OBJECTIVE:

One of the six Brazilian biomes, the Pantanal, formed by the Upper Paraguay basin, is the most extensive floodplain in the world. Although there are studies on this biome's fauna and flora composition, most refer to vertebrates, with few studies on the malacofauna. Thus, this study deals with the richness of species and composition of the freshwater malacofauna found in Pantanal, in four cities of Mato Grosso State, Brazil: Barão de Melgaço, Cáceres, Poconé, and Santo Antônio do Leverger.

MATERIALS AND METHODS:

Samples were collected between 2002 and 2018. Data from the Mollusk Collection of the Oswaldo Cruz Institute (1978-1990) were also used.

RESULTS:

A total of 130 collecting sites were georeferenced, and 18 gastropods (five families) and six bivalves (four families) were identified. Considering the whole area, Pomacea scalaris, Pomacea maculata, Marisa planogyra, and Drepanotrema lucidum were the most frequent species.

CONCLUSION:

We highlight the record of new occurrences, including parasitic disease-transmitting and exotic mollusk species. These results will surely be helpful to subsidize health and conservation programs in this protected area of Central Brazil.