Indonemoura quadrata, Mo, Raorao, Wang, Guoquan, Yang, Ding, Li, Weihai & uranyi, David, 2019

Mo, Raorao, Wang, Guoquan, Yang, Ding, Li, Weihai & uranyi, David, 2019, Two new species and one new regional record of Indonemoura from Guangxi, China, with additions to larval characters (Plecoptera, Nemouridae), ZooKeys 825, pp. 25-42 : 25-28

Indonemoura quadrata sp. n. Figs 1, 2, 3, 4, 10a, b

Adult habitus

(Fig. 1a, b). Medium sized species, forewing length in males 6.8-7.4 mm, females 7.9 mm. Head and mouthparts dark brown, antennae brown; compound eyes black. Thorax brown; pronotum darker with pale band along lateral margins; legs (Fig. 1b) mostly dark brown, distal half of hind femora with distinct yellow brown band; wings subhyaline with darker veins; Abdominal segments mostly brown except terminalia darker; hairs on abdomen mostly pale brown.

Male Terminalia

(Figs 1 c–e, 2 a–e). Tergum IX (Fig. 2a) distinctly sclerotised, gradually constricted medially, bearing scattered, tiny black spines along mid-posterior margin; the median part of tergum IX weakly sclerotised and semicircular. Sternum IX (Fig. 2b) with claviform vesicle, slightly constricted basally; hypoproct broad and subquadrate at basal half, then gradually tapering toward tip, and covered by dense hairs. Tergum X mostly sclerotised, with narrow longitudinal concavity beneath epiproct. Cercus slightly sclerotised, nearly cylindrical with distinct hairs and a black oval process at tip, length varies ca. 2 –3× width. Epiproct (Fig. 2a, c) basal half nearly parallel-sided, apical half slightly enlarged in dorsal view, with distinct apical incision; ventral sclerite strongly sclerotised, broad at base and becoming narrower toward apex, expanded ventrally into a very large semicircular ridge with rows of black spines, and the middle of ventral sclerite with two incisions forming a small semicircular process. Paraproct (Figs 1 c–e, 2a, b, d, e) divided into three lobes: inner lobe sclerotised and slender, adhering to median lobe and mostly hidden by hypoproct then hardly observed; inner portion of median lobe sclerotised forming a hook-like structure with sharp tip, and remainder membranous with dense hairs at the apex; outer lobe darkly sclerotised, much longer than median lobe with two subapical prongs; the outer flat prong pale brown and curved ventrad, bifurcate apically; the inner prong much slim, forked subapically with a shorter spine ca. 1/3 of other spine.

Female

(Figs 1f, 2f). Sternum VII membranous, two dark inner sclerite belonging to inner genitalia easily detected by transparency. Sternum VIII with large quadrate sclerotised subgenital plate covering the entire length, posterior margin slightly concaved, slightly overlapping the anterior margin of sternum IX, paired paragenital plate is pale brown and triangular, located at the posterolateral corner of the subgenital plate, inner portion fused with subgenital plate, being dark brown and nearly semicircular which also can be seen by transparency. Sternum IX sclerotised anteriorly forming a produced arch shaped extension. Sternum X and paraproct typical. Inner genitalia mostly membranous, anterolateral margin of subgenital plate with a pair of curved thin sclerites; a large, beneath the spermathecal ductus with a pair of slender central sclerite.

Mature larva

(Figs 3, 4): Body relatively slender, body length without antennae and cerci 5.5-7.5 mm. General colour brown, with contrasting pale pattern on terminal segments of abdomen, less distinct dark brown pattern on thorax and distinct bands on the femora. Terminal pattern consists of paired lateral and a posteromedial light patch on tergum X (Fig. 3 penultimate and ultimate larvae), and medial light patches on terga VIII–IX; dark bands on femora occupies distal fourth. Antennae, mouth parts and cerci pale, as well as ventral aspect of the body. Setation long but less distinct. Legs moderately long, width of hind femora more than 1/3 of their length. The pronotum is trapezoidal with rounded corners, wider than long, as wide as head. Cervical gills shorter than the length of cervical sclerite where the gill is attached. Wing pads twice as long as the corresponding segments. Abdomen relatively slender, integument light matt brown, first five abdominal segments terga and sterna entirely divided by pleura, next two partly divided by pleura. Posterior margin of sternum IX of the male larva shortly rounded, sternum VIII of female larva slightly incised; paraprocts blunt. Cerci long, with 30-32 cylindrical segments; length of the 15th segment is ca. two times of its width.

Setation of the larva (Fig. 4): Head, antennae and palpi with dense short setae. Pronotum covered with very short setae; marginal setae distinct and blunt, row continuous but setae in anteromedial and posteromedial half, corners have the longest setae that are as long as one 20th of pronotum width (Fig. 4a). Setae on meso- and metanotum short, as long as marginal setae on pronotum; wing pads with short, acute setae. Legs with dense setation, all tibia bears indistinct swimming hairs shorter than femur width (Fig. 4b). Longest acute setae of all outer femur margins are longer than fourth of the corresponding femur width, not arranged in line but restricted to apical half. Tarsi and claws typical. Tergal segments covered with short setae of different width; row of posterior margin with distinctly longer, acute paired setae reaching ca. third of segment length, but on posterior terga more, similar long setae occur; paired setae slightly raised in lateral view (Fig. 4 c–e). Cercal segments with sparse and indistinct intercalary setation but apical setae dense and relatively long; cercomeres 14-16 with an apical whorl of 10-12 acute setae that are as long as 2/3 of segment length (Fig. 4f).

Type material.

Holotype: 1 male (HIST), China: Guangxi Province, Wuming County, Damingshan National Natural Reserve, stream and seep beneath Golden Turtle Waterfall, 1150 m, 23°30.373'N, 108°26.141'E, 2015.III.21, leg. J Kontschán, JN Li, S Li, WH Li, D Murányi, GQ Wang. Paratypes: 2 males and 1 female (HIST), 1 male, 3 pharate male and 2 pharate female larvae, 18 penultimate and ultimate instar larvae, and 1 exuviae (HNHM), same data as holotype; Guangxi Province, Wuming County, Damingshan National Natural Reserve, inflow stream above Dragon Lake, 1225 m, 23°29.751'N, 108°26.242'E, 2015.III.22, leg. J Kontschán, JN Li, S Li, WH Li, D Murányi, GQ Wang: 2 males (one with its exuviae), 3 ultimate instar larvae, and 1 exuviae (HNHM).

Etymology.

The specific name refers to the sternum VIII of female with quadrate subgenital plate.

Distribution.

China (Guangxi).

Ecology.

The species was found only on the plateau of the Daming Mountains, inhabiting the same two habitats where the recently described Cryptoperla teana Li & Murányi, 2018 was collected (Fig. 10a, b). These two species, as well as Rhopalopsole triangulis Li, Murányi & Yang, 2017 (in Li et al. 2017c) seem to be connected to the ‘tea-coloured’ waters of the Damingshan plateau. March is the beginning of its emergence period, since many penultimate and ultimate stage larvae were still in the hygropetric water layer, while only a few pharate and emerged adults were found.

Remarks.

Indonemoura quadrata is a member of the fujianensis complex which is characterised by ventral sclerite of epiproct with a wide, semicircular structure in lateral view. There are nine species in the fujianensis complex ( Sivec and Stark 2010); including seven recorded from China: I. auriformis Li & Yang, 2008a, I. baishanzuensis Li & Yang, 2006, I. fujianensis Li & Yang, 2005, I. guangdongensis Li & Yang, 2006, I. hubeiensis Yang & Yang, 1991, I. macrolamellata (Wu, 1935), and I. yangi Li & Yang, 2006; I. clavata Sivec & Stark, 2010 and I. tricantha Sivec & Stark, 2010 have been described from Vietnam. The members of the complex can also be distinguished from the basis of the outer lobe of paraproct, that is elongated, slender, and armed with spikes.

Indonemoura quadrata is most similar to I. fujianensis Li & Yang, 2005 from Fujian both in number of spines on the outer lobes of left and right paraprocts. However, the new species may be easily separated from I. fujianensis : ventral sclerite of epiproct with an apical semicircular projection in lateral view; outer lobe with two prongs at apex, and both bifurcate subapically; the outer prong is flat and the size of spines approximately equal; the inner prong’s spines with different length; especially, outer lobe of right paraproct added a black spine at distal half which cannot be seen on the left paraproct. In I. fujianensis , apical spines of the outer lobe number three and two on the left and right paraprocts respectively ( Li and Yang 2005: figs 2, 5). This species also easily confused with I. auriformis by the dorsal view of terminalia because of the same inner prong of the outer paraproct lobe, especially when the outer prong of the outer lobe is hardly observed sometimes due to its paler colour and more or less erect position ( Li and Yang 2008a: figs 8, 11). Among the congeners where females are known, the female of I. quadrata is distinctive by its regular quadrate subgenital plate. Hitherto only two congeners, the Himalayan I. adunca (Harper, 1974) and I. indica (Kimmins, 1947) are known in the larval stage ( Sivec 1981). On the basis of these two Himalayan species, the two species described herein and a further larva that we recently reported from Shaanxi as Indonemoura sp. ( Li et al. 2018), there are no distinctive generic character to distinguish Indonemoura larvae from those of Mesonemoura Baumann, 1975. Both genus can be characterised by the presence of single, short cervical gills, posterior row of setae on terga having longer paired setae, and long setae on femora not arranged in line. The larva of I. quadrata can be distinguished from the few known congeners on the basis of characteristic pale and dark pattern on terga VIII–X. However, similar pattern was observed on the Shaanxi larvae, suggesting the pattern is not a specific character.