Phylogenetic Relationships and the Description of a New Species of Enriquebeltrania (Euphorbiaceae s.s.): An Enigmatic Genus Endemic to Mexico

Enriquebeltrania, a genus of trees and shrubs endemic to Mexico, traditionally has been included in Euphorbiaceae (tribe Adelieae, subfamily Acalyphoideae). It was previously thought to be monotypic with a disjunct distribution on the Yucatan Peninsula and along the Pacific coast in Jalisco and Sinaloa. There is some question about whether Enriquebeltrania should be treated as distinct from Adelia. Morphological and molecular characters (trnL-F spacer and rbcL DNA sequences) were utilized in phylogenetic analyses to determine if Enriquebeltrania belongs to the tribe Adelieae, to test whether it should be recognized as a genus separate from Adelia, and to determine the number of species that should be recognized. Results indicate that Enriquebeltrania does not belong to tribe Adelieae, that it should be recognized as a genus separate from Adelia, and that it consists of two species. The second species, Enriquebeltrania disjuncta, is named and described here.