New records of Tardigrada from Bulgaria with the description of Macrobiotus binieki sp. nov. (Eutardigrada: Macrobiotidae) and a key to the species of the harmsworthi group

Abstract

Fifteen moss samples collected in the Sophia Province (Bulgaria) were examined. In these samples six eutardigrade species were found: Hypsibius convergens, Isohypsibius prosostomus, Macrobiotus binieki sp. nov., M. hufelandi, M. pallarii and Ramazzottius oberhaeuseri. The new species belongs to the Macrobiotus harmsworthi group and differs from the most similar M. australis, M. coronatus, M. patiens, M. pseudocoronatus, M. radiatus, M. rigidus and M. simulans mainly by: egg processes covered by small bubbles (not smooth or reticulated), egg shell between processes covered by wrinkles not dots or stripes forming a large radiate crown, a higher number of processes on egg circumference and some morphometric characters of adults. In this paper a key to all species of the harmsworthi group is also given.