2025
Motivation: Groundwater ecosystems sustain a unique and globally important biodiversity but remain understudied due to sampling and exploration challenges, as well as a shortage of taxonomic experts. Groundwater ostracods, like other groundwater taxa, exhibit a high degree of endemism, rarity and subterranean specialisation, positioning them as potentially vulnerable organisms. To better understand biodiversity patterns and the conservation needs of this highly diverse group, we assembled a team of experts to gather the most comprehensive information available about groundwater ostracods in Europe. We present a dataset comprising 2065 occurrence records of 110 species, 11 undescribed species and 5 subspecies of groundwater ostracods. This open dataset may support future research on the distribution, evolutionary pathways and conservation needs of European groundwater ostracods, as well as inspire targeted sampling efforts in regions with currently limited data available.