Molecular systematics, species concepts and myrmecophytism in Cecropia (Cecropieae: Urticaceae): Insights from restriction-site associated DNA

Cecropia is a group of fast-growing pioneer trees that are important in forest regeneration and a common ant-plant mutualism in the Neotropics. To investigate the evolution of mutualism between Cecropia and associated ants a phylogenetic framework is necessary. Cecropia species are difficult to distinguish morphologically and conventional genetic markers are insufficiently variable to resolve phylogeny. Our study aimed to infer relationships in approximately half of the species in the genus using restriction site associated DNA (RAD) sequencing. RAD sequence data resolved and supported species level relationships, despite potential introgression based on D-statistic tests. Our results support a deeply divergent non-myrmecophytic clade including C. sciadophylla and African Musanga. Results from geographically widespread and morphologically heterogenous C. obtusifolia and C. angustifolia suggests that current synonymy lumps together genetically dissimilar lineages. Reconstruction of ant associations on the highly supported Cecropia phylogeny inferred equal probability of the ancestor of Cecropia being myrmecophytic or not. More intensive genetic study is needed to refine species concepts in Cecropia.RADseq data run through pipeline in pyrad 3.0.6