A comprehensive occurrence dataset for European Ostracoda inhabiting groundwater and groundwater-dependent ecosystems

MotivationGroundwater 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 2,065 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.Main Types of ..., , , # A comprehensive occurrence dataset for European Ostracoda inhabiting groundwater and groundwater-dependent ecosystems

Dataset DOI: [10.5061/dryad.1g1jwsv7c](10.5061/dryad.1g1jwsv7c)

## Description of the data and file structure

The European Ostracoda occurrence dataset for groundwater and groundwater-dependent ecosystems (EGWOD) was compiled from several datasets and databases: the European groundwater crustacean dataset (Zagmajster *et al*., 2014), the SubBioDB database (Zagmajster et al., 2008; Zagmajster et al., 2012), the Slovenian Ostracoda dataset (Mori and Å alamun, 2022), and several datasets obtained from individual researchers in the United Kingdom, Ireland, Croatia, Hungary, Romania, Italy, and Austria. Furthermore, additional data from 7 publications were included.

**Main Types of Variables Contain** occurrence records of groundwater ostracods, with details about taxonomy, source of records, occurrence locality, habitat type, and species dependence on groundwater (oblig...,