Neodiversity, Volume 13, Issue 1, Pages 1-38
DOI: 10.13102/neod.131.1, Publication Date: 2020-09-02
The pantropical and morphologically diverse genus Aeschynomene (Leguminosae, Papilionoideae) comprises ca. 180 species, but its monophyly has never been comprehensively addressed in a molecular phylogenetic context of the dalbergioid clade. Here we have assembled the most complete DNA sequence data (nuclear ribosomal ITS/5.8S and the plastid genes trnL intron and protein-coding matK), representatively sampled both in Aeschynomene and the closely related Dalbergia and Machaerium, as well all currently accepted genera from the dalbergioids. The Bayesian and maximum likelihood phylogenetic analyses unequivocally confirm the non-monophyly of Aeschynomene. The pantropically distributed Aeschynomene sect. Aeschynomene, often inhabiting riparian and wetland habitats, is paraphyletic with respect to the mostly African genera Bryaspis, Cyclocarpa, Geissaspis, Humularia, Kotschya, and Smithia, as well as the South American monotypic genus Soemmeringia. The strongly supported and morphologically coherent clade comprising the American species traditionally classified within Aeschynomene sect. Ochopodium, with a greater ecological predilection for neotropical fire-prone savannas and the seasonally dry tropical forests and woodlands, is here elevated to generic rank. As such, this lineage is re-established as the previously monotypic genus Ctenodon. A complete description of Ctenodon and 78 new combinations for the American species and associated infraspecific taxa are provided, as well as 24 lectotypifications.