The tribe Pachygoneae consists of four genera with about 40 species, primarily distributed in tropical and subtropical Asia and America, also in Australasia and Africa. This tribe presents an ideal model to investigate the origin of the tropical and subtropical amphi-Pacific disjunction pattern. More specifically, it allows us to test whether the tropical lineages diverged earlier than the subtropical ones during the fragmentation of the boreotropical flora. In this study, we reconstructed the phylogeny of Pachygoneae using five plastid (rbcL, atpB, matK, ndhF, trnL-F) and one nuclear (26S rDNA) DNA regions. Our results indicate that Pachygoneae is not monophyletic unless Cocculus pendulus and Cocculus balfourii are excluded. We resurrected the genus Cebatha to include these two species and established a new tribe for this genus. Within Pachygoneae, the species of Cocculus are distributed in three different clades, among which two are recognized as two distinct genera, Cocculus s.str. and Nephroia resurrected, and one species is transferred into Pachygone. Our molecular dating and ancestral area reconstruction analyses suggest that Pachygoneae began to diversify in tropical Asia around the early-middle Eocene boundary (c. 48 Ma) and expanded into the New World by c. 44 Ma. In the New World, tropical Hyperbaena originated in the late Eocene (c. 40 Ma), whereas the subtropical Cocculus carolinus and Cocculus diversifolius originated later, in the early Oligocene (c. 32 Ma). These two timings correspond with the two climatic cooling intervals, which suggests that the formation and breakup of the boreotropical floral may have been responsible for the amphi-Pacific disjunct distribution within Pachygoneae. One overland migration event from Asia into Australasia appears to have occurred in the early to late Miocene.

中文翻译：

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Pachygoneae（Menispermaceae）的系统发育和生物地理学，考虑了北冰洋植物区系假设以及Cebatha和Nephroia属的复活。

Pachygoneae部落由四个属组成，约有40种，主要分布于亚洲和美洲的热带和亚热带地区，以及大洋洲和非洲。这个部落提出了一个理想的模型来研究热带和亚热带两栖-太平洋分离模式的起源。更具体地说，它使我们能够测试在北冰洋植物群破碎过程中热带沿袭是否比亚热带沿袭早。在这项研究中，我们使用五个质体（rbcL，atpB，matK，ndhF，trnL-F）和一个核（26S rDNA）DNA区域重建了Pachygoneae的系统发育。我们的研究结果表明，除非排除了球茎球菌和鲍氏球菌，否则厚皮草科不是单系的。我们复活了Cebatha属以包括这两个物种，并为此属建立了一个新部落。在Pachygoneae中，球菌属的物种分布在三个不同的进化枝中，其中两个被认为是两个不同的属，即球菌属。Nephroia复活了，其中一种转移到了Pachygone中。我们的分子测年和祖先区重建分析表明，Pachygoneae开始在始新世中期（约48 Ma）附近的热带亚洲开始多样化，并在c。之后扩展到新大陆。44马。在新世界中，热带双子叶藻起源于始新世晚期（约40 Ma），而亚热带小球藻Carolinus和Cocculus diversifolius则起源于晚渐新世（约32 Ma）。这两个时间与两个气候冷却间隔相对应，这表明北冰洋花卉的形成和破裂可能是Pachygoneae内两栖-太平洋分离分布的原因。从中新世早期到晚期，发生了一次从亚洲到大洋洲的陆上迁徙事件。