Rock Hooktail, Paragomphus cognatus, Kliphakiestert

100 1419 Female Ezemvelo GP RSA Jan 2016r 2

Short description:

Rock Hooktail, Paragomphus cognatus is medium sized, light green, dark brown and yellow with a dark brown and yellow abdomen, with reddish brown club (foliations).

Also known as Boulder Hooktail, Riffle Hooktail

Family Gomphidae Rambur, 1842

More images:

Female Young
Close-up

Female
Thorax Pattern

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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.

Male:

In areas of higher rainfall individuals of this species may be darker in colour.
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 with 2 bright yellow to greenish yellow with dark brown stripes with a stripe broken in 3 parts Between the broken and hind stripes a narrow yellow stripe. In the 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 the hind margin 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 small narrow foliations viewed laterally but large widely flared outward when viewed dorsally on segments 8 and 9, foliations yellow with strong blackish brown margins The foliage's may be all dark. S 2 lateral view Brown with "V" shaped mark. This may be a "cross" shape when young changing with age, Superior appendages are long and down and outward curved at the tips, mainly blackish brown towards the hind 2/3 Inferior appendages are curved and knobby, divergent at their tips when viewed from above darkening to blackish brown towards the hind margin..

Female:

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.

Habitat:

Frequents sandy or gravel margins of rivers, streams, pools perching on rocks or bare gravel ground close to the water's edge.
Inferred to occur from 0 to 2400 m above sea level, but mostly below 1700.

Behaviour:

Perching on rocks or bare gravel ground near water

Comparison Chart

Click HERE for a comparison chart for the 5 Hooktail species seen in Southern Africa

Compared with other species:

Similar to Common Hooktai. 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