Instituto de Investigación Biológica del Paraguay, Del Escudo 1607, CP 1425 Asunción, Paraguay.
Instituto de Investigación Biológica del Paraguay, Del Escudo 1607, CP 1425 Asunción, Paraguay; Itaipu Binacional, División de Áreas Protegidas, Dirección de Coordinación Ejecutiva, Av. Monseñor Rodriguez 150, Ciudad del Este, Alto Paraná, Paraguay.
Mol Phylogenet Evol. 2018 Jun;123:123-136. doi: 10.1016/j.ympev.2018.02.010. Epub 2018 Feb 22.
The Chaco is one the most neglected and least studied regions of the world. This highly-seasonal semiarid biome is an extensive continuous plain without any geographic barrier, and in spite of its high species diversity, the events and processes responsible have never been assessed. Miocene marine introgressions and Pleistocene glaciations have been mentioned as putative drivers of diversification for some groups of vertebrates in adjacent biomes of southern South America. Here we used multilocus data (one mitochondrial and six nuclear loci) from the three species of the endemic frog genus Lepidobatrachus (Lepidobatrachus asper, Lepidobatrachus laevis, and Lepidobatrachus llanensis) to determine if any of the historical events suggested as drivers of vertebrate diversification in southern South America are related to the diversification of the genus and if the Chaco is indeed a biome without barriers. Using fossil calibration in a coalescent framework we estimated that the genus diversified in the second half of the Miocene, coinciding with marine introgressions. Genetic patterns and historical demography suggest an important role of old archs and cratons as refuges during floods. In one species of the genus, L. llanensis, genetic structure reveals some breaks along the landscape, the main one of which corresponds to an area of the central Chaco that may act as a climatic barrier. Additionally, we found differential effects of the main Chacoan rivers on species of Lepidobatrachus that could be related to the time of persistence of populations in the areas influenced by these rivers.
查科是世界上被忽视和研究最少的地区之一。这个高度季节性的半干旱生物群落是一个广阔的连续平原，没有任何地理屏障，尽管物种多样性很高，但负责的事件和过程从未被评估过。中新世的海洋入侵和更新世的冰川作用被认为是导致南美洲南部相邻生物群中一些脊椎动物多样化的潜在驱动因素。在这里，我们使用了来自三种特有青蛙属 Lepidobatrachus（Lepidobatrachus asper、Lepidobatrachus laevis 和 Lepidobatrachus llanensis）的多基因座数据（一个线粒体和六个核基因座），以确定南美南部作为脊椎动物多样化驱动因素的历史事件中是否有任何与该属的多样化有关，以及查科是否确实是一个没有障碍的生物群落。我们使用化石校准在合并框架中估计该属在中新世后半期多样化，与海洋入侵同时发生。遗传模式和历史人口动态表明，古老的拱顶和克拉通在洪水期间作为避难所发挥了重要作用。在该属的一个物种 L. llanensis 中，遗传结构沿景观显示出一些断裂，其中主要的断裂对应于查科中部的一个地区，该地区可能充当气候屏障。此外，我们发现查科主要河流对 Lepidobatrachus 物种的影响存在差异，这可能与受这些河流影响的地区的种群持续时间有关。
