Uncertainty surrounding the number and identity of species of genus Limacia O.F. Müller, 1781, in southern African and European coastal waters presents an ongoing conundrum. Limacia clavigera (O.F. Müller, 1776) was previously thought to be the only species of its genus in the eastern Atlantic, with a distribution covering north- to south-eastern Atlantic waters. In the light of more recent molecular and morphological research, several distinct lineages have been uncovered in both Europe and southern Africa. Here, we gathered this information and included additional specimens from the two regions to produce an integrative morphological and molecular framework in which to delineate species. Molecular data of mitochondrial genes cytochrome oxidase subunit I and the large ribosomal subunit (16S rRNA) were amplified to perform molecular phylogenetic- and species-delimitation analyses. Findings led to the discovery and description of one new species from Europe: Limacia inesae sp. nov., three new species from southern Africa: Limacia jellyi sp. nov., Limacia miali sp. nov., and Limacia langavi sp. nov., and the confirmation of the validity of Limacia lucida (Stimpson, 1855) from southern Africa. Species-specific distributional and ecological traits further support species distinctions and historical biogeographical processes behind the inferred evolutionary relationships are further explored.

在南部非洲和欧洲沿海水域，1781年穆勒利马西亚属物种的数量和特征的不确定性提出了一个持续的难题。利马西亚草（OFMüller，1776）以前被认为是其在大西洋东部的唯一属，分布范围从北到东南大西洋水域。根据最近的分子和形态学研究，在欧洲和南部非洲都发现了几个不同的谱系。在这里，我们收集了这些信息，并包括了来自两个地区的其他标本，以产生一个完整的形态学和分子框架，用以描述物种。线粒体基因细胞色素氧化酶亚基I和大核糖体亚基（16S rRNA）的分子数据被放大，以进行分子系统发育和物种定界分析。这些发现导致发现并描述了欧洲一种新物种：利马西亚（Limacia inesae）sp。11月，来自南部非洲的3个新物种：Limacia jellyi sp.。十一月，利马西亚州miali sp。十一月，和Limacia langavi sp。十一月，以及来自南部非洲的Limacia lucida（Stimpson，1855）的有效性的确认。特定于物种的分布和生态特征进一步支持了物种的区分，并进一步探讨了推断的进化关系背后的历史生物地理过程。