Dichrocephala integrifolia (Astereae, Asteraceae), a new exotic genus and species for Mexico and second record for the New World

Background: Dichrocephala is an Old-World genus of the tribe Astereae within the family Asteraceae. One species, D. integrifolia, has been recently reported as introduced in the New World from a pair of collections from Guatemala. During field work in the state of Chiapas in southern Mexico, the species was found and collected. This is the first record of both the genus and species in Mexico and the second record for these taxa in the Americas. Question: Can D. integrifolia occur in more areas in the New World besides those known from Guatemala and Chiapas? Studied species: Dichrocephala integrifolia Study site and dates: Mexico, Central America, and the Caribbean. Methods: An ecological niche model was made and it was projected into the New World. Results: The ecological niche model predicts the records of D. integrifolia in the New World in addition to other ecologically suitable areas, mostly in pine-oak forests in Mexico and Central America and zones with humid mountain and pine forest in the Caribbean. Moreover, a morphological description and illustrations of the species are provided to help with its identification. Conclusions: It is desirable to avoid the further spreading of D. integrifolia in the New World. Although this species is not considered as invasive, it seems to have a high dispersal potential and the ecological niche modelling indicates larger regions in the Americas that might be affected.