Morphological and molecular evidence for a new endemic species of Triniochloa (Poaceae) from Jalisco, Mexico

Background and aims – Triniochloa is a genus endemic to the Americas. Currently, there are six described species, four of which are Mexican endemics. In this study, we present a description, distribution map, and photographs of a new species of Triniochloa endemic to Jalisco, Mexico and a phylogenetic hypothesis based on a nuclear DNA marker.

Material and methods – This study was based on a phylogenetic analysis of nuclear ITS, fieldwork, and a review of literature and herbarium specimens. The specimens collected were analysed and photographed during fieldwork. The conservation assessment is based on spatial analysis, following the IUCN guidelines and criteria.

Key results – The molecular phylogenetic hypothesis recovered the new Triniochloa species as sister to T. talpensis. Morphologically, T. villalpandoana sp. nov. differs from T. laxa and T. talpensis by its longer spikelets, glumes, and lemma. It is endemic to Cerro de los Bailadores, Zapopan, Jalisco.

This mountain lies just 20 km in a straight line to the northwest of the Guadalajara metropolitan area. The vegetation is an oak-pine forest that grows in rocky, humid ravines at elevations from 1640 to 2000 m. According to our conservation assessment, this species should be considered Critically Endangered.

Conclusion – The discovery of Triniochloa villalpandoana sp. nov. adds a seventh species to this American endemic genus. Morphologically, the new taxon stands out from its closest relatives, T. laxa and T. talpensis, by its substantially larger spikelets, glumes, and lemmas, a combination of traits that supports its recognition as a distinct species.