Mesobiotus datanlanicus sp. nov., a new tardigrade species (Macrobiotidae: Mesobiotus harmsworthi group) from Lâm Đồng Province in Vietnam.

A new species of the Mesobiotus harmsworthi group is described from Datanla Waterfall amusement park in Lâm Đồng Province, Vietnam. An integrative taxonomy approach was applied, by combining morphological and morphometric analyses using light contract microscopy (LCM)) and scanning electron microscopy (SEM) with genetic analysis (18S rRNA, 28S rRNA, ITS-2 and COI markers), to cross-verify the status of the newly discovered population as a new species. By the presence of fully developed areolation around egg processes bases and well developed oral cavity armature (OCA), with all three bands of teeth visible under (LCM), the new species, Mesobiotus datanlanicus sp. nov., is most similar to seven taxa from the harmsworthi complex: M. barbarae (Kaczmarek, Michalczyk Degma, 2007), M. hieronimi (Pilato Claxton, 1988), M. insanis Mapalo, Stec, Mirano-Bascos Michalczyk, 2017, M. neuquensis (Rossi, Claps Ardohain, 2009), M. nuragicus (Pilato Sperlinga, 1975), M. pseudoliviae (Pilato Binda, 1996), M. pseudonuragicus (Pilato, Binda, Lisi, 2004), but differs from them mainly by some specific characters of the egg and adult morphology as well as by morphometrics.