Amphinemura hexalobata, Li, Weihai, Wang, Ying & Yang, Ding, 2017

Li, Weihai, Wang, Ying & Yang, Ding, 2017, Two new species of Amphinemura (Plecoptera: Nemouridae) from Tibet, Zootaxa 4247 (4), pp. 494-500 : 495-499

Amphinemura hexalobata sp. nov.

( Figs. 2 , 3 b, 3d)

Adult habitus ( Figs. 3 b, 3d). Forewing length 5.2–5.3 mm, hind wing length 4.1–4.2 mm in male. Female forewing length 6.3–6.5 mm, hind wing length 5.2–5.3 mm. Body color generally brown. Head brown, antennae and palpi yellowish brown, compound eyes black, ocelli pale. Thorax brown, pronotum subrectangular with distinct irregular rugosities, corners obtuse, posterior margin medially concave; legs yellowish brown without pattern. Wing membranes subhyaline, veins brownish. Abdominal terga brown, terminalia darker.

Male: Tergum IX weakly sclerotized, median portion with shallow anterior and posterior indentations; two groups of long paramedial bristles and tiny spines present along posterior margin ( Fig. 2 a). Vesicle of sternum IX claviform, gradually enlarged toward apex ( Fig. 2 b). Hypoproct broad and somewhat oval basally, gradually tapers toward tubular tip ( Fig. 2 b). Tergum X sclerotized (Fig. 4e), longitudinal concavity beneath epiproct wide and triangular basally, much narrower under base of epiproct. Cercus slightly sclerotized, with a proximal apical nipple. Epiproct elongate, generally subquadrate, apex slightly narrower and nearly truncate ( Fig. 2 c); dorsal sclerite with slender, lateral dark bands deliminating the lateral margins, in dorsal view the band much narrower subapically but in lateral view the band nearly keeping parallel-sided, subapical portion contacting with a M-shaped sclerite extended from anterior constricted portion of ventral sclerite; ventral sclerite gently swollen bulging subapically, fringed spines of different sizes forming a triangular ridge-like arrangement ( Fig. 2 d). Paraproct trilobed ( Figs. 2 e, 2f): outer lobe slender, basally fused with median lobe, medially greatly curved, apex swollen with 4 apical spines; median lobe much wider than outer one, medially out-curved, spherical apex with membrane and armed with a row of 7–8 apical spines along lateral margin ( Figs. 2 a, 2f); inner lobe generally triangular, base relatively wide, mostly hidden by hypoproct.

Female ( Figs. 2 g–2j). Sternum 7 with sclerotized trapezoidal pregenital plate, plate corners obtuse and posterior margin nearly straight, covering ¾ width of sternum 7 and overlapping anterior half of sternum 8.

Sternum 8 with sclerotized subgenital plate, consisting of a pair of tri-lobed lateral sclerites separated by a crescentshaped median notch; paragenital plate pale brownish and slightly sclerotized. Sternum 9 weakly sclerotized, with wide anterior indentation, medially elevated in lateral aspect. Inner genital sclerites better seen through cuticle in ventral view in specimens not fully sclerotized ( Figs. 2 g–h). Paragenital plate ( Figs. 2 g, 2j) extended anteriorly under pre- and subgenital plates forming a foot-shaped sclerite in ventral view, but appearing as a rounded triangle in dorsal view, its light pigmented basal area being covered by the dorsal projection of the subgenital plate that folded and overlapping the paragenital plate; below with paired subrectangular extensions of the subgenital plate, its anterior margins thickened and medially contacting a slender wedge-shaped sclerite extending from the medial notch. Anterior shield absent and a broken ring-shaped sclerite joined to the primary genital organs, the sclerite in posterior view, thickly semicircular with two short slender arms ( Fig. 2 j).

Type material. Holotype male ( HIST), China, Tibet, Eastern Changdu City, Mangkang County, Boundary of Sichuan, Yunnan and Tibet, Mangkang Natural Reserve , Xiarisongduo Village , 3697 m, 2013. VII.5, coll. X.Y. Liu . Paratypes, 7 males (3 in HIST 4 in CAU) 4 females (2 in HIST 2 in CAU), same data as holotype.

Etymology. The specific name refers to the six lobes of the female subgenital plate.

Distribution. China (Tibet).

Diagnosis and remarks. The dorsal outline of epiproct of A. hexalobata is superficially similar to that of A. zhoui Li and Yang, 2008b from Zhejiang and Fujiang provinces, China, and A. lingulata Du & Wang (in Ji et al. 2014) from Shaanxi and Sichuan provinces, China. However, the new species is easily separated from these species by the ventral sclerite of epiproct bearing a compressed row of elongate ventral spines of different sizes forming a triangular ridge in lateral aspect. The ventral spines of epiproct in A. zhoui and A. lingulata are short and of equal sizes. Although, females of most Chinese Amphinemura are unknown, the female of the new species appears distinctive with its peculiar subgenital plate.

Figures

FIGURE 2. Amphinemura hexalobata sp. nov. (a – f male): a. Terminalia, dorsal view. b. Terminalia, ventral view. c. Epiproct, dorsal view. d. Epiproct, lateral view. e. Right paraproct with cercus, caudal view. f. Right paraproct, caudolateral view. g. Female terminalia, ventral view. h. Female terminalia, lateral view. i. Female genital plates, oblique lateral view. j. Female inner sclerites, dorsal view and posterior view of the ring-shaped sclerite.

FIGURE 3. Male habitus (a & b), head and pronotum (c & d), dorsal view. a, c. Amphinemura chayuensis sp. nov. b, d. Amphinemura hexalobata sp. nov.