Identification of the taxonomic status of Scinax nebulosus and Scinax constrictus (Scinaxinae, Anura) based on molecular markers

Abstract The validation of many anuran species is based on a strictly descriptive, morphological analysis of a small number of specimens with a limited geographic distribution. The Scinax Wagler, 1830 genus is a controversial group with many doubtful taxa and taxonomic uncertainties, due a high number of cryptic species. One example is the pair of species Scinax constrictus and Scinax nebulosus, which share a similar morphology. Scinax constrictus is restricted to the Brazilian Cerrado savanna, while S. nebulosus is widely distributed throughout northern South America. Despite the validation of many anuran species, discriminations based only on morphological traits is quite difficult due to the high conservative morphology of some groups. In this context, the present study uses mitochondrial and nuclear genes to provide a more consistent diagnosis and test the validity of S. constrictus as a distinct species from S. nebulosus, as well as evaluate the position of these taxa within the Scinax genus. The topologies obtained herein uphold the monophyletic status of Scinax based on all molecular markers assessed in this study, in all analytical approaches, with high levels of statistical support.

摘要 多数无尾目物种的分类验证均基于对少量地理分布受限标本开展的严格描述性形态学分析。树蟾属（Scinax Wagler, 1830）是一类颇具争议的类群，因存在大量隐存种，其下存在诸多存疑类群与分类学不确定性。狭身树蟾（Scinax constrictus）与云斑树蟾（Scinax nebulosus）即为典型代表，二者形态特征高度相似。狭身树蟾仅分布于巴西塞拉多稀树草原，而云斑树蟾则广泛分布于南美洲北部地区。尽管已有诸多无尾目物种完成分类验证，但由于部分类群的形态高度保守，仅依靠形态特征开展物种区分的难度极大。在此背景下，本研究借助线粒体基因与核基因开展分子分析，旨在提供更为可靠的物种鉴定依据，验证狭身树蟾作为独立于云斑树蟾的有效物种的地位，并评估这两个类群在树蟾属中的系统发育位置。本研究采用的全部分子标记及所有分析方法所得到的系统发育拓扑结构，均支持树蟾属为单系群，且统计支持度较高。