Skip to main content Skip to main navigation menu Skip to site footer
Responsive image
Issue: Vol. 5679 No. 3: 14 Aug. 2025
Type: Article
Published: 2025-08-14
DOI: 10.11646/zootaxa.5679.3.5
Page range: 399-418
Abstract views: 45
PDF downloaded: 0

A new species of Sisubiotus (Tardigrada: Macrobiotidae) from northern Sweden with a key to the genus

Department of Zoology; Swedish Museum of Natural History; Box 50007; 104 05 Stockholm; Sweden
Tardigrada Diversity tardigrade Taxonomic Key Phylogeny Morphology new records

Abstract

The tardigrade community of a moss sample collected from the city of Kiruna in northern Sweden is assessed as part of a biodiversity survey aimed at cataloging Swedish Macrobiotidae. New records for the country, including the new species Sisubiotus splendidus sp. nov., are described using integrative morphological and molecular taxonomy. The new species differs from its congeners by the absence of granulation on the first pair of legs, the dentate lunules of the claws of the fourth pair of legs and by the pattern of areolae on the eggs. The egg morphologies of Sisubiotus are discussed and an identification key to the genus is presented.

 

References

  1. Atherton, S., Hulterström, J., Guidetti, R. & Jönsson, K.I. (2025) Three new species of Mesobiotus (Eutardigrada: Macrobiotidae) from Sweden with an updated phylogeny of the genus. Scientific Reports, 15, 4535. https://doi.org/10.1038/s41598-025-88063-8
  2. Bartels, P.J., Nelson, D.R. & Exline, R.P. (2011) Allometry and the removal of body size effects in the morphometric analysis of tardigrades. Journal of Zoological Systematics and Evolutionary Research, 49 (1), 17–25. https://doi.org/10.1111/j.1439-0469.2010.00593.x
  3. Bertolani, R. (1982) A new genus and five new species of Italian fresh-water tardigrades. Bollettino del Museo Civico di Storia Naturale, 114, 249–254.
  4. Bertolani, R. & Biserov, V.I. (1996) Leg and claw adaptations in soil tardigrades with erection of two new genera of Eutardigrada, Macrobiotidae: Pseudohexapodibius and Xerobiotus. Invertebrate Biology, 115, 299–304. https://doi.org/10.2307/3227019
  5. Bertolani, R., Cesari, M., Giovannini, I., Rebecchi, L., Guidetti, R., Kaczmarek, Ł. & Pilato, G. (2023) The Macrobiotus persimilis-polonicus complex (Eutardigrada, Macrobiotidae) another example of problematic species identification with the description of four new species. Organisms Diversity & Evolution, 23, 329–368. https://doi.org/10.1007/s13127-022-00599-z
  6. Bertolani, R., Rebecchi, L. & Claxton, S.K. (1996) Phylogenetic significance of egg shell variation in tardigrades. Zoological Journal of the Linnean Society, 116 (1–2), 139–148. https://doi.org/10.1111/j.1096-3642.1996.tb02339.x
  7. Binda, M.G. (1974) Tardigradi della Valtellina. Animalia, 1 (1–3), 210–216.
  8. Brandoli, S., Cesari, M., Massa, E., Vecchi, M., Rebecchi, L. & Guidetti, R. (2024) Diverse eggs, diverse species? Production of two egg morphotypes in Paramacrobiotus bifrons, a new eutardigrade species within the areolatus group. The European Zoological Journal, 91, 274–297. https://doi.org/10.1080/24750263.2024.2317465
  9. Dastych, H. (1973) Redescription of Macrobiotus spectabilis Thulin, 1928 (Tardigrada). Bulletin of the Polish Academy of Sciences Technical Sciences, 21 (12), 823–825.
  10. Degma, P. & Guidetti, R. (2024) Actual checklist of Tardigrada species. https://doi.org/10.25431/11380_1178608
  11. Doyère, L.M.F. (1840) Mémoire sur les Tardigrade. Annales des Sciences Naturelles, Zoologie, Series 2, 14, 269–362.
  12. Durante Pasa, M.V. & Maucci, W. (1979) Tardigradi muscicoli della Grecia. Zeszyty Naukowe Uniwersytetu Jagiellońskiego, Prace Zoologiczne, 5, 19–45.
  13. Edgar, R.C. (2004) MUSCLE: multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research, 32, 1792–1797. https://doi.org/10.1093/nar/gkh340
  14. Folmer, O., Black, M., Hoeh, W., Lutz, R. & Vrijenhoek, R. (1994) DNA primers for amplification of mitochondrial cytochrome c oxidase subunit I from diverse metazoan invertebrates. Molecular Marine Biology and Biotechnology, 3, 294–299.
  15. Gąsiorek, P., Stec, D., Zawierucha, K., Kristensen, R.M. & Michalczyk, Ł. (2018) Revision of Testechiniscus Kristensen, 1987 (Heterotardigrada: Echiniscidae) refutes the polar-temperate distribution of the genus. Zootaxa, 4472 (2), 261–297. https://doi.org/10.11646/zootaxa.4472.2.3
  16. Giribet, G., Carranza, S., Baguñà, J., Riutort, M. & Ribera, C. (1996) First molecular evidence for the existence of a Tardigrada + Arthropoda clade. Molecular Biology and Evolution, 13, 76–84. https://doi.org/10.1093/oxfordjournals.molbev.a025573
  17. Guidetti, R., Cesari, M., Bertolani, R., Altiero, T. & Rebecchi, L. (2019) High diversity in species reproductive modes and distribution within the Paramacrobiotus richtersi complex (Eutardigrada, Macrobiotidae). Zoological Letters, 5, 1–28. https://doi.org/10.1186/s40851-018-0113-z
  18. Guidetti, R., Jönsson, K.I. & Kristensen, R.M. (2025) Checklist of Swedish tardigrades 2015–2025. Version 2: 00-00-2025. Available from: http://www.hkr.se/swedishtardigrades (accessed 28 March 2025)
  19. Guidetti, R., Peluffo, J.R., Rocha, A.M., Cesari, M. & Moly de Peluffo, M.C. (2013) The morphological and molecular analyses of a new South American urban tardigrade offer new insights on the biological meaning of the Macrobiotus hufelandi group of species (Tardigrada: Macrobiotidae). Journal of Natural History, 47, 2409–2426. https://doi.org/10.1080/00222933.2013.800610
  20. Guidetti, R., Schill, R.O., Bertolani, R., Dandekar, T. & Wolf, M. (2009) New molecular data for tardigrade phylogeny, with the erection of Paramacrobiotus gen. nov. Journal of Zoological Systematics and Evolutionary Research, 47, 315–321. https://doi.org/10.1111/j.1439-0469.2009.00526.x
  21. Guil, N., Jørgensen, A. & Kristensen, R. (2018) An upgraded comprehensive multilocus phylogeny of the Tardigrada tree of life. Zoological Scripta, 48 (1), 1–18. https://doi.org/10.1111/zsc.12321
  22. Johansson, C., Miller, W.R., Linder, E.T., Adams, B.J. & Boreliz-Alvarado, E. (2013) Tardigrades of Alaska: Distribution patterns, diversity and species richness. Polar Research, 32 (1), 18793. https://doi.org/10.3402/polar.v32i0.18793
  23. Kaczmarek, Ł. & Michalczyk, Ł. (2017) The Macrobiotus hufelandi (Tardigrada) group revisited. Zootaxa, 4363 (1), 101–123. https://doi.org/10.11646/zootaxa.4363.1.4
  24. Kaczmarek, Ł., Roszkowska, M., Poprawa, I., Janelt, K., Kmita, H., Gawlak, M., Fiałkowska, E. & Mioduchowska, M. (2020) Integrative description of bisexual Paramacrobiotus experimentalis sp. nov. (Macrobiotidae) from republic of Madagascar (Africa) with microbiome analysis. Molecular Phylogenetics and Evolution, 145, 106730. https://doi.org/10.1016/j.ympev.2019.106730
  25. Kalyaanamoorthy, S., Minh, B., Wong, T., von Haeseler, A. & Jermiin, L.S. (2017) ModelFinder: Fast model selection for accurate phylogenetic estimates. Nature Methods, 14, 587–589. https://doi.org/10.1038/nmeth.4285
  26. Kapli, P., Lutteropp, S., Zhang, J., Kobert, K., Pavlidis, P., Stamatakis, A. & Flouri, T. (2017) Multi-rate Poisson tree processes for single-locus species delimitation under maximum likelihood and Markov chain Monte Carlo. Bioinformatics, 33, 1630–1638. https://doi.org/10.1093/bioinformatics/btx025
  27. Kihm, J.H., Kim, S., McInnes, S.J., Zawierucha, K., Rho, H.S., Kang, P. & Park, T.S. (2020) Integrative description of a new Dactylobiotus (Eutardigrada: Parachela) from Antarctica that reveals an intraspecific variation in tardigrade egg morphology. Scientific Reports, 10, 9122. https://doi.org/10.1038/s41598-020-65573-1
  28. Kiosya, Y., Pogwizd, J., Matsko, Y., Vecchi, M. & Stec, D. (2021) Phylogenetic position of two Macrobiotus species with a revisional note on Macrobiotus sottilei Pilato, Kiosya, Lisi & Sabella, 2012 (Tardigrada: Eutardigrada: Macrobiotidae). Zootaxa, 4933 (1), 113–135. https://doi.org/10.11646/zootaxa.4933.1.5
  29. Kumar, S., Stecher, G., Li, M., Knyaz, C. & Tamura, K. (2018) MEGA X: molecular evolutionary genetics analysis across computing platforms. Molecular Biology and Evolution, 35, 1547–1549. https://doi.org/10.1093/molbev/msy096
  30. Maucci, W. & Pilato, G. (1974) Macrobiotus spectabilis Thulin, 1928 e Macrobiotus grandis Richters, 1911: Due buone specie di Eutardigradi. Animalia, 1 (1–3), 245–255.
  31. Massa, E., Guidetti, R., Cesari, M., Rebecchi, L. & Jönsson, K.I. (2021) Tardigrades of Kristianstads Vattenrike Biosphere Reserve with description of four new species from Sweden. Scientific Reports, 11 (1), 4861. https://doi.org/10.1038/s41598-021-83627-w
  32. McInnes, S.J. (1994) Zoogeographic distribution of terrestrial/freshwater tardigrades from current literature. Journal of Natural History, 28 (2), 257–352. https://doi.org/10.1080/00222939400770131
  33. Michalczyk, Ł. & Kaczmarek, Ł. (2013) The Tardigrada Register: A comprehensive online data repository for tardigrade taxonomy. Journal of Limnology, 72, 175–181. https://doi.org/10.4081/jlimnol.2013.s1.e22
  34. Mironov, S.V., Dabert, J. & Dabert, M. (2012) A new feather mite species of the genus Proctophyllodes Robin, 1877 (Astigmata: Proctophyllodidae) from the Long-tailed Tit Aegithalos caudatus (Passeriformes: Aegithalidae): morphological description with DNA barcode data. Zootaxa, 3253 (1), 54–61. https://doi.org/10.11646/zootaxa.3253.1.2
  35. Morek, W., Stec, D., Gąsiorek, P., Schill, R.O., Kaczmarek, Ł. & Michalczyk, Ł. (2016) An experimental test of eutardigrade preparation methods for light microscopy. Zoological Journal of the Linnean Society, 178, 785–793. https://doi.org/10.1111/zoj.12457
  36. Nelson, D.R., Guidetti, R. & Rebecchi, L. (2015) Phylum Tardigrada. In: Thorp, J. & Rogers, D.C. (Eds.), Thorp and Covich’s Freshwater Invertebrates. 4th Revised Edition. Academic Press, New York, New York, pp. 347–380. https://doi.org/10.1016/B978-0-12-385026-3.00017-6
  37. Nowak, B. & Stec, D. (2018) An integrative description of Macrobiotus hannae sp. nov. (Tardigrada: Eutardigrada: Macrobiotidae: hufelandi group) from Poland. Turkish Journal of Zoology, 42, 269–286. https://doi.org/10.3906/zoo-1712-31
  38. Pilato, G. & Binda, M.G. (1983) Descrizione du una nuova specie di Eutardigrado d’Australia Macrobiotus joannae n. sp. Animalia, 10, 262–272.
  39. Pilato, G. (1981) Analisi di nuovi caratteri nello studio degli Eutardigradi. Animalia, 8, 51–57.
  40. Pilato, G. & Binda, M.G. (2010) Definition of families, subfamilies, genera and subgenera of the Eutardigrada and keys to their identification. Zootaxa, 2404 (1), 1–54. https://doi.org/10.11646/zootaxa.2404.1.1
  41. Pilato, G. & Lisi, O. (2011) Tenuibiotus, a new genus of Macrobiotidae (Eutardigrada). Zootaxa, 2761 (1), 34–40. https://doi.org/10.11646/zootaxa.2761.1.2
  42. Richters, F. (1911) Faune des mousses. Tardigrades. Duc d’Orleans. Campagne arctique de 1907. Imprimerie Scientifique, Bruxelles, 20 pp.
  43. Richters, F. (1926) Tardigrada. In: Kükenthal, W. & Krumbach, T. (Eds.), Handbuch der Zoologie. Vol. 3. Walter de Gruyter & Co., Berlin & Leipzig, pp. 1–68.
  44. Sands, C.J., Convey, P., Linse, K. & McInnes, S. (2008) Assessing meiofaunal variation among individuals utilising morphological and molecular approaches: An example using the Tardigrada. BMC Ecology, 8, 7. https://doi.org/10.1186/1472-6785-8-7
  45. Schill, R.O., Förster, F., Dandekar, T. & Wolf, M. (2010) Using compensatory base change analysis of internal transcribed spacer 2 secondary structures to identify three new species in Paramacrobiotus (Tardigrada). Organism Diversity and Evolution, 10, 287–296. https://doi.org/10.1007/s13127-010-0025-z
  46. Schultze, C.A.S. (1834) Macrobiotus hufelandii animal e crustaceorum classe novum, reviviscendi post diuturnam asphyxia et ariditaten potens, etc. C. Curths, 8 pp., 1 tab (pp. 6).
  47. Schuster, R.O., Nelson, D.R., Grigarick, A.A. & Christenberry, D. (1980) Systematic Criteria of the Eutardigrada. Transactions of the American Microscopical Society, 99, 284. https://doi.org/10.2307/3226004
  48. Stec, D., Tumanov, D.T. & Kristensen, R.M. (2020) Integrative taxonomy identifies two new tardigrade species (Eutardigrada: Macrobiotidae) from Greenland. European Journal of Taxonomy, 614, 1–40. https://doi.org/10.5852/ejt.2020.614
  49. Stec, D., Vecchi, M., Calhim, S. & Michalczyk, Ł. (2021) New multilocus phylogeny reorganises the family Macrobiotidae (Eutardigrada) and unveils complex morphological evolution of the Macrobiotus hufelandi group. Molecular Phylogenetics and Evolution, 160, 106987. https://doi.org/10.1016/j.ympev.2020.106987
  50. Thulin, G. (1928) Über die Phylogenie und das System der Tardigraden. Hereditas, 11, 207–266. https://doi.org/10.1111/j.1601-5223.1928.tb02488.x
  51. Trifinopoulos, J., Nguyen, L.T., von Haeseler, A. & Minh, B.Q. (2016) W-IQ-TREE: A fast online phylogenetic tool for maximum likelihood analysis. Nucleic Acids Research, 44, W232–W235. https://doi.org/10.1093/nar/gkw256
  52. Vecchi, M., Cesari, M., Bertolani, R., Jönsson, K.I., Rebecchi, L. & Guidetti, R. (2016) Integrative systematic studies on tardigrades from Antarctica identify new genera and new species within Macrobiotoidea and Echiniscoidea. Invertebrate Systematics, 30, 303–322. https://doi.org/10.1071/IS15033
  53. Vecchi, M., Choong, H. & Calhim, S. (2022) Sisubiotus hakaiensis sp. nov. (Tardigrada, Macrobiotidae), a new tardigrade species from Calvert Island (British Columbia, Canada). European Journal of Taxonomy, 823, 64–81. https://doi.org/10.5852/ejt.2022.823.1815
  54. Vecchi, M. & Stec, D. (2021) Integrative descriptions of two new Macrobiotus species (Tardigrada, Eutardigrada, Macrobiotidae) from Mississippi (USA) and Crete (Greece). Zoosystematics and Evolution, 97, 281–306. https://doi.org/10.3897/zse.97.65280
  55. Vincenzi, J., Cesari, M., Kaczmarek, Ł., Roszkowska, M., Mioduchowska, M., Rebecchi, L., Kiosya, Y. & Guidetti, R. (2024) The xerophilic genera Xerobiotus and Pseudohexapodibius (Macrobiotidae; Tardigrada): Biodiversity, biogeography and phylogeny. Zoological Journal of the Linnean Society, 200, 111–141. https://doi.org/10.1093/zoolinnean/zlad129
  56. Vuori, T., Massa, E., Calhim, S. & Vecchi, M. (2020) Tardigrades of Finland: New records and an annotated checklist. Zootaxa, 4851 (3), 477–521. https://doi.org/10.11646/zootaxa.4851.3.3
  57. Zhang, P. & Sun, X. (2014) A new species of the genus Macrobiotus (Tardigrada: Macrobiotidae) from Southeastern China. Zoological Systematics, 39 (2), 224–228.

How to Cite

Atherton, S. (2025) A new species of Sisubiotus (Tardigrada: Macrobiotidae) from northern Sweden with a key to the genus. Zootaxa, 5679 (3), 399–418. https://doi.org/10.11646/zootaxa.5679.3.5