Cyprus is a Mediterranean island of volcanic origin isolated for at least 5.3 Myr from surrounding continental areas. The present study focuses on the diversification of the isopod genus Schizidium within the island, including also specimens from surrounding continental areas. The genus Schizidium sensu lato is probably non monophyletic, comprising 26 species distributed from Greece to Iran. Up to date the only representative of the genus reported from Cyprus was Schizidium fissum. Aiming to investigate the patterns of genetic diversity within the focal island, to evaluate the morphology-based taxonomy of the species in the genus, and at the same time to explore phylogenetic relationships with mainland populations, we applied genome-wide ddRADseq as well as Sanger sequencing targeting three mitochondrial (16S, COI and 12S) and the nuclear NaK loci. Results of phylogenetic analyses support the existence of two distinct epigean Schizidium clades with well-defined geographic boundaries that conform to the known paleogeography of Cyprus, plus one endogean clade with restricted distribution within the island. Genetic data and morphology corroborate the assignment of this latter endogean clade to a new species, Schizidium myrrae n. sp. The two epigean clades are also considered as distinct species, one corresponding to the known S. fissum at the eastern part of the island (Pentadaktylos massif) and the other to the newly described S. christosi n. sp. distributed along the western part of the island (Troodos massif). Even though detailed examination of many specimens could not retrieve any morphological differences among representatives of these two clades, clado-chronological analysis indicates a long isolation between them, estimated at ∼ 9 Mya, as well as the sharing of a common ancestor with S. tiberianum from Israel at ∼ 15 Mya. Hence, we can consider these epigean Schizidium species as one more case of cryptic diversity on Cyprus, exhibiting similar patterns with the recently described case in the genus Armadillo.

塞浦路斯是一个地中海火山岛，与周围大陆地区的距离至少为 5.3 马来西亚林吉特。目前的研究重点是岛上等足类裂殖属的多样化，包括来自周围大陆地区的标本。Schizidium sensu lato属可能不是单系的，包括 26 个物种，分布于希腊至伊朗。迄今为止，塞浦路斯报告的该属的唯一代表是Schizidium fissum。为了研究焦点岛内的遗传多样性模式，评估属内物种的基于形态的分类，同时探索与大陆种群的系统发育关系，我们应用了全基因组 ddRADseq 和 Sanger针对三个线粒体（16S、COI 和 12S）和核 NaK 位点的测序。系统发育分析的结果支持存在两个不同的表生裂殖分支，其具有明确的地理边界，符合塞浦路斯已知的古地理，以及一个在岛上分布有限的内生分支。遗传数据和形态证实了后一个内源进化枝属于一个新物种，Schizidium myrrae n。sp。这两个表层分支也被认为是不同的物种，一个对应于该岛东部（Pentadaktylos 地块）已知的S. fissum ，另一个对应于新描述的S. christosi n。sp。分布于岛屿西部（特罗多斯地块）。尽管对许多标本的详细检查无法检索出这两个分支的代表之间的任何形态差异，但分支年代分析表明它们之间有很长的隔离，估计约为 9 Mya，并且与 S. tiberianum 拥有共同的祖先来自以色列，约 15 迈亚。因此，我们可以将这些表层裂殖属物种视为塞浦路斯神秘多样性的又一案例，表现出与最近描述的犰狳属案例相似的模式。