Ameletus sirotskii Tiunova, 2017

Tiunova, Tatiana M., Semenchenko, Aleksandr A. & Velyaev, Oleg A., 2017, New species of Ameletus Eaton, 1885 from the Russian Far East with notes on Ameletus camtschaticus Ulmer 1927 (Ephemeroptera: Ameletidae), Zootaxa 4276 (2), pp. 151-176 : 161-167

Ameletus sirotskii Tiunova , sp. nov.

(Figs 32‒58)

Material. Holotype male imago (reared from larva), RUSSIA, AMURSKAYA OBLAST’, Zeyskii district , Bolshoi Garmakan River, about 300 m above mouth, 08.VII.2015, T. Tiunova. Paratypes: collected together with the holotype: 4 male, and 1 female imagines (reared from larva), 9 mature larva ; same locality, 23.VI.2004, 1 larvae, T. Tiunova ; same locality, 02.VII.2013, 18 mature larvae, T. Tiunova ; same locality, 07.VII.2013, 4 larvae, 1 larva (AM10), T. Tiunova ; same locality, 7.VII.2014, 1 female subimago (reared from larva), T. Tiunova ; same locality, 02.VII.2015, 8 larvae, T. Tiunova.

Other material examined. RUSSIA: KHABAROVSKIY KRAY: Okhotskii district, Staryi Vodozabor stream, 03.VII.1999, 7 larvae, T. Tiunova ; Malyi Marekan River , about 500 m above mouth, 06.VII.1999, 8 larvae, T. Tiunova ; Ayno-Maisky district , Uyka River , ~ 1 km above mouth, 26.VII.1999, 2 larvae, T. Tiunova; AMURSKAYA OBLAST’: Zeyskii reserve: Malyi Garmakan River, about 200 m above mouth, 02.VII.2013, 13 larvae, 1 larva (AM9), 1 larva (AM11), T. Tiunova ; same locality, 7.VII.2014, 19 larvae, 1 larva (AM112), 1 larva (AM119), T. Tiunova ; same locality, 08.VII.2015, 12 larvae, T. Tiunova ; Bolshaya Erakingra River , 52-i km from Zeya, bridge, at highway Zeya‒Beregovoy, 06.VII.2013, 19 larvae, T. Tiunova ; same locality, 09.VII.2014, 1 female imago (reared from larva), 1 female subimago, 9 mature larvae, 1 larva (AM135), T. Tiunova ; same locality, 04.VII.2015, 6 mature larvae, T. Tiunova ; Shirokovka River , ~ 300 m above mouth, 2.VII.2013, 9 larvae, T. Tiunova ; same locality, 07.VII.2014, 7 larvae, T. Tiunova ; Kamenushka River , bridge, at highway Zeya‒Beregovoy, 06.VII.2015, 23 larvae, T. Tiunova ; Zeya River Basin : Dess River, bridge, at highway Zeya‒Verhnezeysk, 21.VI.2004, 2 larvae, T. Tiunova ; Gulik River , upper reaches, bridge, at highway Zeya‒Verhnezeysk, 06.VII.2013, 12 larvae, T. Tiunova ; Tynda River Basin , Allenga River, bridge, at highway Zeya‒Snezhnogorsk, 14.VII.2012, 4 larvae, T. Tiunova ; same locality, 0.7. VII.2013, 10 larvae, T. Tiunova ; Allenga River , above mouth, 29.VI.2015, 6 larvae, 3 larval skin, T. Tiunova; Savushkin stream, 38 km from Zeya, at highway Zeya‒Steznogorskyi, 09.VII.2015, 13 larvae, 1larva (AM354), 1 larva (AM355), 1 larva (AM386), T. Tiunova; MAGADANSKAYA OBLAST’, Ola River, upper reaches, 24.VI.2013, 3 larvae, E. Khamenkova.

Description. Male imago (in alcohol). Length (mm): body 9.7‒10.5; forewings 9.7‒10.0; cerci 10.5‒12.0. Head: upper portion of the eyes brownish; lower portion dirty grey. Medial and lateral ocelli white. Thorax: Medioscutum and submedioscutum dark brown; median longitudinal suture narrow and dark (Fig. 32). Scutellum dark brown; scuto-scutellar impression white. Posterior scutal protuberance and anteronotal protuberance dark brown. Femur of forelegs light brown or brown; tibia and tarsal segments dark brown; middle and hind legs from brownish to yellowish, tarsal segments slightly darker. Length (mm) of foreleg segments: femora 1.9‒2.0; tibia 1.7‒1.9; tarsal segments 0.5‒0.6, 1.0‒1.3, 1.0‒1.2, 0.8, and 0.4‒0.5. Wings brownish, hyaline; all veins brown with light brown crossveins. Abdomen: terga brown, opaque, posterior margins dark brown (Fig. 37); tergum I dark brown or dark; terga II‒VI with a pair of brownish oblique stripes located medially; tergum VII‒IX light brown with dark brown lateral corner. Sterna brownish or whitish, opaque; sternum I brown; sternum II light brown; sterna III‒VI whitish; sterna III‒V with two brownish, oblique stripes and a pair of brown dots in the middle part of the anterior margin; sterna VII‒VIII with brownish middle area; sternum IX white, all margins are bordered with dark brown (Fig. 38). Styliger and first segment of forceps dark brown, darker than other segments (Fig. 33). Penis lobes light brown on inner sides and brown on the outer side; penis lobes rounded laterally and curved medially (Figs 34, 35); each ventral plate of penis bears large and wide apically pointed denticle (Figs 36, 40), the outer edge with few small denticles (Figs 39, 40); the first small denticle located near the base of apical denticle (Fig. 40). Cerci brown with darker joints and light brown tips.

FIGURES 32–36.

FIGURES 37–38.

Female imago. Length (mm): body 7.6‒9.5; forewings 8.2‒9.5; cerci 8.7‒10.0. Head: Blackish; eyes black. Medial and lateral ocelli contoured by black; antennae brownish with pale tips. Thorax: Pronotum brownish with pale posterior margin. Medioscutum and submedioscutum brown; medioparapsidal suture light brown; anteronotal protuberance and scutellum brown; scuto-scutellar impression pale. Forelegs brown; middle and hind legs yellowish, joints brown. Wings hyaline: all veins brown. Abdomen: Terga brownish; posterior margins and posterolateral corners darker. Sterna pale; sterna I‒II and VII‒VIII dirty pale. Subgenital plate brownish without incision. Cerci brownish, tips pale.

FIGURES 39–40.

Mature larva. Length (mm): body 9.0‒11.2; cerci 3.6‒5.2. Head: Brown (Fig. 42). Antennae light brown. Labrum (length 0.82 that of width) brown with an oval pale spot bordering brown stripe (Figs 42, 43); lateral margins dark; distal area pale. Basal part of clypeus dark brown (Figs 42, 43). First denticle incisor of the left mandible nearly equal to the second (Fig. 44); third denticle of the right incisor nearly equal to the first (Fig. 41). Labium white, shown in Fig. 46. Thorax: Pronotum and mesonotum light brown or brown with pale median strip (Fig. 41). Pronotum with dark brown anterior margin and pale lateral sides. Mesonotum contrasting, with light and dark streaks and spots (Fig. 41). Legs brownish; foreleg slightly darker than middle and hind legs. Femur of foreleg with long pale stripe near outer margin (Fig. 47); femur of the middle and hind legs with a broad pale spot in distal part. Foreleg (mm): femur 1.2‒1.5; tibia 0.6‒0.9; and tarsus 0.8‒1.0. Middle leg: femur 1.2‒1.4; tibia 0.7‒0.9; and tarsus 0.7‒1.0. Hind leg: femur 1.2‒1.5; tibia 0.6‒0.9; and tarsus 0.7‒1.0. Abdomen: Terga I‒VII brown with dark posterior margins and white lateral sides (Figs 41, 48); terga I‒VII with a pair of pale elongated spots connected at midline and with oval pale spot medially; terga VIII‒IX with white posterior area and wide white middle stripe; all terga with almost regular row of spines (Fig. 50). Sterna brownish with white lateral margins (Fig. 49); sterna I‒II lighter than others; sterna II-VI with a pair of small dark spots on the anterolateral corners; sterna VII‒IX with a pair of small white spots on the antero-lateral corners; sterna VI‒VIII without ganglionic marking; abdominal sternum IX (female) with a shallow incision (Fig. 51). Gills white; gills I and II small without an anal rib (Figs 52, 53); gill I only slightly smaller than gill II: width 0.44 of length; gill II: width 0.43 of length; gills III‒VII with an anal rib on the margins (Figs 54, 55); gills III‒VI with rounded distal margins (Fig. 54) and width 0.50‒0.54 of length; gill VII narrower with a pointed tip and slightly smaller than gill VI: width 0.39 of length (Fig. 55). Basal quarter of cerci yellowish, more distally brown, than yellowish, tips brown (Fig. 41); joints of each segment darker.

Eggs. General shape ellipsoidal with a length of 176‒202 µm and a width of 105‒128 µm (Fig. 56). Chorionic surface covered with large-mesh regular pentagonal cells; each cell with a wavy bottom; borders of cells solid, relatively high; every four cells united by one small round knob, that evenly covers the whole egg; large and round knobs arranged on both poles (Fig. 56). Micropyles located in the equatorial area; sperm guide round, well apparent; micropylar rim absent (Fig. 58).

Etymology. The species is named in memory of the Far Eastern hydroecologist Sergey Egorovich Sirotsky, who for a long time was investigator of the Far Eastern Rivers.

Distribution and biology. Russian Far East: Khabarovskiy Kray, Amurskaya and Magadanskaya Oblast’. Adult emergence period from the middle July to the 10 August.

FIGURES 41–42.

FIGURES 43–50.

FIGURES 56–58.