Taxonomic dissection based on molecular evidence of the Eriosyce curvispina complex (Cactaceae): identifying nine endemic species from Central Chile

Chile’s distinctive flora, geographical isolation, and complex topography collectively contribute to a notable endemic species diversity, particularly within central regions identified as critical areas for biodiversity conservation. The cactus genus Eriosyce , as currently circumscribed, encompasses seven sections, with Eriosyce sect. Horridocatus presenting a notably complex species group. This study investigates the E. curvispina complex, a member of the Notocacteae tribe common in central Chile, by incorporating new populations and examining phylogenetic relationships using four plastid and one nuclear molecular marker. The phylogenetic analysis of sampled individuals identified nine independent lineages, each warranting recognition at the species rank. Despite minimal morphological differences among taxa, morphological characters were utilized to support and stabilize the DNA-based phylogenetic hypothesis. The results highlight the high taxonomic diversity in these cactus lineages and have implications for the classification of the E. curvispina complex, including new combinations and proposals of conservation status.