Discovery of Rare Dragonfly Species

Summary:

Recent research by odonatologists has confirmed the existence of the dragonfly species Crocothemis erythraea in the high-elevation regions of the southern Western Ghats, India. This identification is significant since C. erythraea was previously misidentified or overlooked in this area due to its close resemblance to a more common lowland species, Crocothemis servilia. The genus Crocothemis includes only these two species in India.

• Identification of Species:

  • C. servilia is prevalent in lowland areas, while C. erythraea is associated with high-elevation habitats across parts of Europe and Asia, including the Himalayas.
  • Previous identification claims of C. erythraea from the Western Ghats were challenged due to the absence of physical specimens and confusion with C. servilia.

• Research Background:

  • The lead author, Kalesh Sadasivan, stated that potential specimens were photographed during an annual faunal survey in Munnar in 2018. However, these claims were removed from subsequent checklists due to skepticism from other researchers.
  • This skepticism prompted multiple field expeditions between 2019 and 2023, targeting high-altitude sites in the Western Ghats, such as Wagamon, Rajakumari, Pampadum Shola, and Parambikulam.

• Methodology:

  • The researchers collected and analyzed specimens using morphological traits and molecular techniques.
  • Morphological analysis primarily focused on identifying diagnostic characteristics, including male genitalia, especially the hamule structure.
  • DNA barcoding was employed for molecular analysis to confirm the identification of C. erythraea.

• Findings:

  • The molecular data indicated that specimens from the Western Ghats match the genetic material of C. erythraea documented in the Himalayas.
  • Conversely, C. servilia was confirmed to inhabit the lowlands in both the Himalayas and southern India.
  • The study concludes that the Western Ghats supports both species: C. erythraea is confined to colder, high-elevation habitats above 550 meters, whereas C. servilia thrives in lowlands under 600 meters.

• Historical Context:

  • The study discusses the historical biogeography of C. erythraea, suggesting that this species colonized southern India during the Pleistocene Ice Age when climate conditions were cooler, thus facilitating the migration of temperate fauna southward.
  • As the climate warmed, populations of C. erythraea became isolated in montane habitats such as the Sholas and grasslands of Munnar and Parambikulam, where they continue to survive.

Important Points:

• Crocothemis erythraea confirmed in the Southern Western Ghats.
• C. erythraea and C. servilia represent the only species of the genus in India.
• Previous identification claims were challenged and prompted renewed research.
• Field expeditions took place from 2019 to 2023.
• Morphological and molecular techniques were utilized for species confirmation.
• C. erythraea is adapted to high-elevation habitats, while C. servilia is found in lower elevations.
• Historical context indicates that C. erythraea migrated during the Pleistocene and became isolated due to climatic changes.

This research, published in the International Journal of Odonatology, is crucial for understanding the biodiversity of dragonflies and the effects of climate change on their distribution.