Ameletus allengaensis 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 : 154-161

Ameletus allengaensis Tiunova , sp. nov.

(Figs 2‒31)

Material. Holotype male imago (reared from larva), RUSSIA, AMURSKAYA OBLAST’, Zeyskii district , Allenga River, above mouth, 29.VI.2015, T. Tiunova. Paratypes: collected together with the holotype: 12 male and 3 female, 1 female (AM339) imagines (reared from larva); same place, 29. VI.2015, 5 male, 13 female imagines, 11 larvae, 13 larval skin, T. Tiunova.

Other material examined. RUSSIA: KHABAROVSKIY KRAY, Okhotskii district: Ul’ya River Basin, Khetana River , 08. VII.1985, 4 male and 1 female subimagines, 10 larvae, V. Zherikhin; Bulginka River , a turn on the Bulgino village , 26 . VI.1999, 1 male and 2 female imagines (reared from larva), 2 male and 2 female subimagines (reared from larva), 2 larvae, T. Tiunova; same locality, 03 . VII.1999, 2 larvae, T. Tiunova; Amur River Basin, Gera River, about 2 km upper Gera Lake , 26 . VI.2000, 1 larva, T. Tiunova; at highway Khabarovsk ‒ Nikolaevsk-na Amure: Yai River , bridge, 30 . VI.2005, 4 larvae, T. Tiunova; Hivanda River , 1 . VII.2005, 2 larvae, T. Tiunova; AMURSKAYA OBLAST’: Zeya Reservoir Basin: stream, ~ 2 km below the mountain Zolotaya Sopka , at highway Zeya ‒ Beregovoy, 20 . VI.2004, 10 larvae, T. Tiunova; at highway Zeya ‒ Verhnezeysk: Sirik River , bridge, 21 . VI.2004, 12 larvae, T. Tiunova; Dess River , bridge, 21 . VI.2004, 9 larvae, T. Tiunova; Artemiy stream, bridge, 21. VI.2004, 5 larvae, T. Tiunova; Palpaga River , bridge, 22 . VI.2004, 3 larvae, T. Tiunova; Kiryak River , bridge, 22 . VI.2004, 5 larvae, T. Tiunova; ZEYSKII RESERVE: Zeya Reservoir Basin, Bolshoi Garmakan River , about 300 m above mouth, 02 . VII.2015, 2 male, 5 female imagines, 2 male, 1 female subimagines, 11 larvae, T. Tiunova; same locality, 08 . VII.2015, 3 male, 13 female imagines, 6 male, 5 female subimagines, 1 larva, T. Tiunova; Zeya River Basin: Bolshaya Erakingra, 52-i km, 6 . VII.2013, 7 male, 6 female imagines, 4 male, 2 female subimagines, 19 larvae, 1 larva (AM6), T. Tiunova; same locality, 09 . VII.2014, 6 male, 8 female imagines, 2 female subimagines, 6 mature larvae, 1 larva (AM133), 1 larva (AM134), T. Tiunova; same locality, 3‒4 . VII.2015, 17 male, 13 female, 1 female (AM337) imagines (reared from larvae), 17 mature larvae, 1 larva (AM336), T. Tiunova; Bolshaya Makcha River , bridge, at highway Tynda ‒ Zeya, 08 . VII.2014, 1 male imago (AM132), T. Tiunova; same locality, 28 . VI.2015, 3 larvae, 1 larva (AM331), T. Tiunova; Kamenushka River , 06 . VII.2015, 11 larvae, T. Tiunova; Tynda River Basin, Allenga River , bridge, at highway Zeya ‒ Snezhnogorsk, 07 . VII.2013, 2 male, 5 female, 1 female (AM1) (reared from larvae) imagines, 34 larvae, 1 larva (AM2), T. Tiunova; same locality, 06 . VII.2014, 11 larvae, 1 larva (AM105), T. Tiunova; same place, 13 larvae, 1 larva (AM325), T. Tiunova; Savushkin stream, 38 km from Zeya town , at highway Zeya ‒ Steznogorskyi, 09 . VII.2015, 13 larvae, 1 larva (AM338), 1 larva (AM356), T. Tiunova; MAGADANSKAYA OBLAST’: Ola River , upper reaches, 24 . VI.2013, 1 female subimago, 2 larvae, E. Khamenkova; same locality, 30 . V.2014, 2 larvae, 1 larva (AM390), E. Khamenkova; same locality, 16 . VI.2014, 2 larvae, 1 larva (AM143), 1 larva (AM144), 1 larva (AM147), 1 larva (AM150), E. Khamenkova; same locality, 08 . VII.2014, 2 male and 1 female (reared from larvae) imagines, 1 female subimago, 1mature larvae, E. Khamenkova; Ola River Basin, Donyshko River , 16 . VI.2014, 1 larva (AM138), 1 larva (AM139), E. Khamenkova; KAMCHATKA PENINSULA, Poperechnaya River , 28 . VII.2015, 3 mature larvae, 1 larva (AM313), I. Tiunov; SACHA YAKUTIYA: Timpton River Basin, Gorbyllah River , bridge, at highway Tygda ‒ Neryungri, 30-31 . VII.2010, 4 male, 2 female imagines (reared from larvae), 6 larvae, T. Tiunova; same locality, 30 . VII.2016, 7 larvae, 1 larva (AM457), 1 larva (AM458), 1 larva (AM459), 1 larva (AM460), I. Reznik.

Description. Male imago (in alcohol). Length (mm): body 12.9‒14.0; forewings 11.5‒12.7; cerci 12.3‒16.0. Head: upper portion of the eyes grey; lower portion dirty grey. Thorax: Medioscutum and submedioscutum dark brown; median longitudinal suture narrow and dark (Fig. 2). Sublateroscutum dark brown. Scutellum dark brown; scuto-scutellar impression brown or light brown with light lateral margins. Posterior scuttle protuberance dark brown with narrow white spot near the posterior lateral margin. Anteronotal protuberance dark brown; anterolateral sides dark. Forelegs dark brown or dirty brown; middle and hind legs yellowish or brownish; tarsal segments slightly darker. Length (mm) of foreleg segments: femora 2.3‒2.4; tibia 2.0‒2.3; tarsal segments 0.5‒0.6, 1.3‒1.5, 1.3‒1.4, 0.9‒1.0, and 0.5‒0.6. Wings brownish, hyaline; all veins brown with lighter crossveins; pterostigma milky. Abdomen: tergum I dark; terga II-VI brownish or dirty brownish with lateral margins and posterolateral corners dark brown at the posterior margin (Figs 8‒9); in the first third of terga, a wide brown strip that connects with dark lateral angles; a pair of brownish oblique stripes medially; terga VII‒VIII with dark brown posterolateral corners and posterior margins; tergum IX dark brown (Fig. 9). Sternum I dark brown; sterna II‒III brown; sterna IV‒VII FIGURES 2–7.

FIGURES 8–10.

FIGURES 11–12.

brownish; sterna VIII‒IX with two brownish oblique stripes and a pair of brown dots in the middle part of the anterior margin; sterna VII‒VIII white with brownish stripes in the middle area; sterna II‒IV with a pair of brown oblique stripes and spots near the anterior margin; sterna V‒VIII with brown ganglionic markings (Fig. 10). Styliger white and well-contrasted medially with dark brown lateral margins (Fig. 3). First segment of forceps dark brown, sometimes lighter in the distal part; second and third segments light brown or brownish (Fig. 3). Lateral margin of penis lobes rounded and bent medially (Figs 4‒5); each ventral plate bears large and long apical pointed denticle (Figs 6‒7, 11‒12), outer edge with several very small denticles, which are evenly located far from each other (Figs 6, 11‒12); the first small denticle is located far from base of main denticles (Figs 6, 12). Cerci brown with dark brown joints of segments and pale tips.

Female imago. Length (mm): body 13.0‒14.3; forewings 13.0‒13.7; cerci 11.0‒15.0. Head: eyes blackish and tinged grey. Base of the median and lateral ocelli delineated black; antennae brown at the base with remainder part pale. Space between the eyes white with blackish pigmentation. Thorax: Pronotum brown with white granular coating; mesonotum brown; anteronotal protuberance with white median longitudinal suture; posterior margin of mesonotum with a pair of wide and curved white stripes exciting the scuto-scutellar impression, the inner edge of the posterior scutal protuberance and the base of the submedioscutum; sublateroscutum with pairs of dark and white spots. Forelegs brown; middle and hind legs light brown or yellowish. Wings hyaline; all veins brown. Abdomen: Colour of terga as in the male (Fig. 13). Sterna light brown, lateral margins pale; sterna IV‒VII with brown ganglionic maculation; sternum VII brown with pale middle area; sterna VIII‒IX brown with diffuse white pigmentation. Subgenital plate brown with a deep incision. Cerci brownish; joints of segments brown.

Mature larva. Length (mm): body 11.5‒14.2; cerci 4.2‒6.3. Head: Brown with pale triangular spot from the median ocellus to the anterior margin of the clypeus (Fig. 14). Antennae brown at the base, tips pale. Labrum (length 0.8‒0.86 that of the width) light brown with a wide, brown, nearly rectangular spot that does not reach the anterior margin (Figs 14, 16); spot sometimes almost black with an extended anterior margin with a mushroom shape. Clypeus brown, lateral sides pale (Figs 14, 16). First denticle incisor of the left mandible largest, the fourth smallest, the second nearly equal to the third (Fig. 17); third denticle incisor of the right mandible widest (Fig. 18). Labium whitish, shown in Fig. 19. Thorax: pronotum and mesonotum brown with contrasting pale and light brown stripes and spots (Fig. 15). Legs light brown; femur of all legs light brown with brown spots near the joints of segments and a pale spot near the posterior margin (Figs 15, 20); tibia brown; tarsus light brown in the middle and FIGURES 13–15.

FIGURES 16–28.

FIGURES 29–31.

dark brown at the edges; claws dark brown. Foreleg (mm): femur 1.6‒2.0; tibia 0.9‒1.0; and tarsus 1.0‒1.2. Middle leg: femur 1.5‒2.0; tibia 1.0‒1.1; and tarsus 0.9‒1.2. Hind leg: femur 1.5‒2.0; tibia 1.0‒1.1; and tarsus 1.0‒1.2. Abdomen: Brown with contrasting pale maculation (Figs 15, 21); terga I‒VI with oblique white stripe on the sides and brown posterolateral corners; tergum I with a pair of white semilunar spots; posterior margin white; anterolateral corners white; tergum II with a pair of white spots of indefinite shape and a large oval white spot in the middle; tergum III with a pair of drop-shaped spots near the anterolateral corners and a pair of round spots in the posterior part; terga IV‒VI with colour similar to tergum III but fainter; tergum VII with a white spot in the form of a maple leaf; tergum VIII brown with a pair of drop-shaped spots near the anterior margin; tergum IX with a pair of large white spots near the posterior margin, which sometimes merge along the posterior margin into a single spot; tergum X brown or dark brown with a white anterior area (Fig. 21); all terga with a row of long and short spines along of posterior margin (Fig. 23). Sterna brown or dark brown (Fig. 22); sterna I‒IX with pale lateral margins and a pair of small white spots near the anterolateral corners; sternum I pale; sterna II‒V with a large blackish spot in the centre near the anterior margins; sterna VI‒VII with blackish ganglionic markings; sternum VIII dark brown; sternum IX (female) with a pair of pale stripes centrally, near the anterior margin and a deep incision (Fig. 24). Gills white; gills I and II without anal rib (Figs 25, 26); gill I nearly two times smaller than gill II, width 0.50 of length; gill II: width 0.48 of length; gills III-VII with anal rib on the margins; gills III‒VI with rounded distal margins and width 0.52‒0.56 of length (Fig. 27); gill VII narrower and slightly smaller than gill VI, with width 0.49 of length (Fig. 28). Cerci brownish with dark band at the middle part (Fig. 15).

Eggs. General shape elliptical with a length of 189‒208 µm and a width of 105‒121 µm (Fig. 29). Chorionic surface covered with large-mesh, regular pentagonal cells; each cell with a wrinkled bottom (Figs 30, 31); borders of cells solid, relatively high; each four or five cells united by one small round knob that evenly covers the whole egg surface; large and round knobs arranged on both poles, smaller knobs centrally (Fig. 29). Micropyles located in the subequatorial area (Fig. 29); sperm guide round, micropylar rim absent; sperm guide well apparent (Fig. 30).

Etymology. The name refers to the type locality, the Allenga River, where the types were collected.

Distribution and biology. Russian Far East: Khabarovskiy Kray, Amurskaya and Magadanskaya Oblast’, Sacha Yakutiya. According our observations, the period of emergence of the adults continues from 20 June to 30 July.