![](https://sciencepress.mnhn.fr/sites/default/files/periodiques/visuels/grand/zoo_visuel_2019.jpg)
A new diagnosis of Americanura Cassagnau,1983 is done and a discussion on the genus’ morphology is presented. A new species of the genus, from Chiapas State, Mexico, is described and illustrated; it is characterized by the fusion and reduction of the antenno-frontal tubercle and the highest reduction of its setae. A complement to the description of A. mexicana Cassagnau, 1983 is done including the morphological variation.
Antenno-frontal tubercle, setae reduction, México, intraspecific variation, new species.