Parameletus arcuatus, Tiunova, Tatiana M., 2008

Tiunova, Tatiana M., 2008, Two new species of Parameletus Bengtsson, 1908 (Ephemeroptera: Siphlonuridae), and notes on other species from the Far East of Russia, Zootaxa 1725, pp. 17-26 : 19-20

Parameletus arcuatus sp. nov.

( Figs. 9–15 )

Holotype. RUSSIA. Khabarovskiy Kray: Bikin River, 50 m lower motor-car bridge, line Vladivostok-Khabarovsk, 16.VI 2005, T Tiunova, 1 male imago.

Paratypes. Together with holotype, 26 male imagines. Primorskiy Kray, Bolshaya Ussurca River, 2 km lower Zvenigorodka village, 8.VI 2004, T Tiunova, 1 male imago.

Description. Male imago (in alcohol). Dimensions: length (mm): body 13.0 – 15.7; fore wings 11.8 – 13.3; cerci 20.5 – 22.5. Total color of living imago dark brown. Head: upper portion of eyes light brown, lower portion black. Thorax: Mesonotum light brown tinged with grayish; dorsal arc of prealar bridge dark brown, posterior scutal protuberance brown ( Fig. 15 ); mesosternum from dark brown to black. Fore legs brow; middle and hind legs light brown, tinged with grayish. Length (mm) of foreleg segments: femora 2.8– 3.5; tibiae 2.3–2.5; tarsal segments 1.5–1.7, 1.6–1.8, 1.7–1.9, 0.9–1.2. Wings hyaline, tinged with brownish; all veins brown ( Figs. 12–13 ); pterostigma dead. The relation of length to the maximal width makes for fore wing—2.53, hind wing—1.60. Abdomen: terga 2–7 translucent, brown; terga 1 from dark brown to black; terga 4–7 with pair of dark brown spots like stroke in anterior margin; terga 7–8 opaque; lateral part of all terga darkened with brown. Sterna 2–6 translucent, brown or dark brown with pair of small light spots in middle part; sterna 7–9 from dark brown to black. Gonostyli and penis brown or dark brown. Posterior margin of styliger with a broad rectangular projection in middle part ( Fig. 14 ). External penis lobes wide with rounded apices; inner penis lobes narrow, curved in base, with furcated apices, reaching apices of external lobes ( Figs. 9–10 ). Ventral processes dark brown, pointed, reach to 2/3 of length of external lobes ( Figs. 10–11 ). Cerci brown, base dark brown.

Female imago and nymph: Unknown.

Etymology. The epitet arcuatus is connected with form of inner penis lobes ( Fig. 9 ).

Distribution and biology. Sought of Russian Far East: Khabarovskiy Kray and Primorskiy Kray ( Fig. 8 ). The imagines were collected in grass and on leaves of trees which grow near the water together with Parameletus ensiformis sp. nov.

Discussion. Parameletus arcuatus is similar to P. chelifer ; however male imago can be distinguished from that of P. chelifer by the structure of penis ( Figs. 9–10 ) and form of posterior margin of styliger ( Fig. 14 ).

Figures

FIGURE 8. Study area. The thick line indicates the border between administration regions. 1 – Primorskiy Kray, 2 – Khabarovskiy Kray, 3 – Sakhalinskaya Oblast’, 4 – Magadanskaya Oblast’, 5 – Kamchatskaya Oblast’, 6 – Chukotka, 7 – Evreiskaya Autonomous Oblast’, 8 – Amurskaya Oblast’, 9 – Chitinskaya Oblast’, 10 – Republic Sakha Yakutia.

FIGURES 9 – 15. Parameletus arcuatus: 9. Penis, ventral. 10. Penis, dorsal. 11. Penis, lateral. 12. Fore wing. 13. Hind wing. 14. Styliger and gonostyli. 15. Mesonotum, dorsal. Scale (mm): 9 – 11 = 0.02; 12 – 13, 15 = 0.1; 14 = 0.05.