Rock Hooktail,   Paragomphus cognatus   Kliphakiestert

 Family Gomphidae Rambur, 1842
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

More images:

100 604 Male Ezemvelo Jan 2016 r 1 of 1Image Gallery

100 1467 Paragomphus cognatus Rock Hooktail Male Close up Ezemvelo GP RSA Nov 2018r 3Male

100 1465 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 3Male

100 1484 Paragomphus cognatus Rock Hooktail Female Wilgerivier MP RSA Nov 2017r 1Female

100 1472 Wilgerivier MP RSA Nov 2017r 17Thorax 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.100 1474 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 19  100 1469 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 8 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. 100 1474 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 19
  • 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. 100 1466 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 7 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.100 1469 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 8 100 1472 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 17
  • 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 foliages 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, maily blackish brown towards the hind 2/3  Inferior appendages are curved and knobbly, divergent at their tips when viewed from above darkening to blackish brown towards the hind margin.. 100 1479 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 32  100 1481 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 38  100 1480 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 39  100 1481 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 38  Female: 100 1484 Paragomphus cognatus Rock Hooktail Female Wilgerivier MP RSA Nov 2017r 1
  • Female has similar head, 100 1487 Paragomphus cognatus Rock Hooktail Female Wilgerivier MP RSA Nov 2017r 7 thorax 100 1485 Paragomphus cognatus Rock Hooktail Female Wilgerivier MP RSA Nov 2017r 3 , body colour and patterning  100 1484 Paragomphus cognatus Rock Hooktail Female Wilgerivier MP RSA Nov 2017r 1, wings smokier and can be highly smoky in Western Cape form, abdomen stouter, foliations very narrow. 100 1489 Paragomphus cognatus Rock Hooktail Female Wilgerivier MP RSA Nov 2017r 9 100 1490 Paragomphus cognatus Rock Hooktail Female Wilgerivier MP RSA Nov 2017r 8
Compared with other species:
  • Similar to Common Hooktail (P. genei). 100 1886 Paragomphus genei Common Hooktail Male Close UP Ndumo KZN RSA Mch 2018r 3  100 2503 Paragomphus genei Common Hooktail Male Close UP Ndumo KZN RSA Mch 2018r 47  100 2503 Paragomphus genei Common Hooktail Male Close UP Ndumo KZN RSA Mch 2018r 47 Claspers do not curve outwards at the tip. P. cognatus, claspers curve outwards 100 1480 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 39 100 1481 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 38  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).  100 2503 Paragomphus genei Common Hooktail Male Close UP Ndumo KZN RSA Mch 2018r 47  P. cognatus  100 1480 Paragomphus cognatus Rock Hooktail Male Wilgerivier MP RSA Nov 2017r 39
Distribution and habitat:

Paragomphus cognatus Rock Hooktail Distribution Map May 2020Widespread and common in South Africa excluding the dry central interior. A dark form is 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.
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
Further reading:

Websites:
Odonata Atlas of Africa VMU Number 665740
African Dragonflies & Damselflies Online
A Visual Guide to the Damselflies and Dragonflies of South Africa
The IUCN Red List of Threatened Species.   Least Concern

 
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