Six species in the Tapinoma nigerrimum complex (Hymenoptera: Formicidae): Tapinoma elongatum sp. nov. – an endemite of southwest Iberia

A new species of the Tapinoma nigerrimum complex, T. elongatum sp. nov ., is described from SW Spain. Applying a protocol of Numeric Morphology-based Alpha-Taxonomy considering 16 standardised characters recorded by high-resolution stereomicroscopy, the new species can be safely separated from the related species Tapinoma nigerrimum (Nylander, 1846), T. magnum Mayr, 1861, T. ibericum Santschi, 1925, T. darioi Seifert et al., 2017 and T. hispanicum Seifert et al., 2024 by more elongated funiculus segments, scape and mesosoma. T. elongatum sp. nov . appears to be restricted to coastal sand dune habitats of SW Iberia, is not invasive and most probably not supercolonial nor found in urban areas. The new species is eudominant in the most natural parts of coastal sand dunes, obviously saturating the Tapinoma niche there in a way that no related species can move in. Images of the holotype, a revised key and a table comparing the morphological data of all six T. nigerrimum group species are given.