Description of the Final Instar Exuvia of Urothemis edwardsii with reference to its Emergence site Selection (Odonata: Libellulidae)
Khelifa, Rassim; Zebsa, Rabah; Kahalerras, Amin; Laouar, Abdeldjalil; Mahdjoub, Hayat; Houhamdi, Moussa
The last instar exuviae of the critically endangered Urothemis edwardsii Sélys 1849 is described and illustrated based on exuviae collected from Lake Bleu, Numidia (Northeast Algeria). The species is readily distinguishable from other local libellulids by its large size, coloration pattern, and long dorsal spines. The presence of spiniform setae on dorsal spines 6–8 seems to be a key trait to identify the species. The dragonfly usually emerged on water lilies (Nymphaea alba) at about 10 cm above the water surface at water depths ranging from 50–200 cm with a marked preference to stratum between 100 and 150 cm.