Botany Department, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa.
Mol Phylogenet Evol. 2010 Nov;57(2):495-508. doi: 10.1016/j.ympev.2010.07.019. Epub 2010 Aug 7.
The systematics of Mimosoideae has been in a state of flux, which reflects overall poor knowledge of the evolution and biogeography of this group. Preliminary molecular phylogenetic analyses suggest the tribal system of Mimosoideae needs a complete revision. This has led to the use of new generic names for Acacia sensu lato (s.l. hereafter) following the re-typification of Acacia with an Australian type: (i) Acacia sensu stricto (s.s. hereafter), Vachellia, Senegalia, Acaciella and Mariosousa. This study reconstructs the evolutionary history of Mimosoideae, using the most comprehensive sampling to date, with an emphasis on African species. It aims to reconstruct the phylogenetic relationships among the five recognized genera within Acacieae as the precursor to elucidate the paleo-biogeography of mimosoids and their adaptation to open habitats in the Cenozoic. The basal position of Mimoseae lineages with regards to Vachellia and Senegalia+Mariosousa+Acaciella+Ingeae+Acacia s.s. clades is a novel finding. Vachellia (formerly Acacia subgenus Acacia) is found monophyletic. A grade including the remaining Mimoseae lineages is found sister to the Senegalia+Mariosousa+Acaciella+Ingeae+Acacia s.s. clade. The major clades originated in the late Oligocene-early Miocene (∼25mya). The transitions from close to open habitats occurred during the Miocene for at least four mimosoid lineages. These are interpreted as responses to increased seasonality leading to fire climates and drying trends in the Miocene, which allowed the expansion of open habitats, such as savannas, worldwide.
含羞草族的系统分类一直处于变化之中，这反映出人们对该类群的进化和生物地理学的了解还很不完善。初步的分子系统发育分析表明，含羞草族的族级系统需要全面修订。这导致了广泛使用 Acacia 属的新属名（以下简称广义含羞草属），同时对以澳大利亚模式种为代表的 Acacia 进行了重新定义：（i）狭义含羞草属（以下简称狭义含羞草属）、金合欢属、槐属、含羞草亚属和小含羞草属。本研究利用迄今最全面的取样，重点关注非洲物种，重建含羞草族的进化历史。其目的是重建 Acacieae 中五个公认属之间的系统发育关系，为阐明含羞草类的古生物地理学及其在新生代对开阔生境的适应提供基础。含羞草族谱系在金合欢属和槐属+小含羞草属+含羞草亚属+银合欢属+狭义含羞草属分支中的基部分支是一个新的发现。金合欢属（以前为含羞草属的一个亚属）被发现是单系的。一个包含其余含羞草族谱系的等级被发现与槐属+小含羞草属+含羞草亚属+银合欢属+狭义含羞草属分支并列。主要的分支起源于渐新世-中新世晚期（约 2500 万年前）。至少有四个含羞草类谱系从近生境向中生境的转变发生在中新世。这些被解释为对季节性增加的反应，导致中新世出现火灾气候和干燥趋势，从而允许开阔生境（如热带稀树草原）在全球范围内扩张。
