The Nearctic Nedubini: the most basal lineage of katydids is resolved among the paraphyletic “Tettigoniinae” (Orthoptera: Tettigoniidae)

This study investigated the systematics of the Nearctic shield-back katydids (“Tettigoniinae”), a paraphyletic group thought to include genera from a distinctive Gondwanan tribe, the Nedubini, among an otherwise Holarctic fauna. From exemplars of five genera of Nedubini and the majority of other genera of Nearctic “Tettigoniinae,” five gene regions were sequenced, aligned with publicly available sequence data that represent diverse subfamilies of Tettigoniidae, and subjected to phylogenetic analysis under Bayesian and likelihood criteria. Our results render the worldwide Nedubini polyphyletic, strongly support the Nearctic Nedubini as a basal clade that is sister to the remaining Tettigoniidae, and group the remaining Nearctic shield-back katydid genera into a Holarctic clade. Having shared a common ancestor with the remaining katydids 175 ± 24 million years ago, the Nearctic Nedubini joins a considerable assemblage of relict groups that are found in California and the Pacific Northwest...本研究针对新北区覆背螽斯（Tettigoniinae，螽斯亚科）的系统分类学展开探究。该类群为并系群，此前被认为包含源自独特冈瓦纳族——内杜比族（Nedubini）的多个属，而其余类群均隶属于全北区动物区系。本研究采集了内杜比族5个属以及新北区绝大多数其他Tettigoniinae属类群的标本，对5个基因区域进行测序，并与公开可得的、代表螽斯科（Tettigoniidae）多个亚科的序列数据进行比对，随后基于贝叶斯准则与似然法开展系统发育分析。本研究结果显示全球范围内的内杜比族为多系群；本研究强有力地支持新北区内杜比族作为基干支系，与其余螽斯科类群构成姊妹支系；同时将剩余的新北区覆背螽斯属归入一个全北区支系。新北区内杜比族与其余螽斯类群的共同祖先可追溯至1.75±0.24亿年前，该类群与分布于加利福尼亚州及太平洋西北地区的大量孑遗类群同属一个类群。