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Abstract Ranges of tardigrade intraspecific and interspecific variability are not precisely defined, both in terms of morphology and genetics, rendering descriptions of new taxa a cumbersome task. This contribution enhances the morphological and molecular dataset available for the heterotardigrade genusViridiscusby supplying new information on Southern Nearctic populations ofV.perviridis,V.viridianus, and a new species from Tennessee. We demonstrate that, putting aside already well-documented cases of significant variability in chaetotaxy, the dorsal plate sculpturing and other useful diagnostic characters, such as morphology of clavae and pedal platelets, may also be more phenotypically plastic characters at the species level than previously assumed. As a result of our integrative analyses,V.viridianusis redescribed,V.celatussp. nov. described, andV.clavispinosusdesignated asnomeninquirendum, and its junior synonymy with regard toV.viridianussuggested. Morphs of threeViridiscusspecies (V.perviridis,V.viridianus, andV.viridissimus) are depicted, and the implications for general echiniscid taxonomy are drawn. We emphasise that taxonomic conclusions reached solely through morphological or molecular analyses lead to a distorted view on tardigrade α-diversity.