Poulakakis N, Lymberakis P, Valakos E, Pafilis P, Zouros E, Mylonas M
Molecular Systematics Laboratory, Natural History Museum of Crete, University of Crete, Knossos Av., P.O. Box 2208, 71409 Irakleio, Greece.
Mol Ecol. 2005 Jul;14(8):2433-43. doi: 10.1111/j.1365-294X.2005.02588.x.
Wall lizards of the genus Podarcis (Sauria, Lacertidae) comprise 17 currently recognized species in southern Europe, where they are the predominant reptile group. The taxonomy of Podarcis is complex and unstable. Based on DNA sequence data the species of Podarcis falls into four main groups that have substantial geographical conherence (western island group, southwestern group, Italian group and Balkan group). The Balkan species are divided in two subgroups: the subgroup of Podarcis taurica (P. taurica, P. milensis, P. gaigeae and perhaps P. melisellensis), and the subgroup of Podarcis erhardii (P. erhardii and P. peloponnesiaca). We addressed the question of phylogenetic relations among the species of the P. taurica subgroup encountered in Greece, as they can be inferred from partial mtDNA (cyt b and 16S) sequences. Our data support the monophyly of P. taurica subgroup and suggest that P. gaigeae, P. milensis and P. melisellensis form a clade, which thereinafter connects to P. taurica. Within the previous clade, P. gaigeae is more closely related to P. milensis than to P. melisellensis. However, the specimens of P. taurica were subdivided in two different groups. The first one includes the specimens from northeastern Greece, and the other group includes the specimens from the rest of continental Greece and Ionian islands. Because the molecular clock of the cyt b and 16 rRNA genes was not rejected in our model test, it is possible to estimate times of speciation events. Based on the splitting of the island of Crete from Peloponnisos [c. 5 million years ago (Ma)], the evolutionary rate for the cyt b is 1.55% per million years (Myr) and for the 16S rRNA is 0.46% per Myr. These results suggest that the evolutionary history of P. taurica in Greece is more complex than a single evolutionary invasion. The data analysed, stress the need for a reconsideration of the evolutionary history of Greek Podarcis species and help overcome difficulties that classical taxonomy has encountered at both the species level.
南欧的壁蜥属（蜥蜴目，蜥蜴科）包含17个目前已被认可的物种，它们是该地区主要的爬行动物类群。壁蜥属的分类复杂且不稳定。基于DNA序列数据，壁蜥属的物种可分为四个主要的地理连贯组（西部岛屿组、西南部组、意大利组和巴尔干组）。巴尔干地区的物种又分为两个亚组：塔尔其壁蜥亚组（塔尔其壁蜥、米氏壁蜥、盖氏壁蜥以及可能的梅利塞尔壁蜥）和埃氏壁蜥亚组（埃氏壁蜥和伯罗奔尼撒壁蜥）。我们探讨了在希腊发现的塔尔其壁蜥亚组物种之间的系统发育关系问题，这些关系可从部分线粒体DNA（细胞色素b和16S）序列中推断出来。我们的数据支持塔尔其壁蜥亚组的单系性，并表明盖氏壁蜥、米氏壁蜥和梅利塞尔壁蜥形成一个进化枝，随后与塔尔其壁蜥相连。在前一个进化枝中，盖氏壁蜥与米氏壁蜥的亲缘关系比与梅利塞尔壁蜥更近。然而，塔尔其壁蜥的标本被分为两个不同的组。第一组包括来自希腊东北部的标本，另一组包括来自希腊大陆其他地区和伊奥尼亚群岛的标本。由于在我们的模型测试中细胞色素b和16 rRNA基因的分子钟未被否定，因此有可能估计物种形成事件的时间。基于克里特岛从伯罗奔尼撒半岛分离的时间[约500万年前（Ma）]，细胞色素b的进化速率为每百万年1.55%（Myr），16S rRNA的进化速率为每百万年0.46%。这些结果表明，希腊塔尔其壁蜥的进化历史比单一的进化入侵更为复杂。所分析的数据强调了重新考虑希腊壁蜥属物种进化历史的必要性，并有助于克服经典分类学在物种层面所遇到的困难。
