Amphinemura dingoidea, Li, Weihai, Mo, Raorao, Dong, Wenbin, Yang, Ding & uranyi, David, 2018

Li, Weihai, Mo, Raorao, Dong, Wenbin, Yang, Ding & uranyi, David, 2018, Two new species of Amphinemura (Plecoptera, Nemouridae) from the southern Qinling Mountains of China, based on male, female and larvae, ZooKeys 808, pp. 1-21 : 6-12

Amphinemura dingoidea sp. n. Figs 15, 16, 17-21, 22, 23-28, 33-34, 35

Diagnosis.

Male: tergum IX with long setae, ventral vesicle very long, epiproct weakly modified but with apical notch, paraproctal inner lobe long and slightly bilobed, me dian lobe long, curved and with 5 or 6 apical spines, outer lobe short and lacks spine. Female: subgenital plate strongly bilobed with dome-like median notch, paragenital plate with two branches, inner genitalia simple. Larva: general color light brown with specific, distinct dark brown dorsal pattern, setation long.

Description.

Adult habitus (Fig. 16): Head dark brown without pattern; compound eyes dark brown; antennae dark brown; palpi light brown. Pronotum lighter than head, arrangement of brown pattern similar to larvae. Legs generally brown, coxae and venter of femora lighter. Abdominal segments reddish brown, terminalia brown.

Male (Figs 17-20): Forewing length 6.3-6.5 mm. Tergum IX lightly but evenly sclerotized, two paramedial groups of 6-8 long setae present along posterior margin (Fig. 17). Vesicle of sternum IX very long, constricted medially, about 5 times longer than wide (Figs 18, 19). Hypoproct basal half rectangular, medial portion rounded, apex short and up-curved (Fig. 18). Tergum X widely sclerotized, medial light area beneath epiproct very small and narrow, with 3 or 4 very small lateral spinules (Fig. 17). Cercus lightly sclerotized, stout and short. Epiproct (Figs 16, 17, 19) weakly modified, nearly rectangular with lightly sinuous margin, less than 3 times longer than wide, apically scaled and with a dark medioapical notch. Dorsal sclerite mostly membranous, basal sclerite narrow, lateral sclerite evenly thin and S-curved, basal portion hidden beneath the large membrane, appearing as weak stripe in dorsal aspect, apical portion black in dorsal and lateral aspects and ending subapically (Figs 17, 19); ventral sclerite with weak ridge fringed by a row of short ventral teeth (Fig. 19). Paraproct trilobed (Figs 17-20): inner lobe slightly bilobed, relatively elongate and reach end of terminalia, basally connected to median lobe and membranous portion between the lobes bear minute apical setae; median lobe sclerotized, up-curved at apical half, apical portion in dorsal aspect with 5 or 6 medium-sized spines: 2 or 3 upper spines and 3 lateroapical spines (Figs 17, 19, 20); outer lobe sclerotized and medially curved along cerci, apex up-curved, without spines (Figs 18, 20).

Female (Fig. 15): Forewing length 7.5-7.8 mm. Sternum VII posteriorly greatly produced in a large semicircular pregenital plate, the plate mainly being pale but posterior margin brown. Sternum VIII forms bilobed subgenital plate with a deep medial indentation at inner margin of the lobes, the median notch between subgenital plate dome-like. Paragenital plate with two branches, lower plate large, rounded and lightly pigmented lobe with hairs in ventral surface, upper plate forming a dark brown sloping sclerite seemingly like the pod brim. Sternum IX with anterior margin slightly protruded medially. Paraproct and cerci brownish.

Female inner genitalia (Fig. 21): Inner structure under pregenital plate is simple and membranous, lightly sclerotized, ovum-shaped anterior shield attached to the spermathecal ductus; attached muscles linking with margin of paragenital plate easily observed.

Mature larva (Fig. 22): Body relatively stout and small, body length without antennae and cerci 5.5 mm. General color light brown with distinct and characteristic dark brown dorsal pattern: head mostly dark brown with well delimited light brown pattern on occiput; scape and pedicel dark brown, rest of the antennae and palpi light brown; pronotum mostly pale, dark brown pattern similar to adults; meso-, metanotum and wing pads mostly pale but with distinct, paired Z-shaped dark pattern; legs light brown, apex of femora and base of tibiae darker; abdominal terga I–II entirely pale, terga III–V entire dark, terga VI–X laterally dark with medial pale area gradually widened towards the apex; cerci pale brown. Ventral aspect of the body entirely pale. Setation long and distinct. Legs moderately short, width of hind femora about one-third of their length. The pronotum is rounded trapezoidal, wider than long, slightly wider than head. Cervical gills long, inner gills with 6, outer with 7 branches. Wing pads more than twice as long as the corresponding segments. Abdomen relatively stout, integument light matt brown, first 3 abdominal segments fully, further 3 partly divided by pleura. Posterior margin of sternum IX of the male larva short and blunt triangular. Cerci long, with 25 slightly clubbed segments; length of the 15th segment is more than 3 times of its width.

Setation of the larva (Figs 23-28): Head, antennae and palpi with short setae. Pronotum covered with short setae; marginal setae distinct and blunt, row continuous but setae shorter in anteromedial and posteromedial third, corners have setae as long as 1/15th of pronotum width (Fig. 27). Setae on meso- and metanotum with marginal setae as long as longest marginal setae on pronotum; wing pads with short setae besides marginal ones. Legs with relatively sparse but diverse setae, all tibiae bear sparse and indistinct swimming hairs as long as tibia width (Fig. 28). Longest acute setae of all femora are about as long as half of the corresponding femur width, not arranged in line but restricted to apical half. Tarsi and claws normal. Tergal segments covered with thin setae and a few short hairs; posterior margin with row of 14-16 acute and erect setae, of various length, longest reaches more than half of segment length (Figs 23, 24). Cercal segments with relatively sparse and moderately long setation, apical whorl of setae consist of both dark and whitish setae; setae sparser and shorter on the basal segments (Figs 25, 26). Cercomeres 14-16 with intercalary setae-like indistinct fine hairs, as long as the segment width, and an apical whorl of 8 or 9 acute setae that are much shorter than segment length (Fig. 26).

Type material.

Holotype male (HIST): CHINA, Shaanxi Province, Hanzhong, Foping County, brook in Lover’s Valley by Foping Old Town, 885 m, 33°31.838'N, 107°59.432'E, 2018.IV.21, leg. W.H. Li, R.R. Mo and D. Murányi. Paratypes: same data as holotype: 2 females, 1 male larva (HIST), 1 male, 2 females (HNHM); Shaanxi Province, Hanzhong, Foping County, Changjiaoba Town, steep forest brook in Dizhuang valley, 980 m, 33°33.543'N, 107°58.263'E, 2018.IV.21, leg. W.H. Li, R.R. Mo and D. Murányi: 3 larvae (HNHM).

Affinities.

On the basis of the simple epiproct and rather elongated median lobe of the paraproct, the male of A. dingoidea is similar to several other Chinese species, e.g. A. curvispina (Wu, 1973), A. filarmia Li & Yang, 2000, A. microhamita Li, Dong & amp; Yang, 2018, and A. ovalis Li & Yang, 2005. However, the combination of the long and slightly bilobed inner lobe and short, spine-less outer lobe of paraproct, together with simple but apically notched epiproct, distinguish the new species from all congeners. The female can be easily distinguished from females of the hitherto known Asian Amphinemura species on the basis of the distinctive shape of their subgenital plate combined with rather simple inner genitalia. The larva is distinctive by its rather conspicuous pale and dark brown color pattern.

Distribution and ecology.

Most specimens were found along a small forest brook (Fig. 33), but a single male was collected by the upper, faster flowing section of the same large stream where A. albicauda was collected at the lower section (Fig. 35). Both localities are at moderate elevations, have fast current, and the littoral vegetation consists of deciduous forest, willow bush, and dense littoral grasses and sedges. The width of the brook at the type locality is less than 1 m and usually less than 10 cm in depth, but deeper, nearly stagnant pools also occur. The substrate is bedrock with small stones and variable debris (Fig. 34). Only a single mature larva was found among several other Nemouridae larvae, whereas most adults were fully mature and abundant among the adult stoneflies collected at this stream, suggesting late April is after the peak emergence. At the type locality, accompanying stoneflies were Nemouridae : Amphinemura sinensis , A. unihamata (Wu, 1973), Sphaeronemoura grandicauda (Wu, 1973), an unidentified Indonemoura sp. found only as premature larvae, and a yet undetermined Nemoura sp. of the ovocercia species group. In the Dizhuang valley, the paratype male was caught together with the recently described Cryptoperla nangongshana Huo & Du, 2018.

Etymology.

The specific name refers to the shape of the pod-like subgenital plate and the pot-like anterolateral branches, which overall resembles the Chinese “ding”, an ancient pot unique in Chinese culture.

Remarks.

The adults were associated with the single mature larva on the basis of the distinct pronotal pattern and similar, contrasting body color.