Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India; Department of Life Sciences, The Natural History Museum, London SW7 5BD, United Kingdom.
Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India.
Mol Phylogenet Evol. 2018 Mar;120:53-62. doi: 10.1016/j.ympev.2017.11.016. Epub 2017 Dec 13.
The establishment of monsoon climate and the consequent aridification has been one of the most important climate change episodes in the Indian subcontinent. However, little is known about how these events might have shaped the diversification patterns among the widely distributed taxa. Fan-throated lizards (FTL) (Genus: Sitana, Sarada) are widespread, diurnal and restricted to the semi-arid zones of the Indian subcontinent. We sampled FTL in 107 localities across its range. We used molecular species delimitation method and delineated 15 species including six putative species. Thirteen of them were distinguishable based on morphology but two sister species were indistinguishable and have minor overlaps in distribution. Five fossils were used to calibrate and date the phylogeny. Diversification of fan-throated lizards lineage started ~18 mya and higher lineage diversification was observed after 11 my. The initial diversification corresponds to the time when monsoon climate was established and the latter was a period of intensification of monsoon and initiation of aridification. Thirteen out of the fifteen FTL species delimited are from Peninsular India; this is probably due to the landscape heterogeneity in this region. The species poor sister genus Otocryptis is paraphyletic and probably represents relict lineages which are now confined to forested areas. Thus, the seasonality led changes in habitat, from forests to open habitats appear to have driven diversification of fan-throated lizards.
季风气候的建立以及随之而来的干旱化是印度次大陆最重要的气候变化事件之一。然而，人们对这些事件如何影响广泛分布的分类群的多样化模式知之甚少。扇喉蜥蜴（FTL）（属：Sitana、Sarada）分布广泛，昼行性，仅限于印度次大陆的半干旱地区。我们在其分布范围内的 107 个地点对 FTL 进行了采样。我们使用分子物种界定方法，划定了 15 个物种，包括 6 个假定的物种。其中 13 个可以通过形态学区分，但两个姐妹种无法区分，分布有轻微重叠。使用五个化石来校准和确定系统发育的时间。扇喉蜥蜴谱系的多样化始于约 1800 万年前，1100 万年后出现了更高的谱系多样化。最初的多样化与季风气候建立的时间相对应，而后者是季风加强和干旱化开始的时期。划定的 15 种 FTL 物种中有 13 种来自印度半岛；这可能是由于该地区景观的异质性。物种较少的姐妹属 Otocryptis 是并系的，可能代表现在局限于森林地区的残余谱系。因此，季节性导致栖息地从森林到开阔栖息地的变化，似乎推动了扇喉蜥蜴的多样化。
