Rhithrogena lepnevae Brodsky 1930

Tiunova, Tatiana M., 2010, A new species of Rhithrogena Eaton, 1881 from the Far East of Russia with notes on this genus in this area (Ephemeroptera: Heptageniidae), Zootaxa 2639, pp. 1-18 : 9-13

Rhithrogena lepnevae Brodsky 1930

( Figs. 43–59 )

Rhithrogena lepnevae Brodsky, 1930:31 (male imago).

Rhithrogena unicolor Tshernova, 1952:250 (larva); Bajkova, 1972:213 (synonym). Rhithrogena binitata Sinitshenkova, 1982:65 (male, female imago and larva); Kluge, 1995: 21 (synonym).

Material examined. RUSSIA. Southern Yakutiya: Aldan River Basin, Chulman River, upper Nerjungri City, 25.VII 2006, T Tiunova, 1 male imago; Ungra River, base of “Ungra” Nature Reserve, 28.VII – 1.VIII 2006, T Tiunova, 9 male, 3 female imagines, 10 larvae; Duraj River, mouth, right tributary Ungra River, 30.VII 2006, T Tiunova, 5 larvae. Magadanskaya Oblast’: Tauj River, middle part, 1.IX 2001, S Kocharina, 1 male imago; Amurskaya Oblast’: Bureya River, turn on Gulikovka Village, 16.VIII 2003, T Tiunova, 3 male imagines; Bureya River, 500 m below Kulikovka Village, 17–18.VIII 2003, T Tiunova, 13 male imagines; same place, 22.VIII 2004, T Tiunova, 12 male imagines; same place, 3.VIII 2005, T Tiunova, 21 male imagines; same place, 19.VII 2006, T Tiunova, 7 male imagines; same place, 6.VIII 2006, T Tiunova, 9 male imagines; Zeya River, near Krasnoyarovo Village, 22.VIII 2004, T Tiunova, 5 male imagines; Zeya River, near Sakhatino Village, 19.VII 2006, T Tiunova, 7 male imagines; Zeya River, upper Mazanovo Village, 5.VIII 2006, T Tiunova, 2 male imagines; Bolshoi Ol’doi River, 300 m upper motor-car bridge, line Khabarovsk – Chita, 31.VII 2005, T Tiunova, 2 male imagines. Jewish Avtonomnaya Oblast’: Kuldur River, 1 km upper mouth Sutara River, 2 km below Dvurech’e Village, 19.VIII 2003, T Tiunova, 27 male imagines; same place, 18.VII 2005, T Tiunova, 12 male, 2 female imagines; Stolbukha River, 5 km upper Stolbovoe Village, 18.VIII 2004, T Tiunova, 4 male imagines; Bira River, near Razdoljnoe Village, 4.VIII 2005, T Tiunova, 7 male imagines; Bira River, 4 km below Zheltiy Jur, 7.VIII 2006, T Tiunova, 12 male imagines. Khabarovskiy Kray: Chor River, upper mouth Katen River, 17.VI 1995, T. Tiunova, 3 male imagines (reared from larvae), 7 larvae; Chor River, near Kondratjevka Village, 24.VII 1996, T Tiunova, 4 male, 1 female imagines, 3 larvae; Chor River, duct Potopilicha, 14.VII 2005, T Tiunova, 23 male imagines; Chor River, 1 km upper Kondrashevka Village, 16.VII 2006, T Tiunova, 7 male imagines; Kiya River, upper Ekaterinoslavka Village, 10.VIII 2004, T Tiunova, 1 male imago; Gur River, 100 m upper motor-car bridge, line Khabarovsk – Komsomolsk, 1.VIII 1996, T Tiunova, 1 male, 1 female imago; Mutii River, tributary Yaj River, below motor-car bridge, line Khabarovsk – De-Kastri, 4.VIII 2005, E Makarchenko, 5 male imagines; Machtovaya River, below motor-car bridge, line Khabarovsk – De-Kastri, 1. VII 2005, T Tiunova, 19 male, 2 female imagines, 4 larvae; Manoma River, middle part, tributary Anjuj River, 28.VII 1996, T Tiunova, 23 male, 4 female imagines; Anjuj River, about 70 km upper mouth, 20.VII 2007, E Makarchenko, 1 male imago; Moadi River, tributary Anjuj River, about 6 km from Arsenjevo Village, 12.VII 2007, E Makarchenko, 4 male imagines; Tatar Strait Basin, Tumnin River, near mouth Tun’ River, 18–19.VII 1997, T Tiunova, 5 male, 1 female imagines; Aldan River Basin, Maya River Basin, Chuya Rive, right tributary Maya River, near Nel’kan Village, 6.VIII 1999, T Tiunova, 1 male imago; Maya River, 1 km below Nel’kan Village, 8.VIII 1999, T Tiunova, 15 male, 7 female imagines (reared from larvae), 133 male imagines; Aldoma River, near mouth Keniy River, 11–12.VIII 1999, T Tiunova, 1 male imago; Priokhot’e, Uda River, about 5 km upper mouth, 13.VIII 2000, T Tiunova, 27 male, 2 female imagines; Uda River, about 140 km upper mouth, 15– 20.VIII 2000, T Tiunova, 2 male imagines. Primorskiy Kray: Partizanskaya River, near Sergeevka Village, 30.VI 1988, T Tiunova, 2 male imagines; Bolshaya Ussurka River, 1,5 km upper mouth Daljnaya River, 20– 23.VI 1990, T Tiunova, 2 male, 1 female imagines (reared from larvae), 9 male, 3 female imagines, 4 larvae; Bolshaya Ussurka River, 6 km below mouth Armu River, 18.VI 1990, T Tiunova, 3 female imagines (reared from larvae), 6 larvae; Bolshaya Ussurka River, near Vostrezovo Village, 1.X 1991, E Makarchenko, 1 male imago; Bolshaya Ussurka River, near Melnichnoe Village, 5.VIII 1997, T Tiunova, 2 male imagines; same place, 15.IX 2001, V Luborez, 4 male imagines; Malinovka River, tributary Bolshaya Ussurka River, 3.VII 1991, T Tiunova, 18 male imagines; Armu River, tributary Bolshaya Ussurka River, 23.VII 2004, V Luborez, 10 male imagines; Rasdol’naya River, near Fadeevka Village, 5.IX 1991, T Vshivkova, 1 male imago; Rasdol’naya River, near Zarechnoe Village, 4.VIII 2007, T Tiunova, 3 male imagines; Komarovka River, tributary Rasdol’naya River, 29.VI 1999, T Vshivkova, 5 male imagines; Ussuri River, near mouth Arsenjevka River, 18.VII 1991, T Tiunova, 2 female imagines (reared from larvae), 4 male, 2 female imagines; Ussuri River, 3 km below Podgorniy stream, 21.VII 1991, T Tiunova, 11 male imagines; Ussuri River, 0,5 km upper Arkhipov Stream, 29.VII 1994, T Tiunova, 11 male imagines, 6 larvae; Ussuri River, Gornie Kluchi Village, 2 km below motor-car bridge, line Vladivostok - Khabarovsk, 18.VII 1996, T Tiunova, 1 male imago; Ussuri River, near Kamenka Village, 15.VI 1998, T Tiunova, 1 male imago; same place, 30.VIII 1999, T Tiunova, 27 male imagines; Bikin River Basin, Zewa River, upper part, 17.VII 1995, T Tiunova, 2 male imagines, 2 male subimago, 3 larvae; Zewa River, below mouth Berezovaya River, 24.VII 1995, T Tiunova, 9 male, 1 female imagines, 3 larvae; Zewa River, 4 km below Kamenniy Stream, 25.VII 1995, T Tiunova, 1 male subimago (reared from larvae), 2 male imagines; Bikin River, 4 km below mouth Omorochka River, 30.VII 1995, T Tiunova, 16 male imagines; Bikin River, 50 m upper mouth Takhalo River, 1.VII 1995, T Tiunova, 1 male, 2 female imagines (reared from larvae), 3 male, 2 female imagines, 1 larvae; Bikin River, Ysenevii Village, 2.VIII 1995, T Tiunova, 1 male imago (reared from larvae), 12 male imagines; Khanka Lake Basin, Ilistaya River, upper part, 29.VI 1999, V Luborez, 3 male imagines; Basin Sea of Japan, Barabashevka River, about 5 km upper mouth, 2.VII 2000, T Tiunova, 23 male, 4 female imagines; Razanovka River 10–11.VI 2003, T Tiunova, 5 male imagines; Narva River, below motor-car bridge, line Vladivostok - Khasan, 2.VIII 2007, T Tiunova, 6 male imagines; Suvorovka River, near mouth Krivaya River, 23.VIII 2002, T Tiunova, 1 male imago; Lazovka River, near Lazo City, 6.VII 2005, Y Sundukov, 1 male imago; same place, 6–8.VIII 2006, Y Sundukov, 5 male, 8 female imagines; Maksimovka River, Sevastjyanov Stream, 17.VII 2006, V Luborez, 3 male imagines; Perekatnaya River, Lazovskiy Reserve, 10.VII 2007, O Zorina, 3 male imagines. Sakhalin Island: Rogatka River, about 2 km from Yuzhno-Sakhalinsk, 7.VIII 2001, T Tiunova, 1 male imago; Tym River, upper part, 8.VIII 2001, N Minakava, 2 male imagines; Tym River, middle part, 3.VIII 2002, V Teslenko, 2 male imagines; Leonidovka River, 28 km from Paronaisk, 4.VIII 2001, B Martin, 1 male imago; Tiobut River, tributary Lutoga River, 26.VII 2001, V Teslenko, 5 male imagines; Belaya River, base “Sokol”, 16.VII 2002, V Teslenko, 2 male imagines. Shikotan Island: southern part, Dmitrova bay, small stream, 13.VIII 1998, D Bennet, 1 male subimago; middle part, Zvezdnaya bay, river without name, 16.VIII 1998, T Arefina, 3 male subimago, 1 male, 5 female imagines; Zvezdnaya bay, Zvezdniy Stream, 16.VIII 1998, V Teslenko, 2 male, 2 female subimago, 1 male, 2 female imagines.

Description. Male imago (in alcohol). Dimensions: length (mm): body 7.0–8.8; forewings 7.8–10.3; cerci 18.0–24.0. Thorax: pronotum light brown, mesonotum generally brown with two distinct thin, dark longitudinal lines; medioscutum brown, submedioscutum light brown, scutellum dark brown, sublateroscutum white ( Fig. 43 ); metanotum and metasternum from light brown to brown. Length (mm) of foreleg segments: femora 1.7–2.0; tibia 2.6–3.3; tarsal segments 0.2–0.3, 1.3–1.8, 1.4–1.9, 1.0–1.4, 0.3–0.5. Abdomen: terga 1–6 brown with a darker base, translucent; terga 2–4 with a pair of small specks in the middle portion; terga 8–9 brown-tinged white, opaque. Sterna 2–6 light brown with the last two segments being whitish and opaque. Forceps and styliger plate brown; penis lobes yellowish, titillators and inner tooth brown; penis lobes slightly jut out to the edge of the styliger plate; tops of penis lobes rounded externally, inner tooth long and pointed ( Fig. 44–45 ). Latero-dorsoventral teeth on penis lobes are present, bifurcated ( Fig. 45, 47 ). Titillators wide, with 3–5 teeth ( Fig. 46 ). Cerci: brown the in proximal third, and from light brown to yellow distally, with the base of each segment ringed with dark brown.

Female imago. Dimensions: length (mm): 6.3–9.0; forewings 9.5–10.3; cerci 10.0–14.0. Thorax: pronotum and mesonotum light brown. Legs yellowish, joints and claws darker; femora of all legs dark brown or having a dark spot in the middle light area. Wings hyaline, all veins brown. Abdomen: terga colored as in males. Sterna yellowish. Cerci light brown at the base and yellowish at the tip.

Male subimago. Thorax: pronotum light brown with white edging along the margin; mesonotum white; anteronotal protuberance dark brown; along the posterior margin of the submedioscutum there is a narrow dark brown strip, which is expanded on top of the posterior scutal protuberance; parascutellum brown. Legs brownish, forelegs darker; femora of all legs with a dark spot in the middle area. Wings light brown, translucent. Abdomen: terga light brown; lateral area darker; terga 2–7 with a pair of small light colored spots and strips. Sterna are yellowish. Cerci brownish with a darker base.

Mature larva. Dimensions: length (mm): body 7.2–9.4, cerci 9.0–10.1. Head: forehead brown, sometimes with a white spot above the eyes; posterior half of the head with a pair of small white spots in the middle area ( Fig. 48 ). Maxilla with 10–11 comb-shaped setae at the apical margin ( Fig. 50 ). Thorax: pronotum brown with light anterior and posterior margins; mesonotum brown with a wide light median longitudinal stripe. Legs light brown; femurs of all legs with dark spots in the middle of the light central area; setae on the dorsal surface of fore-femora with distinct divergent margins and a rounded apex ( Fig. 55 ). Claws of fore- and middle legs with 3–4 subapical denticles ( Fig. 56–57 ). Length (mm) of leg segments are as follows. Foreleg: femur 1.5–1.9, tibia 1.3–1.6, tarsus 0.4–0.6; middle leg: femur 1.4–1.9, tibia 1.2–1.5, tarsus 0.4–0.5; hind leg: femur 1.9–2.5, tibia 1.3–1.8, tarsus 0.4–0.5. Abdomen: terga brown, usually uniform; terga 2–7 sometimes having a pair of bow-shaped white stripes in middle area; terga 10 with a pair of white longitudinal spots at the distal margin; central portion of the posterior margin of terga 5 constituted by long and pointed teeth of uniform size ( Fig. 58 ). Sterna light brown; sterna 7–9 darker; abdominal sternum 9 in females having a posteromedian emargination ( Fig. 59 ). Gills white; tufted tracheal tubes white or grayish; gill I large with an even outer margin ( Fig. 51 ); gills III–IV oval with rounded distal margins ( Fig. 52–53 ), approximately 1.7 times as long as they are wide; gill VII broadened in its middle region ( Fig. 54 ). Cerci are brownish, with the shaded tips.

Distribution and biology. Rhithrogena lepnevae is an East Palaearctic species distributed in East Siberia ( Bajkova 1972; Tshernova et al. 1986), including southern Yakutiya (Tiunova et al. 2009), Altai ( Brodsky 1930), the Russian Far East ( Bajkova 1979; Kluge 1997; Arefina et al. 2003; Tiunova & Potikha 2005; Tiunova 2007a, 2008, 2009), Sakhalin Island ( Tiunova 2007b), Kuril Islands (Tiunova, 2009) and Mongolia ( Bajkova & Varychanova 1978, Bajkova 1984; Braasch 1979, 1986; Landa & Soldán 1983; Enkhtaivan, Soldán, 2008; Soldán et al. 2009).

Larvae of this species were found associated with stones, gravel and pebbles in small rivers or streams and in the middle part of large rivers, which can be characterized as rivers of moderately cold and moderately warm types.

Figures

FIGURES 43 – 47. Rhithrogena lepnevae, male imago: 43. Mesonotum, dorsal. 44. Penis, ventral. 45. Penis, dorsal. 46. Titillators, lateral. 47. Penis lobes lateral. Scale (mm): 43 = 1.0; 44 – 45,47 = 0.2; 46 = 0.05.

FIGURES 48 – 59. Rhithrogena lepnevae, larva: 48. Head, dorsal. 49. Labrum, dorsal. 50. Comb-shaped setae of the maxilla. 51. Gill I. 52. Gill III. 53. Gill IV. 54. Gill VII. 55. Setae on the dorsal surface of fore femora. 56. Tarsal claw of fore leg. 57. Tarsal claw of middle leg. 58. Posterior margin of terga 5. 59. Abdominal sternum 9 (female). Scale (mm): 48,51 = 1.0; 49 = 0.2; 50,55,58 = 0.05; 52 – 54, 59 = 0.5; 56 – 57 = 0.1.