Last Updated on Friday, 16 June, 2023 11:19:13 PM

INDEX  >  Dragonflies of Borneo  >  Family  Aeshnidae  > Genus Oligoaeschna

Family of Aeshnidae
Genus Oligoaeschna

Oligoaeschna foliacea

Male 63mm 2008-06-03 SRI AMAN
Female 66mm 2008-06-02 SRI AMAN

There are 7 Borneo species in this Genus. 4 are endemic of Borneo

1- Oligoaeschna amata (Forster, 1903)

2- Oligoaeschna huehri (Forster, 1903)

3- Oligoaeschna elacatura (Needham, 1907)  Endemic of Borneo

4- Oligoaeschna foliacea Lieftinck, 1968

5- Oligoaeschna mutata Lieftinck, 1940 Endemic of Borneo

6- Oligoaeschna platrura Lieftinck, 1940 Endemic of Borneo

7- Oligoaeschna venusta Lieftinck, 1968 Endemic of Borneo

Genus : Oligoaeschna

Oligoaeschna species are medium to moderately large and rather heavily built.

Top : Male, Bottom : Female

In color they range from dark reddish-brown to black, marked darkly with green.
 

Genus  Oligoaeschna	Genus  Indaeschna	Genus  Gynacantha
Oligoaeschna foliacea ♂ Body length 59+4=63mm	Indaeschna grubaueri ♂Body length 95mm	Gynacantha dohrni ♂ Body length 62+6=68mm

They are among the smallest of the Bornean aeshnids. Apart from their distinctive form, they may generally be separated from most other members of the family by the presence of fewer crossveins in the discoidal triangle, which is usually divided into only three cells in both wings, uncommonly four, whereas in most other genera it is usually divided into five or more, and never fewer than four cells.

Male
O. foliacea wings have fewer cross veins in the discoidal triangle, which is usually divided into only three cells in both wings. Whereas in most other genera it is usually divided into five or more cells.

In most species the male wings are lightly and uniformly coloured, generally a pale amber, but females often have extensive semi-hyaline reddish-brown patches.

The male superior appendages are only moderately long and are robust, in many cases flattened and expanded.
Female appendages normally break off with mating, but when intact they are long and very broadly paddle-shaped with a thin stalk. The function of these long racquet like appendage curious structures is unknown.

Males are generally separated by the structure of their anal appendages although species also differ in their markings and wing venation.
Females show a good deal of interspecific variation in wing venation, wing marking and the shape of the abdomen.

Oligoaeschna is one of the more taxonomically difficult genera of the Anisoptera. Seven species, four endemic, are recorded from Borneo to which may be added a probable further four, known only from females, which were described but not named by Lieftinck in his 1968 revision and key (Tijdschrift voor Entomologie 111: 137-186). To this should be added that some specimens recently collected in Brunei do not fit well with any forms discussed by Lieftinck and may either represent undescribed females of known males or undescribed species.
 

The 3 families of dragonflies found in Borneo Island:

1 Family of Aeshnidae

2 Family of Gomphid

3 Family Libellulidae

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1- using Ovipositor Structure
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