Abstract
Helvella lacunosa is a species complex, with Helvella lacunosa s.s. not currently distributed in America. The objective of this study was to resolve the taxonomy of specimens from central Mexico identified as Helvella lacunosa s.l. associated with Abies religiosa forests. The nuclear ITS and LSU regions were PCR-amplified and sequenced from dry herbaria specimens. Phylogenetic analyses were based on Parsimony, Maximum Likelihood and Bayesian Inference approaches. Sequences of Helvella from A. religiosa forests grouped into a well-supported lineage within the North American clade together with Helvella dryophila (associated with Quercus in western USA) and Helvella vespertina (associated with conifer forests in western USA). Therefore, we describe and illustrate Helvella jocatoi as a new species based on phylogeny and morphological traits. In central Mexico, this taxon is an edible mushroom known as “gachupín”, has high cultural importance and is sold in large quantities. The description of this new species restricted to A. religiosa forests has implications for its conservation since its habitat is endangered.