Cobra Clubtail

The cobra clubtail (Gomphurus vastus) is a large, robust dragonfly belonging to the family Gomphidae, distinguished by the characteristic club-shaped expansion at the terminal segments of the male's abdomen—a feature that lends the entire clubtail family its common name. This species is one of the largest gomphids in eastern North America, with a body length typically reaching 60–75 millimeters. Males display striking yellow and black patterning along the abdomen, with the club markings particularly vivid during territorial displays. Cobra clubtails inhabit large, clean rivers with moderate to swift currents and sandy or gravelly substrates, where larvae burrow into the riverbed during their multi-year aquatic development. The species is distributed across the eastern United States, with strongholds in river systems draining the Appalachian foothills and the Midwest, including portions of the Ohio, Tennessee, and Mississippi River drainages. Adults are strong fliers that perch on rocks and logs near the water's edge, making short forays to catch flying insect prey in mid-air. Mating occurs in flight over the river, and females deposit eggs directly into the water by tapping the abdomen on the surface. The cobra clubtail is sensitive to water quality degradation and siltation, serving as a bioindicator of river health. It is listed as Least Concern given its relatively broad distribution across river systems with adequate habitat quality.