Integrative description of Paramacrobiotus bengalensis sp. nov. (Tardigrada: Eutardigrada: Macrobiotidae), a new limno-terrestrial tardigrade species from the state of West Bengal, India

Keywords: Paramacrobiotus richtersi morphogroup, morphometry, new species, COI, 18S rRNA


Paramacrobiotus bengalensis sp. nov. was discovered in a moss sample collected from a tree in West Bengal, India. We describe this new species using detailed morphological and morphometric data obtained from phase contrast microscopy and scanning electron microscopy, along with molecular and phylogenetic data analyses. Due to the presence of a cap-like structure at the distal portion of egg processes, the new species showed the highest similarity with Paramacrobiotus garynahi (Kaczmarek, Michalczyk & Diduszko, 2005), Paramacrobiotus alekseevi (Tumanov, 2005), Paramacrobiotus filipi Dudziak, Stec & Michalczyk, 2020, Paramacrobiotus sagani Daza, Caicedo, Lisi & Quiroga, 2017, Paramacrobiotus vanescens (Pilato, Binda & Catanzaro, 1991) and Paramacrobiotus gadabouti Kayastha, Stec, Mioduchowska & Kaczmarek, 2023. However, it can be differentiated from them by some morphological and morphometric characteristics. The genetic data corroborated our phenotypic outcome further supporting the new species hypothesis.


Beasley C.W. & Miller W.R. 2007. Tardigrada of Xinjiang Uygur Autonomous Region, China. Journal of Limnology 66 (S1): 49–55.

Bertolani R. 2003. Thulinius, new generic name substituting for Thulinia Bertolani, 1981 (Tardigrada, Eutardigrada). Zootaxa 195 (1): 1–8.

Bertolani R., Rebecchi L. & Claxton S. 1996. Phylogenetic signifiance of egg shell variation in tardigrades. Zoological Journal of Linnnean Society 116 (1–2): 139–148.

Bertolani R., Guidetti R., Marchioro T., Altiero T., Rebecchi L. & Cesari M. 2014. Phylogeny of Eutardigrada: new molecular data and their morphological support lead to the identification of new evolutionary lineages. Molecular Phylogenetics and Evolution 76: 110–126.

Bhakare K. & Pai K. 2021. An overview of freshwater Tardigrada in Northern Western Ghats of India. Aquatic Ecology 55: 1327–1338.

Campbell L.I., Rota-Stabelli O., Edgecombe G.D., Marchioro T., Longhorn S.J., Telford M.J., Philippe H., Rebecchi L., Peterson K.J. & Pisani D. 2011. MicroRNAs and phylogenomics resolve the relationships of Tardigrada and suggest that velvet worms are the sister group of Arthropoda. Proceedings of the National Academy of Sciences 108 (38): 15920–15924.

Casquet J.T., Thebaud C. & Gillespie R.G. 2012. Chelex without boiling, a rapid and easy technique to obtain stable amplifiable DNA from small amounts of ethanol-stored spiders. Molecular Ecology Resources 12 (1): 136–141.

Coughlan K. & Stec D. 2019. Two new species of the Macrobiotus hufelandi complex (Tardigrada: Eutardigrada: Macrobiotidae) from Australia and India, with notes on their phylogenetic position. European Journal of Taxonomy 573: 1–38.

Daza A., Caicedo M., Lisi O. & Quiroga S. 2017. New records of tardigrades from Colombia with the description of Paramacrobiotus sagani sp. nov. and Doryphoribius rosanae sp. nov. Zootaxa 4362 (1): 29–50.

Degma P. & Guidetti R. 2009–2023. Actual Checklist of Tardigrada Species (2009–2023, Ver. 42). Available from [accessed 15 Jan. 2023].

Doyère M. 1840. Mémoire sur les tardigrades. Annales des Sciences naturelles Zoologie Sér. 2 14: 269–362. Available from [accessed 15 Jan. 2023].

Edgar R.C. 2004. MUSCLE: multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research 32 (5): 1792–1797.

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 (5): 294–299.

Gąsiorek P., Vončina K. & Ciosek J. 2021. New Indomalayan Nebularmis species (Heterotardigrada: Echiniscidae) provoke a discussion on its intrageneric diversity. Zoological Letters 7: 6.

Grimaldi de Zio S., D’Addabbo Gallo M., Morone de Lucia M.R. & D’Addabbo L. 1987. Marine Arthrotardigrada and Echiniscoidea (Tardigrada, Heterotardigrada) from the Indian Ocean. Bollettino di Zoologia 54 (4): 347–357.

Guidetti R., Rebecchi L. & Bertolani R. 2000. Cuticule structure and systematics of Macrobiotidae (Tardigrada: Eutardigrada). Acta Zoologica 81 (1): 27–36.

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 (4): 315–321.

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 (37–38): 2409–2426.

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.

Hall T.A. 1999. BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucleic Acids Symposium Series 41: 95–98.

Hoang D.T., Chernomor O., Von Haeseler A., Minh B.Q. & Vinh L.S. 2018. UFBoot2: improving the ultrafast bootstrap approximation. Molecular Biology and Evolution 35 (2): 518–522.

Kaczmarek Ł. & Michalczyk Ł. 2017. The Macrobiotus hufelandi roup (Tardigrada) revisited. Zootaxa 4363 (1): 101–123.

Kaczmarek Ł., Michalczyk Ł. & Diduszko D. 2005. Some tardigrades from Siberia (Russia, Baikal region) with a description of Macrobiotus garynahi sp. nov. (Eutardigrada: Macrobiotidae: richtersi group). Zootaxa 1053 (1): 35–45.

Kaczmarek Ł., Cytan J., Zawierucha K., Diduszko D. & Michalczyk Ł. 2014. Tardigrades from Peru (South America), with descriptions of three new species of Parachela. Zootaxa 3790 (2): 357–379.

Kaczmarek Ł., Gawlak M., Bartels P.J., Nelson D.R. & Roszkowska M. 2017. Revision of the genus Paramacrobiotus Guidetti et al., 2009 with the description of a new species, re-descriptions and a key. Annales Zoologici 67 (4): 627–656.

Kaczmarek Ł., Bartylak T., Stec D., Kulpa A., Kepel M., Kepel A. & Roszkowska M. 2020. Revisiting the genus Mesobiotus Vecchi et al. 2016 (Eutardigrada, Macrobiotidae) – remarks, updated dichotomous key and an integrative description of new species from Madagascar. Zoologischer Anzeiger 287: 121–146.

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 (Oxford, England) 33 (11): 1630–1638.

Katoh K. & Toh H. 2008. Recent developments in the MAFFT multiple sequence alignment program. Brief Bioinformatics 9 (4): 286–298.

Katoh K., Misawa K., Kuma K. & Miyata T. 2002. MAFFT: a novel method for rapid multiple sequence alignment based on fast Fourier transform. Nucleic Acids Research 30: 3059–3066.

Kayastha P., Stec D., Sługocki Ł., Gawlak M., Mioduchowska M. & Kaczmarek Ł. 2023. Integrative taxonomy reveals new, widely distributed tardigrade species of the genus Paramacrobiotus (Eutardigrada: Macrobiotidae). Scientific Reports 13 (1): 2196.

Lanfear R., Calcott B., Ho S.Y. & Guindon S. 2012. PartitionFinder: combined selection of partitioning schemes and substitution models for phylogenetic analyses. Molecular Biology and Evolution 29 (6): 1695–1701.

Lanfear R., Frandsen P.B., Wright A.M., Senfeld T. & Calcott B. 2016. PartitionFinder 2: new methods for selecting partitioned models of evolution for molecular and morphological phylogenetic analyses. Molecular Biology and Evolution 34 (3): 772–773.

Marley N.J., McInnes S.J. & Sands C.J. 2011. Phylum Tardigrada: a re-evaluation of the Parachela. Zootaxa 2819 (1): 51–64.

Maucci W. & Durante Pasa M.V. 1980. Tardigradi muscicoli delle Isole Andamane. Bollettino del Museo civico di Storia Naturale di Verona 7: 281–291.

Maucci W. & Ramazzotti G. 1981. Cornechiniscus gen. nov.: nuova posizione sistematica per i cosiddetti “Pseudechiniscus gruppo cornutus” con descrizione di una nuova specie (Tardigrada, Echiniscidae). Memorie dell’Istituto Italiano di Idrobiologia 39: 147–151.

Michalczyk Ł. & Kaczmarek Ł. 2003. A description of the new tardigrade Macrobiotus reinhardti (Eutardigrada, Macrobiotidae, harmsworthi group) with some remarks on the oral cavity armature within the genus Macrobiotus Schultze. Zootaxa 331 (1): 1–24.

Michalczyk Ł. & Kaczmarek Ł. 2013. The Tardigrada Register: a comprehensive online data repository for tardigrade taxonomy. Journal of Limnology 72 (S1): 175–181.

Minh B.Q., Schmidt H.A., Chernomor O., Schrempf D., Woodhams M.D., von Haeseler A. & Lanfear R. 2020. IQ-TREE 2: new models and efficient methods for phylogenetic inference in the genomic era. Molecular Biology and Evolution 37 (5): 1530–1534.

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.

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 (4): 785–793.

Murray J. 1907. Arctic Tardigrada, collected by William S. Bruce. Earth and Environmental Science Transactions of The Royal Society of Edinburgh 45 (3): 669–681.

Nelson D.R., Marley N.J. & Bertolani R. 1999. Re-description of the genus Pseudobiotus (Eutardigrada, Hypsibiidae) and of the new type species Pseudobiotus kathmanae sp. n. Zoologischer Anzeiger 238 (3/4): 311–318.

Nelson D.R., Guidetti R. & Rebecchi L. 2015. Phylum Tardigrada. In: Thorp J.H. & Covich A.P. (eds) Ecology and General Biology, Vol. 1. Freshwater Invertebrates: 347–380. Academic Press, London.

Pilato G. 1969. Evoluzione e nuova sistemazione degli Eutardigrada. Bollettino di Zoologia 36 (3): 327–345.

Pilato G. 1981. Analisi di nuovi caratteri nello studio degli Eutardigradi. Animalia 8: 51–57.

Pilato G. & Binda M.G. 2010. Definition of families, subfamilies, genera and subgenera of the Eutardigrada, and keys to their identification. Zootaxa 2404 (1): 1–52.

Pilato G. & Lisi O. 2011. Tenuibiotus, a new genus of Macrobiotidae (Eutardigrada). Zootaxa 2761 (1): 34–40.

Pilato G., Binda M.G. & Catanzaro R. 1991. Remarks on some tardigrades of the African fauna with the description of three new species of Macrobiotus Schultze 1834. Tropical Zoology 4 (2): 167–178.

Pilato G., Kiosya Y., Lisi O. & Sabella G. 2012. New records of Eutardigrada from Belarus with the description of three new species. Zootaxa 3179 (1): 39–60.

Prendini L., Weygoldt P. & Wheeler W.C. 2005. Systematics of the Damon variegatus group of African whip spiders (Chelicerata: Amblypygi): evidence from behaviour, morphology and DNA. Organisms Diversity & Evolution 5 (3): 203–236.

Puillandre N., Brouillet S. & Achaz G. 2021. ASAP: assemble species by automatic partitioning. Molecular Ecology Resources 21 (2): 609–620.

Ramazzotti G. 1956. Tre nuove specie di Tardigradi ed altre specie poco comuni. Atti della Società Italiana di Scienze Naturali 95 (3–4): 284–291.

Rambaut A., Drummond A.J., Xie D., Baele G. & Suchard M.A. 2018. Posterior summarization in Bayesian phylogenetics using Tracer 1.7. Systematic Biology 67 (5): 901–904.

Rao G.C. 1969. The marine interstitial fauna inhabiting the beach sands of Orissa coast. Journal of the Zoological Society of India 21 (1): 89–103.

Rao G.C. 1971. On two species of marine interstitial Tardigrada from the east coast of India. Proceedings of the Indian Academy of Science Section B 73: 53–57.

Rao G.C. 1975. The interstitial fauna in the intertidal sands of Andaman and Nicobar group of islands. Journal of the Marine Biological Association of India 17: 116–128.

Rao G.C. & Ganapati P.N. 1968. The interstitial fauna inhabiting the beach sands of Waltair coast. Proceedings of the Indian Academy of Science 34 (2): 82–125.

Richters F. 1926. Tardigrada. In: Kükenthal W. & Krumbach T. (eds) Handbuch der Zoologie Vol. 3: 58–61. Walter de Gruyter & Co., Berlin and Leipzig.

Ronquist F., Teslenko M., van der Mark P., Ayres D.L., Darling A., Höhna S., Larget B., Liu L., Suchard M.A. & Huelsenbeck J.P. 2012. MrBayes 3.2: efficient Bayesian phylogenetic inference and model choice across a large model space. Systematic Biology 61 (3): 539–542.

Schill RO., Forster F., Dandekar T. & Wolf N. 2010. Using compensatory base change analysis of internal transcribed spacer 2 secondary structures to identify three new species in Paramacrobiotus (Tardigrada). Organisms Diversity and Evolution 10 (4): 287–296.

Schultze K.A.S. 1834. Macrobiotus Hufelandii, animal e crustaceorum classe novum, reviviscendi post diuturnam asphyxiam et ariditatem potens. Curths.

Schulz E. 1951. Über Stygarctus bradypus n. g. n. sp., einen Tardigraden aus dem Küstengrundwasser, und seine phylogenetische Bedeutung. Kieler Meeresforschung 8 (1): 86–97.

Schuster R.O., Nelson D.R., Grigarick A.A. & Christenberry D. 1980. Systematic criteria of the Eutardigrada. Transactions of the American Microscopical Society 99 (3): 284–303.

Stec D. 2022. An integrative description of two new Mesobiotus species (Tardigrada: Eutardigrada: Macrobiotidae) with updated genus phylogeny. Zoological Studies 61: 85.

Stec D., Smolak R., Kaczmarek Ł. & Michalczyk Ł. 2015. An integrative description of Macrobiotus paulinae sp. nov. (Tardigrada: Eutardigrada: Macrobiotidae: hufelandi group) from Kenya. Zootaxa 4052 (5): 501–526.

Stec D., Gąsiorek P., Morek W., Kosztyła P., Zawierucha K., Michno K., Kaczmarek Ł., Prokop Z.M. & Michalczyk Ł. 2016a. Estimating optimal sample size for tardigrade morphometry. Zoological Journal of the Linnean Society 178 (4): 776–784.

Stec D., Morek W., Gąsiorek P., Kaczmarek Ł. & Michalczyk Ł. 2016b. Determinants and taxonomic consequences of extreme egg shell variability in Ramazzottius subanomalus (Biserov, 1985) (Tardigrada). Zootaxa 4208 (2): 176–188.

Stec D., Zawierucha K. & Michalczyk Ł. 2017. An integrative description of Ramazzottius subanomalus (Biserov, 1985) (Tardigrada) from Poland. Zootaxa 4300 (3): 403–420.

Stec D., Roszkowska M., Kaczmarek Ł. & Michalczyk Ł. 2018. Paramacrobiotus lachowskae, a new species of Tardigrada from Colombia (Eutardigrada: Parachela: Macrobiotidae). New Zealand Journal of Zoology 45 (1): 43–60.

Stec D., Dudziak M. & Michalczyk Ł. 2020a. Integrative descriptions of two new Macrobiotidae species (Tardigrada: Eutardigrada: Macrobiotoidea) from French Guiana and Malaysian Borneo. Zoological Studies 59: 23.

Stec D., Kristensen R.M. & Michalczyk Ł. 2020b. An integrative description of Minibiotus ioculator sp. nov. from the Republic of South Africa with notes on Minibiotus pentannulatus Londoño et al. 2017 (Tardigrada: Macrobiotidae). Zoologischer Anzeiger 286: 117–134. https://doi:10.1016/j.jcz.2020.03.007

Stec D., Krzywański Ł., Zawierucha K. & Michalczyk Ł. 2020c. Untangling systematics of the Paramacrobiotus areolatus species complex by an integrative redescription of the nominal species for the group, with multilocus phylogeny and species delineation within the genus Paramacrobiotus. Zoological Journal of the Linnean Society 188 (3): 694–716.

Stec D., Tumanov D.T. & Kristensen R.M. 2020d. Integrative taxonomy identifies two new tardigrade species (Eutardigrada: Macrobiotidae) from Greenland. European Journal of Taxonomy 614: 1–40.

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.

Sugiura K., Matsumoto M. & Kunieda T. 2022. Description of a model tardigrade Paramacrobiotus metropolitanus sp. nov.(Eutardigrada) from Japan with a summary of its life history, reproduction and genomics. Zootaxa 5134 (1): 92–112.

Suma H.R., Prakash S. & Eswarappa S.M. 2020. Naturally occurring fluorescence protects the eutardigrade Paramacrobiotus sp. from ultraviolet radiation. Biology Letters 16 (10): 20200391.

Tamura K., Stecher G. & Kumar S. 2021. MEGA11: molecular evolutionary genetics analysis version 11. Molecular Biology and Evolution 38 (7): 3022–3027.

Thulin G. 1928. Über die Phylogenie und das System der Tardigraden. Hereditas 11 (2–3): 207–266.

Tumanov D. 2005. Notes on the Tardigrada of Thailand, with a description of Macrobiotus alekseevi sp. nov. (Eutardigrada, Macrobiotidae). Zootaxa 980 (1): 1–16. https.//

Tumanov D. 2006. Five new species of the genus Milnesium (Tardigrada, Eutardigrada, Milnesiidae). Zootaxa 1122 (1): 1–23.

Tumanov D. 2007. Three new species of Macrobiotus (Eutardigrada, Macrobiotidae, tenuis-group) from Tien Shan (Kirghizia) and Spitsbergen. Journal of Limnology 66 (S1): 40–48.

Tumanov D. 2018. First data on the freshwater Tardigrada in India: a find of Pseudobiotus kathmanae in a small Himalayan lake. Zoosystematica Rossica 27 (2): 218–223.

Vaidya G., Lohman D.J. & Meier R. 2011. SequenceMatrix: concatenation software for the fast assembly of multi-gene datasets with character set and codon information. Cladistics 27 (2): 171–180.

Vecchi M., Stec D., Vuori T., Ryndov S., Chartrain J. & Calhim S. 2022. Macrobiotus naginae sp. nov., a new xerophilous tardigrade species from Rokua sand dunes (Finland). Zoological Studies 61: 22.

Vishnudattan N.K., Nandan S.B., Hansen J.G. & Jayachandran P.R. 2021. A new tardigrade species, Stygarctus keralensis sp. nov. (Arthrotardigrada: Stygarctidae) from the intertidal zone of Southwest coast of India. Zootaxa 4985 (3): 381–391.

White T.J., Bruns T., Lee S.J.W.T., Taylor J., Innis M.A., Gelfand D.H. & Sninsky J.J. 1990. PCR Protocols: A Guide to Methods and Applications.

Zawierucha K., Kolicka M. & Kaczmarek Ł. 2016. Re-description of the Arctic tardigrade Tenuibiotus voronkovi (Tumanov, 2007) (Eutardigrada; Macrobiotidea), with the first molecular data for the genus. Zootaxa 4196 (4): 498–510.

How to Cite
Basu, S., Babu, R., Siddique, A., & Purushothaman, J. (2023). Integrative description of Paramacrobiotus bengalensis sp. nov. (Tardigrada: Eutardigrada: Macrobiotidae), a new limno-terrestrial tardigrade species from the state of West Bengal, India . European Journal of Taxonomy, 890(1), 23–48.
Research article