A new species of Myoxanthus (Pleurothallidinae: Orchidaceae) from Peru with a horn-shaped labellar callus

Rizo Patrón F.L.; Ocupa-Horna L.; Rojas-Alvarado G. · Phytotaxa (2026) · DOI: 10.11646/phytotaxa.756.1.1

Resumen

The genus Myoxanthus comprises 54 species distributed from Mexico to southeastern Brazil and belongs to the subtribe Pleurothallidinae, the most diverse lineage within Orchidaceae. Since the last revision of the genus, several additional species have been described, mainly from South America, where new taxa continue to be discovered, particularly in the forest of the Andean Mountain Range that harbor remarkable diversity. Here we describe a new species, Myoxanthus triceratops, from the cloud forest of Oxapampa department, Peru. This new species is similar to M. hirsuticaulis, from which it differs by having an ovate acute synsepal; petals filiform above the basal third; a labellum with a horn-like callus at the apex; and a pair of lamellae forming a hourglass-shaped pattern. The new species can be readily distinguished from all other members of the genus by the presence of a horn-shaped callus at the apex of the labellum, a character not previously reported in any species of Myoxanthus. For the new species, we provide a Lankester Digital Composite Plate (LCDP), a detailed illustration, a taxonomic discussion, and photographs of the most closely related species. The discovery of Myoxanthus triceratops highlights the still underestimated diversity of Myoxanthus in Andean forests and emphasizes the importance of continued fieldwork and taxonomic study in these highly biodiverse ecosystems. Copyright

Instituciones: Universidad Peruana Cayetano Heredia; Universidad Nacional Pedro Ruiz Gallo