<scp>EGCop</scp>: An Expert‐Curated Occurrence Dataset of European Groundwater‐Dwelling Copepods (Crustacea: Copepoda)

ABSTRACT Motivation Subterranean biodiversity is increasingly threatened by multiple intertwined anthropogenic impacts, including habitat loss, pollution, overexploitation of resources, biological invasions and climate change. Worryingly, subterranean biodiversity is still poorly represented in conservation agendas, also due to persisting gaps in our knowledge of the organisms thriving in the often‐secluded and difficult‐to‐access subterranean ecosystems. This is even more apparent for small‐sized (body size &lt; 1 mm) groundwater‐dwelling metazoans, among which copepods (Crustacea: Copepoda) represent the dominant group in terms of both species richness and biomass. We present a dataset including 6986 occurrence records of 588 species/subspecies of European obligate groundwater‐dwelling copepods. We curated all records to make their taxonomy consistent with the current systematics of Copepoda, while assessing uncertainty in the geographic coordinates by coupling in‐depth web and literature searches with GIS analyses. We suggest the data provided can be used to explore a range of eco‐evolutionary questions—from the drivers of the distribution of groundwater fauna to the assembly of groundwater communities—as well as to prompt the conservation of groundwater biodiversity and more. Main Types of Variables Contained Occurrence records of groundwater‐dwelling copepods, with details about specimen taxonomy, source of the record, occurrence locality and habitat type. Spatial Location and Grain Geographical Europe (including western Russian Federation), along with Turkey and Georgia. Occurrence records were assigned projected geographic coordinates (EPSG:3035) at 100 m resolution but with varying spatial uncertainty. Time Period and Grain 1907–2017. Major Taxa and Level of Measurement Crustacea: Copepoda. Most records have species‐level identification, while some of them are identified at the subspecies level. Software Format Comma‐separated values file (.csv) and Excel file (.xlsx), with UTF‐8 encoding and meta‐data provided following the Darwin Core standard.