Vol. 61, 2022

(update: 2022.12.15)

An Integrative Description of Two New Mesobiotus Species (Tardigrada: Eutardigrada: Macrobiotidae) with Updated Genus Phylogeny

^1,*

¹Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, Poland. *Correspondence: E-mail: daniel.stec@isez.pan.krakow.pl

Received 21 August 2022 / Accepted 15 October 2022
Communicated by Benny K.K. Chan

This work presents two new Mesobiotus species from the Republic of South Africa, formally described using integrative analyses. Specimens of the new species are examined in terms of morphology and morphometry under a contrast phase light microscope (PCM) and scanning electron microscope (SEM). For both new species, genetic data in the form of DNA sequences of commonly used molecular markers are also provided (18S rRNA, 28S rRNA, COI, ITS-2). Furthermore, such genetic data are also provided for the first time for Mesobiotus peterseni (Maucci, 1991) from Greenland. The study also presents a multilocus molecular phylogeny of the genus and an elaborated discussion on the taxa groupings and species composition. This results in the ratification of three informal morpho-groups in order to ease and improve communication in further taxonomic studies on the genus. Finally, an updated key to all valid nominal Mesobiotus taxa (71 species) is provided to enhance species identification in this morphologically diverse group of limno-terrestrial tardigrades.

Key words: Egg ornamentation, Integrative taxonomy, Mesobiotus diegoi sp. nov., Mesobiotus maklowiczi sp. nov., Tardigrades.

Citation: Stec D. 2022. An integrative description of two new Mesobiotus species (Tardigrada: Eutardigrada: Macrobiotidae) with updated genus phylogeny. Zool Stud 61:85. doi:10.6620/ZS.2022.61-85.

Supplementary materials: SM. 1丨SM. 2丨SM. 3