Stout Pintail    Acisoma inflatum      Dikpylstertjie.

100 1850   Male Tzaneen LP RSA Dec 2017r 3

100 1854  Male Tzaneen LP RSA Mch 2016r 7

100 1845   Female Tzaneen LP RSA Nov 2015r 2

Family Libellulidae Leach, 1815
Short description:

Stout Pintail, Acisoma inflatum, Dikpylstertjie is very small to small, mosaic bluish grey, greenish yellow and black, with bulbous (spindle shaped) abdomens that taper sharply at mid length, becoming black and ending in cream appendages..

Previously grouped with Acisoma variegatum (Slender Pintail) as one species,  Acisoma panorpoides (Grizzled Pintail).

More images

100 1855 Acisoma inflatum Stout Pintail Male1 Tzaneen LP RSA Nov 2015r 2Image Gallery

100 1863 Acisoma inflatum Stout Pintail Male Hertzogberg MP Nov 2017r 1Male

100 1869 Acisoma inflatum Stout Pintail Hertzogberg MP Nov 2017r 1Female

 

 

 

 

 

 

 

Click on all images to enlarge or view more

Key identification features:

Male:

  • Face has various light colours and black stripes. Labrum is cream with basal central black dot. Anteclypeusis pencil grey.
    Postclypeusis light blue. Frons has a black band in lower part, some black above and at sides and light blue centrally. Head is black above.100 1867 Acisoma inflatum Stout Pintail Male Hertzogberg MP Nov 2017r 6
  • Eyes are bright turquoise.
  • Thorax is light bluish grey, covered with myriad of irregular black lines and dots above and at sides.100 1864 Acisoma inflatum Stout Pintail Male Hertzogberg MP Nov 2017r 3
  • Wings are clear, with dark brown basil patch in hind wing. Pterostigmas are relatively long (3 mm), whitish, slightly transparent.
  • Abdomen underside of segments 1 to 3 bluish. Abdomen Segments 1 to 4 swollen, contrasting with segments 5 to 10 which are narrow.
    S 1 to 7 light bluish grey with black markings, including dorsal stripe. S 8 to 10 black. S 6 is 2½ x as long as high. S6 shorter in length than s7 100 2477 Acisoma variegatum Slender pintail Female Close up Skukuza MP RSA Febr 2018f 1411

Female:

  • Similar in shape as male but abdomen broader.
  • Young males and females similar
  • Pruinose to grey with very little detail visible with age
  • Eyes stray coloured greenish above with light greenish white below with light blue streaks.
  • Thorax (dorsal) and dorsal abdomen is straw coloured to greenish yellow with dark brown and blackish markings Thorax in lateral view greenish yellow above becoming light yellowish green becoming light whitish blue below. 100 1871 Acisoma inflatum Stout Pintail Hertzogberg MP Nov 2017r 3
  • Wings clear who. Basel amber patch. Pterostigmas light grey.
  • Abdomen underside of segments 1 to 3 bluish. Abdomen Segments 1 to 4 swollen, contrasting with segments 5 to 10 which are narrow. S 1 to 7 light bluish grey with black markings, including dorsal stripe. S 8 to 10 black. S 6 is 2½ x as long as high. S6 shorter in length than s7 100 2478 Hertzogberg MP Nov 2017f 511 Lateral abdomen carina all black
Compared with other species:
  • Acisoma variegatum (Slender Pintail) abdomen segment 6 is 3× as long as high (side View). S6 and s7 is approximately equal in length. (Male 100 2476  Male Close up Skukuza Sept 2018f 1111 Female 100 2477 Acisoma variegatum Slender pintail Female Close up Skukuza MP RSA Febr 2018f 1411)
  • A. inflatum (Stout Pintail) abdomen segment 6 is 2½ x as long as high. S6 is shorter than s7
  • A. inflatum has more extensive black markings on the abdomen than the A. variegatum
  • Side view the lower region of segment 4 is black in the A. inflatum but whitish in the A. variegatum (Male 100 2479   Male Hertzogberg MP Nov 2017f 1011 Female 100 2478 Acisoma inflatum Stout Pintail Hertzogberg MP Nov 2017f 511)
  • Despite marked differences in mature males, females and fresh males are less distinctly marked and may be confused
Distribution and habitat:

Acisoma inflatum Stout Pintail Distribution Map May 2020Northwards from KZN to MP, LP, and GP.
Found in most African countries
Occurs in swampy and well vegetated habitats along lakes, pools and slow parts of rivers and streams in Savannah and woodland.

Behaviour:

Their flight is almost wasp-like as it darts over the floating vegetation, frequently settling, usually at least a metre from the bank.

Further reading:

Websites of Interest
Odonata Atlas of Africa VMU Number 666750
The IUCN Red List of Threatened Species (Least Concern)
African Dragonflies and Damselflies Online

 

 
X

Right Click

Copyrighted material - contact us if you want to buy a photo