This dataset was developed to identify in detail the predictors of sampling bias affecting Spirostreptida species distribution in the Atlantic Forest. It corresponds to part of the results submitted to the journal Austral Ecology, authored by XXX. This dataset is open to the journal editor, reviewers, and readers. The list of species and their respective distributions were compiled from Iniesta et al. (2023a, b) for Spirostreptidae and from Iniesta et al. (2023c) for Pseudonannolenidae, based exclusively on specimens examined in scientific collections. The R packages associated with this dataset include: sampbias, terra, tidyverse, data.table, sf, viridis, purrr, hablar, rnaturalearthdata, and rnaturalearth. Users are encouraged to consult the full references and documentation of these articles and packages for further details regarding their functionalities and information.