Sphaeronemoura tetragona Du & Zhao, 2020

Zhao, Meng-Yuan & Du, Yu-Zhou, 2020, A new species of Sphaeronemoura (Plecoptera: Nemouridae) from China and additions to three other species of the genus, Zootaxa 4851 (3), pp. 583-592 : 583-585

Sphaeronemoura tetragona Du & Zhao , sp. nov.

Type material: Holotype, 1♂, China, Hunan Province, Taoyuan County, Yunwujie Nature Reserve , 2014-III-22, leg. Du Yu-Zhou ( ICYZU) ; Paratypes, 1♂, the same data as holotype ( ICYZU) .

Distribution: Southeastern China (Hunan Province)

Adult habitus: Head dark smoky brown, antennae brown; head wider than pronotum, pronotum subquadrate, angles blunt rounded, with darker rugosity; cervical gills sausage-like in shape, one simple gill located on either side of each cervical sclerite; wings subhyaline, infuscate, veins dark brown; legs brown.

Male: Body length 9.0 mm, Forewing length 10.2 mm, hindwing length 8.8 mm. Tergum 8 posteromedially expanded and forming a wide hood with a weak notch at the middle of hind margin reaching over distal margin of tergum 9. Tergum 9 broad, unmodified. Tergite 10 with a vertical membranous area medially and a group of long hairs situated on either side below the epiproct. Hypoproct small, rounded, with a blunt rounded apex curving inward, vesicle slender. Paraprocts divided into 3 lobes, inner lobe simple; median lobe broad at base and then branched into two portions, inner portion slender, slightly sclerotized, slightly shorter than inner lobe of epiproct, outer portion membranous and gently projected posteriorly to flat blunt projection; outer lobe linearly and darkly sclerotized ( Fig. 1 ). Epiproct with a long flagellum, which is grooved dorsomedially, apex of the flagellum arcuate with a single slight curve; dorsal sclerite with a notch at the colloidal tapering tip, base of dorsal sclerite slightly sclerotized; ventral sclerite wider than dorsal sclerite, about ⅔ length of dorsal sclerite, with a notch median of apex, bearing several scattered setae ventrolaterally ( Figs. 1-2 ). Cerci truncate and weakly bent inward with a median small spot, and 4 knobs at apex of each cercus.

Female: Unknown.

Etymology: The name refers to cerci truncate and with four knobs at apex. The Latin “ tetragona ” meaning four angles.

Remarks: The male of the new species is most similar to the Taiwanese S. plutonis Banks, 1937 with tergum 8 forming a wide hood with a weak notch medially at the hind margin of tergum 8, but can be separated from the latter species by the rounded hypoproct and the four knobs at the apex of cerci. The new species seems also related to S. asymmetria Li, Yang & Yang, 2016 from Guizhou Province of southwestern China sharing similar cerci. Sphaeronemoura tetragona is distinguished from the latter by the hood of tergum 8 with a weak notch at the middle of hind margin reaching over distal margin of tergum 9 and the simple inner lobe of the paraproct. In S. asymmetria , the hood of tergum 8 is characterized of two asymmetrical lobes and the inner lobe of paraprocts are finger-like with a blunt apex. The apex of the flagellum arcuate with a single slight curve in S. tetragona whereas the apex of the flagellum of S. asymmetria appears straight, not curved.

Figures

FIGURE 1. Sphaeronemoura tetragona Du & Zhao, sp. nov.A: Male terminalia, dorsal view; B: Male terminalia, ventral view; C: Male terminalia, lateral view; D: Male paraproct (left); E: Male epiproct, dorsal view; F: Male epiproct, ventral view; G: Male epiproct, lateral view.

FIGURE 2. Sphaeronemoura tetragona Du & Zhao, sp. nov. Male terminalia, A: dorsal view; B: ventral view; C: lateral view; D: epiproct and flagellum, lateral view.