title: Revisiting the phylogeny of Bombacoideae (Malvaceae): Novel relationships, morphologically cohesive clades, and a new tribal classification based on multilocus phylogenetic analyses.
abstract: Bombacoideae (Malvaceae) is a clade of deciduous trees with a marked dominance in many forests, especially in the Neotropics. The historical lack of a well-resolved phylogenetic framework for Bombacoideae hinders studies in this ecologically important group. We reexamined phylogenetic relationships in this clade based on a matrix of 6465 nuclear (ETS, ITS) and plastid (matK, trnL-trnF, trnS-trnG) DNA characters. We used maximum parsimony, maximum likelihood, and Bayesian inference to infer relationships among 108 species (∼70% of the total number of known species). We analyzed the evolution of selected morphological traits: trunk or branch prickles, calyx shape, endocarp type, seed shape, and seed number per fruit, using ML reconstructions of their ancestral states to identify possible synapomorphies for major clades. Novel phylogenetic relationships emerged from our analyses, including three major lineages marked by fruit or seed traits: the winged-seed clade (Bernoullia, Gyranthera, and Huberodendron), the spongy endocarp clade (Adansonia, Aguiaria, Catostemma, Cavanillesia, and Scleronema), and the Kapok clade (Bombax, Ceiba, Eriotheca, Neobuchia, Pachira, Pseudobombax, Rhodognaphalon, and Spirotheca). The Kapok clade, the most diverse lineage of the subfamily, includes sister relationships (i) between Pseudobombax and "Pochota fendleri" a historically incertae sedis taxon, and (ii) between the Paleotropical genera Bombax and Rhodognaphalon, implying just two bombacoid dispersals to the Old World, the other one involving Adansonia. This new phylogenetic framework offers new insights and a promising avenue for further evolutionary studies. In view of this information, we present a new tribal classification of the subfamily, accompanied by an identification key.
authors.affiliation: Colegiado de Ciências Biológicas, Universidade Federal do Vale do São Francisco - UNIVASF, BR-407, Km 12, Vila CS-01, Petrolina, Pernambuco 56300-990, Brazil. Electronic address: jefferson.sobrinho@univasf.edu.br.
authors.forename: Jefferson G
authors.initials: JG
authors.lastname: Carvalho-Sobrinho
authors.affiliation: Department of Botany, Birge Hall, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: William S
authors.initials: WS
authors.lastname: Alverson
authors.affiliation: Departamento de Botânica-CCB, Universidade Federal de Santa Catarina - UFSC, Florianópolis, SC 88040900, Brazil.
authors.forename: Suzana
authors.initials: S
authors.lastname: Alcantara
authors.affiliation: Programa de Pós-Graduação em Botânica, Universidade Estadual de Feira de Santana - UEFS, Av. Transnordestina, s/n, Novo Horizonte, Feira de Santana, Bahia 44036900, Brazil.
authors.forename: Luciano P
authors.initials: LP
authors.lastname: Queiroz
authors.affiliation: Programa de Pós-Graduação em Botânica, Universidade Estadual de Feira de Santana - UEFS, Av. Transnordestina, s/n, Novo Horizonte, Feira de Santana, Bahia 44036900, Brazil.
authors.forename: Aline C
authors.initials: AC
authors.lastname: Mota
authors.affiliation: Department of Botany, Birge Hall, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Baum
mesh_terms: D001499:Bayes Theorem; D030541:Databases, Genetic; D056426:Genetic Loci; D019660:Malvaceae / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D019655:Quantitative Trait, Heritable; D012639:Seeds / Q000033:anatomy & histology
keywords: Baobab; Fruit traits; Kapok group; Neotropics; Tribal classification