Hercostomus exarticulatoides Stackelberg, 1949

Grichanov, I. Ya., Nourti, M. & Kettani, K., 2020, The Hercostomus exarticulatus species group in the Palaearctic Region (Diptera: Dolichopodidae), Caucasian Entomological Bulletin (Caucas. entomol. bull.) 16 (1), pp. 27-34 : 33

Hercostomus exarticulatoides Stackelberg, 1949

( Figs 16–23 )

Hercostomus exarticulatoides Stackelberg, 1949: 680 .

Hercostomus exarticulatus: Negrobov, Rodionova, 2004: 202 (misidentification).

Material. Lecotype, ♂ ( ZIN), labeled: Rakhaty, Gissar Valley, Tajikistan, 6.08.1943, Stackelberg (in Russian), “ Syntypus Hercostomus exarticulatoides Stackelberg, 1949 ”, “Lecotype Hercostomus exarticulatoides Stack. , des. Grichanov, 2019”. Paralectotypes: 1♂, 1♀ ( ZIN), same 1 st and 3 rd labels with collecting dates 6.08 (♂) and 5.08.1949. Lecotype is designated here according to the articles 61.1 and 74.7.3 of the International Code of Zoological Nomenclature [1999] to fix the current taxonomic concept and ensure consistent future interpretation .

Diagnosis. Fore coxa and femora light yellow; hind tibia entirely yellow; hind tibia with sclerotized triangular dorsolateral apical projection; hypandrium with 2 pairs of arms concealed, more or less straight, thin and curved at apex; outer hypandrial arm worm-like at apex; cercus yellow, dark at apex.

Notes. Stackelberg [1949] provided two pictures (figs 11 and 15) for this species with different shape of male cercus. His picture (fig. 36) and description of hind leg is correct from lateral aspect, but being incorrect, if looking from other aspects. The black and thick transverse spine at base of hind tarsus is visible from only ventrolateral aspect. In fact, the sclerotized dorsolateral apical projection on the hind tibia looks like a regular triangle from lateral aspect, but resembling strongly curved spine from dorsolateral aspect. Hercostomus exarticulatoides was never recorded again after its description. However, Negrobov and Rodionova [2004] mentioned H. exarticulatus females (including one H. exarticulatoides topotype) from Tajikistan (Gissar Range) and Kyrgyzstan (Chatkal Range) that must be associated with H. exarticulatoides . The exact type locality of the species is unknown for us; we were not able to trace the geographical name “Rakhaty” within the borders of Tajikistan. Anyway, H. exarticulatoides types were certainly collected in one of gorges on southern slope of the Gissar Range between Tajik-Uzbek border and Kofarnihon River head (the distance is about 100 km), i.e., in the same area of the country where several other species were described by Stackelberg.

Distribution. Type locality: Tajikistan, “Rakhaty, Gissar Valley” (originally published as “Rakhaty, Gissar Range, 1000–1200 m ”). Palaearctic: Kyrgyzstan, Tajikistan.

Figures

Figs 16–23. Hercostomus exarticulatoides Stackelberg, 1949. 16 – habitus, with inset showing labels under the fly; 17 – head; 18 – wing; 19 – mid femur; 20 – hitching lock between hind tibia and basitarsus, dorsolateral aspect; 21 – hitching lock between hind tibia and basitarsus, ventrolateral aspect; 22 – hypopygium, ventral view; 23 – apex of hypopygium, ventrolateral view. Рис. 9–15. Hercostomus exarticulatoides Stackelberg, 1949. 16 – общий виΑ и этикетки; 17 – гоΛова; 18 – крыΛо; 19 – среΑнее беΑро; 20 – сцепΛение заΑней гоΛени и Λапки, виΑ сверху сбоку; 21 – сцепΛение заΑней гоΛени и Λапки, виΑ снизу сбоку; 22 – гипопигий, виΑ снизу; 23 – вершина гипопигия, виΑ снизу сбоку.