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| Atrostemma mexicanum Pío-León, Mart.-Domínguez, L.O.Alvarado & Rodríguez-Gómez, in Martínez-Domínguez, Rodríguez-Gómez, Alvarado-Cárdenas, Díaz-Mota et Pío-Léon, 2026. |
Abstract
Background and Aims: The genus Atrostemma (Apocynaceae) includes 10 climbing plant species of subtribe Gonolobinae, which are distributed from Guatemala to Brazil. This paper describes a new species of Atrostemma for the state of Veracruz, Mexico; this is also the first record of the genus for the country.
Methods: The new species was discovered during botanical expeditions in the municipality of Emiliano Zapata, Veracruz, from December 2025 to June 2026. The taxonomic identification was carried out by reviewing specialized literature and consulting type specimens available online. Its conservation status was assessed according to IUCN Red List criteria.
Key results: Atrostemma mexicanum sp. nov. is endemic to Veracruz, Mexico, and grows in riparian vegetation similar to subtropical evergreen forest and in transition zones between oak forest and tropical deciduous forest, at elevations above 700 m. It is distinguished from the other Atrostemma species of Central America (A. glaberrimum, A. hadrostemmum, and A. hammelii) by its shorter calyx lobes, as well as differences in indumentum and the length of the gynostegium stipite. A record on iNaturalist suggests the presence of a second population between the municipalities of Córdoba and Orizaba, Veracruz. However, it could not be physically located despite explorations in the area where the record was made. Due to its restricted distribution and highly fragmented habitat, it is proposed that the new species be listed as Critically Endangered (CR).
Conclusions: The number of known species in the genus increases to 11 and it is the first species recorded in Mexico, which extends its northern range. This study highlights the importance of continuing botanical and conservation explorations of ecosystems, even when these are already fragmented.
Keywords: flora of Veracruz, iNaturalist, oak forest, tropical deciduous forest, tropical subdeciduous forest
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| Atrostemma mexicanum Pío-León, Mart.-Domínguez, L.O.Alvarado, Rodríguez-Gómez |
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| (A-C) Atrostemma mexicanum Pío-León, Mart.-Domínguez, L.O.Alvarado, Rodríguez-Gómez (D-F) Atrostemma hadrostemmum (W.D.Stevens) Morillo |
Atrostemma mexicanum Pío-León, Mart.-Domínguez, L.O.Alvarado, Rodríguez-Gómez sp. nov.
Atrostemma mexicanum differs from its Mesoamerican congeners by having shorter calyx lobes. This species is most similar to Atrostemma glaberrimum, but can be distinguished by having glandular trichomes and a stipitate gynostegium
Lilí Martínez-Domínguez, Carlos J. Rodríguez-Gómez, Leonardo O. Alvarado-Cárdenas, Sarahí Díaz-Mota and Juan Fernando Pío-Léon. 2026. A New Species and first record of the Genus Atrostemma (Apocynaceae, Asclepiadoideae, Gonolobinae) in Mexico. Acta Botanica Mexicana. 133; DOI: doi.org/10.21829/abm133.2026.2640 [2026-08-12]
