SW Indian Ocean comprised the most divergent lineage that was reciprocally monophyletic with respect to all other P. homarus (approx. 9% divergence in COI), and has likely evolved reproductive barriers. The putative P. h. “Brown” subspecies from the Marquesas Is in the central Pacific also comprised a somewhat divergent monophyletic lineage (approx. 3% in COI), but may simply be an allopatric population. The widespread P. h. homarus was not diverged at all from the described P. h. megasculpta from the NW Indian Ocean. The degree of evolutionary divergence of populations at the extremes distribution of the species is somewhat surprising, given the long pelagic larval stage, but suggests that allopatric speciation has been an important driver in the evolution of the genus.波纹龙虾（*Panulirus homarus*）是一类具有重要经济价值的棘刺龙虾，广泛分布于印度-西太平洋海域，但其分类地位尚未明确，目前已有3至4个地理亚种被正式描述。本研究借助线粒体DNA的16S核糖体RNA（16S rRNA）、细胞色素c氧化酶亚基I（COI）及控制区序列，与核DNA的18S核糖体RNA（18S rRNA）、内转录间隔区1（ITS-1）序列，对该物种所有推定亚种及地理型的全域分布样本进行了分析，以明确其分类学有效性，并解析该物种的演化历史。尽管所检测的基因座呈现出丰富的遗传多样性，但各基因的分析结果均保持一致。来自西南印度洋的P. h. rubellus构成了与其他所有波纹龙虾种群互为单系群的分化最显著支系（COI基因序列分化率约为9%），且大概率已演化出生殖隔离屏障。来自中太平洋马克萨斯群岛的推定亚种P. h. "Brown"同样构成了具有一定分化程度的单系群支系（COI基因分化率约为3%），但该类群可能仅为异地分布的种群。广泛分布的指名亚种P. h. homarus与来自西北印度洋的P. h. megasculpta并未出现任何遗传分化。考虑到该物种拥有较长的浮游幼体阶段，其分布范围两端种群间的演化分化程度多少有些出人意料，但该结果暗示异地物种形成在龙虾属（*Panulirus*）的演化进程中发挥了重要驱动作用。