Phylogeny, phylogeography, and diversification history of Caspian cobra

We conducted a comprehensive analysis of the phylogenetic,
phylogeographic, and demographic relationships of Caspian cobra (Naja
oxiana; Eichwald, 1831) populations based on a concatenated dataset of two
mtDNA genes (cyt b and ND4) across the species’ range in Iran,
Afghanistan, and Turkmenistan, along with other members of Asian cobras
(i.e. subgenus Naja Laurenti, 1768). Our results provided strong support
that N. oxiana is monophyletic and its divergence from its sister taxon,
N. kaouthia, during early Pleistocene. Our results also highlight the
existence of only one major evolutionary lineage in the Trans-Caspian
region, suggesting a rapid expansion of the Caspian cobra from eastern to
western Asia, coupled with a rapid range expansion from east of Iran to
the northeast. However, the subdivision of eastern and northeastern
populations in Iran was not supported; hence we propose only one
evolutionary significant unit across the Iranian range of N. oxiana to be
considered for conservation efforts.

本研究针对里海眼镜蛇（Caspian cobra, Naja oxiana; Eichwald, 1831），基于覆盖伊朗、阿富汗与土库曼斯坦境内其分布范围的两段线粒体DNA（mtDNA）基因片段（细胞色素b（cyt b）与烟酰胺腺嘌呤二核苷酸脱氢酶亚基4（ND4））的联合数据集，并结合亚洲眼镜蛇类群的其他物种数据（即眼镜蛇亚属Naja，Laurenti于1768年建立），对其种群的系统发育、系统地理学及种群统计学关系开展了全面分析。研究结果强力支持里海眼镜蛇为单系群（monophyletic），且其与姊妹类群孟加拉眼镜蛇（Naja kaouthia）的分化事件发生于更新世早期。本研究同时发现，跨里海地区（Trans-Caspian region）仅存在一个主要进化谱系，表明里海眼镜蛇曾从亚洲东部快速向西亚扩张，并从伊朗东部向东北部快速扩散。然而，伊朗境内东部与东北部种群的分化并未得到统计支持；因此我们建议，将伊朗分布范围内的里海眼镜蛇划分为单一进化显著单元（evolutionary significant unit），用于后续保护工作。