The Hercostomus exarticulatus species group in the Palaearctic Region (Diptera: Dolichopodidae)

Abstract

The Hercostomus exarticulatusspecies group in the Palaearctic Region is defined and reviewed. It comprises 4 species belonging to the nominotypical Hercostomus longiventris lineage. The species group is differentiated from other Hercostomus by the male mid femur bearing ventral tubercle at base, one subtriangular and one semirounded projections at middle of narrow cercus directed ventrally, peculiar hitching lock between hind tibia and basitarsus. Syntypes of H. exarticulatoides Stackelberg, 1949 are studied. Lectotype is designated for the latter species. Hercostomus tanjusilus Negrobov et Tsurikov, 1988, syn. n. is proposed as a junior synonym of H. exarticulatus (Loew, 1857). Photographs of H. exarticulatoides, H. exarticulatus and H. canariensis Santos Abreu, 1929 are published for the first time. A key for the species group is provided. The known distribution of H. exarticulatus group is briefly discussed

Keywords

• hercostomus
• species group
• distribution
• lectotype
• synonym