Zamia urarinorum (Cycadales, Zamiaceae), a new cycad species from wetland forests of Loreto, Peru

Abstract

We describe and illustrate Zamia urarinorum, a new species of arborescent cycad from wetland forests in the Tigrillo and Urituyacu river basins of Loreto, Peru. It is the only cycad known to inhabit permanently waterlogged wetland forests, a unique and ecologically challenging environment. Morphologically, the species most closely resembles Zamia multidentata, but differs in both vegetative and reproductive traits. Vegetative distinctions include fewer leaves per stem and longer, more narrowly shaped leaflets with marginal teeth confined to the distal portion. Reproductive differences include significantly smaller pollen strobili with a tomentose rachis, and ovulate strobili with shorter peduncles and smaller seeds. We also document a range extension of Z. multidentata into Peru, expanding its known distribution beyond Acre, Brazil. These findings highlight the underexplored diversity of Amazonian Zamia and contribute to a growing understanding of its biogeographic and ecological complexity.