Terra Vanessa, Ringelberg Jens J, Maslin Bruce, Koenen Erik J M, Ebinger John, Seigler David, Hughes Colin E
Instituto de Ciências Agrárias, Universidade Federal de Uberlândia, Rodovia LMG 746, Km01, s/n, Bloco 1A, sala 413, 38500-000, Monte Carmelo, Minas Gerais, Brazil Universidade Federal de Uberlândia Monte Carmelo Brazil.
Department of Systematic and Evolutionary Botany, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland University of Zurich Zurich Switzerland.
PhytoKeys. 2022 Aug 22;205:261-278. doi: 10.3897/phytokeys.205.79378. eCollection 2022.
comprises 219 species distributed in tropical and subtropical regions of North and South America, Africa, Asia and Australia. Two sections are currently recognised within and these are most readily distinguished by the differences in disposition of their cauline prickles, i.e. sect. Senegalia with prickles at or near leaf nodes and sect. Monacanthea with mostly internodal prickles. Previous phylogenetic studies, based primarily on small numbers of plastid DNA loci, found to be monophyletic with two large subclades corresponding to the sections. Here, we present new phylogenomic evidence from 997 single-copy nuclear gene sequences for a small, but representative set of species. These new analyses show that is non-monophyletic, but instead, forms a grade that is paraphyletic with respect to the remainder of the ingoid clade (i.e. Ingeae + s.s. + ), comprising two well-supported subclades most likely representing the same clades as found in previous phylogenetic studies of the genus and, interspersed between these, a third, moderately supported clade, comprising the genera , and . In marked contrast to the nuclear phylogeny, the two clades are sister groups in the plastid phylogeny, based on analyses of 72 chloroplast genes, rendering the genus monophyletic, based on plastid data alone. We discuss this new evidence that is non-monophyletic in relation to the marked cytonuclear discordance, high gene tree conflict and lack of resolution across this senegalioid grade and review the consistency of the key morphological characters distinguishing the two sections of . We conclude that it is likely that will need to be split into two (or possibly more) genera: a re-circumscribed s.s. that corresponds to the existing Senegaliasect.Senegalia plus the group (Senegaliasect.Monacanthea s.s.; future studies may show that this group warrants generic status) and a new genus corresponding to the remainder of sect. Monacanthea (here designated as Senegaliasect.Monacanthea p.p.). However, re-delimiting now would be premature given that the key morphological characters are not fully congruent with the two sections and pending denser phylogenetic sampling of taxa. A judiciously selected list of critical taxa is presented to facilitate future phylogenomic studies. Finally, we discuss the identity of , which is also placed in this senegalioid grade in these new phylogenomic analyses and place it in synonymy with .
包含219个物种，分布于南北美洲、非洲、亚洲和澳大利亚的热带和亚热带地区。目前在该属内可识别出两个组，它们最容易通过茎刺的分布差异来区分，即塞内加尔组（Senegalia）茎刺位于叶节点处或附近，以及单刺组（Monacanthea）大多为节间刺。以往的系统发育研究主要基于少量质体DNA位点，发现该属是单系的，有两个对应于组的大分支。在此，我们展示了来自997个单拷贝核基因序列的新系统基因组证据，涉及一小部分但具有代表性的物种。这些新分析表明，该属不是单系的，而是形成了一个相对于印加类分支（Ingeae + 狭义的该属 + 其他属）其余部分而言是并系的类群，包括两个得到充分支持的分支，很可能与该属先前系统发育研究中发现的分支相同，并且在它们之间散布着第三个得到适度支持的分支，包括其他属。与核系统发育形成显著对比的是，基于72个叶绿体基因的分析，该属的两个分支在质体系统发育中是姐妹群，仅基于质体数据使该属成为单系。我们讨论了这一新证据，即该属在显著的细胞核与细胞质不一致、高基因树冲突以及该塞内加尔类群缺乏分辨率的情况下不是单系的，并回顾了区分该属两个组的关键形态特征的一致性。我们得出结论，很可能需要将该属分为两个（或可能更多）属：重新界定的狭义的该属，对应于现有的塞内加尔组（Senegalia sect.Senegalia）加上其他属（塞内加尔组狭义的单刺组；未来研究可能表明这个类群具有属的地位），以及一个对应于单刺组其余部分的新属（这里指定为塞内加尔组部分成员（Senegalia sect.Monacanthea p.p.））。然而，鉴于关键形态特征与两个组并不完全一致且有待对分类群进行更密集的系统发育采样，现在重新界定该属还为时过早。列出了一份经过审慎选择的关键分类群清单，以促进未来的系统基因组研究。最后，我们讨论了其他属的身份，在这些新的系统基因组分析中它也被置于这个塞内加尔类群中，并将其与其他属同义。
