A new species of Gonatodes from central Guyana is described, illustrated, and named in honor of one of Guyana's outstanding citizens, Mr. Alexander Mendes. To date, the species is known only from rain forest habitat at two localities. One (the type locality) is in the drainage system of the Konawaruk River, a western tributary of the Essequibo River, with its confluence to the south of the Potaro River confluence. The other locality is Kaieteur National Park, on the Potaro River.

This report is dedicated to Mr. Gerald King (deceased), an American Indian from Wiruni, on the lower Berbice River, Guyana. Like other native Americans and Guyanese of his time, Mr. King lived in close association with the rain forest, and he knew its plants and animals well, particularly the larger species that were useful for various purposes. Carol R. Townsend and C.J.C. had great pleasure working with Mr. King and his teenage son, Wesley, for two years, during which they built our comfortable remote camps out of local forest resources. The Kings eagerly assisted with our fieldwork, anxious to learn more about their native amphibians and reptiles and to travel and explore in parts of their country they had never seen.