Amphinemura albicauda, 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 : 1-6

Amphinemura albicauda sp. n. Figs 1, 2-6, 7, 8-13, 14, 31, 32, 35

Diagnosis.

Male: tergum IX with short spines and long setae, epiproct with closely spaced lateral processes having sharp and out-curved apex, paraproctal outer lobe long and armed with large apical teeth, median lobe apically bilobed. Female: subgenital plate subquadrate and slightly lobed, inner sclerite with ear-shaped lobes. Larva: general color brown but cerci contrasting white and hairy, legs with distinct swimming hairs.

Description.

Adult habitus (Fig. 1): General color light brown to brown. Head and antennae brown, palpi light brown. Thorax brownish, pronotum with distinct rugosities. Legs light brown. Wing membranes grayish, veins brown. Abdomen brown with darker terminalia.

Male (Fig. 2-5): Forewing length 6.4-6.6 mm. Tergum IX (Fig. 2) moderately sclerotized, with 11-13 short mesal spines and 4 or 5 paramedial long hairs along mid-posterior margin. Sternum IX with claviform vesicle, distal ½ membranous (Fig. 3). Hypoproct subquadrate at base, apical ½ tapering, apex tubular (Fig. 3). Tergum X weakly sclerotized, concavity beneath epiproct narrow with 10-12 small to medium-sized spines along lateral sides (Figs 1, 2). Cercus slightly sclerotized, stout and short. Epiproct (Figs 1, 2, 4) ca 3.5 times longer than wide, distal portion trifurcate but median process nearly unpigmented and hardly detected in dorsal view (Fig. 2). The lateral processes horn-shaped and closely located, with apex sharp and out-curved; median process originates from ventral sclerite and shorter than lateral ones, subapically forming distinct rounded ridge in lateral view (Fig. 4). Paraproct trilobed (Figs 2-5): inner lobe triangular, short and well sclerotized, mostly hidden by hypoproct; median lobe long and tubular, apical portion up-curved, apex membranous with 6 or 7 long marginal spines, outer margin with an additional small lobe bearing 3 long spines of same size; outer lobe extends along with median lobe but shorter, well sclerotized, dilated apex with 3 or 4 lateral, large teeth along outer margin.

Female (Fig. 14): Forewing length 7.8 mm. Sternum VII produced in a broad semicircular pregenital plate covering anterior half of subgenital plate; the plate is mostly pale with brownish posterior margin. Sternum VIII forms sclerotized subquadrate subgenital plate with narrowed anterior portion, medial notch is being broad but shallow medially; inner portion of the posterior lobes with small, sometimes indistinct secondary lobes. Paragenital plate paired, forming quadrate brownish lobe connected with posterolateral corner of subgenital plate. Sternum IX trapezoidal, median half much protruded anteriorly, in ventral aspect with anterior indentation. Paraproct and cerci brownish.

Female inner genitalia (Fig. 6): Inner sclerite is medially separated into triangular sclerites located anteriorly to the subgenital plate; anterior portion of the sclerite halves with a small, ear-shaped projection, easily observed in oblique or caudal view. Between the sclerites is a membranous tunnel with a tubular median sclerite leading to spermathecal ductus.

Mature larva (Fig. 7): Body relatively slender and small, body length without antennae and cerci 5.5-6.0 mm. General color brown, with some indistinct pattern on pronotum and abdomen, legs and antennae light brown but cerci contrasting white and hairy. Setation long and distinct. Legs moderately long, width of hind femora ca ¼ of their length. The pronotum is trapezoidal, wider than long, as wide as head. Cervical gills long, inner gills with 7, outer with 8 branches. Wing pads more than twice as long as the corresponding segments. Abdomen relatively slender and uniformly brown, integument light matt brown, first 2 abdominal segments divided by pleura. Posterior margin of sternum IX of the male larva short triangular, sternum VIII of female larva slightly incised; paraprocts blunt. Cerci long, with 24-26 cylindrical segments; length of the 15th segment is about 3 times of its width.

Setation of the larva (Figs 8-13): Head, antennae and palpi with dense short setae. Pronotum covered with very short setae; marginal setae distinct and blunt, row interrupted in anteromedial and posteromedial third, corners have setae as long as one 15th of pronotum width (Fig. 12). Setae on meso- and metanotum as long as longest marginal setae on pronotum; wing pads with long and acute, whitish setae. Legs with dense setation, all tibiae bear distinct swimming hairs as long as femur width (Fig. 13). Longest acute setae of all femora are longer than half of the corresponding femur width, long setae on fore femur arranged in an incomplete transversal line. Tarsi and claws relatively long. Tergal segments covered with thin setae, all segments bear a pair of thin, erect and irregularly curved hairs that are distinct in lateral view and reach nearly the segment length (Fig. 9); posterior margin with row of 14-16 acute setae, of various length, longest nearly reaches half of segment length (Figs 8, 10). Cercal segments with dense and long, white setation; setae sparser and shorter on basal and apical segments (Figs 10, 11). Cercomeres 14-16 with intercalary setae-like fine hairs, longer than the segment width, and an apical whorl of 14-17 acute setae that are as long as segment length (Fig. 11).

Type material.

Holotype male (HIST): CHINA, Shaanxi Province, Hanzhong, Foping County, Changjiaoba Town, lower section of a large unnamed stream in Dizhuang valley, 895 m, 33°33.344'N, 107°59.018'E, 2018.IV.21, leg. W.H. Li, R.R. Mo and D. Murányi. Paratypes: same data as holotype: 1 male and 1 female, 1 female larva (HIST), 1 male larva (CAUC) 1 male and 1 female larva, with pharate adult terminalia dissected (HNHM).

Affinities.

The new species belongs to a lineage of Amphinemura that is distributed in Oriental areas of China and Vietnam. This lineage can be characterized by the horn-shaped lateral processes of the dorsal sclerite, and pointed ventral sclerite of the male epiproct. It is defined here as the A. sinensis species group. The species belonging to this group are A. ancistroidea Li & Yang, 2007a, A. caoae Stark & Sivec, 2010, A. cestroidea Li & Yang, 2005, A. chui Wu, 1935, A. divergens Stark & Sivec, 2010, A. elongata Li, Yang & Sivec, 2005, A. fleurdelia (Wu, 1949), A. furcostyla (Wu, 1973), A. giay Stark & Sivec, 2010, A. guangdongensis Yang, Li & Zhu, 2004, A. hamiornata Li & Yang, 2008b, A. leigong Wang & Du in Wang et al. 2006, A. licenti (Wu, 1938), A. malleicapitata Li & Yang, 2006, A. maoi (Wu, 1938), A. nanlingensis Yang, Li & Sivec, 2005, A. nigritubulata Li & Yang, 2008d, A. sinensis (Wu, 1926), A. tianmushana Li & Yang, 2011, A. viet Stark & Sivec, 2010, and A. yao Mo, Yang, Wang & Li, 2017. Males of the new species can be distinguished from other members of the group by their armed outer lobe of the paraproct, which is unique within the group, and also by the distinctive shape of the processes of epiproct. The female outer genital sclerites are less distinctive, but the inner sclerite is unique because of the ear-shaped projections. The larva is distinctive by its conspicuous white and rather hairy cerci.

Distribution and ecology.

The new species was found at a single locality at the lower section of a large stream at moderate elevation (Figs 31, 35). The stream runs between forests, less-used agricultural areas, and ruderal bush. Its width varies between 3 and 8 m, and its maximum depth is less than 1 m. Rocky rapids are mixed with nearly stagnant pools and slow, stony sections. The substrate is mostly stony or sandy, with a moderate amount of debris (Fig. 32). Both last instar larvae and fully mature adults were present, suggesting April is the peak season of its emergence. Accompanying stoneflies were A. sinensis , a Rhopalopsole sp. collected as females, a few larvae of a Neoperla sp., and larvae of a Kamimuria sp. that occurred in high numbers.

Etymology.

The specific name is composed of the Latin words albus (white) and cauda (tail), and refers to the distinctive white cerci of the larva.

Remarks.

The adults and larvae were associated on the basis of pharate male and female adult terminalia dissected from matured larvae.