A1 Journal article (refereed)
Integrative taxonomy resolves species identities within the Macrobiotus pallarii complex (Eutardigrada: Macrobiotidae) (2021)

Stec, D., Vecchi, M., Dudziak, M., Bartels, P. J., Calhim, S., & Michalczyk, Ł. (2021). Integrative taxonomy resolves species identities within the Macrobiotus pallarii complex (Eutardigrada: Macrobiotidae). Zoological Letters, 7, Article 9. https://doi.org/10.1186/s40851-021-00176-w

JYU authors or editors

Publication details

All authors or editorsStec, Daniel; Vecchi, Matteo; Dudziak, Magdalena; Bartels, Paul J.; Calhim, Sara; Michalczyk, Łukasz

Journal or seriesZoological Letters


Publication year2021

Publication date27/05/2021


Article number9

PublisherBiomed Central

Publication countryUnited Kingdom

Publication languageEnglish


Publication open accessOpenly available

Publication channel open accessOpen Access channel

Publication is parallel published (JYX)https://jyx.jyu.fi/handle/123456789/76081


The taxonomy of many groups of meiofauna is challenging due to their low number of diagnostic morphological characters and their small body size. Therefore, with the advent of molecular techniques that provide a new source of traits, many cryptic species have started to be discovered. Tardigrades are not an exception, and many once thought to be cosmopolitan taxa are being found to be complexes of phenotypically similar species. Macrobiotus pallarii Maucci, 1954 was originally described in South Italy and has been subsequently recorded in Europe, America, and Asia. This allegedly wide geographic range suggests that multiple species may be hidden under this name. Moreover, recently, genetic evidence to support this was put forward, and the Macrobiotus pallarii complex has been proposed to accommodate putative species related to M. pallarii. Here, we describe three new pseudocryptic species based on populations that would have been all classified as Macrobiotus pallarii if molecular methods were not employed. Using an integrative taxonomy approach, we analyzed animals and eggs from the topotypic population of Macrobiotus pallarii, together with four other populations of the complex. We recovered four distinct phylogenetic lineages that, despite the overlap of morphometric traits, can be separated phenotypically by subtle but discrete morphological characters. One lineage corresponds to Macrobiotus pallarii, whereas the other three are newly described as Macrobiotus margoae Stec, Vecchi & Bartels, sp. nov. from the USA, Macrobiotus ripperi Stec, Vecchi & Michalczyk, sp. nov. from Poland and Finland, and Macrobiotus pseudopallarii Stec, Vecchi & Michalczyk, sp. nov. from Montenegro. To facilitate species identification, we provide a dichotomous key for species of the M. pallarii complex. Delimitation of these pseudocryptic taxa highlights the need for an integrative approach to uncover the phylum’s diversity in full.

KeywordsTardigradasystematicsphylogeneticsdetermination of speciesDNADNA barcodes

Free keywordscryptic taxa; DNA barcoding; egg ornamentation; new species; species complex; species delimitation

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Ministry reportingYes

Reporting Year2021

JUFO rating1

Last updated on 2024-22-04 at 18:58