Spalerosophis Jan,1865,是游蛇属,分布于从非洲西北部到印度北部的干旱和半干旱地区。根据传统形态学,鉴定出六种Spalerosophis ;然而,对其系统地位存在争议。我们使用 c 的核苷酸序列对该属进行了首次分子系统发育分析。来自三个线粒体基因(12S rRNA、16S rRNA 和 cyt b)的 2278 bp,用于研究鲜为人知的Spalerosophis物种和可疑种群的系统发育关系和历史进化。我们使用化石校准来确定年代差异。我们的系统发育分析清楚地显示了五个具有高支持值的独立物种,包括S. arenarius、S. atriceps、S. microlepis、S. diadema schirasianus和S. diadema Cliffordii。贝叶斯校准分子钟表明,Spalerosophis属在古近纪 35.28 Mya (25.89–44.66) 左右从共同祖先中分化出来。我们的分析表明,分离出的S. atriceps在 21.72 Mya (10.86–33.04) 左右被分离,作为该属的基础分化种。这表明, Spalerosophis物种可能起源于伊朗高原某处的祖先,然后扩散到目前的地理范围。Spalerosophis arenarius和S. atriceps被确定为该属最后两个分歧的成员,与S. d.分开。中中新世时期的schirasianus约 13.31 Mya (5.52–22.33)。这些结果表明, Spalerosophis物种的分离与伊朗西部扎格罗斯山脉和阿富汗、印度和巴基斯坦苏莱曼山脉的造山事件同时发生。因此,它们的多样化可能是促进其当前分布的替代事件的结果。这项工作为未来研究Spalerosophis属的系统发育、多样性和进化奠定了基础,并强调了对未知蛇进行更多分子研究的必要性。
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Phylogenetic relationships and divergence times of the poorly known genus Spalerosophis (Serpentes: Colubridae)
Spalerosophis Jan, 1865, is a colubrid snake genus distributed in arid and semiarid regions from northwestern Africa to northern India. Six species of Spalerosophis are identified based on traditional morphology; however, there are arguments about their systematic status. We performed the first molecular phylogenetic analyses for this genus using nucleotide sequences of c. 2278 bp from three mitochondrial genes (12S rRNA, 16S rRNA, and cyt b) to investigate the phylogenetic relationships and historical evolution of the poorly known Spalerosophis species and doubtful populations. We used fossil calibrations for dating divergences. Our phylogenetic analyses clearly showed five separate species with high support values, including S. arenarius, S. atriceps, S. microlepis, S. diadema schirasianus, and S. diadema cliffordii. Bayesian calibrated molecular clock suggested that the genus Spalerosophis diverged from the common ancestor in the Paleogene around 35.28 Mya (25.89–44.66). Our analysis indicated that isolated S. atriceps was separated around 21.72 Mya (10.86–33.04) as the basal diverged species of the genus. This suggested that the species of Spalerosophis probably originated from an ancestor somewhere in the Iranian Plateau and then dispersed to its current geographical range. Spalerosophis arenarius and S. atriceps were identified as the two last diverged members of the genus, separated from S. d. schirasianus during the Middle Miocene about 13.31 Mya (5.52–22.33). These results indicate that the separation of Spalerosophis species coincided with the orogenic events of the Zagros Mountains in western Iran and the Sulaiman Mountains in Afghanistan, India, and Pakistan. Their diversification may therefore be the result of vicariance events that promoted their current distribution. This work provides a foundation for future studies on the phylogeny, diversity, and evolution of the genus Spalerosophis and highlights the need for more molecular studies on unknown snakes.