Programa de Pós-Graduação em Biodiversidade, Universidade Federal do Oeste do Pará, Rua Vera Paz, sn, Santarém, PA 68040-255, Brazil; Programa de Pós-Graduação em Botânica, Instituto Nacional De Pesquisas Da Amazônia, Av. André Araújo, 2936 - Aleixo, Manaus, AM 69060-001, Brazil.
Programa de Pós-Graduação em Biodiversidade, Universidade Federal do Oeste do Pará, Rua Vera Paz, sn, Santarém, PA 68040-255, Brazil.
Mol Phylogenet Evol. 2021 Sep;162:107195. doi: 10.1016/j.ympev.2021.107195. Epub 2021 May 5.
Patterns of diversification in Neotropical plants have been studied intensively over the past decades. Most studies have focused on groups that migrated to and radiated into the Neotropics, however, with little focus on understanding diversification patterns in indigenous Neotropical groups. This study focuses on Solanum section Brevantherum Seithe (Solanaceae), a group of Neotropical nightshade shrubs or treelets defined mostly by terminal inflorescences with long peduncles, plurifoliate sympodial units and porrect-stellate, dendritic-echinoid, or lepidote trichomes. We generated sequences from two nuclear (ITS, waxy) and one plastid marker (trnT-F) to infer phylogenetic relationships under Bayesian and Maximum likelihood approaches. We reconstructed a time-calibrated tree to estimate both the ages of main splits and the ancestral ranges of the lineages. Finally, we carried out a biogeographic stochastic mapping (BSM) analysis to determine the main processes driving current distributions of the group. Results show the non-monophyly of the section as previously recognized and the homoplasy of morphological characters traditionally used to circumscribe it. Two main clades that encompass most species formerly recognized in section Brevantherum are recovered and named as the Erianthum and Abutiloides clades. Divergence time estimates suggest that the Erianthum and Abutiloides clades split around 5.7 Mya in the upper Miocene. Two main dispersal events from the Atlantic rainforest are supported in the Erianthum clade: one dispersal to Mesoamerica and a second dispersal to the Northern Andes. Within the Abutiloides clade, cladogenetic events were restricted to the Andean region. Our BSM analysis suggests within-area speciation and range expansion as the main processes shaping the extant distribution of species of both clades. As no putative morphological synapomorphies can yet be assigned to what could correspond to a new circumscription of Solanum section Brevantherum (with the exclusion of Solanum bullatum Vell. and inclusion of S. inelegans Rusby and four species described since the group last revision) we discourage the continued use of what would be an ambiguous sectional nomenclature.
在过去的几十年里，人们对新热带植物的多样化模式进行了深入研究。大多数研究都集中在迁移到新热带地区并在那里辐射的群体上，然而，对于理解新热带地区本土群体的多样化模式关注甚少。本研究集中于茄科(Solanaceae)的 Solanum 组 BrevantherumSeithe（夜茄属），这是一组新热带的灌木或小乔木，主要通过具长花梗的顶生花序、多叶合轴节段和伸展星状、树枝状-具刺状、或鳞片状的毛来定义。我们从两个核（ITS、蜡质）和一个质体标记（trnT-F）生成序列，以贝叶斯和最大似然方法推断系统发育关系。我们构建了一个时间校准的树来估计主要分支的年龄和谱系的祖先范围。最后，我们进行了生物地理随机映射（BSM）分析，以确定驱动该组当前分布的主要过程。结果表明，该组与以前的认识一样，不具有单系性，并且传统上用于界定它的形态特征具有同形性。两个主要的分支，包含了以前在 Brevantherum 组中识别的大多数物种，被恢复并命名为 Erianthum 和 Abutiloides 分支。分歧时间估计表明，Erianthum 和 Abutiloides 分支大约在 570 万年前的上新世开始分裂。Erianthum 分支支持从大西洋雨林发生的两次主要扩散事件：一次扩散到中美洲，另一次扩散到北安第斯山脉。在 Abutiloides 分支内，分支事件仅限于安第斯地区。我们的 BSM 分析表明，区内物种形成和范围扩张是塑造两个分支现存物种分布的主要过程。由于目前还不能将任何假定的形态同源特征分配给可能对应于 Solanum 组 Brevantherum 的新定义（排除 Solanum bullatum Vell.，包括 S. inelegans Rusby 和自该组上次修订以来描述的四个物种），我们不鼓励继续使用可能会产生歧义的分类名称。
