Erythrodiplax nigricans
| Erythrodiplax nigricans | ||||||||||||
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| Erythrodiplax nigricans | ||||||||||||
| ( Rambur , 1842) |
Erythrodiplax nigricans is a slender species of dragonfly from the subfamily Sympetrinae . It occurs in the southern part of South America .
features
Erythrodiplax nigricans has a slender abdomen . While the sides run parallel in the females, the abdomen in the males narrows at the level of the fourth and fifth segments and widens again towards the tip.
A reliable determination of the species is only possible via the structure of the genitals arranged on the second abdominal segment. The almost upright hamuli bend abruptly backwards and are slightly higher than the genital lobe . The outer part is slightly longer than the inner, straight part. At the top, the inner part also bends abruptly upwards towards the outer part. The genital lobe covers the rear area and is particularly narrowed at the tip. The penis structure similar to that of when erect basalis group otherwise that of the congenital group . While the penis is quite slim at the tip, it is almost as wide as it is long at the base. There are small lobes on the side. The tip is broadly rounded and bends slightly backwards. The middle process usually extends beyond the tip of the lateral lobes. It is slim, slightly sclerotized and swellable. The abdominal appendages of the males are covered with eight to ten small teeth on the two thirds of the belly located further out. In females, the shovel-shaped vulvar lamina measures about half to two thirds of the length of the ninth segment.
Depending on age and gender, the coloring varies greatly within the species. Young adults are characterized by a distinctive pattern: the back of the head is dark brown to bluish with a brownish lower edge. On the front of the forehead , blue predominates in males and yellow in females. In addition, a greenish yellow line runs on the front edge. The sides of the forehead and the lower lip are also colored greenish yellow . The upper lip, however, is yellowish brown. The head is yellowish on the back, sides and behind the eyes. The slightly square posterior lobe of the prothorax is yellowish brown. From the back of the thorax , the brown shade above runs laterally into greenish, whereby it drifts into yellowish in the rear part and towards the abdomen. The legs are black, with the exception of the yellow outside of the first leg segment and the outermost basimesal parts of the second and third leg segments. The abdomen is mostly yellow. There is a brownish black keel on the first two segments; on the posterior segments, a narrow brown or black band runs along the dorsal keel, which widens slightly towards the rear. In addition, a band runs laterally just above the lateral keels, which begins in the rear half of the third segment, widens in the area of the fourth and seventh segments towards the end of the segment and is finally widened completely on the eighth and ninth segments. The tenth segment is black and has an elongated spot on both sides. The abdominal appendages are yellow. With increasing age, the animals darken from the top of the head and from the end of the abdomen and become bluish black, with the forehead remaining metallic blue. The abdominal appendages of the males remain partially yellowish. In addition, yellow or brownish lateral spots usually remain on the seventh segment.
The hind wings are transparent and have a brown spot in the area of the base. Some individuals also have another spot just behind the wing mark .
credentials
- ↑ a b c d e f Donald Joyce Borror - A Revision of the Libelluline Genus Erythrodiplax (Odonata) [p. 144ff ], The Ohio State University, Columbus 1942
