Ceratozamia chinantlensis (Zamiaceae): A New Cycad Species from La Chinantla, Oaxaca, Mexico

Ceratozamia chinantlensis sp. nov., a new cliff-dwelling cycad species from Sierra de La Chinantla, Oaxaca, Mexico, is described and compared with its congeners. The species is morphologically similar to Ceratozamia zoquorum and Ceratozamia santillanii, two geographically distant species, yet it is effortlessly distinguishable from its most proximally geographic congeners. Ceratozamia chinantlensis can be recognized based on several qualitative traits, such as its very coriaceous, long, linear to oblanceolate leaflets. Also, it has bronze-colored emerging leaves and mature leaves with articulations of a light copper color. Compared with C. zoquorum and C. santillanii, C. chinantlensis has significantly longer and wider leaflets. C. chinantlensis should be considered a critically threatened species due to its limited number of populations and individuals. Habitat destruction—historically through the extraction of Dioscorea mexicana and Vanilla planifolia, along with ongoing coffee and corn plantations—is an ongoing threat that narrows its distribution range.