Onychogomphus cazuma
Onychogomphus cazuma Barona, Cardo & Diaz 2020
Local names: Cazuma pincertail, Cazumatanglibel
Species Information
Description
Newly discovered species (first new speceis found in South-western Europe since the 19th century!). It looks like a mix of O. forcipatus and O. uncatus, but the male appendages and female vulvar scale are unique. GEnetically it is closest to O. boudoti found in Morocco (discovered only six years earlier). Both species seem highly localized due to specific habitat preferences and even more new speceis may be discovered.
Appears paler and smaller than O. uncatus, with the lower male appendages never being darker than the uppers. May thus also be mistaken for O. forcipatus, but with a confusing mix of features recalling both species, such as yellow antehumeral stripes connected dorsally to the broader yellow stripes before them like on O. uncatus. It has a yellow 'collar' anteriorly on the thorax not (or very narrowly) interrupted by black like O. forcipatus. It has a yellow patch on the vertex that is small and circular, while it is typically a wider bar on O. forcipatus and absent in O. uncatus.
Identification requires close examination of male and female sexual characters. The shape of the male appendages is somewhat in-between O. uncatus and O. boudoti. The lower appendage not only lacks the subterminal knobs of O. forcipatus, but also the subbasal knobs found in that species and O. uncatus. Instead there is a subbasal ridge with a peak that is directed straight upward , which thus does not project outwards when viewed from above. The upper appendages are not lobed dorsally like O. forcipatus, but have a spoon-shaped tip simillar to O. uncatus. Anal triangles of Hw in males usually contain 3 cells (as in O. forcipatus), while most O. uncatus have 4 or 5.
Females lack the two small tubercles behind the eyes of O. forcipatus (thus like O. uncatus). However, the lobes of the vulvar scale are nto narrowand finger-like as in O. uncatus, but broad (more like O. forcipatus), although more pointed and the cleft separating them is about half as deep as the vulvar scale is long, rather than dividing the lobes almost completely (thus most like O. boudoti).
Size
Habitat
Springs, streams and upper courses of small rivers in low mountains. These are calcareous with very clear, nutrient-poor water. Males perch at more vegetated slower-flowing sections than those of O. uncatus, often alternating between shallow parts and small pools.
Distribution
Onychogomphus cazuma is so far only found on well-preserved tributaries of two river systems in Valencia province of eastern Spain.As these habitats have very low flow and are vulnerable to development, pollution and drought, the species may well be threatened unde IUCN Red List criteria.
Flight Period
Early June to early September
Behavior
Similar to other Onychogomphus
Conservation Status
Similar Species
Onychogomphus forcipatus, Onychogomphus uncatus, Onychogomphus boudoti
Genus: Onychogomphus
Onychogomphus is a genus of dragonflies in the family Gomphidae. They are commonly known as Pincertails.
Identification
These dragonflies are best known for the male's large appendages. The upper and lower appendages are both distinctly longer than S10 and are curved strongly inwards, like pincers. All species, except O. costae, have a yellow abdomen ringed with black markings, and a yellow thorax with black stripes O. costae is more brown and less distinctly marked. The hindwing has a small anal loop consisting of 1-3 cells. Therefore there is not a straight perpendicular vein running directly to the wing's hind margin from the last thick lengthwise vein in the wing base.
Separation from other genera
The males can hardly be misidentified because of their conspicuous appendages, but females are less obvious. They may be mistaken for Gomphus, Ophiogomphus or Paragomphus. Only Ophiogomphus also has an anal loop, but in this genus the thorax is largely green and the female has two crests on top of the occiput. Paragomphus species are smaller. The male has broad flaps on S8-9 and the female has a row of small black denticles on the rear of the occiput. Gomphus is marked differently, the abdomen generally blacker and is lenghtwise striped, rather than ringed.
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.