horned clubtail

LC - Least Concern

N4 - Apparently Secure

SNR - Unranked

not listed

Horned clubtail is an early season, medium-sized, 23 ⁄16″ long, pond clubtail. It is the most common pond clubtail (genus Arigomphus) in Minnesota. It is found throughout the state except in the southwest corner.

The thorax is yellowish-green or greenish-yellow with black stripes: two shoulder stripes on each side, the upper stripe thick, the lower stripe thinner; and a thin top stripe on each side that wraps around and connects to the thinner shoulder stripe.

The abdomen is slender and black with yellow markings. Unlike most clubtails, the abdomen has no club. The upper (dorsal) surface or abdominal segments 1 through 8 have yellow, elongated, triangular spots. Segment 9 is unmarked. Segment 10 is mostly yellow on top. All segments have a yellow lower margin. On segments 8 and 9, these are sometimes rusty red. On the male, segment 10 is wider than segment 9, a characteristic not seen on any other clubtail. At the tip of segment 10 the male has a pair of distinctive, widely forked claspers. The claspers are yellowish with black tips and resemble bulls horns in shape. Unlike other clubtails, the female has an ovipositor. It is spout-like and about ⅛ to ½ as long as the ninth abdominal segment.

The head is small. The face is yellow. The large compound eyes are blue and do not meet at the top of the head. The area behind the compound eyes at the top of the head (occiput) on both sexes is high, convex, and plate-like. On the female it is yellow, very high, convex, and cleft in the middle. It is the most conspicuous occiput of any clubtail. The female also has a pair of tiny, black, horn-like protuberances between the compound eyes. This is the only pond clubtail (genus Arigomphus), but not the only clubtail (family Gomphidae), with these “horns”. It is the feature that gives this species its common name.

The legs are black. The third and largest segment (femur) of the hind leg on the female is mostly yellow.

The wings are clear except for a dark cell (stigma) on the leading edge near the tip. The vein on the leading edge of the forewing (costa) is yellow in front but may appear black from above or behind. The wing triangle, a section of intersecting veins about 20% of the way from the base to the wingtip, is about the same size in the forewing and the hindwing.

Total length: 23 ⁄16″

Small marshy lakes, muddy ponds, slow streams

Late May to late July

Breeding takes place in still waters. After mating the females deposits eggs by flying close to the water surface and tapping the tip of her abdomen into water. After the eggs hatch the young (naiads) live in submerged vegetation. When they mature they crawl onto a lily pad or partly out of the water on a vegetative stem to emerge as adults.

Sources

17, 18, 24, 27, 29, 30, 82.

Fairly common, locally common

This species was formerly classified as Gomphus cornutus, placed in the subgenus Arigomphus under the genus Gomphus. That genus was recently split and the former subgenera are now the new genera.

Horned Clubtail Dragonfly...

Came across this interesting dragonfly at a pond in Norman County June 2018. Colorful eyes on this Horned Clubtail (Gomphidae) Dragonfly.

Location: Woodbury, MN

Location: Woodbury, MN

Location: Norman County

Came across this interesting dragonfly at a pond in Norman County June 2018. Colorful eyes on this Horned Clubtail (Gomphidae) Dragonfly.