Guidetti Roberto, Cesari Michele, Bertolani Roberto, Altiero Tiziana, Rebecchi Lorena
1Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 213/D, 41125 Modena, Italy.
2Department of Education and Humanities, University of Modena and Reggio Emilia, Via Allegri 9, 42121 Reggio Emilia, Italy.
Zoological Lett. 2019 Jan 3;5:1. doi: 10.1186/s40851-018-0113-z. eCollection 2019.
For many years, was reported to consist of populations with different chromosome numbers and reproductive modes. To clarify the relationships among different populations, the type locality of the species (Clare Island, Ireland) and several Italian localities were sampled. Populations were investigated with an integrated approach, using morphological (LM, CLSM, SEM), morphometric, karyological, and molecular (18S rRNA, genes) data. was redescribed and a neotype designed from the Irish bisexual population. Animals of all populations had very similar qualitative and quantitative characters, apart from the absence of males and the presence of triploidy in some of them, whereas some differences were recorded in the egg shell. All populations examined had the same 18S haplotype, while 21 haplotypes were found in the gene. In four cases, those qualitative characters were correlated with clear molecular () differences (genetic distance 14.6-21.8%). The integrative approach, which considered the morphological differences in the eggs, the reproductive biology and the wide genetic distances among putative species, led to the description of four new species ( sp. n., sp. n., sp. n., sp. n.) and two Unconfirmed Candidate Species (UCS) within the complex. , the only ascertained parthenogenetic, triploid species, was redescribed and showed a wide distribution (Italy, Spain, Poland, Alaska), while the amphimictic species showed limited distributions. The difference in distribution between apomictic and amphimictic populations can be explained by the difference in the dispersal potentials associated with these two types of reproduction.
多年来，据报道该物种由具有不同染色体数目和生殖方式的种群组成。为了阐明不同种群之间的关系，对该物种的模式产地（爱尔兰克莱尔岛）和几个意大利产地进行了采样。采用综合方法对种群进行研究，使用形态学（光学显微镜、共聚焦激光扫描显微镜、扫描电子显微镜）、形态测量学、核型学和分子（18S rRNA、基因）数据。根据爱尔兰双性种群重新描述了该物种并设计了新模。除了某些种群中没有雄性以及存在三倍体外，所有种群的动物在定性和定量特征上非常相似，而在卵壳方面记录到了一些差异。所有检测的种群具有相同的18S单倍型，而在基因中发现了21种单倍型。在四个案例中，那些定性特征与明显的分子（）差异相关（遗传距离14.6 - 21.8%）。综合方法考虑了卵的形态差异、生殖生物学以及假定物种之间广泛的遗传距离，从而在该复合体中描述了四个新物种（新物种1、新物种2、新物种3、新物种4）和两个未确认候选物种（UCS）。唯一确定的孤雌生殖三倍体物种被重新描述，并显示出广泛的分布（意大利、西班牙、波兰、阿拉斯加），而两性生殖物种分布有限。孤雌生殖和两性生殖种群分布的差异可以通过与这两种繁殖类型相关的扩散潜力差异来解释。
