Ceratozamia aurantiaca (Zamiaceae): A New Cycad Species from the Northern Rainforests of Oaxaca, Mexico

Abstract

Ceratozamia aurantiaca, a new cycad species from Oaxaca, Mexico, is described. The new species is endemic to lowland karst tropical rainforests of the northern mountains (Sierra Norte region). This species is related to C. subroseophylla and C. robusta, together considered part of the C. robusta species complex due to their shared characteristics: robust, upright trunk; large and long leaves with densely armed petioles and linear to subfalcate leaflets; and large megastrobili. Ceratozamia aurantiaca, as the epithet suggests, is easily distinguished from other species by the orange color of its emerging leaves, a trait unique in the genus. Additionally, C. aurantiaca is distinguished from C. subroseophylla and C. robusta by having significantly shorter petioles, wider spacing between leaflets, and wider median leaflets. The taxonomic recognition of this species represents a step toward clarifying species delimitation in the C. robusta complex.