Gomphus pulchellus
Gomphus pulchellus Selys, 1840
Local names: Western clubtail, Westliche Keiljungfer, Plasrombout, Gomphe gentil, Smal klubbtrollslända
Species Information
Description
A clubtail with yelow or yellow to light-olive-green body with black pattern. Eyes are rather pale blue. The wings have yellow costa and sub-costa, while the other veins are black. The pterostigmas are long and yellowish brown in colour. The legs are yellow with black lines, and the tarsi are mainly black. All the segments of the abdomen, the last three included, are on the upper side crossed by a yellow line.
Distinctive with respect to the other clubails are the black pattern with very thin lines on the thorax, both on the upper side and on the sides. Also the intrapleural line; a thin and wavy black line extending from the base of the fore wings to the second legs.
Another unique characteristic of the males is the terminal part of the abdomen, not being clubbed like other clubtails, but cylindrical like in the females. Males and females can be distinguished by the shape of the abdominal appendages: divergent in the males and straight as an extension of the abdomen in the females.
G. graslinii, Stylurus flavipes, G. simillimus and G. vulgatissimus may co-occur with G. pulchellum, but are brighter in colour, with thicker thorax black markings and a more club-shaped abdomen. Their interpleural stripe always stop just above the metastigma. The thin thorax lines resemble Onychogomphus cecilia, which has a bright green thorax.
Size
Habitat
Gomphus pulchellum breeds in many different kinds of standing and slow to moderately fast flowing habitats, including large rivers, canals, oxbows, lakes, gravel pits, larger cattle ponds and occasional mountain peat bogs. The species is absent from rocky or faster flowing streams and is rarely found in mountains although breeding has been recorded up to 1 500 m.
Distribution
Gomphus pulchellum is a west Europe endemic ranging from the Iberian Peninsula to the Netherlands and to the western and southern parts of Germany. During recent decades it has expanded northwards and eastwards, and is presently known from the westernmost of Austria and the western two-thirds of Germany. The species is widespread in the south-western half of the Iberian Peninsula but is has a much more scattered occurrence in other parts of Spain. Two old records from Italy and one from Croatia may refer to vagrants.
Flight Period
April to August. Most abundant from mid-May to mid-August.
Behavior
Males search along the shoreline for females, flying in a wave-like flight; constantly varying their height but staying just a few centimeters above the water.
Conservation Status
Similar Species
Gomphus graslinii, Gomphus simillimus, Gomphus vulgatissimus, Onychogomphus cecilia, Stylurus flavipes
External Links
Genus: Gomphus
Gomphus is a genus of clubtail dragonflies in the family Gomphidae. As a result of phylogenetic studies, Gomphus subgenera Gomphurus, Hylogomphus, Phanogomphus, and Stenogomphurus were elevated in rank to genus in 2017. With the removal of their member species, Gomphus ended up with 11 of its previous 54 species.
Identification
Medium-sized dragonflies with a yellow to greenish body, with black markings. They have a diagnostic yellow line, almost uninterrupted, running from S1 to S7, or even S10. Eyes are clearly separated. The abdomen is club-shaped in most species, but lacks any leaf-like lateral flaps. The males have rather short, clearly diverging, upper appendages. The size is about equal to S10. The lower appendages are only slightly shorter, and their branches are largely eclipsed by the uppers when viewed from above. These short, splayed, eclipsing appendages are unique in Europe. The hindwing lacks an anal loop, therefore an uninterrupted perpendicular vein connects the subtriangle and the hind margin.
Separation from other genera
All gomphids in Europe are rather similar in general appearance and size, except for the large Lindenia and small Paragomphus. Males of both these genera bear abdominal flaps and have very long, parallel upper appendages. Ophiogomphus and Onychogomphus have an hind wing anal loop, and incurved upper appendages that do not eclipse the parallel branches of the lower appendage. Moreover, the Onychogomphus male appendages are long and pincer-like. Their abdomen appears ringed or spotted, rather than striped. In the field, confusion with Ophiogomphus is most likely, but mature adults are unmistakable because of their bright green head and thorax, as well as the yellow upper appendages.
When seen poorly, particularly in flight, females and immatures of some libellulids, particularly Orthetrum cancellatum, might resemble Gomphus. These have their eyes touching each other.
Separation of the species
Few of the genera of Europe seem as uniform as this one, and all nine species may be confused. The separation of three species (G. schneiderii, G. ubadschii, G. lucash) from their more widespread counterparts (G. vulgatissimus, G. simillimus) is still somewhat questionable, although the species in each pair are geographically (largely) separated.
Behaviour
Relatively shy dragonflies. The large numbers of exuviae found on river banks may correlate poorly to the occasional adult seen at the same site. After emerging, adults leave the water to mature in surrounding terrain, such as overgrown fields, borders and fallow land. These are often better places to search than the waterside. Mature males perch on twigs or rocks at the water's edge, waiting for females. At larger rivers they may also fly for long periods in midstream (G. vulgatissimus), or search the edges (G. pulchellus). It might be useful to search for individuals in the middle of the stream with binoculars. Females are especially shy, dashing out to open water, often in the centre of a stream, depositing many eggs in only one or several dips.
Family: Gomphidae
The Gomphidae are a family of dragonflies commonly referred to as clubtails or club-tailed dragonflies. The family contains about 90 genera and 900 species found across Europe, Asia, North and South America and Australia. The name refers to the club-like widening of the end of the abdomen (S7-S9). However, this club is usually less pronounced in females and is entirely absent in some species.
Characteristics
Clubtails have small, widely separated compound eyes, a trait they share with the Petaluridae and with damselflies. The eyes are blue, turquoise, or green. The thorax in most species is pale with dark stripes, and the pattern of the stripes is often diagnostic. They lack the bright metallic colors of many dragonfly groups and are mostly cryptically colored to avoid detection and little difference between the sexes is seen. Adults are usually from 40 to 70 mm in length.
Clubtails are fast-flying dragonflies with short flight seasons. They spend much time at rest, perching in a suitable position to dart forth to prey on flying insects. They tend to perch on the ground or on leaves with the abdomen sloping up and its tip curling down a little. Larger species may perch with a drooping abdomen or lie flat on a leaf. Another stance adopted by clubtails perching in the open is obelisking, standing with the abdomen raised vertically, a posture adopted otherwise only by the skimmers.
Most clubtails breed in streams, rivers, or lakes. The nymphs are unusual in having a flat mentum, part of the mouthparts, and their antennae have only four segments. They burrow in the sediment at the bottom of the water body.