Journal of Threatened Taxa | www.threatenedtaxa.org | 26 June 2025 | 17(6): 27167–27170

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

https://doi.org/10.11609/jott.9392.17.6.27167-27170

#9392 | Received 20 September 2024 | Final received 15 May 2025 | Finally accepted 23 May 2025

Lesser Blue-wing Rhyothemis triangularis Kirby, 1889 (Insecta: Libellulidae), a new addition to the dragonfly diversity of Rajasthan, India

Anil Sarsavan ¹ , Manohar Pawar ², Satish Kumar Sharma ³ & Vinod Paliwal ⁴

^1,2.4 Foundation for Ecological Security, post box no. 29, Jahangirpura, Hadgud, Anand district, Gujarat 388370, India.

³ 14–15, Chakriya Amba, Saket Colony, Rampura Circle, Jhadol Road, Post-Nai, Udaipur, Rajasthan 313031, India.

¹ anil@fes.org.in, ² manohar.pawar@fes.org.in (corresponding author), ³ sksharma56@gmail.com, ⁴ vinod@fes.org.in

Editor: R.J. Andrew, Hislop College, Maharashtra, India. Date of publication: 26 June 2025 (online & print)

Citation: Sarsavan, A., M. Pawar, S.K. Sharma & V. Paliwal (2025). Lesser Blue-wing Rhyothemis triangularis Kirby, 1889 (Insecta: Libellulidae), a new addition to the dragonfly diversity of Rajasthan, India. Journal of Threatened Taxa 17(6): 27167–27170. https://doi.org/10.11609/jott.9392.17.6.27167-27170

Copyright: © Sarsavan et al. 2025. 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: We would like to extend our sincere gratitude to the Foundation for Ecological Security (FES) for providing the essential facilities that contributed to the success of this study. We are also indebted to the FES Udaipur team for their invaluable support during our field surveys. In particular, we would like to acknowledge the exceptional assistance of Mr. Laxman Bhai N. Cholaviya and Mr. Arjun Ameta, whose contributions were instrumental in the present findings of this species.

Abstract: The present study reports the first confirmed record of the Lesser Blue-wing Rhyothemis triangularis Kirby, 1889 from Udaipur District, Rajasthan, India. Previously unreported in the state, this finding significantly expands this dragonfly’s known geographical range into a new area. During the wetland monitoring program in September 2024, an opportunistic sighting of a dragonfly was observed in Jhadol and Gogunda, two adjoining blocks (tehsils) of Udaipur District. The previous findings of this species are mainly from the high rainfall zone, but the present finding is from a drier zone of western India, having low rainfall. The findings contribute to the understanding of the species distribution and ecological preferences, particularly in semi-arid regions like Jhadol and Gogunda block of Udaipur District. These findings contribute to the natural history of the species and highlight the habitat quality and suitability for this species in low-rainfall areas.

Keywords: Habitat preference, new geographic record, Odonata, semi-arid zone, Udaipur, village pond, western India, wetland health assessment.

Development activities around waterbodies have negatively impacted the riparian vegetation and water quality (Córdoba-Aguilar et al. 2019). Dragonflies and damselflies (Odonata) are valuable bioindicators for assessing and monitoring aquatic habitats. These insects, with their sensitivity to environmental changes, can provide insights into water quality, habitat health, and the impacts of various stressors on aquatic ecosystems (Oertli 2008). The presence of some stenotopic species reflects the effect of vegetation structure, environmental parameters, water quality parameters, and pollutants. Odontesare considered as representatives of health of wetlands, running water, and ponds. Family Libellulidae is one of the largest families within the suborder Anisoptera, encompassing over 1,035 species across 144 genera worldwide (Paulson et al. 2024). The genus Rhyothemis is a member of the Libellulidae family, commonly referred to as flutterers due to their distinctive flight pattern. The genus includes 23 species, distributed across Africa, Asia, Australia, and the Pacific region. This species has a wide distribution, encompassing China, Hong Kong, India, Indonesia, Malaysia, the Philippines, Singapore, Sri Lanka, Thailand (Dow & Sharma 2010); Cambodia, and Myanmar (Nu & Bu 2019); Bangladesh, Bhutan, India, Nepal, Pakistan, and Sri Lanka (Kalkman et al. 2020; Hopkins 2024). In India R. triangularis has previously been recorded from the states like Assam, Himachal Pradesh, Kerala, Karnataka, Odisha, Tamil Nadu, and West Bengal (Mitra 2002; Dow & Sharma 2010; Sajan & Mohapatra 2014; Thakur & Mattu 2015; Dawn 2021; Sadasivan et al. 2022).

In India, the genus Rhyothemis is represented by four species: Rhyothemis phyllis, R. plutonia, R. triangularis, and R. variegata. Among these, R. variegata is the most widespread species within the country (Subramanian & Babu 2024).

In this context, the presence of R. triangularis in low-rainfall zones such as Jhadol & Gogunda underscores the ecological importance of these wetlands. It offers valuable insight into the species’ distribution, habitat preferences, and resilience. As a bio indicator species sensitive to habitat quality and water conditions, its occurrence in this region suggests a relatively healthy wetland ecosystem despite the challenging climatic conditions. These findings enrich the understanding of the species’ natural history and support future conservation planning by identifying key habitats outside its traditionally known range. .

Materials and Methods

During the wetland health study, a dragonfly survey was conducted as a part of water quality assessment, focusing on species richness, and abundance. The Tropic of Cancer passes below the southern edge of Udaipur District from Dungarpur and Banswara districts. The area adjacent to this line is frost-free hence suitable for insects, including dragonflies. Udaipur District experiences a semi-arid climate with an average annual rainfall of 600 mm. Temperatures fluctuate significantly between seasons, ranging from a minimum of 2 ⁰C in winter to a maximum of 45 ⁰C in summer.

An Odonata monitoring programme was conducted from August 2023 to September 2024 in Gogunda (24.846⁰ N, 73.426⁰ E) and Jhadol (24.461⁰ N, 73.483⁰ E) blocks of Udaipur District to assess the health of wetlands and streams. Dragonflies and damselflies were searched, identified, and noted from and around the various water bodies of the region. The data was recorded in the notebook. The odonate species along with their key identifying features, were documented and photographed using a Canon 5D mark III camera with a 100 mm fixed lens. Specimens were identified mainly based on the morphological characters and keys provided by Ramachandran & Raju (2020) and Anonymous (2024).

Results

While recording odonate species at a community pond (24.461⁰ N, 73.483⁰ E) in Barhamano-ka-Kherwada Village, Jhadol Block, Udaipur District on 30 August 2024, one individual was observed and suspected to be Rhyothemis triangularis because of its wing colouration. Half of the wing area from the base was metallic blue, and the hindwing base was much broader than that of the forewings. This distinctive pattern confirmed it to be a member of the genus Rhyothemis. Based on key identification features, the observed dragonfly was confirmed to be R. triangularis. On 30 August 2024, a female R. triangularis was spotted in a pasture land approximately 500 m away from the Barhamano-ka-Kherwada village pond. Males and females are morphologically similar. Females are characterized by reduced, small anal appendages. Males exhibit a ventral abdominal bulge, prominent secondary genitalia near the thorax-abdomen junction, and large anal appendages, all absent in females. Later, on 02 September 2024, three females and one male R. triangularis were recorded in the bushes near a pond in Palidana Village (24.846⁰ N, 73.426⁰ E). One mating pair of R. triangularis was observed in the bushes near a pond in Paneriyon-Ki-Bhagal Village (24.833⁰ N, 73.431⁰ E) during the survey period. A total of seven R. triangularis individuals (two males and five female) were recorded perched on various vegetation (Schoenoplectus sp., Chrysopogon zizanioides, and Parthenium hysterophorus) in three locations of Gogunda and Jhadol tehsils of Udaipur District.

Discussion

R. triangularis, commonly called the Lesser Blue-wing, is a striking species known for its distinctive triangular wing markings. Previous studies reported R. triangularis inhabiting forest streams (Ramachandran & Raju 2020), the present findings indicate that it can also inhabit seasonal village ponds. All the surveyed ponds are seasonal and primarily used for livestock drinking purposes. All ponds exhibit a diverse mosaic of wetland habitats, supporting a variety of aquatic vegetation. Submerged plants, primarily Limnophila species, dominate the underwater environment. The free-floating vegetation is characterized by Trapa natans, while Schoenoplectus species are the most prevalent emergent plants. Shoreline and upland areas are primarily covered by Chrysopogon zizanioides and Parthenium hysterophorus. The surrounding landscape is a mosaic of agriculture, pasture, forests, small streams, and small ponds.

This finding significantly expands knowledge of the geographic distribution of R. triangularis and its habitat preferences in village ponds of semi-arid area of Rajasthan. R. triangularis has been documented in various biogeographically zones across India, including the Western Ghats, Eastern Ghats, Deccan Peninsula, coastal zone, northeastern zone, and the Himalaya (Dow & Sharma 2010). All three current observations are spread across Gogunda and Jhadol block of Udaipur District, all within a 50 km radius. This demonstrates the species wider distribution throughout the area. The presence of R. triangularis species in village ponds, demonstrates the significance of community ponds for the conservation of such Odonata species. This is the first report from the semi-arid region, suggesting a potentially wider range for this species than previously thought.

Conclusion

This article presents the first record of R. triangularis from Udaipur, Rajasthan, India. The finding contributes to the understanding of the species’ geographical range and habitat preferences. Further research is needed to assess the population status and ecological significance of R. triangularis in this kind of community-conserved ponds.

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