Macrobiotus caelestis sp. nov., a new tardigrade species (Macrobiotidae: Hufelandi Group) from the Tien Shan Mountains (Kyrgyzstan)

In this paper we describe a new species of a tardigrade of the Macrobiotus hufelandi group from the Tien Shan mountains in Kyrgyzstan. Live specimens extracted from a moss sample were used to establish a laboratory culture in order to obtain more eggs and animals needed for an integrative description of the new species. This description is based on traditional morphological and morphometric data collected using both light and scanning electron microscopy, which at the same time were combined in an integrative approach with DNA sequences of four genetic markers, three nuclear (18S rRNA, 28S rRNA and ITS-2) and one mitochondrial (COI). The analysis showed that Macrobiotus caelestissp. nov. is most similar to Macrobiotus kazmierskiiKaczmarek and Michalczyk, 2009 from Argentina by having eggs with the persimilis type egg shell surface. However the new species can be easily distinguished from it by having very wide terminal discs on the egg shell processes and a small number of processes around the egg circumference. The use of DNA sequences allowed for the more accurate verification of the taxonomic status of M. caelestissp. nov. as an independent species within the hufelandi group.