Rock Hooktail. Kliphakiestert.
Paragomphus cognatus (Rambur, 1842)
Also known as Boulder Hooktail, Riffle Hooktail
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Paragomphus cognatus, Rock Hooktail, Genus Paragomphus, Family Gomphidae, is medium sized, light green, dark brown and yellow with a dark brown and yellow abdomen, with reddish brown club (foliations).
Key identification features:
Two forms exist. A lighter form mostly is seen in the northern region and a darker form primarily in the Western Cape, Eastern Cape and KZN areas but, records of the darker form exist form the Limpopo and northern region. The dark form tends to lack the green colour of the light form, the yellow is much darker and the brown tends towards black.
- Face is mostly all yellow but lighter yellow to white in the lighter northern form. Labrum is yellow with central brown spot and blackish brown basal line, which is strong in darker coloured Western Cape form. Clypeus yellow, Western Cape form may have two dark brown crescent-shaped markings on postclypeus. Frons is yellow with diffuse brown band in front, which can be bold and distinct in Western Cape form.Head is black with yellow spots above (all black in Western Cape form), back of head yellow.
- Eyes light greenish grey.
- Thorax is bright yellow to greenish yellow with dark brown stripes, in Western Cape form the brown stripes in the lower region of thorax may be pruinescent. Dorsal thorax pattern indicate a long neck birdlike pattern when looked at from the from with a dark brown spot at the "head of the bird followed by a short bullet like pattern ending at the neck.
- Wings clear, sometimes slightly smoky in Western Cape form. Pterostigmas black, 3.75 mm long.
- Abdomen alternately black and yellow with large foliations on segments 8 and 9, foliations yellow with strong blackish brown margins. S 2 lateral view Brown with "V" shaped mark. This may be a "cross" shape when young. Superior appendages are long and down-curved, with blackish brown tips. Inferior appendages are curved and knobbly, divergent at their tips when viewed from above.
- Female has similar head, thorax , body colour and patterning , wings smokier and can be highly smoky in Western Cape form, abdomen stouter, foliations very narrow.
Compared with other species:
- Similar to Common Hooktail (P. genei). Claspers do not curve outwards at the tip. P. cognatus, claspers curve outwards at the tip. Corkscrew Hooktail, P. elpidius, upper claspers are much longer than the bottom claspers. Top claspers curl in toward the abdomen at the tips.
- All the Hooktails have different shaped foliations. Common Hooktail (P. genei). P. cognatus
Distribution and habitat:
- Widespread and common in South Africa. A dark formis present in the western cape
- Frequents sandy or gravel margins of rivers, streams, pools perching on rocks or bare gravel ground close to the water's edge.
- Perching on rocks or bare gravel ground near water