Somatochlora sahlbergi

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Somatochlora sahlbergi
Somatochlora sahlbergi 93175624.jpg
adult female
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Odonata
Infraorder: Anisoptera
Family: Corduliidae
Genus: Somatochlora
Species:
S. sahlbergi
Binomial name
Somatochlora sahlbergi
Trybom, 1889
Synonyms [2]
  • Somatochlora theeli Trybom, 1889
  • Somatochlora walkeri Kennedy, 1917

Somatochlora sahlbergi, the treeline emerald, is a species of dragonfly in the family Corduliidae. It is found at high latitudes across northern Eurasia and North America, and occurs farther north than any other dragonfly.

Contents

Taxonomy

male specimen Somatochlora sahlbergi, male.png
male specimen

Somatochlora sahlbergi was first scientifically described in 1889 by Swedish entomologist Filip Trybom, based on four specimens collected on an 1876 expedition to the Yenisei River. [3] The species was named after Finnish entomologist Johan Reinhold Sahlberg. [4]

In 1917, American entomologist Clarence Hamilton Kennedy described a new species Somatochlora walkeri based on a male specimen from Alaska and a female specimen from Saskatchewan, naming it after Canadian entomologist Edmund Murton Walker. [5] In his 1925 monograph on the genus Somatochlora in North America, Walker determined that his namesake species was actually a synonym of S. sahlbergi, and that the Saskatchewan specimen did not belong to this species. [6]

Illustrations from the 1917 description of S. walkeri. The species was later determined to be synonymous with S. sahlbergi, and note that fig 12. is misidentified and is not S. sahlbergi A New Species of Somatochlora (Odonata) with Notes on the Cingulata Group - Clarence Thomas Kennedy 1917 - Plate 13 - Fig 9-12.jpg
Illustrations from the 1917 description of S. walkeri. The species was later determined to be synonymous with S. sahlbergi, and note that fig 12. is misidentified and is not S. sahlbergi

S. sahlbergi has no close relatives within the genus, being the sister species to a clade consisting of most other species of Somatochlora. [7] It is known to hybridise with Somatochlora albicincta and Somatochlora hudsonica in Alaska and Yukon. [1]

Despite its broad distribution, genetic studies reveal that there is very little genetic variation among populations of S. sahlbergi, and the species interbreeds across its entire range. [7]

Description

Larva Somatochlora sahlbergi nymph.jpg
Larva

Somatochlora sahlbergi adults are medium-sized (about 4.8 cm long [6] ) dragonflies with dark, metallic green bodies and transparent wings, much like other species of Somatochlora. [7] Unlike some other species in the genus, there is very little paler yellow marking on the thorax and abdomen. [6] The body is covered in a dense coat of setae. [7] The shape of the male cerci, on the tip of the abdomen, is distinctive. [7]

The larva is dark reddish-brown or orange-brown on top, and paler below, and also has a dense coat of setae. [7] Some sources indicate that the larva has long lateral spines on the 8th and 9th abdominal segments, but it is not clear if this is consistent across the species' range. [7]

Distribution

The distribution of Somatochlora sahlbergi is somewhat poorly known, with under 100 specimens known worldwide. [7] The species is found across northern portions of Norway, Sweden, Finland, Russia, and Alaska. In Canada, it is known from Yukon and Northwest Territories, but has not been found anywhere east of the Mackenzie River and may be absent from e.g. Nunavut and Quebec. [7] Reports from Kazakhstan and southern portions of Russia are erroneous. [8]

The species occurs further north than any other species of dragonfly or damselfly, and the southern limit of its breeding range, typically coinciding with the northern treeline, is to the north of most North American and Eurasian dragonflies. [7] [9] Locations where the species is found typically have annual mean temperatures under 0 degrees Celsius, and annual mean rainfall under 450 mm. [7]

Life History

Somatochlora sahlbergi is associated with palsa in the European portion of its range. Palsaaerialview.jpg
Somatochlora sahlbergi is associated with palsa in the European portion of its range.

Somatochlora sahlbergi is found at pools, ponds and small lakes near treeline and in fens and bogs. [10] Pools are typically lined with sedges and contain aquatic mosses, and may be underlain by permafrost. [10] The species has been observed in Siberia in clear, cold, slow-moving water surrounded by forest, but this habitat has not been noted in North America. [10] In Fennoscandia, S. sahlbergi may be closely associated with palsa mires. [7] Larvae are found in the pools, while adults fly around the surrounding habitats. [7]

Larvae prey upon zooplankton and aquatic insects, while adults feed on flying insects. [7] Adults are most active in the afternoon, and do not fly at night, in shade, or in inclement weather. [7]

Males patrol breeding sites searching for females. [10] When a female is found, males grab the female by the head, with copulation occurring in nearby vegetation. [10] Females lay eggs in open water away from the shoreline. [10] It likely takes up to 4-5 years for larvae to mature due to the short summer season in the breeding range of this species. [10]

Conservation

The species is ranked as least concern by the IUCN [1] and as apparently secure (G4) by NatureServe. [11] In its North American range, the species is ranked as S1 (critically imperiled) in the Northwest Territories. [11] The species may be at risk due to climate change. [1]

Related Research Articles

<span class="mw-page-title-main">Corduliidae</span> Family of insects

Corduliidae, also knowns as the emeralds, emerald dragonflies, or green-eyed skimmers, is a family of dragonflies. These dragonflies are usually black or dark brown with areas of metallic green or yellow, and most of them have large, emerald-green eyes. The larvae are black, hairy-looking, and usually semiaquatic. This family include species called "baskettails", "emeralds", "sundragons", "shadowdragons", and "boghaunters". They are not uncommon and are found nearly worldwide, but some individual species are quite rare. Hine's emerald dragonfly, for example, is an endangered species in the United States.

<i>Somatochlora</i> Genus of dragonflies

Somatochlora, or the striped emeralds, is a genus of dragonflies in the family Corduliidae with 42 described species found across the Northern Hemisphere.

<i>Somatochlora incurvata</i> Species of dragonfly

The incurvate emerald is a species of dragonfly in the family Corduliidae. It is found in Canada and the United States. Its natural habitat is fens.

<i>Williamsonia lintneri</i> Species of dragonfly

The ringed boghaunter is a species of dragonfly in the emerald family (Corduliidae). It is found at acid bogs in the northeastern United States and southeastern Canada.

<i>Aeshna canadensis</i> Species of dragonfly

Aeshna canadensis, the Canada darner, is a species of dragonfly in the family Aeshnidae. It is common throughout southern Canada and the northern United States.

<span class="mw-page-title-main">Brilliant emerald</span> Species of dragonfly

The brilliant emerald, Somatochlora metallica, is a middle-sized species of dragonfly. It is the largest and greenest of the Somatochlora species; 50–55 millimetres (2.0–2.2 in) long.

<i>Williamsonia fletcheri</i> Species of dragonfly

The ebony boghaunter is a species of dragonfly in the emerald family Corduliidae. It is found in southeastern Canada and the northeastern United States. Larvae occur in acidic bogs.

<i>Somatochlora flavomaculata</i> Species of dragonfly

Somatochlora flavomaculata, also called yellow-spotted emerald, is a common species of dragonfly in the family Corduliidae. Its distribution stretches from France to Siberia and Mongolia. It frequents wetlands in its range. The males are known to defend their territory.

<i>Somatochlora elongata</i> Species of dragonfly

Somatochlora elongata, the ski-tipped emerald or ski-tailed emerald, is a species of dragonfly in the family Corduliidae. It is found in North America.

<i>Somatochlora franklini</i> Species of dragonfly

Somatochlora franklini, the delicate emerald, is a species of emerald dragonfly in the family Corduliidae. It is found in North America.

<i>Somatochlora hudsonica</i> Species of dragonfly

Somatochlora hudsonica, the Hudsonian emerald, is a species of emerald dragonfly in the family Corduliidae. It is found in North America.

<i>Somatochlora cingulata</i> Species of dragonfly

Somatochlora cingulata, the lake emerald, is a species of emerald dragonfly in the family Corduliidae. It is found in North America.

<i>Somatochlora ensigera</i> Species of dragonfly

Somatochlora ensigera, the plains emerald, is a species of dragonfly in the family Corduliidae. It is found in central North America.

<i>Somatochlora linearis</i> Species of dragonfly

Somatochlora linearis, the mocha emerald, is a species of emerald dragonfly in the family Corduliidae. It is found in North America.

<i>Somatochlora alpestris</i> Species of dragonfly

Somatochlora alpestris, or the alpine emerald, is a species of dragonfly from the family Corduliidae. It is found in European highlands, southern Scandinavia, and east to southern Siberia in Asia.

<i>Somatochlora septentrionalis</i> Species of dragonfly

Somatochlora septentrionalis, the muskeg emerald, is a species of dragonfly in the family Corduliidae. It is endemic to Canada, where it is found from Yukon and British Columbia east to Nova Scotia and Newfoundland.

Somatochlora daviesi is a species of dragonfly in the family Corduliidae. It was first described in 1977 based on specimens from Meghalaya, India, and is also known from Nepal and Bhutan. It resembles the east Asian S. dido in its small size and lack of yellow markings on most of the abdomen. Like other species in the genus, S. davisi is predominantly dark metallic brown to green. The formerly recognised Somatochlora nepalensis is now considered to be a synonym of S. daviesi.

<i>Somatochlora viridiaenea</i> Species of dragonfly

Somatochlora viridiaenea is a species of dragonfly in the family Corduliidae. The species was described in 1858 by American entomologist Philip Reese Uhler based on a female specimen from Hokkaido, Japan. It has also been recorded on Honshu and in eastern Russia.

<i>Somatochlora uchidai</i> Species of dragonfly

Somatochlora uchidai is a species of dragonfly in the family Corduliidae. It is native to Japan, China and Russia. It was described in 1909 by German entomologist Friedrich Förster based on specimens from Japan; the name uchidai refers to the Japanese odonate researcher Uchidas from whom Förster received the specimens.

<i>Somatochlora graeseri</i> Species of dragonfly

Somatochlora graeseri is a species of dragonfly in the family Corduliidae. It is found in Asia, where it occurs in Japan, Korea, northern China, and Russia.

References

  1. 1 2 3 4 Sahlen, G.; Paulson, D.R. (2017). "Somatochlora sahlbergi". IUCN Red List of Threatened Species . 2017: e.T60310A65819567. doi: 10.2305/IUCN.UK.2017-3.RLTS.T60310A65819567.en . Retrieved 15 November 2021.
  2. ↑ Paulson, D.; Schorr, M.; Abbott, J.; Bota-Sierra, C.; Deliry, C.; Dijkstra, K.-D.; Lozano, F. (2023). "World Odonata List". OdonataCentral, University of Alabama . Retrieved 14 Mar 2023.
  3. ↑ Trybom, Filip (1889). "Trollsländor (Odonata), insamlade unter Svenska expeditionen till Jenisei 1876". Bihang till Kungliga Svenska Vetenskapsakademiens Handlingar. 15 (4): 4:1–21.
  4. ↑ Paulson, Dennis R.; Dunkle, Sidney W. (2016). "A Checklist of North American Odonata Including English Name, Etymology, Type Locality, and Distribution" (PDF). Retrieved 3 February 2021.{{cite journal}}: Cite journal requires |journal= (help)
  5. ↑ Kennedy, Clarence Hamilton (1917). "A New Species of Somatochlora (Odonata) with Notes on the Cingulata Group". The Canadian Entomologist. 49 (7): 229–236. doi:10.4039/Ent49229-7.
  6. 1 2 3 Walker, Edmund Morton (1925). The North American Dragonflies of the Genus Somatochlora. Toronto: University of Toronto. pp. 163–167.
  7. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Kohli, Manpreet K.; Sahlén, Göran; Kuhn, William R.; Ware, Jessica L. (2018). "Extremely low genetic diversity in a circumpolar dragonfy species, Somatochlora sahlbergi (Insecta: Odonata: Anisoptera)". Scientific Reports. 8 (15114): 15114. Bibcode:2018NatSR...815114K. doi:10.1038/s41598-018-32365-7. PMC   6181962 . PMID   30310089.
  8. ↑ Kosterin, Oleg E. (2020). "A misleading representation of the Asian distribution of a most intriguing dragonfly, Somatochlora sahlbergi Trybom, 1889: a critique of Kohli et al. (2018)". Odonatologica. 49 (1/2): 51–56. doi:10.5281/zenodo.3823327.
  9. ↑ Schröter, Asmus (2011). "Review of the distribution of Somatochlora sahlbergi (Odonata: Corduliidae)". International Dragonfly Fund - Report. 41: 1–27.
  10. 1 2 3 4 5 6 7 McClory, J. G.; Gotthardt, T. A. (2006). Treeline Emerald (PDF). Anchorage: Alaska Natural Heritage Program, Environment and Natural Resources Institute, University of Alaska. Retrieved 18 January 2021.
  11. 1 2 "Somatochlora sahlbergi". Natureserve Explorer. Retrieved 18 January 2021.
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