Macrobiotus hupingensis, a New Tardigrade Species in the Macrobiotus pallarii Complex from China

In this paper we describe Macrobiotus hupingensis, a new tardigrade species of the Macrobiotus pallarii complex from southern China. We used the traditional morphology-based taxonomic analysis, supported by detailed morphometrics, light microscopy imaging, scanning electron microscopy, and analysis of four genetic markers (18S rRNA, 28S rRNA, COI and ITS-2). Macrobiotus hupingensis sp. nov. is characterized by eggs with large, conical processes, each surrounded by six (only sometimes five) hexagonal areolae. Based on the morphological characters of the animals (two macroplacoids, one microplacoid, porous curicle, Y-shaped claws) as well as genetic data, we demonstrate the new species to be a member of the M. pallarii complex. However, it differs specifically from M. pallarii, M. pseudopallarii, and M. ripperi mainly by the absence of sparse granulation between legs III and IV. It also differs from M. margoae mostly by the presence of meshes within the entire egg process wall. Finally, the new species can be easily distinguished from M. caymanensis by the presence of granulation visible in light microscopy in all legs.