Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) is a new species on my life list of odonates. This is the first one that I spotted during a photowalk along the Potomac River at Riverbend Park.
This individual is a male, as indicated by its terminal appendages and the shape of its hind wings.
Contrast the size of the “club” at the tip of male’s abdomen with the female club, shown in my last photoblog post. Notice the male club is slightly larger than the female club.
The following dorsal view of the dragonfly shows its hind wings are “indented” near the body, a good field marker for male clubtail dragonflies. In contrast, the hind wings of female clubtails are rounded.
Black-shouldered Spinyleg is the only clubtail with broad, pale green thoracic stripes. Also notice the broad dark stripe on the “shoulder” of the thorax, hence the common name “Black-shouldered.” Although all dragonflies have spiny legs, Black-shouldered Spinyleg has large leg spines, especially on their hind legs.
Copyright © 2016 Walter Sanford. All rights reserved.