Phylogeny and taxonomy of Syngonanthus and Comanthera (Eriocaulaceae): Evidence from expanded sampling

Comanthera and Syngonanthus (Eriocaulaceae) are monocotyledonous herbs that occur mainly in neotropical savannas in the Guiana Shield and in southeastern Brazil, with a few species in Africa. Phylogenetic relationships in Syngonanthus and Comanthera are still unresolved and have not yet been assessed using a broad and comprehensive sampling. The present study aimed to test the monophyly of both genera and their putative infrageneric taxa and to evaluate their taxonomy and supporting synapomorphies in the light of a resolved phylogeny. The resulting phylogenetic hypotheses were then used to infer the biogeographical histories of the taxa, especially in Brazil. Molecular analyses based on plastid (trnL-F, psbA-trnH) and nuclear (ITS) markers using parsimony and Bayesian inference were conducted on 62 species belonging to the ingroup. Syngonanthus s.l. (composed of Syngonanthus, Philodice and Comanthera), Syngonanthus s.str. (including Philodice), Comanthera and both of its subgenera were retrieved as monophyletic, strongly supported by molecular and morphological apomorphies. However Syngonanthus sect. Carphocephalus appeared polyphyletic, and its species were embedded within a paraphyletic S. sect. Syngonanthus. Within Comanthera, clades restricted to equatorial savannas appeared to be sisters to clades restricted to southeastern Brazil, especially in the Espinhaço Range, with a disjunct pattern between Bahia and Minas Gerais states. Within Syngonanthus s.str., Andean and African species appeared embedded in Brazilian clades, but resolution and support within the genus must be improved in future research.