Urothemis edwardsii

 
Common Name:
Blue Basker 
Odonata
Order:
Odonata
Suborder:
Anisoptera
Family:
Libellulidae
Genus:
Urothemis
Species:
U. edwardsii
Species Description
Urothemis is a genus of dragonfly in family Libellulidae. Species occur from Africa, across Asia to Indonesia and Australia. The genus contains the following species:
         Urothemis abbotti (Laidlaw, 1927) 
         Urothemis aliena (Selys, 1878) - Red Baron 
         Urothemis assignata (Selys, 1872) - Red Basker 
         Urothemis bisignata (Brauer, 1868)
         Urothemis consignata (Selys, 1897) 
         Urothemis edwardsii (Selys, 1849) - Blue Basker 
         Urothemis luciana (Balinsky, 1961) - St Lucia Basker 
         Urothemis signata (Rambur, 1842) 
         Urothemis thomasi (Longfield, 1932) 

Urothemis edwardsii (Selys, 1849), the Blue Basker, is a stout, medium-sized dragonfly. With length 40 - 42 mm, hindwing length 33.5 - 35 mm, it is an attractive species with deep blue and black markings. The blue colouration of the male's abdomen is overlain with a distinctive ladder-like pattern of black along the upper surface. The blue basker's head is shiny black with light grey patches in places, and the eyes are generally black. Its hindwings are marked at the base with a black to purplish patch, which is outlined with an amber halo. The pterostigmas (the dark coloured cells near the tip of the wings) are light yellowish with a thin, black margin along the front edge.

Although similar in size to the male, the female blue basker differs in colour. Instead of blue, the female is light yellow to greyish-brown, overlain with dark brown markings. The hindwing patch is much less intensely coloured than in the male, and the wing tips of the female are also marked with dark amber 

A freshwater species, the blue basker can be found in or around reedy pools, marshes and lakes, as well as slow flowing, almost stagnant, streams, rivers and floodplains. It can also occasionally be found in grasslands, and may also sporadically colonise high-elevation pools if conditions are suitable.

Subspecies includes:
         Urothemis edwardsii edwardsii  (Selys, 1849) 
         Urothemis edwardsii hulae (Dumont, 1975) 

Widespread in tropical Africa, Urothemis edwardsii mainly occurs south of the Sahara. Its western range includes Mauritania, Senegal, Gambia and Sierra Leone, extending eastwards to Egypt, Sudan and Somalia. The southern extent of its range includes South Africa. A relict population of the blue basker exists in North Africa, in the north of Algeria. It also occurs in the Middle East, including Arabia and Oman. This species was previously found in Palestine, where it is now believed to be extinct. 

In view of its wide distribution, and because it is unlikely to be declining fast enough to qualify for listing in a threatened category, Urothemis edwardsii is classified as Least Concern (LC) on the IUCN Red List, but it is accessed as Critically Endangered (CR) on the IUCN Mediterranean Red List.
 
 
 

Reference:
http://en.wikipedia.org/wiki/Urothemis_edwardsii
http://www.iucnredlist.org/details/60073/0
http://www.arkive.org/blue-basker/urothemis-edwardsii

 

 

 

The Species on Stamps
Namibia
2007.04.16

 

 


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