Megalagrion williamsoni
| Megalagrion williamsoni | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Megalagrion williamsoni | ||||||||||||
| ( Perkins , 1910) |
Megalagrion williamsoni is a possibly extinct dragonfly species from the family of slender dragonflies(Coenagrionidae). It was endemic to the Hawaiian island of Kauai and is only known from two specimens collected in 1910 and 1920. The species epithet honors the entomologist Edward Bruce Williamson (1877-1933), a dragonfly expert from the University of Michigan Museum of Zoology.
features
Dimensions and characteristics are only known from the male holotype. The body length is 45 mm and the wingspan is 50 mm. The head is black on top. The mouthparts are dark yellow. The eyes are dark red. The black thorax has broad, coarse yellow spots on the underside, similar to the sympatric species Megalagrion adytum . The entomologist John Maciolek, who carried out intensive field work on the Megalagrion species on Kauai in the 1970s , therefore considers both taxa to be conspecific . The legs are yellowish-brown. The abdomen is predominantly black on the front half and red on the back half. The upper and lower abdominal appendages are almost equally long. Seen from the side, the upper abdominal appendages are broadly forked at the tips. Seen from above, they curve sharply inward. The females and the larvae are undescribed.
Habitat and way of life
Megalagrion williamsoni was known from the Alakai swamp on Kauai, where the type specimen was collected near Lihue at an altitude of 1,500 feet (about 460 m) on a watercourse. The size and color of the male imago suggest that reproduction occurred either terrestrially or in seepage water habitats. Nothing is known about the way of life.
Systematics
Robert Cyril Layton Perkins described this form in 1910 as Agrion williamsoni . Clarence Hamilton Kennedy placed them in the genus Megalagrion in 1917 .
status
Megalagrion williamsoni is not included in the IUCN Red List . However, the species is in the GH (possibly extinct) category on the NatureServe portal. Megalagrion williamsoni was initially only known from the male holotype collected in 1910 in the Alakai Swamp on Kauai. In 2000, entomologist Jerrell J. Daigle received another specimen, which was collected in 1920. Intensive search expeditions on Kauai in the 1970s and 1990s were unsuccessful, so that this species could possibly already be extinct.
literature
- Dan A. Polhemus: Damsels in distress: A review of the conservation status of Hawaiian Megalagrion damselflies (Odonata: Coenagrionidae). Aquatic Conservation: Marine and Freshwater Ecosystems Special Issue: Endangered Aquatic Habitats - A Symposium of the Entomological Society of America December 1992 3 (4), 1993: 343-349
- Dan A. Polhemus and Adam Asquith: Hawaiian Damselflies. A field identification guide. A Hawaii Biological Survey Handbook. Bishop Museum Press, Honolulu, 1996. ISBN 0-930897-91-9 . P. 89
Individual evidence
- ^ Dan A. Polhemus: Damsels in distress: A review of the conservation status of Hawaiian Megalagrion damselflies (Odonata: Coenagrionidae). Aquatic Conservation: Marine and Freshwater Ecosystems Special Issue: Endangered Aquatic Habitats - A Symposium of the Entomological Society of America December 1992 3 (4), 1993: 343-349
- ↑ a b Megalagrion williamsoni: Entry in Natureserve
- ^ RCL Perkins: Supplement to Neuroptera. In: Fauna Hawaiiensis 2 (6), Cambridge University Press, 1910: 693-696.
- ^ CH Kennedy: Notes on the penes of damselflies (Odonata). No. 2. The close relations inter se of the Hawaiian agrionines. Entomological News 28, 1917: 9-14. pls. 2–3, figs. 149.
- ↑ Jerrell J. Daigle: The distribution of the odonata of Hawaii. Bulletin of American Odonatology 6 (1), 2000: 1-5.