Species boundaries inferred from ISSR markers in the Myrcia laruotteana complex (Myrtaceae)

Myrtaceae is a family with high taxonomic complexity, especially the very rich genera such as Myrcia. For this genus, there is not a complete and recent taxonomic revision, and it has some species complexes that are poorly delimited. One of these complexes includes M. laruotteana, M. selloi, M. lajeana and M. tomentosa. In order to better understand the species boundaries in this complex, we analyzed the genetic variability and structure of multiple populations of these four species using inter simple sequence repeat markers, checking if there is any relationship between genetic, morphological and geographical patterns. The amount of genetic diversity found was similar (HE = 0.215) compared to species with similar biological characteristics. No groupings that were previously tested (morphological, geographical and the ones used in the traditional taxonomy) showed significant genetic structure. The groups suggested by Bayesian analysis showed a higher genetic structure through analyses of molecular variance: 12 % of the variation between populations within groups and 27 % of the variation between groups. The Bayesian analysis and the neighbor-joining dendrogram showed two major groups, the first with all populations of M. tomentosa, and the second containing populations from the other species. According to the unified species concept, there is enough evidence for the recognition of M. tomentosa,M. laruotteana and M. selloi, but not for M. lajeana. These data will be used as the basis of a new taxonomic classification of the species in the M. laruotteana complex.