Occurrence Records of Brazilian Spirostreptida (Myriapoda: Diplopoda) in the Atlantic Forest Are Biased Towards Proximity to State Highways and Urban Areas

Diplopoda is one of the most diverse terrestrial arthropod groups in Brazil, with the order Spirostreptida Brandt, 1833 standing out for its species richness. Most of the ~180 Brazilian Spirostreptida species occur in the Atlantic Forest, primarily along its coastal region. However, knowledge of their distribution patterns and associated sampling biases remains limited. We applied a Bayesian framework to 453 presence‐only occurrence records of Spirostreptida from the Atlantic Forest to evaluate predictors of sampling bias affecting species distribution knowledge. Two sets of predictors (low‐ and high‐impact) were analysed jointly to identify areas with strong bias or areas associated with anthropogenic impacts. Geographic projections of sampling rates conditioned on these predictors indicate that the Atlantic Forest encompasses extensive areas with low sampling rates. Our results reveal a dense concentration of occurrence records in the Serra do Mar coastal forests, with the southeastern mountain ranges standing out as the area with the highest density of well‐sampled sites across the biome. In contrast, many of the northeastern regions, particularly the Bahia and Pernambuco coastal forests, exhibit low sampling effort. Sampling bias was primarily associated with high‐impact predictors, especially proximity to state highways and urban areas. The combined effects of these variables, along with proximity to railroads and protected areas, should be considered when assessing millipede distributions in Brazil and elsewhere, as they invariably would lead to a Wallacean shortfall. Mitigating these biases requires increased survey efforts in poorly accessible and under‐sampled regions, especially outside the southeast, digitization and mobilization of data stored in biological collections and investment in the training of new taxonomists.