Cinygmula irina Tshernova & Belov, 1982

Tiunova, Tatiana M. & Gorovaya, Ekaterina A., 2013, New species of Cinygmula McDunnough, 1933 and larval description of Cinygmula irina Tshernova & Belov, 1982 from the Russian Far East (Ephemeroptera: Heptageniidae), Zootaxa 3691 (1), pp. 135-144 : 140-143

Cinygmula irina Tshernova & Belov, 1982

( Figs. 30–55 )

Material examined. Russia: Khabarovskiy Kray, Ayano-Maisky region, Sarafanovka River, Ayan village, 2.VIII.1999, T. Tiunova, 5 male, 3 female imagines (reared from larvae), 20 mature larvae; Berandya River, upper part, 4.VIII.1999, T. Tiunova, 9 male, 2 female imagines (reared), 2 male, 1 female subimagines, 14 larvae; Anikei Stream, 0.5 km from Lantarsky cape, 28.VII.1999, T.Tiunova, 1 male imago (reared); Komsomolsky region, Silinka River, upper part, left tributary of Amur River, 8.IX.2003, V. Luborez, 6 male, 4 female imagines, 19 larvae.

Description. Male imago (in alcohol). Length (mm): body 7.0–8.2; forewings 8.7–9.4; cerci 15.6–18.0. Head: eyes non-contiguous ( Fig. 30 ), black tinged greenish. Thorax: Medioscutum and submedioscutum light brown but submedioscutum lighter; anteronotal protuberance brown; medial longitudinal suture narrow and brown. Scutellum duty brown; scuto-scutellar impression duty dark. Foreleg duty yellowish, joint brown; femur and tibia middle and hind legs yellowish, joint darker; tarsus brownish.

Length (mm) of foreleg segments: femora 2.0–2.1; tibia 2.6–3.1; tarsal segments 0.9–1.1, 1.2–1.6, 1.2–1.5, 0.9–1.1, and 0.4–0.5. Wings hyaline, all veins brown ( Figs. 31–32 ). Pterostigma unpigmented, branched veins few ( Fig. 31 ). Abdomen: terga without maculation; tergum I brown; terga II–VI brownish, translucent, lateral corner near posterior margin duty brown; terga VII–IX brown. Sterna brownish, translucent; sterna I-VII with ganglionic markings; sterna VIII–IX light brown. Styliger light brown; gonostyli brown and three-segmented ( Fig. 33 ); sometimes first and second segments of gonostylus darker than other. Penes lobes light brown, lateral margin brown; tops dark brown, widely separated, with deep groove at apical margin ( Figs. 34–35 ); penis lobes with long lateral spine; spine wide at base, strongly narrowing to top, with pointed tips ( Figs. 34, 36 ). Titillators long and strong with pointed tips, almost reaching top, curved laterally ( Figs. 34, 36 ). Cerci light brown, some darker at base.

Female imago. Length (mm): body 7.2–8.0; forewings 8.4–9.0; cerci 11.0–12.0. Overall color brown. Thorax: Mesonotum brown. Sublateroscutum and scuto-scutellar impression white. All legs light brown, tarsus brown. Length (mm) of foreleg segments: femora 1.7–2.0; tibia 1.9–2.2; tarsal 1.1–1.3. Wings hyaline; all veins brown, contrasting. Abdomen: terga dark brown. Sterna brown (abdomen with eggs), or duty brown, translucent (without eggs). Subanal plate with relatively deep depression ( Fig. 37 ). Cerci brownish, darker at base.

Mature larva. Length (mm): body 6.5–8.5; cerci 6.5–7.5. Head: brown, with somewhat darker anterior margin and shallow apical incision ( Fig. 38 ). Labrum light brown, posterior and lateral margins brown; width 3 times as long ( Fig. 39 ). Glossae wide with rounded tops ( Figs. 40–41 ). Thorax: pronotum light brown with pair of pale spots at anterior margin and light outer edges. Mesonotum brown; antero lateral corners with light spots. Legs light brown, tarsus brown; femur of forelegs with oval pale longitudinal stripe; strong brown setae cover dorsal surface of femur, located especially in light area ( Fig. 43 ). Claws of foreleg with four subapical denticles ( Fig. 44 ). Lengths (mm) of leg segments as follows. Foreleg: 1.5–1.8; tibia 1.5–1.8; and tarsus 0.7–0.8. Middle leg: femur 1.7–2.0; tibia 1.4–1.7; and tarsus 0.6. Hind leg: femur 1.8–2.1; tibia 1.5–1.8; and tarsus 0.6–0.7. Abdomen: terga brown or light brown with pale lateral sides; terga I–VIII with pair brown curved strokes in middle area and dark stripes on sides; terga I–III lighter than others; sometimes tergum VII–VIII white with brown anterior margin and lateral sides ( Fig. 45 ). Sterna brown with pale lateral sides; sterna I–II white; sterna III–IX each with pair of light drop-like spots at anterior margin, and pair of brown spots at posterior margin ( Fig. 46 ); abdominal sternum IX with relatively deep posteromedian emargination ( Fig. 47 ). Gills white. Gill I large, heart-shaped, with extended inner edge, width almost equal to length; two short gill filaments ( Fig. 48 ). Gills II, III and IV with similar shape and size ( Fig. 49 ). Gill V with drawn and pointed tip ( Fig. 50 ). Gill VI oval, with short gill filament ( Fig. 51 ). Gill VII narrow and uniformly tapered to rounded tip ( Fig. 52 ), length 2.3 times width. Cerci brown.

Eggs. General form cylindrical, with length of 138–163 μm and width of 99–114 μm ( Fig. 53 ). Surface of chorion rough, with clear granular structures ( Fig. 54 ).

Numerous small round granules and small KCT (knob-terminated coiled thread) attachment structures evenly spaced over whole surface ( Figs. 53–54 ); large and round knobs arranged on one pole ( Fig. 53, 55 ). Two round micropiles located in equatorial area; sperm guide round; micropylar rim well-expressed ( Fig. 53 ).

Distribution and biology. Cinygmula irina is an East Asian species that is distributed in the Russian Far East: Primorskiy Kray, Khabarovskiy Kray and Amurskaya oblast’ (Tshernova & Belov 1982; Tiunova 2007, 2009).

The larvae of this species are associated with stones, gravel and pebbles in small rivers or streams, which can be characterized as rivers of cold and moderately cold types. Emergence occurs in late July and August. Discussion. Only the male and female adult forms of Cinygmula irina have been described previously, and the larva was unknown (Tshernova & Belov 1982). The presence of reared material allowed the description of all the stages of development for Cinygmula irina . Here, we presented a description of the eggs of both species, which, based on our data, are useful for the diagnosis of species within the genus Cinygmula .

Figures

FIGURES 30 – 37. Cinygmula irina, male imago: 30. Head, dorsal view. 31. Fore wing. 32. Hind wing. 33. Sternum IX, styliger and gonostyli. 34. Penes, ventral view. 35. Penes, dorsal view. 36. Penes, lateral view. 37. Subgenital plate, female, ventral view.

FIGURES 38 – 52. Cinygmula irina, larva: 38. Head, dorsal view. 39. Labrum, dorsal view. 40 – 41. Labium: 40 — ventral view, 41 — dorsal view. 42. Pro- and meso-notum. 43. Femur of fore leg. 44. Tarsal claw of fore leg. 45. Abdominal terga VI – VIII. 46. Abdominal sterna VI – VIII. 47. Abdominal sternum IX (female). 48 – 52. Gills: 48. Gill I, 49. Gill II, 50. Gill V, 51. Gill VI, 52. Gill. VII.

FIGURES 53 – 55. Cinygmula irina, egg: 53. General view. 54. Structure of chorion and small knob- terminated coiled threads. 55. Large knobs. The arrow shows the micropiles (mp).