Sweltsa hamula Chen & Du, 2017

Zhi-Teng Chen & Yu-Zhou Du, 2017, A new species of Sweltsa (Plecoptera: Chloroperlidae) from China, with a key to the Sweltsa males of China, Zootaxa 4337 (2), pp. 291-293 : 291-292

Sweltsa hamula Chen & Du , sp. nov. ( Figs. 1–11 .)

Adult habitus. Triocellate. General color brown. Head with dark brown stigmas; compound eyes dark, ocelli with dark margins; antennae brown ( Figs. 1–2 ). Pronotum with symmetrical rugosities and dark margins; meso- and metanota with dark U-marks. Wings hyaline, Rs of forewing branched, anal field of hindwing small and folded with three veins ( Fig. 3 ). Tergum 1 to anterior of tergum 8 with a continuous, brown median stripe ( Fig. 1 ). Cerci brown with long setae.

Male. Body length 8.5–9.0 mm; forewings length 8.0– 8.5 mm, hindwings length 7.0– 7.5 mm. Tergum 9 with an upraised, medially notched transverse ridge ( Figs. 4–5 ). Tergum 10 divided, median portion forming a sclerotized area. From dorsal aspect, epiproct sub-elliptical and with thin lateral margins on basal half, then gradually tapered to a sharp apex; mesally, epiproct with dense hairs ( Figs. 4, 6 , 10). In lateral aspect, epiproct constricted basally and sub-medially, apically back curved, forming a hook-shaped apex ( Figs. 5, 7 , 11). Aedeagus membranous, apically with two fingershaped, hairy lobes ( Fig. 8 ). Tenth sternum broad and trapezoidal ( Fig. 9 ).

Female. Unknown.

Type material. Holotype: male, China: Sichuan Province, Mianyang City, Pingwu County, Wanglang National Nature Reserve , Baixionggou River , 2886 m, 33.0068 N, 104.0270 E, 25 June, 2017, leg. Zhi-Teng Chen, Yue Shen ( ICYZU) . Paratypes: 1 male, same locality and data as holotype ; 1 male, Wanglang National Nature Reserve, Panda protection station, 2566 m, 32.9753 N, 104.0896 E, 24 June, 2017, leg. Zhi-Teng Chen, Yue Shen (ICYZU); 2 males, Wanglang National Nature Reserve, Muyangchang, 2560 m, 32.9701 N, 104.0930 E, 22 June, 2017, leg. Zhi-Teng Chen, Yue Shen (ICYZU).

Etymology. The specific epithet refers to the hook-shaped apex of the epiproct.

Remarks. Sweltsa hamula can be easily distinguished from other Chinese species by the hook-shaped apex of the epiproct. Several male paratypes of the S. hamula have much paler body color than the holotype. To date, the aedeagi of chloroperlids have not been well studied. However, descriptions of everted aedeagi may assist in determining species limits of these taxa.

Adults of the new species were collected from low-growing shrubs along the fast flowing Baixionggou River in the Wanglang National Nature Reserve, established to protect the panda. This area is used primarily for grazing. No other adult stoneflies were present at the time of the above collections.

Figures

FIGURES 1 – 9. Sweltsa hamula, sp. nov., holotype. 1. Male habitus, dorsal view; 2. Male head and pronotum, dorsal view; 3. Wings; 4. Male terminalia, dorsal view; 5. Male terminalia, dorsolateral view; 6. Epiproct, dorsal view; 7. Epiproct, lateral view; 8. Aedeagus, ventral view; 9. Male terminalia, ventral view.