Helius, Lepeletier and Serville, 1828

Wu, Siyuan, Krzemiński, Wiesław, Soszyńska-Maj, Agnieszka & Ren, Dong, 2019, New fossil representative of the genus Helius (Diptera, Limoniidae) from the little known and newly discovered locality Caergen Village of northeastern Tibetan Plateau (China), Palaeontologia Electronica (2 A) 22 (1), pp. 1-8 : 3-4

Genus HELIUS Lepeletier and Serville, 1828

Type species. Limnobia longirostris Meigen, 1818

Subgenus. Helius Lepeletier and Serville, 1828

Type species. Limnobia longirostris Meigen, 1818

Helius (Helius) qinghai sp. nov. Wu and Krzemiński

Figures 3-4

zoobank.org/ AB485B8C-DFF7-4125-8C49-5D5747200027

Material. Holotype NO. CNU-DIP-QZ2017001, male, deposited in the collection of the Key Laboratory of Insects Evolution and Environment Changes , College of Life Sciences, Capital Normal University, Beijing, China.

Etymology. The species name is derived from the name of the province where specimen was found.

Age and occurrence. Garang Formation at Caergen Village, Duohemao Town, Zeku County, eastern Qinghai Province, north-west China, Early Miocene, 16-19 Ma.

Diagnosis. Last segment of palpus slightly shorter than all remaining segments combined together; rostrum only slightly longer than palpus; antenna almost twice as long as rostrum and two and a half times as long as head; vein R 2+3+4 is almost twice longer than vein Rs; d-cell is as long as 1/7 of wing; hypopygium with short and broad gonocoxite, outer gonostylus strongly sclerotized, short, broad at base and gradually narrowing to distal part; inner gonostylus as long as outer one, lobe-shape.

Comparison. Helius (H.) qinghai sp. nov. differs significantly from other fossil congenerics in the length of the rostrum and wing venation and from the only closely related species H. (H.) oosterbroeki Kopeć, Kania and Krzemiński, 2016 , by the wing venation and male hypopygium. Vein R 2+3+ 4 in H. (H.) oosterbroeki is very short, only about only a quarter longer than Rs, and Rs starts beyond cross vein sc-r, while in H. (H.) qinhghai sp. nov. vein R 2+3+4 is elongated, slightly curved and slightly less than twice as long as vein Rs, and Rs forks at the level of cross-vein sc-r. Moreover, d-cell in H. (H.) oosterbroeki is rounder, while in H. (H.) qinghai sp. nov. is elongated. New species differs by the morphology of male genitalia, both gonostyli are equal in length and shape, while in H. (H.) oosterbroeki outer gonostylus is much thinner and slightly longer than inner gonostylus.

Description. Specimen very well preserved with body and wings ( Figure 3 ); body about 7 mm long, including head and rostrum. Rostrum slightly longer than palpus; head almost 1.3 times wider than long; last segment of palpus only slightly shorter than all remaining segment combined together; antenna twice as long as rostrum and 2.5 times as long as a head, 16-segmented, scapus elongated, cylindrical, pedicel short and widen; first flagellomere as long as following ones ( Figures 3.2 , 4.1 ); wing about 8 mm long ( Figures 3.4 , 4.4 ), narrow. Vein Sc ends behind forking of Rs; R 1 reaches outer margin almost opposite 2/3 length of vein R 2+3+4, R 2+3+4 almost twice as long as Rs; R 5 long, three times longer than Rs, strongly arching and waved at distal part; d-cell big, widen at base; cross-vein m-cu in forking Mb. Fore and middle and left hind legs preserved, long, without spines on femur. Hypopygium ( Figures 3.2 , 4.3 ) with short and broad gonocoxite, outer gonostylus strongly sclerotized, short, broad at base and gradually narrowing to distal part, shorter than 1/3 of gonocoxite; inner gonostylus as long as outer one, lobe-shape, not sclerotize.

Figures

FIGURE 3. Helius (Helius) qinghai n. sp., photography of the holotype No. CNU-DIP-QZ2017001; 1 – body, 2 – male genitalia, 3 – head, 4 – left wing (photo by Siyuan Wu).

FIGURE 4. Helius (Helius) qinghai n. sp., drawings of the holotype No. CNU-DIP-QZ2017001; 1 – head, 2 – male genitalia, 3 – relation between the length of palpi (p), antenna (a) and rostrum, 4 – wing (a – antenna, fl – flagellomeres, g – gonocoxite, ing – inner gonostylus, oug – outer gonostylus, p – pedicel, pl – palpi, r – rostrum, scp – scapus, t – tergite) (drawings by W. Krzemiński).