The genus Cayratia Juss. in the traditional sense (i.e., Cayratia s.l.) of the grape family has been shown to be non‐monophyletic. Previous studies supported the splitting of Cayratia s.l. into three genera, that is, Cayratia s.s., Causonis Raf., and a new genus representing the African Cayratia clade. However, the morphology of the African Cayratia clade has not been studied carefully and its phylogenetic position within Vitaceae remains unclear. Our study integrates molecular, distributional, and morphological data and supports the recognition of the new genus Afrocayratia from continental Africa and Madagascar. Phylogenetic analyses strongly support the monophyly of Afrocayratia and resolve it as a sister of Cayratia s.s. based on the chloroplast data, but it is placed sister to Cyphostemma based on the internal transcribed spacer dataset. Molecular dating suggests that Afrocayratia split with Cayratia s.s. during the Paleocene, but that the extant species of Afrocayratia did not diversify until the early Miocene. Afrocayratia differs from its allied genera in having short stigmas and seeds with subcircular ventral infold cavities in cross‐section. Three clades are detected within Afrocayratia, with A. debilis (Baker) J.Wen & L.M.Lu as the first diverged lineage. The second diverged lineage includes A. delicatula (Willems) J.Wen & Z.D.Chen and A. gracilis (Guill. & Perr.) J.Wen & Z.D.Chen. The third diverged lineage includes A. imerinensis (Baker) J.Wen & L.M.Lu, A. longiflora (Desc.) J.Wen & Rabarijaona, and A. triternata (Baker) J.Wen & Rabarijaona from Madagascar, which form a monophyletic group that diverged from the second lineage in the middle Miocene. Combining the morphological and molecular evidence, we formally describe the new genus Afrocayratia, make seven new combinations, and provide a key to species of the genus.

中文翻译：

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非洲大陆和马达加斯加葡萄科新属 Afrocayratia 的系统发育和分类学

Cayratia Juss 属。传统意义上的葡萄家族（即 Cayratia sl）已被证明是非单系的。以前的研究支持将 Cayratia sl 分为三个属，即 Cayratia ss、Causonis Raf. 和代表非洲 Cayratia 进化枝的一个新属。然而，非洲 Cayratia 进化枝的形态尚未得到仔细研究，其在 Vitaceae 中的系统发育位置仍不清楚。我们的研究整合了分子、分布和形态学数据，并支持对来自非洲大陆和马达加斯加的新属 Afrocayratia 的识别。系统发育分析强烈支持 Afrocayratia 的单系性，并根据叶绿体数据将其解析为 Cayratia ss 的姐妹，但根据内部转录间隔数据集，它被放置为 Cyphostemma 的姐妹。分子年代测定表明，Afrocayratia 在古新世与 Cayratia ss 分裂，但 Afrocayratia 的现存物种直到中新世早期才开始多样化。Afrocayratia 与其近缘属的不同之处在于柱头短，种子在横截面上具有亚圆形腹侧内折腔。在 Afrocayratia 中检测到三个进化枝，A. debilis (Baker) J.Wen 和 LMLu 作为第一个分化的谱系。第二个分化的谱系包括 A. delicatula (Willems) J.Wen & ZDChen 和 A. gracilis (Guill. & Perr.) J.Wen & ZDChen。第三个不同的谱系包括来自马达加斯加的 A. imerinensis (Baker) J.Wen & LMLu、A. longiflora (Desc.) J.Wen & Rabarijaona 和 A. triternata (Baker) J.Wen & Rabarijaona，它们形成了一个单系群，从中中新世的第二个谱系中分离出来。结合形态学和分子学证据，我们正式描述了新属Afrocayratia，进行了七种新组合，并提供了该属物种的关键。