Sweltsa lateoblonga Rehman, Du & Huo, 2022

Rehman, Abdur, Huo, Qing-Bo & Du, Yu-Zhou, 2022, A new species and new species group of Sweltsa Ricker, 1943 (Plecoptera: Chloroperlidae), Zootaxa 5154 (1), pp. 60-70 : 61-63

Sweltsa lateoblonga Rehman, Du & Huo sp. nov.

( Figs. 1–4 )

Adult habitus: Triocellate. General body color pale, yellow to brown in alcohol. Head pale brown, compound eyes black, ocelli greyish with black margins, anterior ocellus paler; an obscure interocellar brown spot present, antennae and palpi light brown ( Fig. 1A ). Pronotum with a solid median stripe bearing asymmetrical rugosities and covered with dark brown margins ( Fig. 1A ). Thoracic sclerite paler, mesonotum and metanotum have dark brown U-shaped markings; without a dark medial stripe in the middle ( Fig. 2A ). Wings transparent, legs pale. Abdominal terga 1–8 each bearing brown longitudinal stripes, tergum 1–4 dorsally with triangular stripe and laterally with brown bands, tergum 5–7 with trapezoidal stripe; tergum 8 stripe is rounded and smaller than the other stripes. Cerci pale brown, basal segment brown, terminal segments paler and covered with long setae ( Fig. 2A ).

Male: Body length 9.0–10.0 mm, forewing length 7.5–8.0, hindwing length 6.5–7.0 (n = 7). Tergum 9 without any transverse process, anteriorly with paired brown spots and without median excavation on posterior margins ( Fig. 1B ). Tergum 10 with a pair of distinct dark brown transverse lateral bands, the medial area of the bands greatly enlarged in the shield-like darkly sclerotized basal anchor; the shield dorsally bears two sclerotized posterolateral arms, the anchor wider than long, and with broad typical trapezoidal membranous groove and paragential plates between hemiterga ( Fig. 1B ). Epiproct is broad, widely oblong, but longer than its basal width; medially slightly constricted, apically broad in dorsal view ( Figs. 3A–B ), the basal ring with dorsal and lateral bare areas ( Fig. 3B ); sclerotized dorsally, dark brown from base to the median area, apically yellowish. Basal sclerite of epiproct bears two oval shape patches; in lateral view, margins are much constricted from the base to the apical third, sub-apically wide and rounded ( Figs. 3C–D ). The apex is smooth, bearing a shiny triangular shape cap, but most of the dorsal and ventral surface is covered with golden brown, appressed setae ( Figs. 3A–D ). The aedeagus is completely membranous and subtriangular in shape ( Fig. 1B ). The dorsal and dorsolateral lobes are slightly rounded ( Fig. 1C ). The posterior portion of the aedeagus bears a pair of nipple-shaped lobes mesally, each covered with numerous long hairs ( Fig. 1D ).

Female: Body length 9.5–10.5 mm, forewing length 8.0–9.0 mm, hindwing length 7.5–8.0 mm (n = 9). Habitus is generally similar to the male. Abdominal tergum 1–7 dorsally with medial stripes ( Fig. 2B ). The posterior margins of sternum 8 bear a subtriangular subgenital plate ventrally, reaching near the middle of sternum 9; the posterior tip of the subgenital plate is broadly rounded and connected to preceding segments that are slightly incised at the base ( Figs. 4B–D ).

Nymph and egg: Unknown

Type materials: Holotype male, China, Sichuan Province, Pingwu County, Wanglang, Nature Reserve , Changbaigou , 2016-VII-17, N 32.1577, E 104.0269, 2564 m, Leg. Du Yu-Zhou, Zhao Meng-Yuan, Qing-Bo Huo ; Paratypes, 7 males, 9 females same data as for the holotype .

Distribution: China (Sichuan Province).

Etymology: The name of the new species refers to the shape of the epiproct that is widely oblong. The Latin “ lateoblonga ” means widely oblong.

Remarks: The new species is closely similar to S. wui and S. yunnan Tierno de Figueroa & Fochetti, 2002 . The new species can be distinguished from S. wui by the head, pronotum pigmentation, and the epiproct. The head of S. wui bears a distinct interocellar triangular spot and the pronotum has a dark median band (fig. 1 in Stark & Sivec 2009). In contrast, the head of the new species lacks a triangular spot and the pronotum bears a solid median line with asymmetrical rugosities ( Fig. 1A ). The base of the epiproct of S.wui is broad and rectangular dorsally then constricted from near base to apical third and apically widened (figs. 5–6 in Stark & Sivec 2009), while the new species epiproct base is circular, slightly widened towards the apex dorsally ( Fig. 3A ) and laterally much constricted almost to two-thirds of the epiproct and wider apically ( Fig. 3D ). The epiproct cap of new species is also different from S. wui . The epiproct cap of S. wui is circular, almost lying above the tip of the epiproct (figs. 6, 8 in Stark & Sivec 2009), while the new species with the rounded triangular cap, dorsally ( Figs. 3A–B ). The new species also show similar characteristics to S. yunnan . The epiproct of S. yunnan lacks an apical cap and is almost parallel from the base to the apex (figs. 1–4 in Tierno de Figueroa and Fochetti, 2002). The females of S. wui and S. yunnan are unknown, while the subgenital plate of S. lateoblonga sp. nov. is closely similar to S. insularis Zhiltzova & Levanidova 1978 (fig. 511 in Teslenko and Zhiltzova 2009).

Figures

FIGURE 1. Sweltsa lateoblonga Rehman, Du & Huo sp. nov., male. A. head and pronotum; B: terminalia, dorsal view; C: terminalia, lateral view; D: terminalia, ventral view.

FIGURE 2. Sweltsa lateoblonga Rehman, Du & Huo sp. nov. A: male abdomen, dorsal view; B: female abdomen, dorsal view.

FIGURE 3. Sweltsa lateoblonga Rehman, Du & Huo sp. nov., male. A and B: epiproct, dorsal view; C and D, lateral view.

FIGURE 4. Sweltsa lateoblonga Rehman, Du & Huo sp. nov., female. A: head and pronotum; B: terminalia, dorsal view; C: terminalia, ventral view; D: subgenital plate.