The Mochima National Park is located in the northeastern region of Venezuela (10°9’50” and 10°26’0” N; 64°13’20”- 64°47’32” W), has a variety of ecosystems which include sandy beaches, rocky substrates, Thalassia meadows, coral bottoms and mangroves. Due to the presence of these environments, the park presents important levels of biological diversity. The roots of the Rhizophora mangle support a unique substrate for many species of marine invertebrates, where gastropods stand out; In this environment, the presence of the microgastropod Amphithalamus rauli (Rrolán 1991), a species of the Anabathridae family, is reported. This finding is part of a study whose objective is the evaluation of the temporal space of the malacofauna in the Mochima National Park. The specie was found in 5 of the 6 sampled stations, with a greater presence in the months of upwelling and in the most protected areas of the park. A description of the species is made that allows differentiating it from A. vallei, which is until now the first and best known of the genus. The results obtained allow expanding the malacological fauna recorded in mangrove roots, especially the microfauna, and highlight the importance of research in this group, so far with few studies in Venezuela.
