Journal of Threatened Taxa | www.threatenedtaxa.org | 26 July 2026 | 18(7): 29350–29353

 

ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print) 

https://doi.org/10.11609/jott.10446.18.7.29350-29353

#10446 | Received 09 February 2026 | Final received 25 June 2026| Finally accepted 02 July 2026

 

 

Recorded and lost: Methles indicus Régimbart, 1899 (Coleoptera: Dytiscidae) a new distribution record from the state of Telangana: a case study on habitat loss due to urban encroachment

 

Shiva Shankar 1 , Deepa Jaiswal 2  & Devadoss Kumar 3        

 

1,2 Freshwater Biology Regional Centre, Zoological Survey of India, Hyderabad, Telangana 500048, India.

1,3 Department of Zoology, Virudhunagar Hindu Nadars Senthikumara Nadar College (Autonomous) (Affiliated to Madurai Kamaraj University), Virudhunagar, Tamil Nadu 625021, India.

1 cshivashankarchinna@gmail.com (corresponding author), 2 deepajzsi@gmail.com, 3 kumar@vhnsnc.edu.in

 

 

Editor: Shiju T. Raj, St. Joseph’s College, Kozhikode, India.          Date of publication: 26 July 2026 (online & print)

 

Citation: Shankar, S., D. Jaiswal & D. Kumar (2026). Recorded and lost: Methles indicus Régimbart, 1899 (Coleoptera: Dytiscidae) a new distribution record from the state of Telangana: a case study on habitat loss due to urban encroachment. Journal of Threatened Taxa 18(7): 29350–29353. https://doi.org/10.11609/jott.10446.18.7.29350-29353

  

Copyright: © Shankar et al. 2026. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by providing adequate credit to the author(s) and the source of publication.

 

Funding: None.

 

Competing interests: The authors declare no competing interests.

 

Acknowledgements: The authors are grateful to the director, Zoological Survey of India, Kolkata, and the officer-in-charge, ZSI, Hyderabad, for providing the necessary facilities and constant encouragement. Special thanks to Somesh Banerjee for support in field surveys.

 

 

Abstract: Globally, freshwater ecosystems are facing a high level of threat due to rapid development, urbanization, and anthropogenic pressures. Ameenpur Lake, a designated biodiversity heritage site in Hyderabad, Telangana, has significantly supported wide variety of aquatic biodiversity. During field explorations, the aquatic coleopteran species Methles indicus Régimbart, 1899, was recorded from banks of this lake and marked as first distributional occurrence from the state. However, subsequent habitat degradation caused by extensive construction and encroachment has led to the apparent local elimination of this species. The study highlights the loss of Methles indicus as a sign of declining freshwater habitat health and emphasizes the urgent need for habitat preservation and successful conservation strategies.

 

Keywords: Ameenpur Lake, anthropogenic pressure, aquatic beetle, biodiversity heritage site, biodiversity loss, Coleoptera, habitat condition, riparian vegetation.

 

 

Aquatic coleopterans play an important role in freshwater ecosystems as bioindicators, predators, and scavengers. The presence or absence of aquatic beetles often indicates the habitat condition of wetlands and lakes. The aquatic beetles diversity of India is rich with 902 species (Ghosh & Nilsson 2012; Chandra et al. 2017; Gupta et al. 2024; Shankar et al. 2025); however, numerous species remain understudied and vulnerable to habitat alteration. The predatory water beetle genus Methles is associated with small pools, ponds, and streams along with the riparian vegetation. Globally, eight species and one subspecies have been documented within the genus Methles: M. freyi Guignot, 1953; M. laevis Zimmermann, 1933; M. norberti Pederzani & Schizerotto, 2014; and M. punctatissimus Gschwendtner, 1943, all of which are distributed in the Afrotropical region. M. rectus Sharp, 1882 and M. spinosus Sharp, 1882 are known from the Palearctic region, whereas M. cribratellus (Fairmaire, 1880) has been reported from both the Afrotropical and Palearctic regions. Only one species M. indicus is known from India, oriental region and the subspecies M. cribratellus sparsepunctatus Guignot, 1956 shows Afrotropical distribution (Régimbart 1889; Vazirani 1970; Shankar et al. 2024).

Ameenpur Lake, situated in Hyderabad, Telangana, is designated as the first biodiversity heritage site within the state due to its high biodiversity, including migratory birds, amphibians, reptiles, aquatic invertebrates, and its support for aquatic vegetation and macroinvertebrate communities. Despite its protected status, in recent years, large portions of the wetland have been encroached upon by construction activities, leading to sedimentation, pollution, loss of aquatic vegetation, and alteration of hydrological regimes (Srinidhi et al. 2021, 2022).

 

Materials and Methods

A common strainer was employed to collect the specimens of Meth----les indicus from the shores of Ameenpur Lake (17.528o N, 78.329o E) biodiversity heritage site, Hyderabad, Telangana (Image 1). The collected specimens of Meth----les indicus were stored in 70% ethanol. Leica EZ4 and Leica M205A microscopes were used for observing and dissecting the specimens. Habitat photographs were captured using a Canon D500 DSLR camera. Species identification was carried out using the standard taxonomic keys provided by Régimbart (1889) and Shankar et al. (2024). Collected specimens were identified, registered, and deposited in the National Zoological Collection of Freshwater Biology Regional Centre, Zoological Survey of India, Hyderabad.

 

Results and Discussion

Taxonomic treatment

Family: Dytiscidae Sharp, 1882

Genus: Methles Sharp, 1882

Methles indicus Régimbart, 1899

 

Material examined

Two males, three females, Ameenpur Lake, Ranga Reddy, Telangana (17.528o N 78.329o E), 10.ii.2022, Leg.: D. Jaiswal & S. Shankar, Reg. No. FBRC/ZSI/INS/5260.

 

Distribution

Oriental region (India [Bihar, Jharkhand, Odisha, Telangana, West Bengal]) (Régimbart 1889; Vazirani 1970; Shankar et al. 2024).

Methles indicus originally described from Chota Nagpur Plateau, Jharkhand, later recorded from Kolkata, West Bengal, and most recently it has been documented from Sakti Waterfall, Jeypore, Odisha (Shankar et al. 2024).

Anthropogenic activity is becoming the foremost threat to aquatic biodiversity (Bashir et al. 2020). The main threat to biodiversity is habitat degradation, changes in land use, fragmentation, and pollution (IUCN 2024). In this current study we highlight the habitat loss and its effects on biodiversity. In the year of 2022, we conducted a first field survey in the banks of Ameenpur Lake to study the aquatic beetle diversity and their distribution. During the field survey to Ameenpur Lake, five individuals of Methles indicus were collected from small pools which are part of the lake. Since then, multiple attempts have been made to recollect the species from the banks of this lake but failed, suggesting its local extinction from the habitat. The sampling sites are now encroached and buildings constructed which has resulted in the elimination of small pools and species from the lake (Image 2). However, more survey was undertaken in the banks of adjacent water bodies, i.e., Himayat Sagar Lake (25 km south of Ameenpur Lake), Osman Sagar Lake (24 km south of Ameenpur Lake), RK Puram Cheruvu (28 km east of Ameenpur Lake), Shamirpet Lake (35 km north-east of Ameenpur Lake), and Turkayamjal Masab Cheruvu (48 km south-east of Ameenpur Lake) to know the occurrence of the species but ended up with no collections of the species. The causes of species elimination from its habitat can be attributed to many interrelated factors; first and foremost, habitat destruction or fragmentation, including encroachment and construction has rapidly eliminated shallow littoral zones essential for the beetle’s life cycle. Water quality plays a significant role in the aquatic ecosystem; pollution in water that is derived from construction debris, chemicals, and sewage has degraded water quality beyond the tolerance limits of sensitive aquatic beetles (Burghelea 2011). Absence of submerged and emergent floral species has reduced shelter, breeding sites, and food resources to the aquatic beetles. Changes in water flow and depth disrupt the ecological stability required for aquatic beetle populations. The local elimination of Methles indicus is not merely the loss of a single species but an indicator of broader ecosystem degradation. Aquatic beetles are key components to freshwater food chain, webs (Dong et al. 2014), and their decline indicates declining water quality and ecosystem resilience (Roth et al. 2020). Such losses may precede further declines in other aquatic organisms, including fish and amphibians. Immediate actions are required at the habitat level to preserve the biodiversity of Ameenpur Lake; strict action should be taken on further encroachment and construction. The biodiversity heritage site authority and the government should take necessary action to restoration of littoral and wetland vegetation. Regular biodiversity monitoring activities, particularly of indicator species need to be undertaken. Awareness among the local community and involvement in lake conservation need to be promoted. Environmental protection laws must be strongly implemented.

The elimination of Methles indicus from the banks of Ameenpur Lake highlights the negative impact of unchecked urban development on the banks of freshwater biodiversity and ecosystem. Protecting remaining habitats and restoring degraded wetlands are important to preventing further local extinctions. This case study underscores the urgent need to balance urban growth with ecological sustainability, especially in legally protected biodiversity sites.

 

For images - - click here for full PDF

 

 

References

 

Bashir, I., F.A. Lone, R.A. Bhat, S.A. Mir, Z.A. Dar & S.A. Dar (2020). Concerns and Threats of Contamination on Aquatic Ecosystems, pp. 1–26. In: Hakeem, K.R., R.A. Bhat & H. Qadri (eds.). Bioremediation and Biotechnology. Sustainable Approaches to Pollution Degradation. Springer Nature, xviii+327 pp. https://doi.org/10.1007/978-3-030-35691-0_1

Burghelea, C.I., D.G. Zaharescu, P.S. Hooda & A. Palanca-Soler (2011). Predatory aquatic beetles, suitable trace elements bioindicators. Journal of Environmental Monitoring 13(5): 1308–1315. https://doi.org/10.1039/C1EM10016E

Chandra, K., D. Jaiswal & D. Gupta (2017). Insecta: Coleoptera, pp. 379–400. In: Chandra, K., K.C. Gopi, D.V. Rao, K. Valarmathi & J.R.B. Alfred. Current Status of Freshwater Faunal Diversity In India. Zoological Survey of India, Kolkata.

Dong, B., C. Geng, Y. Cai & L. Ji (2014). Aquatic Coleoptera response to environmental factors of freshwater ecosystems in Changbai Mountain, northeast China. Aquatic Ecosystem Health & Management 17(2): 171–178. https://doi.org/10.1080/14634988.2014.910441

Fairmaire, L. (1880). Descriptions de coléoptères nouveaux du nord de l’Afrique. 4. Partie (1). Annales de la Société Entomologique de France 10(5): 245–252.

Gupta, D., K. Chandra, D. Banerjee, P. Das, J. Ghosh, D. Jaiswal, V.D. Hegde, A. Sharma, S.K. Ghosh, J. Dasgupta, D. Bhunia, P. Ghosh, S. Sonali, A.K. Ghosh, R. Deb, R.K. Kushwaha & I. Wani (2024). Fauna of India checklist: Arthropoda: Insecta: Coleoptera, Version 1.0, Zoological Survey of India. https://doi.org/10.26515/Fauna/1/2023/Arthropoda:Insecta:Coleoptera. Accessed on 01.ii.2026.

Ghosh, S.K. & A.N. Nilsson (2012). Catalogue of the diving beetles of India and adjacent countries (Coleoptera: Dytiscidae). Skorvnopparn Umel Supplement 3: 1–77. https://doi.org/10.26515/rzsi/v118/i2/2018/119527

IUCN (2024). Biodiversity Risks and Opportunities (Rep-2016-001). IUCN Global Species Programme.

Régimbart, M. (1889). Revision des Dytiscidae de la Région Indo-Sino-Malaise. Annales de la Société entomologique de France 68(2): 185–367. https://doi.org/10.1080/21686351.1899.12279737

Roth, N., S. Zoder, A.A. Zaman, S. Thorn & J. Schmidl (2020). Long-term monitoring reveals decreasing water beetle diversity, loss of specialists and community shifts over the past 28 years. Insect Conservation and Diversity 13(2): 140–150. https://doi.org/10.1111/icad.12411

Shankar, S., D. Kumar & D. Jaiswal (2024). Molecular characterization of rare predaceous aquatic beetle Methles indicus Régimbart, 1899 (Coleoptera: Dytiscidae) from Eastern Ghats, India. Proceedings of the Zoological Society 77(2): 280–285. https://doi.org/10.1007/s12595-024-00523-7

Shankar, S., D. Kumar, D. Jaiswal, K. Madasamy & S.S. Jadhav (2025). Aquatic beetles (Dytiscidae, Gyrinidae, Haliplidae, Hydrophilidae, Noteridae) of the Papikonda National Park from the Eastern Ghats, Andhra Pradesh, India. Entomon 50(3): 269–290. https://doi.org/10.33307/entomon.v50i3.1522

Srinidhi, N.S., P.M. Reddy & M.A. Reddy (2021). Evaluation of water quality status of Ameenpur lake, Hyderabad, Telangana, India using water quality index (WQI) and geo-spatial technology. Plant Archives 21(1): 1917–1923. https://doi.org/10.51470/PLANTARCHIVES.2021.v21.no1.267

Srinidhi, N.S., P.M. Reddy & M.A. Reddy (2022). GIS based approach for the assessment of water quality of the biodiversity heritage site of India- the Ameenpur lake, Hyderabad. Research Journal of Chemistry and Environment 26(4): 152–162. https://doi.org/10.25303/2604rjce152162

Vazirani, T.G. (1970). Contributions to the study of aquatic beetles (Coleoptera). V. A review of Hydroporinae: Dytiscidae in part, from India. Oriental Insects 4(1): 93–129. https://doi.org/10.1080/00305316.1970.10433945