Epiophlebia laidlawi

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Epiophlebia laidlawi
Epiophlebia laidlawi by OpenCage.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Odonata
Family: Epiophlebiidae
Genus: Epiophlebia
Species:
E. laidlawi
Binomial name
Epiophlebia laidlawi
Tillyard, 1921

Epiophlebia laidlawi, the Himalayan relict dragonfly, is one of four species of Epiprocta in the family Epiophlebiidae. They have at one time been classified as a suborder Anisozygoptera, considered as intermediate between the dragonflies and the damselflies, partly because the hind wings and fore wings are very similar in size and shape, and partly because the insect at rest holds them back over the body as damselflies do. These attributes now are known to be misleading however; the genus Epiophlebia shares a more recent ancestor with dragonflies and became separated from other Anisoptera in and around the uplifting Himalayas. [2] [3]

Contents

The species was first described from a larva collected in June 1918 by Stanley Kemp in a stream just above Sonada in the vicinity of Darjeeling. It was identified as an Epiophlebia by Dr. F. F. Laidlaw of Devon who dissected the wing sheaths of the specimen and his identification was endorsed by R.J. Tillyard, who described and gave it the commemorative name. [4]

Subspecies

Appearance

Adults

The head of an adult is spherical and densely sclerotized, with large, laterally placed compound eyes that do not meet medially. Ocelli are arranged triangularly, with the median ocellus positioned anterior to an elevated transverse vertex ridge. The vertex is U- to V-shaped in dorsal view and lacks bright markings. Antennae are composed of five segments: a short cylindrical scape, a dorsoventrally flattened and elongated pedicel, and a slender three-segmented flagellum. Mouthparts are compact; the labrum is broad and short, covered with fine hairs. Overall head coloration is dark brown to black, without contrasting yellow markings. [6]

The thorax is powerfully built and tilted posteriorly, typical of odonates. The prothorax is small and weakly developed, while the meso- and metathorax form a large pterothorax with well-defined sclerites and wing articulation structures. Two narrow yellow longitudinal stripes may be present on the lateral thorax, contrasting with an otherwise dark brown background. Legs are strong; femora are cylindrical with rows of small spines, and tibiae bear long, robust spines. [6]

Wings are long and narrow, with venation showing considerable intraspecific variability. Vein patterns may differ even between left and right wings of the same individual, reducing their taxonomic usefulness. [6]

Venation of E. laidlawi EpiophlebiaVenation.jpg
Venation of E. laidlawi

The abdomen is cylindrical and composed of ten segments. Segments 3–6 are laterally compressed, while segments 8–9 broaden slightly, giving a funnel-like appearance toward the tip. Coloration ranges from brown to nearly black distally, often with faint yellow dorsal markings on mid-segments. [6]

Secondary male genitalia are located on abdominal segments 2–3 and are highly distinctive, particularly the anchor-shaped hamulus posterior. Female genitalia form a well-developed ovipositor on segments 8–9, with a blunt, hook-like process on sternite 8. [6]

Larvae

Larvae resemble those of dragonflies, with a stout body that becomes more elongated through development. The cuticle is thick and covered with small wart-like projections. Coloration varies from light brown in early instars to darker brown in later stages. [6]

The head is broad with large compound eyes and a well-developed prehensile labium (“mask”). Antennae are five-segmented, with a notably elongated first flagellomere. The thorax bears pronounced ridges and spearhead-like projections. The abdomen is cylindrical and ventrally flattened, with rounded dorsolateral processes on segments 7–9. Anal appendages are short, with the epiproct slightly divided at the apex. [6]

Distribution

This species has been found in several locations along the Himalayas including Chittrey, Mt. Shivapuri, Kathmandu area, Solokhumbu region, all in Nepal, where it breeds in streams between 6,000 and 11,500 ft (1,800–3,500m). However, studies since 2015 have determined its range to also include Bhutan, [7] India (Himalayas) and China (Hengduan Mountains). [5]

Habitat

Epiophlebia laidlawi flies at 3000 to 3650 m and has few predators. Alan Davies suggested in 1992 that they bred in waterfalls at 2000 m with the adults flying higher later. Breeding sites at lower altitudes were discovered later. Peter Northcott mentioned 1860-2380m in 1988 but Stephen Butler discovered larvae on Shivapuri at 1800m.

Ecology

The larvae grow for five to six years, which is believed to be the longest for any odonate. Specimens may emerge after nine years in many cases. Stephen Butler notes that the larvae stridulate when disturbed. The larvae appear like those of the Anisoptera but are unable to use the Anisopteran jet-propulsion mode of escape; instead they must walk.

The adult flight is slow and rather uncoordinated. The discoidal cell in the forewing is uncrossed and four sided and in the hindwing the crossvein is long making the cell distally wide. The arculus is situated between the primary antenodals.

Reproduction

In mating, the male grasps the female behind the head as in the Anisoptera. The female is not accompanied during egg laying. She lays eggs into plant tissue while sitting on the stem of a waterside plant. The eggs are laid from bottom to top in a regular zig-zag pattern. The preferred plants are usually bryophytes. [8]

Cited references

  1. ↑ Clausnitzer, V. (2006). "Epiophlebia laidlawi". IUCN Red List of Threatened Species . 2006 e.T7896A12863095. doi: 10.2305/IUCN.UK.2006.RLTS.T7896A12863095.en . Retrieved 29 July 2023.
  2. ↑ Tillyard R J (1921). "On an Anisozygopterous Larva from the Himalayas (Order Odonata)". Records of the Indian Museum. 22 (2): 93–107. doi: 10.5962/bhl.part.1469 .
  3. ↑ Fraser FC (1934). Fauna of British India. Odonata. Volume 2. Taylor & Francis. p. 151.
  4. ↑ Fraser, F.C. (1935). "A missing link". The Journal of the Darjeeling Natural History Society. 10 (2): 56–59.
  5. 1 2 Yang, Guo-Hui; et al. (2025). "Epiophlebia laidlawi daliensis, a new subspecies from Hengduan Mountains in Yunnan (Insecta, Odonata, Epiophlebiidae)". Zootaxa.
  6. 1 2 3 4 5 6 7 Büsse, Sebastian (December 2016). "Morphological re-examination of Epiophlebia laidlawi (Insecta: Odonata) including remarks on taxonomy". International Journal of Odonatology. 19 (4): 221–238. doi:10.1080/13887890.2016.1257442. S2CID   90624447.
  7. ↑ Dorji, T. (2015). "New distribution records of Epiophlebia laidlawi Tillyard, 1921 (Insecta: Odonata) in Bhutan". Journal of Threatened Taxa. 7 (10): 7668–7675. doi: 10.11609/JoTT.o4092.7668-75 .
  8. ↑ Silby, Jill (2001) Dragonflies of the world. The Natural History Museum. London.

References

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