Nemoura manchuriana Ueno, 1941

Teslenko, Valentina A., 2017, Larvae of three East-Asian species of Nemoura (Plecoptera: Nemouridae), Zootaxa 4282 (2), pp. 309-323 : 313-317

Nemoura manchuriana Ueno, 1941

( Figs. 12 ¯22)

Uéno, 1941, Kontyû, 15 (2):25, fig. 3 (original description of male); Zapekina-Dulkeit, 1959,

Reports of Far Eastern Branch , the Siberian Department of Sciences of USSR, 11:147 (first report for Bira R., the Middle Amur R. Basin); Zhiltzova & Zapekina-Dulkeit, 1986: 214, fig. 6 (male terminalia, ventral); Zhiltzova, 2003, Fauna of Russia and Neighbouring Countries. New Series No. 145:299–301, figs. 504–506 (description of male and female); Yang et al., 2014, Fauna Sinica, 58:367–368, fig. 268 (description of male).

Material examined. RFE, Primorsky Region, 16 mature larvae, mass emergence in the outlet of small unnamed lake near Surazhevka Settlement, Ivnyanka River Basin , Artyomovka River Basin , N 43°25.139' E 132°19. 402', 26.05.2016, rearing, coll. V. Teslenko.

Mature larva. Body length 6.5–7.5 mm, antenna 6.0–7.0 mm, cerci 8.1–8.4 mm. General color brown, pattern consists of dark brown and pale patches on head and legs, a narrow pale mesal stripe on thorax ( Figs. 12, 13). Head with dark brown tentorial callosities; dark brown inverted V-shaped mark directed from lateral ocelli and epicranial suture to anterior ocellus; a few diffuse dark brown patches in front of the anterior ocellus extending to clypeus ( Figs. 12, 13); clypeus with prominent rounded and pale corners. Epicranial suture appear as pale Y-shaped mark between lateral ocelli; V-shaped pale mark to the inside of each compound eye, occiput brown ( Figs. 12, 13). Antennae fragile, delicate, long, length, 93% of body length; scape and pedicel light brown and paler, than head.

Pronotum slightly trapezoid, approximately 1.2–1.4Χ wider than long, pattern diffuse brown with patches of small dark brown spots; U-shaped dark brown band on anterior margin in the area of the mesal seam; anterior and posterior corners and lateral margins pale, narrow mesal pale stripe extends to posterior margin of pronotum as well as on meso-, metanotum ( Figs. 12, 13). Meso- and metanotum brown, with diffuse pattern on posterior margins dark brown. Legs with contrasting dark brown bands and pale patches. Fore femur dark brown with diffuse pale patch basally, 2.5Χ longer than wide ( Fig. 17 ) and hind femur about 4.3¯4.4Χ longer than wide. Tibia with narrow diffuse dark brown band in the basal ¼ ( Fig. 17 ) and pale patch basally. Abdomen relatively slender, terga brown with a mesal row of narrow pale patches forming medial longitudinal band ( Figs. 12, 13), integument light, matte in appearance. Cerci pale, weakly setose, long, length 123¯126% of body length, with 31¯33 segments, each segment darkened basally and distally, pale medially ( Figs. 12, 13, 19 ).

Setation black, well visible, especially on legs and posterior margins of abdominal segments ( Fig 13). Setal fringe around pronotum dense, consisting of occasional long hairs and bristles narrowed to the apices, apices blunt at magnification of 100Χ ( Figs. 14, 15 ). Length of the longest blunted bristles on the anterior and posterior corners approximately 6.0% of pronotum width. Pronotum disc bears tiny oval setae and short blunted setae ( Fig. 15 ). Outer wing pad margin covered with long delicate and acute bristles of different length; tiny oval setae and long acute spine-like setae in the lines on wing-pads ( Fig. 16 ). Legs with uniform chaetotaxy: all femora covered mainly with short acute dark brown bristles, occasionally fine procumbent setae and seldom thin long hairs ( Fig 17 ). Setal fringe on outer femur margin in the apical half consisting of very shot spine-like bristles in an irregular arrangement on fore and hind legs, the longest spine-like bristles attains 12% of femur width on the fore leg ( Fig. 17 ). Tibia with the same spine-like bristles, sporadic fine procumbent setae; the outer edge bears tiny acute setae and a few long hairs. Terga covered with short acute bristles and fine procumbent setae. Posterior tergal margins with relatively sparse, mostly short spine-like black bristles ( Fig. 18 ). Length of long spine-like bristles not exceeding 25–31% of segment length on terga 5¯6 ( Fig. 18 ). Cercal chaetotaxy uniform, apical whorl comprises a set of short stout acute bristles and relatively long thin hairs; intercalary setae sparse ( Figs. 20 ¯22). Length of acute bristles of apical whorl not exceeding 44% of segment length on cercal segments 8¯10 ( Fig. 20 ); stout acute bristles of medial cercal segments not exceeding 20% of the segment length on cercal segments 16¯17, length of hairs, 68% of segment length ( Fig. 21 ). On apical cercal segments. apical whorls with tiny setae with rounded apices and a few thin hairs, length 29% of apical segment length ( Fig. 22 ).

Diagnosis. The larvae of N. manchuriana differ from other known larvae of East-Asian Nemoura species by the contrasting pattern on the head and legs; long cerci exceeding the body length, length of antenna not exceeding body length, and black setation on the legs and abdomen. The pronotal setal fringe dense, bristles cylindrical, narrowed to the apices, and apices blunt. Legs, abdominal segments and apical whorl of cercal segments feature homogeneous chaetotaxy: the bristles or setae are stout short acute at apices. Length of bristles and hairs in apical whorl of cerci does not exceed the length of the segment, intercalary setation sparse.

Distribution. Nemoura manchuriana is known from China and south of the RFE. The type locality of the species is in the northernmost Chinese Heilongjiang Province ( Yang et al. 2014) known as the "Land of the Black Dragon River", another name for the Amur River. Nemoura manchuriana is restricted in distribution to rivers south of the RFE of the Middle Amur River Basin, Sikhote-Aline Range, Khanka Lake Basin and Black Mountains (Changbai Mountain Range). The flight period extends from June to August.

Figures

FIGURE 14 – 17. Larva of Nemoura manchuriana. 14. Anterior pronotal margin with bristles narrowed to the apices, apices blunted. 15. Chaetotaxy on disc, right anterior pronotal corner and lateral margin with dense bristles. 16. Outer wing pad margin covered with long delicate and acute bristles, tiny oval setae and long acute spine-like setae in the lines on wing pads. 17. Right fore leg. Scale (mm): 14, 16 = 0.1; 17 = 0.3.

FIGURES 18 – 22. Larva of Nemoura manchuriana. 18. Chaetotaxy of terga 5 – 6. 19. Right cercus. 20. Cercus segments 8 ‾ 10 with stout acute bristles and sparse intercalary setae. 21. Cercus segments 15 & 16 with stout acute bristles, hairs and intercalary setae. 22. Apical cercus segment. Scale (mm): 19 = 0.3; 20 – 22 = 0.1.