A Dragonhunter dragonfly (Hagenius brevistylus) exuvia was collected along the Little Patuxent River by Richard Orr, renowned expert on odonates of the mid-Atlantic region of the United States, during an Audubon Naturalist Society adult class and field trip on 15 June 2014 to the North Tract of Patuxent Research Refuge, Anne Arundel County, Maryland USA.
Dragonhunter [larvae] crawl out of the river and often cling on wet wood or roots/vegetation. I have seen them on mud but they seem to like vegetation or wood to cling to during emergence. I took a photo…of a cast skin at the same area [where this specimen was collected]. Source Credit: Personal communication from Richard Orr.
The decision tree used to identify the exuvia as a member of Family Gomphidae (Clubtails) is fairly simple and straightforward.
- The specimen has a flat labium (not mask-like).
- Antennae are either club-shaped or paddle-like (not thin and threadlike as in Aeshnidae).
Dragonhunter is the largest of North American clubtails; accordingly the large size and shape of a Dragonhunter exuvia is so distinctive that it is relatively easy to identify to the species level.
Lateral view showing left side, facing forward (annotated).
(See a full-size version of the original photo, without annotation.)
Notice the large, paddle-like antennae. They remind me of ping pong paddles.
Head-on view (annotated).
(See a full-size version of the original photo, without annotation.)
The large size and shape of Dragonhunter exuviae are key field marks.
Dorsal view.
All clubtail larvae/evuviae have a flat labium that doesn’t cover the face.
Ventral view (annotated).
(See a full-size version of the original photo, without annotation.)
Related Resources
- Photo showing dorsal view of a Dragonhunter exuvia (in situ), taken by Richard Orr on 01 June 2016 along the Little Patuxent River, Patuxent Research Refuge.
- Photo showing dorsal view of a Dragonhunter nymph [ruler shown for scale], embedded on the following Web page: “Dragons and Damsels”: Odonata, Pt. I.
- Photo of a Dragonhunter naiad [nymph] (Hagenius brevistylus), showing a good head-on view of the paddle-like antennae.
- Odonate Exuviae, by Walter Sanford
Tech Tips
The following equipment was used to shoot the preceding photographs: Fujifilm X-T1 digital camera; Fujinon XF18-55mm (27mm-82.5mm, 35mm equivalent) zoom lens plus “Fotasy” brand 10mm extension tube; Fujifilm Shoe Mount Flash EF-42 (on-camera, in TTL mode); Nissin i40 external flash unit (off-camera, in SD mode). A snap-on plastic diffuser was used for each external flash.
Adobe Photoshop CC 2015 was used to annotate selected images.
Copyright © 2016 Walter Sanford. All rights reserved.
Tags: Dragonhunter dragonfly, exuvia, Family Gomphidae (Clubtails), gear talk, Gomphidae, Hagenius brevistylus, Patuxent Research Refuge
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June 24, 2016 at 4:06 am |
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