Nomenclatural and taxonomic updates in Rourea subgen. Rourea sect. Multifoliolatae (Connaraceae)

Phylogenomics of the pantropical Connaraceae: revised infrafamilial classification and the evolution of heterostyly

Connaraceae is a pantropical family of about 200 species containing lianas and small trees with remarkably diverse floral polymorphisms, including distyly, tristyly, homostyly, and dioecy. To date, relationships within the family have not been investigated using a targeted molecular phylogenetic treatment, severely limiting systematic understanding and reconstruction of trait evolution. Accordingly, their last infrafamilial classification was based only on morphological data. Here, we used phylogenomic data obtained using the Angiosperms353 nuclear target sequence capture probes, sampling all tribes and almost all genera, entirely from herbarium specimens, to revise infrafamilial classification and investigate the evolution of heterostyly. The backbone of the resulting molecular phylogenetic tree is almost entirely resolved. Connaraceae consists of two clades, one containing only the African genus Manotes (4 or 5 species), which we newly recognize at the subfamily level. Vegetative and reproductive synapomorphies are proposed for Manotoideae. Within Connaroideae, Connareae is expanded to include the former Jollydoreae. The backbone of Cnestideae, which contains more than half of the Connaraceae species, remains incompletely resolved. Reconstructions of reproductive system evolution are presented that tentatively support tristyly as the ancestral state for the family, with multiple parallel losses, in agreement with previous hypotheses, plus possible re-gains. However, the great diversity of stylar polymorphisms and their phylogenetic lability preclude a definitive answer. Overall, this study reinforces the usefulness of herbarium phylogenomics, and unlocks the reproductive diversity of Connaraceae as a model system for the evolution of complex biological phenomena.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00606-024-01909-y.

Flora of Espírito Santo, Brazil: Connaraceae

Abstract The pantropical family Connaraceae includes 12-13 genera and about 200 species, with species richness centered in Amazonia and Atlantic Forest. Most neotropical species of this family occur in Brazil, where several taxa are exclusively found. In Espírito Santo (southeast Brazil), two genera (Connarus and Rourea) and nine species of Connaraceae occur, all of which are exclusive to Brazil and mostly distributed in tableland forests or restingas from Rio de Janeiro up to south Bahia, with some taxa restricted to a few sites or even endemic to a particular area in Espírito Santo. In order to contribute to the flora of Espírito Santo, this taxonomic treatment presents morphological descriptions of the family, the two genera and their respective species, along with identification keys, illustrations, distribution maps and recognition notes.