Abstract
India has a long history of research on freshwater and marine Gastrotricha. In more than 110 years of study on Order Chaetonotida, two families consisting of 11 genera and 39 species have been described. Thirty of these species are taxa originally described from other continents, while only nine species (7 freshwater, 2 marine) are only known from India. The large percentage (77%) of so-called cosmopolitan species in India has contributed to the phenomenon known as the “meiofauna paradox”. However, a careful review of the pertaining literature provides a different biogeographical picture of the chaetonotidan fauna of India. Herein we show that the high incidence of European and North American species reported from India is mainly due to a mixture of misidentification and species lumping. In fact, for only 12 species there are enough data that would make the Indian specimens morphological similar to taxa previously reported from Europe and/or North America. However, without the appropriate molecular sequence data for comparison, there is no way to rule out the possibility of cryptic speciation.We conclude that further sampling throughout India and the use of more powerful microscopical techniques (e.g., DIC optics) and molecular sequencing will reveal more species and improve the quality of re-descriptions of those (9 spp.) that so far appear to be endemic to the subcontinent. Here we recommend six species to be excluded from the fauna of India while another 11 species (non endemic to India) should be considered dubitatively present in the Indian fauna.
References
Annandale, N. (1907) The fauna of brackish water ponds at Port Canning, lower Bengal. Records of the Indian Museum, 1, 35–43.
Balsamo, M. (1982) Three new gastrotrichs from a Tuscan-Emilian Apennine Lake. Bollettino di Zoologia, 49, 287–295. https://doi.org/10.1080/11250008209439402
Balsamo, M. (1983) Gastrotrichi. Consiglio Nazionale delle Ricerche, Guide per il riconoscimento delle specie animali delle acque interne italiane, 20, 1–92.
Bharti, D. & Kumar, S. (2019) First record of Lepidochaetus zelinkai (Gastrotricha Chaetonotida) from India. Records of Zoological Survey of India, 119 (4), 474–479.
Brunson, R.B. (1950) An introduction to the taxonomy of the Gastrotricha with a study of eighteen species from Michigan. Transactions of the American Microscopical Society, 69, 325–352. https://doi.org/10.2307/3223127
Chatterjee, T., Priyalakshmi, G. & Todaro, M.A. (2019) An annotated checklist of the macrodasyidan Gastrotricha from India. Zootaxa, 4545 (4), 495–510. https://doi.org/10.11646/zootaxa.4545.4.3
Dhanapathi, M.V.S.S.S. (1976) Taxonomic notes on some Gastrotricha from coastal Andhra Pradesh. Memoirs of the Society of Zoology of Guntur, 1, 76–78.
Egger, B., Lapraz, F., Tomiczek, B., Müller, S., Dessimoz, C, Girstmair, J., Škunca, N., Rawlinson, K.A., Cameron, C.B., Beli E., Todaro, M.A., Gammoudi, M., Noreña, C. & Telford, M.J. (2015) A transcriptomic-phylogenomic analysis of the evolutionary relationships of flatworms. Current Biology, 25, 1347–1353. https://doi.org/10.1016/J.Cub.2015.03.034
Ganapati, P.N. & Rao, G.C. (1967) On some marine interstitial gastrotrichs from the beach sands of Waltair coast. Proceeding of Indian Academy of Sciences, 66 B, 214–225.
Giere, O. (2009) Meiobentology: The microscopic motile fauna of aquatic sediments. Springer-Verlag, Berlin, 328 pp.
Greuter, A. (1917) Beiträge zur Systematik der Gastrotrichen in der Schweiz. Revue Suisse de Zoologie, 25, 35–76. https://doi.org/10.5962/bhl.part.31929
Harkal, A.D. & Mokashe, S.S. (2013) Record of two species of Gastrotricha from littoral epiphytic habitat of Kagzipura Lake, Aurangabad, Maharashtra, India. Research and Reviews: Journal of Ecology and Environmental Sciences, 1 (1), 27–29.
Harkal, A.D. & Mokashe, S.S. (2015) An assessment of periphytic fauna of Kagzipura Lake, District Aurangabad, Maharashtra, India. Journal of Basic Sciences, 1, 34–38.
Hummon, W.D. (2010) Global Distribution of Marine Gastrotricha. Available from: http://www.gastrotricha.unimore.it/checklist.htm (accessed 15 October 2018).
Hummon, W.D. & Todaro, M.A. (2010) Analytic taxonomy and notes on marine, brackish-water and estuarine Gastrotricha. Zootaxa, 2392 (1), 1–32. https://doi.org/10.11646/zootaxa.2392.1.1
Kånneby, T., Todaro, M.A. & Jondelius, U. (2009) One new species and records of Ichthydium Ehrenberg, 1830 (Gastrotricha: Chaetonotida) from Sweden with a key to the genus. Zootaxa, 2278 (1), 26–46. https://doi.org/10.11646/zootaxa.2278.1.2
Kånneby, T., Todaro, M.A. & Jondelius, U. (2012) A phylogenetic approach to species delimitation in freshwater Gastrotricha from Sweden. Hydrobiologia, 683, 185–202. https://doi.org/10.1007/s10750-011-0956-1
Kieneke, A. & Todaro, M.A. (2020) Discovery of two ‘chimeric’ Gastrotricha and their systematic placement based on an integrative approach. Zoological Journal of the Linnean Society. [published online] https://doi.org/10.1093/zoolinnean/zlaa117
Kisielewski, J. (1981) Gastrotricha from raised and transitional peat bogs in Poland. Monografie Fauny Polski, 11, 1–143.
Kisielewski, J. (1984) Three new freshwater gastrotrichs of the genus Chaetonotus Ehrenberg (Chaetonotida) from Poland. Bulletin De l’Académie Polonaise Des Sciences. Série Des Sciences Biologiques, 32, 293–301.
Kisielewski, J. (1991) Inland-water Gastrotricha from Brazil. Annales Zoologici, 43, 1–168.
Kisielewski, J. (1997) On the subgeneric division of the genus Chaetonotus Ehrenberg (Gastrotricha). Annales Zoologici, 46, 145–151.
Križanová, F. & Vďačný, P. (2021) Description of Lepidochaetustirjakovae sp. nov. (Gastrotricha: Paucitubulatina: Chaetonotidae), using morphology and DNA barcoding. Zoologischer Anzeiger, 292, 207–224. https://doi.org/10.1016/j.jcz.2021.04.003
Kulkarni, M.R., Padhye, S., Vanjare, A.I., Jakhalekar, S.S., Shinde, Y.S., Paripatyadar, S.V.,Sheth, S.D., Kulkarni, S., Phuge, S.K., Bhakare, K., Kulkarni, A.S., Pai, K. & Ghate, H.V. (2015) Documenting the fauna of a small temporary pond from Pune, Maharastra, India. Journal of Threatened Taxa, 7 (6), 7196–7210. https://doi.org/10.11609/JoTT.o4190.7196-210
Lad, D. & Patil, S. (2016) Diversity of intertidal meiobenthos from estuary of Bhayander and Naigaon, Thane, Maharashtra, India. International Journal of Recent Scientific Research, 52, 245–246.
Leasi, F. & Todaro, M.A. (2008) The muscular system of Musellifer delamarei (Renaud-Mornant, 1968) and other chaetonotidans with implications for the phylogeny and systematisation of the Paucitubulatina (Gastrotricha). Biological Journal of the Linnean Society, 94, 379–398.
Levi, C. (1950) Contribution a étude des gastrotriches de la region de Roscoff. Archives de Zoologie Experimentale and Générale, 87, 31–42.
Magpali, L., Machado, D.R.P., Araujo, T.Q., Andre, R.S. & Garraffoni, R.S. (2021) Long distance dispersal and pseudo-cryptic species in Gastrotricha: first description of a new species (Chaetonotida, Chaetonotidae, Polymerurus) from an oceanic island with volcanic rocks. European Journal of Taxonomy, 746, 62–93. https://doi.org/ejt.2021.746.1319
Naidu, K.V. (1962) Three species of Gastrotrichs from fresh Waters of Cuddapah, India. The Annals and Magazine of Natural History, Series 13, 5, 1–4. https://doi.org/10.1080/00222936208651207
Naidu, K.V. & Rao, G.C. (2004) Gastrotricha. In: Fauna of India and the adjacent countries. Zoological Survey of India, Kolkata, pp. 169.
Purushothaman, J. (2017) Gastrotricha. Chapter 8. In: Chandra, K., Gopi, K.C., Rao, D.V., Valarmathi, K. & Alfred, J.R.B. (Eds.), Current Status of Freshwater Faunal Diversity in India. Published by the Director, Zoological. Survey of India, Kolkata, pp. 8115–125.
Priyalakshmi, G. & Menon, N.R. (2012) Kerala - an abode of taxonomically challenging permanent meiofauna, Gastrotricha. Journal of the Marine Biology Association of India, 54, 61–64. https://doi.org/10.6024/jmbai.2012.54.2.01724-10
Rao, D.V.S. (2005) Comprehensive review of the records of the biota of the Indian sea and introduction of non-indigenous species. Aquatic conservation: Marine and Freshwater ecosystems, 15, 117–146. https://doi.org/10.1002/aqc.659
Rao, G.C. (1969) The marine interstitial fauna inhabiting the beach sands of Orissa coast. Journal of Zoological Society of India, 21, 89–104.
Rao, G.C. (1972) On the geographical distribution of interstitial fauna of marine beach sand. Proceedings of the Indian National Science Academy, 38B, 164–178.
Rao, G.C. (1980) On the zoogeography of the interstitial meiofauna of the Andaman and Nicobar Islands, Indian Ocean. Records of Zoological Survey of India, 77, 153–178.
Rao, G.C. (1989) Interstitial Meiofauna. In: State Fauna Series 1. Fauna of Orissa. Zoological Survey of India, Calcutta, pp. 20–32.
Rao, G.C. (1991) Meiofauna. In: State Fauna Series 2. Fauna of Lakshadweep. Zoological Survey of India, Calcutta, pp. 220.
Rao, G.C. (1993) Littoral meiofauna of little Andaman. Records of Zoological Survey of India, 155, 1–120.
Rao, G.C. & Ganapati P.N. (1968) The interstitial fauna inhabiting beach sands of Waltair coast. Proceedings of the National Institute of Sciences of India, 34B, 82–125.
Rao, R.K. & Mohan, P.C. (1977) New records of some Gastrotricha from India with notes on their ecology. Geobios, 4, 204–206.
Rao, R.K. & Mohan, P.C. (1984) Ichthydium auritum Brunson, 1950 (Gastrotricha), a new record for India. Geobios New Report, 3, 45–46.
Rao, R.K. & Mohan, P.C. (1987) Gastrotrich fauna of India with notes on their distribution. Uttar Pradesh Journal of Zoology, 7, 146–153.
Real, G.A. (1940) Esubrimiento de los Gastrotricos en aguas de Madrid. Anales de Ciencias Naturales, Madrid, 96–103
Remane, A. (1926) Morphologie und Verwandtschaftsbeziehungen der aberranten Gastrotrichen I . Zeitschrift für Morphologie und Ökologie der Tiere, 5, 625–754. https://doi.org/10.1007/BF00408293
Remane, A. (1934) Die Gastrotrichen des Küstengrundwassers von Schilksee. Schriften des Naturwissenschaftlichen Vereins für Schleswig Holstein, 20, 473–478.
Remane, A. (1936) Gastrotricha, In: Bronns, H.G. (Ed.), Klassen und Ordnungen des Tierreichs. Band 4. Abteilung II. Buch I. Teil 2. Liefrungen 1–2. Akademie Verlagsgesellschaft, Berlin, pp. 1–142.
Ruppert, E.E. (1979) Morphology and systematics of the Xenotrichulidae (Gastrotricha, Chaetonotida). Mikrofauna des Meeresbodens, 76, 1–56.
Sarma, N.S.R. & Mohan, P.C. (1981) On the ecology of the interstitial fauna inhabiting the Bhimlipatnam coast (Bay of Bengal). Mahasagar—Bulletin of the National Institute of Oceanography, 14, 257–263.
Schwank, P. (1990) Gastrotricha. In: Braur, A., Schwoerbel, J. & Zwick, P. (Eds.), Süsswasser Fauna von Mitteleuropa. Band 3. Heft 1. 2. Gastrotricha und Nemertini. Gustav Fischer Verlag, Stuttgart and Jenai, pp. i–xvi + 1–262.
Sharma, B.K. (1980) Taxonomic notes on some freshwater Gastrotricha from West Bengal, India. Hydrobiologia, 70, 265–267. https://doi.org/10.1007/BF00016769
Sharma, B.K. (1987) Gastrotricha (Freshwater). In: Fauna of Orissa. State Fauna Series 1, Zoological Survey of India, Calcutta, pp. 319–322.
Sharma B.K. & Sharma S. (1990) On some Freshwater Gastrotricha from N.E. Region. Records of the Zoological Survey of India, 86, 211–215.
Sharma, S. & Sharma, B.K. (2008) Zooplankton Diversity in Floodplain Lakes of Assam. Records of the Zoological Survey of India Occasional Paper, No. 290, 1–307.
Struck, T.H., Wey-Fabrizius, A.R., Golombek, A., Hering, L., Weigert, A., Bleidorn, C., Klebow, S., Iakovenko, N., Hausdorf, B., Petersen, M., Kück, P., Herlyn, H. & Hankeln, T. (2014) Platyzoan paraphyly based on phylogenomic data supports a noncoelomate ancestry of Spiralia. Molecular Biology and Evolution, 31, 1833–1849. https://doi.org/10.1093/molbev/msu143
Todaro, M.A., Fleeger, J.W., Hu, Y.P., Hrincevich, A.W. & Foltz, D.W. (1996) Are meiofauna species cosmopolitan? Morphological and molecular analysis of Xenotrichula intermedia (Gastrotricha: Chaetonotida). Marine Biology, 125, 735–742. https://doi.org/10.1007/BF00349256
Todaro, M.A., Perissinotto, R. & Bownes, S.J. (2013) Neogosseidae (Gastrotricha, Chaetonotida) from the iSimangaliso Wetland Park, KwaZulu-Natal, South Africa. Zookeys, 315, 77–94. https://doi.org/10.3897/zookeys.315.5593
Thorp, J.H. & Covich, A.P. (Eds.) (2001) Ecology and Classification of North American Freshwater Invertebrates. Academic Press, San Diego, California, 950 pp.
Visvesvara, G. (1963) On some Gastrotricha from India with description of two new species. Annals and Magazine of Natural History, 6, 435–443. https://doi.org/10.1080/00222936308651379
Visvesvara, G. (1964) On some Gastrotricha of genus Chaetonotus from India. Annals and Magazine of Natural History, 7, 209–216. https://doi.org/10.1080/00222936408651460
Weiss, M.J. (2001) Widespread hermaphroditism in freshwater gastrotrichs. Invertebrate Biology, 120, 308–341. https://doi.org/10.1111/j.1744-7410.2001.tb00040.x
Wilke, U. (1954) Mediterrane Gastrotrichen. Zoologische Jahrbücher. Abteilung für Systematik, Jena, 82, 497–550.
WoRMS (2021) Gastrotricha. Available from: http://www.marinespecies.org/aphia.php?p=taxdetails&id=114461 (accessed 15 July 2021).
Zelinka, C. (1889) Die Gastrotrichen. Eine Monographische Darstellung ihrer Anatomie, Biologie und Systematik. Zeitschrift für wissenschaftliche Zoologie, 49, 209–384.