The photo above (by Wayne Johnston) can be viewed in OdonataMAP here.
Find this species in the FBIS database (Freshwater Biodiversity Information System) here.
Family Libellulidae
Acisoma inflatum – STOUT PINTAIL
Identification
Small size
Hindwing – 22mm.
Easily recognised as an Acisoma species by the swollen abdomen base that tapers off sharply from segment 6 down to the tip.
Most similar to the Slender Pintail (Acisoma variegatum). The two species bear a close resemblance to one another and co-occur at many sites.
The most conclusive way to separate the two is the colouration difference, on the S4 ventral corner, along the sides of the abdomen. In A. variegatum the ventral corner is mostly white, while it is edged with black in A. inflatum. Additionally the S5 lateral carina is partly white in A. variegatum and all-black in A. inflatum.
Acisoma variegatum shows segments 6 and 7 of equal length, while in Acisoma inflatum segment 6 is shorter than segment 7.
Additionally Acisoma inflatum tends to be slightly smaller and somewhat duller in colour, sometimes showing a yellowish-brown wash on the thorax.
Click here for more details on identification.
Okavango Delta, Botswana
Photo by Ryan Tippett
Habitat
Inhabits marshes and floodplains with pools that support a rich growth of aquatic plants, particularly sedge, reeds and grasses. May also be found along slow moving sections of rivers.
Photo by Ryan Tippett
Behaviour
Sits close to the water on floating or emergent plant stems. Hunts from a perch and quickly resettles again. The flight is fast and wasp-like.
Status and Conservation
Locally common. Listed as of Least Concern in the IUCN Red List of Threatened Species. Most common in natural habitats but will make use of suitable man-made sites like dams and ponds.
Distribution
Acisoma inflatum occurs widely across the savanna regions of Sub-Saharan Africa. Also occurs very locally along parts of the Mediterranean coastline of North Africa.
In South Africa it is found in the higher rainfall areas of the north and east.
Below is a map showing the distribution of records for Stout Pintail in the OdonataMAP database as at February 2020.
The next map below is an imputed map, produced by an interpolation algorithm, which attempts to generate a full distribution map from the partial information in the map above. This map will be improved by the submission of records to the OdonataMAP section of the Virtual Museum.
Ultimately, we will produce a series of maps for all the odonata species in the region. The current algorithm is a new algorithm. The objective is mainly to produce “smoothed” maps that could go into a field guide for odonata. This basic version of the algorithm (as mapped above) does not make use of “explanatory variables” (e.g. altitude, terrain roughness, presence of freshwater — we will be producing maps that take these variables into account soon). Currently, it only makes use of the OdonataMAP records for the species being mapped, as well as all the other records of all other species. The basic maps are “optimistic” and will generally show ranges to be larger than what they probably are.
These maps use the data in the OdonataMAP section of the Virtual Museum, and also the database assembled by the previous JRS funded project, which was led by Professor Michael Samways and Dr KD Dijkstra.
