Integrative taxonomy reveals four new species in the superdiverse genus Macrobiotus (Tardigrada: Eutardigrada: Macrobiotidae)

Four new species of the genus Macrobiotus are described from Asia and Africa: Macrobiotus witalinskii sp. nov., M. dalaticus sp. nov., M. surmaczi sp. nov., and M. hoianicus sp. nov. Species delimitation is based on detailed morphological and morphometric analyses using phase-contrast light microscopy and scanning electron microscopy, complemented by molecular data from four commonly used genetic markers. Phylogenetic analyses consistently place all four species within Macrobiotus clade C, each forming a distinct, well-supported monophyletic lineage. The newly described taxa expand the known morphological and ecological diversity of clade C and show that egg and body coloration characters previously considered diagnostic for this lineage are not evolutionarily conserved. These results further emphasize the value of integrative taxonomy for documenting hidden diversity and for supporting future biodiversity assessments, including large-scale DNA barcoding and metabarcoding surveys of tardigrades.