Abstract

The Mediterranean region is one of the 25 biodiversity hotspots, with several species distributed on both sides of the Adriatic Sea, i.e. on the Apennine and the Balkan Peninsulas. One of these is Euphorbia spinosa, distributed in the coastal regions of the Ligurian, Tyrrhenian, Ionian and Adriatic Seas, whereas its closest relative, E. glabriflora, occurs in continental regions of the western and southern Balkan Peninsula, mostly on serpentine substrates. They differ morphologically, but transitional forms resembling E. glabriflora can be found within the range of E. spinosa and in the overlapping areas of both species, and phylogenetic relationships between them remain unclear. Using nuclear ribosomal ITS sequences, we here show that these two species form a monophyletic group closely related to the E. acanthothamnos alliance, but the relationships between them remain unresolved. Also, amplified fragment length polymorphism (AFLP) fingerprints are weakly structured, but indicate a north-west to south-east trend in genetic differentiation and two main genetic groups; however, these are not entirely congruent with morphological species boundaries. In addition, morphometric analyses indicate only weak differentiation between the taxa, mostly due to occurrence of morphologically transitional forms in contact areas between the two genetic groups. Based on our results we propose to treat both taxa as subspecies of E. spinosa and provide a taxonomic treatment with descriptions. Finally, based on the high genetic variability on the Balkan Peninsula, we hypothesize a trans-Adriatic dispersal from the Balkans to the Apennine Peninsula, probably during the Pleistocene. This is in line with previous studies of different plants with amphi-Adriatic distributions, with the exception that in E. spinosa the distributions on both peninsulas are of similar size, whereas in most other cases the distribution area on the Balkan Peninsula is larger than on the Apennine Peninsula.

中文翻译：

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两栖-亚得里亚大戟棘和巴尔干地方性大肠埃希菌（大戟科）之间的关系解开。

摘要

地中海地区是25个生物多样性热点之一，在亚得里亚海的两侧，即亚平宁和巴尔干半岛，分布着几种物种。其中一种是大戟大戟，分布在利古里亚海，第勒尼安海，爱奥尼亚海和亚得里亚海的沿海地区，而其最接近的亲缘种E. glabriflora则出现在巴尔干半岛西部和南部的大陆地区，主要分布在蛇纹岩基底上。它们在形态上有所不同，但是在棘孢菌的范围内可以找到类似于花斑棘球菌的过渡形式。在这两个物种的重叠区域，它们之间的系统发育关系仍然不清楚。使用核糖核糖体ITS序列，我们在这里显示这两个物种形成了一个与E. acanthothamnos密切相关的单系群联盟，但它们之间的关系仍未解决。同样，扩增片段长度多态性（AFLP）指纹的结构较弱，但表明遗传分化和两个主要遗传群体呈西北向东南趋势。但是，这些与形态物种边界并不完全一致。此外，形态计量学分析仅显示了分类单元之间的弱区分，这主要是由于两个遗传群体之间的接触区域发生了形态学上的过渡形式。根据我们的研究结果，我们建议将这两个分类单元都视为E. spinosa的亚种。并提供带有描述的分类处理。最后，基于巴尔干半岛的高遗传变异性，我们推测可能是在更新世期间从巴尔干半岛到亚平宁半岛的跨亚得里亚海扩散。这与先前对具有两亲亚得里亚海分布的不同植物的研究一致，不同的是，在E. spinosa中，两个半岛上的分布具有相似的大小，而在其他大多数情况下，巴尔干半岛上的分布面积大于在两个半岛上的分布面积。亚平宁半岛。