117 555 Ceratogomphus pictus Common Thorntail 100 1122 Ceratogomphus pictus Common Thorntail Male Ezemvelo GP RSA Dec 2015r 1 100 1124 Ceratogomphus pictus Common Thorntail Female Ezemvelo Dec 2015r 2

Common Thorntail.  Gewone Doringstert.

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Short description:

Common Thorntail, Ceratogomphus pictus, Genus Ceratogomphusis, Family Gomphidae, medium sized yellow, greenish yellow and brownish black, with a narrow club formed mostly by large foliations at the end of the abdomen. It has a sharp, forward-pointing dorsal spike (thorn, hence the name Thorntail) on the last abdominal segment.

Key identification features:

Male:

  • Face yellow, labrum yellow with three black transverse lines. Clypeus light yellow. Frons greenish yellow with two black bands running across in front. Head black above with central yellow dot, back of head yellow with black margin.
  • Eyes dark greyish blue above and light greyish blue below.
  • Thorax has white, greenish yellow to yellow stripes, with brown diagonal stripes separating the yellow/white stripes. Dorsal abdomen with smooth tiger-like stripes.
  • Wings clear, with faint greenish tint and prominent yellow costa. Pterostigmas of moderate length (4 mm), black.
  • Abdomen has series of broken black and yellow rings on the abdomen with narrow strait foliations on S 8. The foliations have a diagnostic thin black line on the lower border. There is a strong forward pointing spike on s 10 that folds into s 9 when the abdomen is held straight rendering the spike invisible. When s10 is held in a downward pointing posture the spike is clearly visible. Claspers short black with yellow. Lower clasper club-like, sharply curved upwards with dark protrusion on lower half
  • A dark variant is also found.

Female:

  • Brighter with smaller foliations and no spine on S 10. S 9-10 downwards curved. 
  • A dark variant is also found.
Compared with other species:
  • Ceratogomphus triceraticus, Cape Thorntail is larger in size and overall darker than C. pictus (Common Thorntail) which is more yellow. Black markings on thorax, abdomen and foliation are considerably darker in C. triceraticus.
  • The yellow thorax stripes, abdominal markings can be confused with Lined Claspertail (Onychogomphus supinus) and Clubbed Talontail (Crenigomphus hartmanni). Correlate identity with the club and clasper structures
Distribution and habitat:
  • Found all provinces except dry areas of Northern Cape Province
  • Prefers open margins of large and small water bodies, streams, rivers, standing waters in open landscapes and open areas in forest. Often with rocks and a gravelly and/or sandy bottom, probably especially calm sections (like pools) with coarse detritus. Also easily colonises newly created trapped bodies of water (unusual for Gomphids). From 0 to 2100 m above sea level, but mostly between 700 and 1900.
Behaviour:
  • It perches on the ground, frequently rests on bare patches of soil or on a small boulder.
Further reading:
Books:
A Guide to Dragonflies and Damselflies of South Africa      p 130
Dragonflies and Damselflies of South Africa   p 131
The Dragonflies and Damselflies Of Eastern Africa    p 106
Dragonfly Biotic Index     p 122

Websites of interest:

Warwick Tarboton
A Visual Guide to the Damselflies and Dragonflies of South Africa

Odonata Atlas of Africa VMU Number 664550
African Dragonflies and Damselflies Online
The IUCR Red list of Threatened Species
Other Information:
Size Comparison Diagram: Dragonflies and Damselflies
Morphology of a Dragonfly 
and Damselfly
Map of South Africa
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