Disentangling the identity of Zamia from Mexican Pacific seaboard, with a description of a new species

16 July 2019

Nicolalde-Morejón, Fernando; Martínez-Domínguez, Lilí; Stevenson, Dennis; Vergara-Silva, Francisco

Here we present a circumscription with qualitative and quantitative morphological comparison including all populations of Zamia along the coastal plain of Pacific Mexico. We recognize four species in this area: Z. paucijuga, Z. herrerae, Z. spartea and the new species, Z. stenophyllidia is described as new cycad species from Michoacán, Mexico. This new cycad species from Michoacán have distinct characters in both vegetative and reproductive structures; namely, linear, lanceolate, papyraceous and narrow leaflets (up to 0.8 cm wide), robust and short prickles (up to 2 mm), and ovoid, yellowish, ovulate strobili. The description of this species implies a recircumscription of the Z. paucijuga concept; on this basis, in accordance with the International Code of Botanical Nomenclature, an epitype for the species is presented here. We also introduce a key for all species of Zamia from Mexico. Biogeographically, the new species is interesting for its sympatry with Dioon stevensonii, a species that has been a model for the study of the formation of modern Neotropical forests.