Yellow Presba, Syncordulia gracilis, Geelswalker.
Short Description:
Syncordulia gracilis, Yellow Presba, Geelswalker is medium-sized to fairly large, slender, dark brown, light brown, black and yellow.
Family Libelluloidea incertae sedis
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Key identification features:
Male:
- Face is yellow to sunflower yellow with the vertex rounded and shiny black.
- Eyes are dark to light grey.
- Thorax is dark brown with two narrow yellow to bright yellow stripes that is bordered by black lines. A thin yellow dorsal line on thorax and between wing bases. Wings are smoky becoming clear in older individuals but may have a smoky patch at the base of the wing.
- Abdomen is slender when viewed from above with a broken dark brown to light brown line along its length. Appendages are long and black.
Female:
- Similar to males but with much stouter abdomen in side view and more extensive amber in wings.
Distribution and habitat:
- Frequents swift shallow montane rivers flowing over a bed of flat rocks in open valleys, with fynbos and grassy banks.
- Inferred to occur from 0 to 900 m above sea level, but possibly higher up.
Behaviour:
- Frequents swift shallow montane rivers flowing over a bed of flat rocks in open valleys, with fynbos and grassy banks in mostly open landscapes, but also open areas in forest. Probably especially calmer sections (like pools) with submerged roots and probably coarse detritus. Occurs from 0 to 900 m above sea level, but possibly higher up.
- It is rarely over water, normally flying in fynbos or over low bushy vegetation, often several hundred metres from the water.
- Rests close to the ground in thick vegetation, sometimes on the underside of branches where it is highly camouflaged.
Compared with other species:
- S. venator (Mahogany Presba) is very a distinctive reddish brown, yellow-spotted species, which is much redder overall than Syncordulia gracilis (Yellow Presba) and S. legator (Gilded Presba)both of which are essentially yellowish.
- S. venator does not have the distinctive yellow stripes on side of thorax as does S. gracilis.
- S. venator is similar to S. serendipator (Rustic Presba), both in overall colour and size.
- S. venator abdominal spots are 'hoof' shaped and pale yellow when viewed from above, whereas they are more solid and orangish in S. serendipator.
- S. venator also has a fine, widening line along the mid-line of the thorax, barely present in S. serendipator.
Full credit for this comparison to Michael J Samways.
Distribution
South Africa:
- Endemic to the mountainous areas of the south western part of the Western Cape Province of South Africa.
- Very rare and localised everywhere in its range, and for a long time it has not been seen at many sites where it historically was present (e.g., Michell's Pass). With the removal of invasive alien trees, it has recovered at some localities (e.g., Franschhoek Pass), however it is still vulnerable. It is known only from a few sites (around six locations).May change as more data is gathered.
Further reading:
Odonata Atlas of Africa - VMU Number 666270
A Visual Guide to the Damselflies and Dragonflies of South Africa
The IUCN Red List of Threatened Species Vulnerable
African Dragonflies & Damselflies Online