Museo de Zoología, Escuela de Biología, Pontificia Universidad Católica del Ecuador, Avenida 12 de Octubre y Roca, Apartado 17-01-2184, Quito, Ecuador.
Laboratório de Sistemática de Vertebrados, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Mol Phylogenet Evol. 2019 Jan;130:315-329. doi: 10.1016/j.ympev.2018.10.022. Epub 2018 Oct 24.
Neotropical sipo snakes (Chironius) are large diurnal snakes with a long tail and big eyes that differ from other Neotropical snakes in having 10 or 12 dorsal scale rows at midbody. The 22 currently recognized species occur from Central America south to Uruguay and northeastern Argentina. Based on the largest geographical sampling to date including ∼90% of all species, we analyzed one nuclear and three mitochondrial genes using phylogenetic methods to (1) test the monophyly of Chironius and some of its widely distributed species; (2) identify lineages that could represent undescribed species; and (3) reconstruct ancestral distributions. Our best hypothesis placed C. grandisquamis (Chocoan Rainforest) + C. challenger (Pantepui) as sister to all other species. Based on phylogeny and geographic distribution, we identified 14 subclades as putative species within Chironius fuscus, C. multiventris (including C. foveatus and C. laurenti), C. monticola, and C. exoletus. Under current taxonomy, these species show nearly twice as much genetic diversity as other species of Chironius for ND4. Biogeographical analyses using BioGeoBEARS suggest that current distribution patterns of Chironius species across South America resulted from multiple range expansions. The MRCA of the clade C. challenger + C. grandisquamis was most likely distributed over the Pantepui region, the Andes, and the Chocoan Rainforest, whereas the remaining lineages probably evolved from an Amazonian ancestor.
新热带錾蛇（Chironius）是大型日行性蛇类，尾部较长，眼睛较大，与其他新热带蛇类不同的是，它们的中体背部有 10 或 12 行鳞片。目前已确认的 22 个物种分布于中美洲南部至乌拉圭和阿根廷东北部。基于迄今为止最大的地理采样，包括约 90%的所有物种，我们使用系统发育方法分析了一个核基因和三个线粒体基因，以（1）检验 Chironius 及其一些广泛分布的物种的单系性；（2）确定可能代表未描述物种的谱系；（3）重建祖先的分布。我们的最佳假设是，C. grandisquamis（Chocoan Rainforest）+ C. challenger（Pantepui）与其他所有物种的亲缘关系最近。根据系统发育和地理分布，我们在 Chironius fuscus、C. multiventris（包括 C. foveatus 和 C. laurenti）、C. monticola 和 C. exoletus 中确定了 14 个亚群为潜在的物种。根据当前的分类学，这些物种在 ND4 上的遗传多样性几乎是 Chironius 其他物种的两倍。使用 BioGeoBEARS 的生物地理分析表明，Chironius 物种在南美洲的当前分布模式是由多次范围扩张造成的。C. challenger + C. grandisquamis 分支的共同祖先最有可能分布在 Pantepui 地区、安第斯山脉和 Chocoan Rainforest，而其余的谱系可能是从亚马逊祖先进化而来的。
