Molecular phylogeny supports a new circumscription of Mimosa subser. Polycephalae, a species-rich lineage centered in the Brazilian Cerrado

• Published in: Revista brasileira de botânica Vol. 48; no. 1; p. 12
• Main Authors: Mendes, Thainara Policarpo, Simon, Marcelo Fragomeni, da Silva, Marcos José
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.12.2025; Springer Nature B.V
• Subjects: Bayesian analysis; Bayesian theory; Biomedical and Life Sciences; Brazil; calyx; cerrado; chloroplast DNA; Filaments; Genera; Geographical distribution; Life Sciences; Lobes; Mimosa; monophyly; Phylogenetics; Phylogeny; Plant Systematics/Taxonomy/Biogeography; Species; Spicules; Statistical inference; Systematics & Phylogeny - Original Article; Taxa; Cerrado Biome; Brazil; Molecular phylogeny; Diversification; Morphology; Fabaceae
• ISSN: 1806-9959; 0100-8404; 1806-9959
• DOI: 10.1007/s40415-024-01042-7

With a Pantropical distribution, Mimosa is one of the most diverse genera of Tribe Mimoseae, with about 615 species. It circumscribes five sections ( M. sect. Batocaulon DC., M . sect. Calothamnos Barneby, M . sect. Habbasia DC., M . sect. Mimadenia Barneby, M . sect. Mimosa ), 41 series and 37 subseries, being M . subser. Polycephalae (Benth.) Barneby, the largest of them with 34 species distributed in Central Brazil. Although the species in this subseries are recognized by leaves with a pair of multifoliolate pinnae, unarmed branches, paleaceous calyx with fimbriated lobes and monadelphous filaments at the base, previous phylogenetic study recovered it as non-monophyletic with their taxa mixed with representatives of subseries Discobolae Barneby, Dicerastae Barneby, Hirsutae (Benth.) Barneby and series Modestae (Benth.) Barneby. We performed a phylogenetic reconstruction of Mimosa subser. Polycephalae and closely related taxa aiming to recircumscribe it to a monophyletic taxon and understand the relationship among its species. We sampled 30 species of M . subser. Polycephalae plus 22 from immediately related groups and performed isolated and combined analyzes of ITS (nrDNA) and trnD-trnT (cpDNA) markers using Maximum Likelihood and Bayesian Inference methods. Our analyzes confirm the non-monophyly of Mimosa subser. Polycephalae , with its taxa mixed with members of other infrageneric taxa. To make Mimosa subser. Polycephalae monophyletic, we excluded M. brevicalyx and M. cyclophylla from its concept and recognized a clade here called the Polycephalae clade, which includes taxa from subseries Discobolae , Dicerastae and Hirsutae, and ser. Modestae . Mimosa subser. Polycephalae now comprises 40 species distributed mainly in the Brazilian Cerrado, characterized by leaves lacking interpinnal spicules and predominantly with 1 pair of pinnae, which may vary between 2–4 pairs, glomerule solitary or in synflorescences, calyx vestigial or paleaceous with fimbriated lobes, and free or strongly monadelphous filaments at the base.