Clusia suborbicularis is not a synonym of Clusia flava: Molecular and metabolomic evidence

The genus Clusia (Clusiaceae) is notorious for its difficult taxonomy; most species are dioecious, with distantly related species having similar morphology, and closely related species having cryptic morphological differences. Because of this, Clusia spp. are often misidentified or, as in the case of C. suborbicularis and C. flava, considered to be the same species. Chemometric analyses of the HPLC metabolic profiles from bark extracts of C. suborbicularis and C. flava, combined with molecular evidence from ITS molecular markers were used to establish the metabolomic similarities and phylogenetic relationship between C. suborbicularis and C. flava, previously identified on the basis of their morphological characteristics. The principal component analyses of the HPLC metabolic profiles of bark extracts from individuals of C. suborbicularis and C. flava showed significant differences, suggesting they should be recognized as distinct species. This assumption was confirmed by phylogenetic reconstructions based on the molecular marker ITS. Furthermore, a theoretical geographical distribution analysis suggests C. suborbicularis could be considered a native species to the Yucatan Peninsula. The results from this investigation support C. suborbicularis as a distinct species, and not a synonym of C. flava. The identification of these two species represents a relevant contribution for the cataloguing, conservation and bioprospecting of Clusia spp. occurring in the Yucatan Peninsula.