NEW DISCOVERIES IN TAXONOMY OF Dalbergia GENUS IN GUATEMALA REVEALED BY MOLECULAR APPROACHES

Abstract

Background. The Dalbergia genus (Fabaceae) in Guatemala harbors valuable rosewood species; however, these timber species face significant threats from illegal logging and deforestation. Due to the morphological similarity between closely related Dalbergia species, accurate morphological identification is challenging, leading to uncertainty about the occurrence of new species in the country. The lack of information about the actual number of Dalbergia tree species complicates the development of management and conservation strategies for this endangered timber species. Objective. To elucidate the taxonomy of the tree species of the Dalbergia genus in Guatemala using species molecular delimitation methods. Methodology. Sixty-one Dalbergia specimens, collected in its natural range in Guatemala, were analyzed using nuclear (ITS) and chloroplast (matK and trnH-psbA) markers. Species delimitation was performed using three methods based on genetic distance, two based on single-locus phylogenetic trees, and two multi-loci. Results. Different Molecular Operational Taxonomic Units (MOTU) were estimated, ranging from 2 to 9 depending on the method and locus used. The molecular approaches consistently delimited the 6 species already reported for Guatemala. Furthermore, 3 MOTUs were identified that did not align with these known species, implying the presence of 3 new species for the country. Implications. Efficient molecular methods identify Dalbergia species from leaf samples, but standardizing wood sample identification is recommended for uncertain wood confiscation origins. This study proposes a new taxonomy of the genus Dalbergia in Guatemala and offers a fast and reliable identification method. Conclusions. With the molecular methods used in the study, three new Dalbergia species in Guatemala are proposed, corroborating previous suggestions based on morphological characterization. This discovery expands the existing inventory of Dalbergia tree species in Guatemala, comprising six previously documented species and three novel species that require detailed botanical descriptions for final naming.

Keywords

• dalbergia
• species delimitation
• dna barcoding
• molecular markers
• conservation