Skip to main content Skip to main navigation menu Skip to site footer
Responsive image
Issue: Vol. 5752 No. 2: 27 Jan. 2026
Type: Article
Published: 2026-01-27
DOI: 10.11646/zootaxa.5752.2.7
Page range: 285-294
Abstract views: 52
PDF downloaded: 1

Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India—A significant contribution after a quarter of a century

Zoological Survey of India (Ministry of Environment; Forest and Climate Change; Government of India); FPS Building; Indian Museum Campus; 27 JL Nehru Road; Kolkata-700016; India
Oligochaetology Laboratory; Kitchener; Ontario; N2A 4E1 Canada and New Brunswick Museum; Saint John; New Brunswick; E2K 1E5; Canada
Zoological Survey of India (Ministry of Environment; Forest and Climate Change; Government of India); FPS Building; Indian Museum Campus; 27 JL Nehru Road; Kolkata-700016; India
School of Biological Sciences; National Institute of Science Education and Research (NISER); Bhubaneswar; An OCC of Homi Bhabha National Institute; Bhubaneswar; 752050; Odisha; India
Zoological Survey of India (Ministry of Environment; Forest and Climate Change; Government of India); FPS Building; Indian Museum Campus; 27 JL Nehru Road; Kolkata-700016; India
Zoological Survey of India (Ministry of Environment; Forest and Climate Change; Government of India); FPS Building; Indian Museum Campus; 27 JL Nehru Road; Kolkata-700016; India
Annelida earthworm India Tonoscolex monorchis taxonomy darjeeling West Bengal

Abstract

The species Tonoscolex monorchis (Stephenson, 1916) was originally described from a single immature specimen collected from Darjeeling district, West Bengal, India. It remains a subject of discussion due to its metandric condition (testes present only in segment 9) and the presence of three pairs of seminal vesicles in segments 10, 11, and 12. Since the original description, one more record was documented with a brief description and without any significant contribution to the taxonomy of the species (Halder, 1999a). In this study, the species is redescribed and illustrated based on fresh collections from Tamsing forest, Darjeeling district, West Bengal, marking a significant contribution to the understanding of the species. Additionally, a brief description and an identification key to the Indian Tonoscolex species are provided to support future research in this field.

 

References

  1. Ahmed, S., Emiliyamma, K.G., Marimuthu, N., Sajan, S. & Julka, J.M. (2022) A new species of the genus Tonoscolex Gates, 1933 (Clitellata: Megascolecidae) from India. Zootaxa, 5124 (3), 375–382. https://doi.org/10.11646/zootaxa.5124.3.6
  2. Ahmed, S., Banerjee, D. & Marimuthu, N. (2025) Two new earthworm species of the genera Eutyphoeus Michaelsen, 1900 and Priodoscolex Gates, 1940 (Crassiclitellata: Acanthodrilidae) from India. Zootaxa, 5609 (2), 236–248. https://doi.org/10.11646/zootaxa.5609.2.5
  3. Bhadauria, T. & Ramakrishnan, P.S. (1989) Earthworm population dynamics and contribution to nutrient cycling during cropping and fallow phases of shifting agriculture (jhum) in north-east India. Journal of Applied Ecology, 26, 505–520. https://doi.org/10.2307/2404077
  4. Blakemore, R.J. (2006) Checklist of Myanmar taxa updated from Gates’ (1972) “Burmese Earthworms”. In: A Series of Searchable Texts on Earthworm Biodiversity, Ecology and Systematics from Various Regions of the World. 2nd Edition. COE Soil Ecology Research Group, Yokohama National University, Yokohama, pp. 1–21.
  5. Csuzdi, C., Szederjesi, T., Win, T.M., Cho, N. & Aye, M.M. (2015) Data to the earthworm fauna of Myanmar with notes on some little-known species (Annelida: Oligochaeta). Opuscula Zoologica Budapest, 46 (2), 177–182. https://doi.org/10.18348/opzool.2015.2.177
  6. Dash, M.C. & Senapati, B.K. (1986) Vermitechnology, an option for organic waste management in India. In: Dash, M.C., Senapati, B.K. & Mishra, P.C. (Eds.), Vermes and Vermicomposting. School of Life Sciences, Sambalpur University, Odisha, pp. 157–172.
  7. Gates, G.E. (1933) The earthworms of Burma. IV. Records of the Indian Museum, 35, 413–606. https://doi.org/10.26515/rzsi/v35/i4/1933/162584
  8. Gates, G.E. (1934) Notes on some earthworms from the Indian Museum. Records of the Indian Museum, 36, 233–277. https://doi.org/10.26515/rzsi/v36/i3/1934/162933
  9. Gates, G.E. (1936) The earthworms of Burma. V. Records of the Indian Museum, 38, 377–468. https://doi.org/10.26515/rzsi/v38/i4/1936/162306
  10. Gates, G.E. (1945) On some Indian earthworms. II. Journal of the Royal Asiatic Society of Bengal, 11, 54–91.
  11. Gates, G.E. (1972) Burmese earthworms: An introduction to the systematics and biology of megadrile oligochaetes with special reference to Southeast Asia. Transactions of the American Philosophical Society, 62, 1–326. https://doi.org/10.2307/1006214
  12. Grube, A.E. (1850) Die Familien der Anneliden. Archiv für Naturgeschichte, 16, 249–364.
  13. Halder, K.R. (1999a) Annelida: Oligochaeta: Earthworms. In: State Fauna Series 3. Fauna of West Bengal. Part 10. Zoological Survey of India, Calcutta, pp. 17–93.
  14. Halder, K.R. (1999b) Oligochaeta: Earthworm. In: State Fauna Series 4. Fauna of Meghalaya. Part 9. Zoological Survey of India, Calcutta, pp. 393–439.
  15. Halder, K.R., Dhani, S. & Mandal, C.K. (2007) On some earthworms present in unnamed collections of Zoological Survey of India. Records of the Zoological Survey of India, 107, 79–93. https://doi.org/10.26515/rzsi/v107/i3/2007/159128
  16. Howmiller, R.P. & Beeton, A.M. (1971) Biological evaluation of environmental quality, Green Bay, Lake Michigan. Journal of Water Pollution Control Federation, 42 (3), 123–133. [https://www.jstor.org/stable/25036868]
  17. Julka, J.M. (1976) Studies on the earthworms collected during the Daphabum expedition in Arunachal Pradesh, India. Records of the Zoological Survey of India, 69, 229–239. https://doi.org/10.26515/rzsi/v69/i1-4/1971/161410
  18. Julka, J.M. (1977) Contribution to the knowledge of earthworm fauna (Oligochaeta: Annelida) of Meghalaya. Newsletter of the Zoological Survey of India, 3, 398–400.
  19. Julka, J.M. (1981) Taxonomic studies on the earthworms collected during the Subansiri expedition in Arunachal Pradesh, India. Records of the Zoological Survey of India, 26, 1–53.
  20. Julka, J.M. (1988) The Fauna of India and Adjacent Countries: Megadrile Oligochaeta (Earthworms). Haplotaxida: Lumbricina: Megascolecoidea: Octochaetidae. Zoological Survey of India, Calcutta, 400 pp.
  21. Jamieson, B.G.M. (1988) On the phylogeny and higher classification of the Oligochaeta. Cladistics, 4, 367–410. https://doi.org/10.1111/j.1096-0031.1988.tb00520.x
  22. Kharkongor, I.J. (2018) Taxonomic and ecological studies on the earthworms (Annelida: Oligochaeta) of West Khasi Hills District, Meghalaya. Records of the Zoological Survey of India, 118, 56–74. https://doi.org/10.26515/rzsi/v118/i1/2018/123034
  23. Lavelle, P., Decaëns, T., Aubert, M., Barot, S., Blouin, M., Bureau, F. & Rossi, J.P. (2006) Soil invertebrates and ecosystem services. European Journal of Soil Biology, 42, S3–S15. https://doi.org/10.1016/j.ejsobi.2006.10.002
  24. Martins, R.T., Stephan, N.N.C. & Alves, R.G. (2008) Tubificidae (Annelida: Oligochaeta) as an indicator of water quality in an urban stream in southeast Brazil. Acta Limnologica Brasiliensia, 20 (3), 221–226.
  25. Michaelsen, W. (1919) Über die Beziehungen der Hirudineen zu den Oligochäten. Mitteilungen aus dem Hamburgischen Zoologischen Museum und Institut, 36, 131–153.
  26. Narayanan, S.P., Paliwal, R., Kurien, V.T., Thomas, A.P. & Julka, J.M. (2023) Earthworms (Clitellata: Moniligastrida, Crassiclitellata) of India: Distribution and Status. Department of Printing and Publishing, Mahatma Gandhi University, Kottayam, 378 pp.
  27. Özdemir, A., Duran, M. & Şen, A. (2011) Potential use of the oligochaete Limnodrilus profundicola (Verrill, 1871) as a bioindicator of contaminant exposure. Environmental Toxicology, 26 (1), 37–44. https://doi.org/10.1002/tox.20526
  28. Pelosi, C. & Römbke, J. (2016) Are Enchytraeidae (Oligochaeta, Annelida) good indicators of agricultural management practices? Soil Biology and Biochemistry, 100, 255–263. https://doi.org/10.1016/j.soilbio.2016.06.030
  29. Reynolds, J.W. & Eggen, A.B. (1993) Earthworm biology and vermicomposting I. Sir Sandford Fleming College, Lindsay, 72 pp.
  30. Rosa, D. (1891) Die exotischen Terricolen des k. k. naturhistorischen Hofmuseums. Annalen des K. K. Naturhistorischen Hofmuseums, Wien, 6, 379–406. [https://biodiversitylibrary.org/page/5374870]
  31. Stephenson, J. (1914) Zoological results of the Abor Expedition, 1911–1912, XXIX. Oligochaeta. Records of the Indian Museum, 8, 365–410. https://doi.org/10.5962/bhl.part.1193
  32. Stephenson, J. (1916) On a collection of Oligochaeta belonging to the Indian Museum. Records of the Indian Museum, 12, 299–354. https://doi.org/10.26515/rzsi/v12/i7/1916/163025
  33. Stephenson, J. (1922) Some earthworms from Kashmir, Bombay, and other parts of India. Records of the Indian Museum, 24, 427–443. https://doi.org/10.26515/rzsi/v24/i4/1922/162710
  34. Stephenson, J. (1923) The Fauna of British India, including Ceylon and Burma: Oligochaeta. Taylor & Francis, London, 518 pp.
  35. Tiwari, N., Paliwal, R., Rashid, A. & Yadav, S. (2020) Checklist of earthworm species (Oligochaeta) of the North Eastern Region of India. Zootaxa, 4772 (2), 277–305. https://doi.org/10.11646/zootaxa.4772.2.3
  36. Velki, M. & Ecimović, S. (2017) Earthworms as a suitable organism for soil pollution monitoring: possibilities and limitations. In: Horton, C.G. (Ed.), Earthworms: Types, Roles and Research. Nova Science Publishers, New York, New York, pp. 179–206.
  37. Wang, A.R., Hong, Y., Win, T.M. & Kim, I. (2015) Complete mitochondrial genome of the Burmese giant earthworm, Tonoscolex birmanicus (Clitellata: Megascolecidae). Mitochondrial DNA, 26 (3), 467–468. https://doi.org/10.3109/19401736.2013.830300
  38. Weber, G.B.C. (2007) The role of earthworms as biological indicators of soil contamination. Bulletin of the University of Agricultural Sciences and Veterinary Medicine, Calea Mănăştur, 68 (1–2), 63–64.

How to Cite

Hasan, M.N., Reynolds, J.W., Ahmed, S., Ghosh, S., Mandal, C.K. & Kosygin, L. (2026) Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India—A significant contribution after a quarter of a century. Zootaxa, 5752 (2), 285–294. https://doi.org/10.11646/zootaxa.5752.2.7