Analysis of ultraconserved elements supports African origins of narrow-mouthed frogs

Narrow-mouthed frogs (Anura: Microhylidae) are globally distributed and molecular data suggest the rapid evolution of multiple subfamilies shortly after their origin. Despite recent progress, several subfamilial relationships remain unexplored using phylogenomic data. We analysed 1,796 nuclear ultraconserved elements, a total matrix of 400,664 nucleotides, from representatives of most microhylid subfamilies. Summary method species tree and maximum likelihood analyses unambiguously supported Hoplophryninae, as the earliest diverging microhylid and Chaperininae as a junior synonym of Microhylinae. Given the emerging consensus that subfamilies from mainland Africa diverged early, microhylids have likely occupied the continent for more than 66 million years.

狭口蛙类（无尾目: 狭口蛙科 Microhylidae）全球广泛分布，分子数据显示其起源后多个亚科曾经历快速演化。尽管近期相关研究取得一定进展，但仍有不少亚科间的系统发育关系尚未通过系统基因组学数据得到解析。本研究针对多数狭口蛙亚科的代表类群，分析了1796个核基因组超保守元件（ultraconserved elements），总序列矩阵包含400664个核苷酸位点。基于汇总法物种树与最大似然分析均明确支持：盾胸蛙亚科（Hoplophryninae）为狭口蛙科中最早分化的类群，且加勒比蛙亚科（Chaperininae）应作为狭口蛙亚科（Microhylinae）的同物异名。鉴于当前学界逐渐达成的共识——非洲大陆的狭口蛙亚科类群分化时间较早，狭口蛙科在非洲大陆的定居历史可能已超过6600万年。