Origin and hidden diversity within the poorly known Galápagos snake radiation (Serpentes: Dipsadidae)

Galápagos snakes are among the least studied terrestrial vertebrates of the Archipelago. Here, we provide a phylogenetic analysis and a time calibrated tree for the group, based on a sampling of the major populations known to occur in the Archipelago. Our study revealed the presence of two previously unknown species from Santiago and Rábida Islands, and one from Tortuga, Isabela, and Fernandina. We also recognize six additional species of Pseudalsophis in the Galápagos Archipelago (Pseudalsophis biserialis from San Cristobal, Floreana and adjacent islets; Pseudalsophis hoodensis from Española and adjacent islets; Pseudalsophis dorsalis from Santa Cruz, Baltra, Santa Fé, and adjacent islets; Pseudalsophis occidentalis from Fernandina, Isabela, and Tortuga; Pseudalsophis slevini from Pinzon, and Pseudalsophis steindachneri from Baltra, Santa Cruz and adjacent islets). Our time calibrated tree suggests that the genus Pseudalsophis colonized the Galápagos Archipelago through a single event ...

加拉帕戈斯蛇（Galápagos snakes）是该群岛中研究程度最低的陆生脊椎动物类群之一。本研究基于对该群岛已知主要种群的采样，开展了该类群的系统发育分析并构建了时间校准树。研究结果显示，圣地亚哥岛与拉维达岛存在2个此前未被记录的新物种，托尔图加岛、伊莎贝拉岛及费尔南迪纳岛存在1个新物种。本研究同时确认了加拉帕戈斯群岛内另外6种加拉帕戈斯蛇属（Pseudalsophis）物种：分布于圣克里斯托瓦尔岛、弗洛雷亚纳岛及邻近小岛的双带加拉帕戈斯蛇（Pseudalsophis biserialis）；分布于埃斯帕诺拉岛及邻近小岛的胡德加拉帕戈斯蛇（Pseudalsophis hoodensis）；分布于圣克鲁斯岛、巴尔特拉岛、圣菲岛及邻近小岛的背纹加拉帕戈斯蛇（Pseudalsophis dorsalis）；分布于费尔南迪纳岛、伊莎贝拉岛及托尔图加岛的西方加拉帕戈斯蛇（Pseudalsophis occidentalis）；分布于平松岛的斯莱文加拉帕戈斯蛇（Pseudalsophis slevini），以及分布于巴尔特拉岛、圣克鲁斯岛及邻近小岛的斯坦达赫纳加拉帕戈斯蛇（Pseudalsophis steindachneri）。本研究的时间校准树表明，加拉帕戈斯蛇属（Pseudalsophis）仅通过单次殖民事件拓殖加拉帕戈斯群岛……