More Eastern Ringtail dragonflies

One female and two male Eastern Ringtail dragonflies (Erpetogomphus designatus) were spotted during a follow-up photowalk along the Potomac River at Riverbend Park.

Female and male Eastern Ringtail are somewhat similar in appearance. Terminal appendages, the shape of their hind wings, and the relative size of their club are good field markers to differentiate specimens by gender.

Female

The first individual is a female, as indicated by her terminal appendages. Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

08 AUG 2016 | Riverbend Park | Eastern Ringtail (female)

(See a full-size version of the original photo, without annotation.)

The preceding dorsal view of the dragonfly shows its hind wings are rounded near the body, a good field marker for female clubtail dragonflies. In contrast, the hind wings of male clubtails are “indented.” Also notice the female “club” is slightly smaller than the male club, as shown in the following photos.

Male 1

The male’s abdomen is slightly thinner (shown below); the female’s abdomen is slightly thicker (shown above).

08 AUG 2016 | Riverbend Park | Eastern Ringtail (male)

Male 2

Male dragonflies have three terminal appendages, collectively called “claspers,” that are used to grab and hold female dragonflies during mating: an upper pair of cerci (“superior appendages”); and a lower unpaired epiproct (“inferior appendage”).

08 AUG 2016 | Riverbend Park | Eastern Ringtail (male)

(See a full-size version of the original photo, without annotation.)

Notice the male’s hind wings are “indented” near the body, as shown in the last two photos.

08 AUG 2016 | Riverbend Park | Eastern Ringtail (male)

08 AUG 2016 | Riverbend Park | Eastern Ringtail (male)

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

• Genus Erpetogomphus | Erpetogomphus designatus | Eastern Ringtail | female | top view
• Genus Erpetogomphus | Erpetogomphus designatus | Eastern Ringtail | female | side view
• Genus Erpetogomphus | Erpetogomphus designatus | Eastern Ringtail | male | top view
• Genus Erpetogomphus | Erpetogomphus designatus | Eastern Ringtail | male | side view

Copyright © 2016 Walter Sanford. All rights reserved.

Tags: cerci, claspers, Clubtail Family, Eastern Ringtail dragonfly, epiproct, Erpetogomphus designatus, Potomac River, Riverbend Park, terminal appendages, wildlife photography