This is the first published database of a Bathynellacea Chappuis, 1915 collection of slices and DNA extracts. It includes all data of bathynellaceans (Crustacea: Syncarida) collected in the last 48 years (1968 to 2016) on the Iberian Peninsula and Balearic Islands, studied since 1984. It also includes specimens studied across many countries of Europe (Portugal, Romania, France, Italy, Slovenia, Bulgaria, and England), as well as some specimens obtained from samples of North America (Montana, Washington, Alaska and Texas), South America (Brazil, Chile and Argentina), Asia (China, Thailand, Vietnam, Mongolia and India), Africa (Morocco and Chad) and Australia (New South Wales –NSW- and Queensland). The samples come from groundwater (caves, springs, wells and hyporrheic habitat associated with rivers) obtained from both, sampling campaigns and occasional sampling efforts. The data set includes 3399 records (2657 slices and 742 DNA extracts) corresponding to three families (Parabathynellidae Noodt, 1965, Leptobathynellidae Noodt, 1965 and Bathynellidae Grobben, 1905) of the order Bathynellacea; the existence of three families is accepted, but this is a controversial issue and here is not the appropriate context to address this problem; 52 genera and 92 species formally described, in addition to 30 taxa under study and, thus, still unpublished. This represents more than half of all the genera known worldwide (80) and almost one third of the species currently known in the world (329, which increases every year). This dataset contains especially relevant collection that includes holotypes and type series of 43 new species of Bathynellacea (33 from the Parabathynellidae and ten from the Bathynellidae) described by Ana I. Camacho (AIC hereinafter); eleven of these are the type species for new genera described from all around the world, ten belonging to the Parabathynellidae and one from the Bathynellidae. As previously mentioned, these new species come from all continents, although 26 of them are from the Iberian Peninsula. The most important feature of this collection is that it has been created and reviewed by a specialist of the group (AIC), and each specimen, regardless of its shape (either permanent slices or DNA extracts), includes taxonomic, geographical and authorship information. The specialist has been involved in all stages of the process, from field sampling to the digitization of the results we are now presenting, and has worked in close collaboration with the curators responsible for the different collections involved in this project.
