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Diversity patterns of aquatic insects among sampling sites lying with!c the unprotected and protected areas of Western Ghats were studied. This study primarily emphasizes whether anthropogenic influence is the prime cause for the presence of aquatic insects especialIy of pollution-sensitive organisms belonging to the orders Ephemeroptera, Plecoptera and Trichoptera, or to factors such as the physico-chemical features of the water, or sampling methods. Six streams were sampled quantitatively, of which three streams (Abbifalls, Monkey falls and SiIver Cascade) were within protected areas and the remaining three streams (Kumbakarai, Shenbagadevi and Manimutharu falls) were in unprotected areas. A total of 3,209 individual aquatic insects belonging to 25 genera, 18 families and 7 orders were collected. The highest species richness and abundance was observed in Monkey falls followed by Kumbakkarai falls. Large cumbers of more habitat-sensitive organisms such as Ecdyonurus sp., Epeorus sp., Thalerosphyrus sp., Euthraulus sp., and Nathanella sp., were found in Monkey falls. Though the species assemblage was somewhat different, pollution-sensitive taxa were also observed in Kumbakkarai falls. Shenbagadevi and Manimutharu falls had a lower diversity of aquatic insects. The likely causes of these differences are discussed.

A female imago of Ecdyonurus groehnorum sp. nov. from the Baltic amber (Eocene) is described and illustrated. We have placed this new species within the early described subgenus Nestormeus Godunko, 2004 because of the presence of the short, curved lateroparapsidal sutures on the mesonotum, which are noncontiguous with the medioparapsidal sutures.

Ecdyonurus solus Godunko, Kłonowska-Olejnik and Prokopov, sp. nov. (Figs 1���25) Ecdyonurus venosus: Kiseleva and Ezernitskii 1985: 112; Kiseleva 1993: 163; Godunko 2001: 81 Ecdyonurus fluminum: Kiseleva and Ezernitsikii 1985: 112; Kiseleva 1992: 116; Kiseleva 1997: 39 Description. Male imago (all adults were reared from larvae). Size: body 10.0��� 10.4 mm; fore wing 11.0��� 11.2 mm; hind wings 3.9���4.3 mm; fore legs 10.2���10.9 mm (femur 2.6���2.7 mm; tibia 2.5���2.7 mm; tarsal segments: T 1 = 0.8 ���1.0 mm; T 2 = 1.4���1.5 mm; T 3 = 1.3���1.4 mm; T 4 = 1.1 mm; T 5 = 0.5 mm; gradation of tarsal segments: 2>= 3> 4> 1> 5); cerci 29.6���30.5 mm. General color of body yellow to brown. Head yellowish with brownish and brownish-gray smudges on short facial keel. Antennae brown. Ocelli black basally with subapical yellowish-brown ring and whitish or white-gray apically. Eyes are separated by a distinct gap comparable in size with the central ocellus, gray-blackish, with light gray ring around of margin. Lateral portion of eyes with two light gray rings (Figs 1, 2). Thorax yellow to brown, dorsally with dark brown maculation on metanotum and hind part of mesonotum. Pronotum light yellowish-brown. Lateral part of thorax generally whitish to yellowish-brown. Ventral part of thorax distinctly brown to brownish-black. Wing hyaline, transparent, unicolorous. Pterostigmatic area clearly yellow, costal area yellowish-white. Venation brown to blackish, lighter basally. Fore legs distinctly darker than middle and hind legs: femora dark brown; tibiae and tarsi brown, with slightly dark last tarsal segment. Middle and hind legs with yellow femora and tibiae; tarsi yellowish-brown basally with brownish last segment. Abdominal terga yellow to yellowish-brown. Tergum 1 brown, with blackish-brown strips near hind margin of segment; tergum 2 with central longitudinal light band and two brownish paramedian bands; terga 3���10 yellowish, with two longitudinal narrow paramedia bands (terga 7���10 slightly darker that others ones). Laterally terga 2���8 with distinct blackish-brown stripes connected dorsally in posterior part of segments (Fig. 3). Sterna 1 and 9 brown, sterna 2���8 uniformly yellowish with two unclear brownish spots. Violet or blackish nerve ganglia well visible on the sterna 2���8. Cerci brownish, lighter apically. Joints of segments blackish. Styliger plate light brown, with two small and rounded apically protuberance near forceps base (Fig. 4). Forceps brown. Penis lobes light brown, slightly stretched laterally and convergent toward outer margins, with rounded distal part. Penis light brown. Basal sclerite large, partially cover the basal part of lateral sclerite. Lateral sclerite narrow and curved, distinctly convergent distally. Apical sclerite relatively wide, not convergent apically. Titilators wide, brown (Fig. 5). Female imago. Size: body 12.2 mm; fore wing 12.0 mm; hind wings 4.0 mm; cerci 19.5 mm. Head yellow with blackish smudges on facial keel. Eyes and apical part of ocelli grayish-black. Central part of ocelli light yellow; apical part whitish. Antennae light brown. Thorax yellow to dark brown. Pronotum yellowish-gray with two brownish spots centrally. Mesonotum yellowish-brown with brown to dark brown distal part. Metanotum dark brown. Lateral part of thorax yellowish-brown. Sterna of thorax brown to dark brown. Wings transparent, hyaline slightly yellowish color. Pterostigmatic area yellowish, opaque. Venation yellow to dark brown. Fore legs with light brown femora, and brown to dark brown tibiae and tarsi. Middle and hind legs with unicolorous yellow femora and yellowish-brown tibiae. Tarsi brown to dark-brown. Abdominal terga with central longitudinal bands and two short reddish strokes on the segments. Two distinct triangular reddish or brownish spots are present on central part of tergum 1; lateral part of terga 2���8 with blackish stripes. Abdominal sterna yellow to reddish-brown, with uniformly pattern on the segments 1���7 (generally present two central light short strokes). Sterna 2-8 with visible violet or blackish nerve ganglia. Subgenital and subanal plates as in Fig. 6. Male subimago. Size: body 9.5 mm; fore wing 12.0 mm; hind wings 4.0 mm; cerci 19.5 mm. General color of body yellow and yellowish-gray to brown and dark brown. Head grayish brown, antennae brownish. Eyes grayish-black with one hard visible grayish-white ring laterally. Ocelli blackish basally, with grayish-white tip. Pronotum brownish-gray. Mesonotum and metanotum yellowish-white with distinct dark brown bands. Wings unicolorous yellowish, relatively transparent. Venation whitish-gray to brownish. Transversal veins darker than longitudinal with grayish-brown smudges around veins. Fore legs dark: femora brown slightly darker distally; tibiae dark brown; tarsi unicolorous brown. Middle and hind legs: femora yellow with elongate brownish spot apically; tibiae yellowish-brown; tarsi yellowish. Abdominal terga yellow to yellowish-brown. Sterna 1���8 slightly darker than terga with two light short strokes and two light spots centrally. Sternum 8 with violet nerve ganglia. Lateral part of terga 1���8 with distinct blackish-brown stripes connected distally in posterior part of segments. Styliger plate yellowish-brown, forceps slightly darker. Cerci light brown. Joints of segments blackish. Female subimago. Size: body 12.7���13.8 mm; fore wing 13.0��� 14.2 mm; hind wings 4.2 ���5.0 mm; cerci 12.2���13.7 mm. General color of body very similar to those of female imago except wings and legs. Thorax yellow to dark brown. Wings distinctly yellowish to light brown, slightly opaque, especially in pterostigmatic area. Veins dark brown to black. Brownish smudges around veins are presented. Fore legs unicolorous dark brown with black tarsi. Middle and hind legs light brown. Tarsi dark brown to black. Abdominal terga with distinct drawing: tergum 1 with diffuse central brownish spots; terga 2���3 with central diffuse brownish and two yellow spots; terga 4���5 with longitudinal brownish spot; terga 6���7 with two pair of small brownish spots near anterior part of segment; terga 8���10 uniformly yellowish with central brownish smudges. Lateral side of terga 1���8 with distinct dark brown strips. Sternum 8 with violet nerve ganglia. Cerci dark brown. Mature larva. Body length 11.2���13.5 mm; caudal filaments 7.4 ���10.0 mm. General color yellow to light brown. Abdominal segments of mature larvae with well visible pattern similar to adults. Head yellow, oval, relatively large, the part at the eyes level not widest. Antennae yellow to light brown. Mouthparts: Labrum not large, slightly stretched laterally, dorsally with one row of 7���9 median strong bristles (Fig. 7), typical for the E. venosus species-group (Belfiore & Buffagni 1994). Hypopharynx without specific features, generally with long hair on the outer margin and distal part, typical for the E. venosus species-group (Fig. 8). Mandibles (n = 20) with 6���9 prosthecal bristles. Maxillae (n = 20) (characters listed by Haybach (1999)): number of comb-shaped bristles (N_ CBS) = 17���22; number of teeth on 5 th comb-shaped bristle (N_TCB 5) = 14���17; number of hairs on dorsal upper side (N_ DOR) = 14���18; outer margin of maxillae without hairs (N_ OUT = 0); number of hairs on ventral basal part of maxillae (N_VEN) = 21���24; number of hairs at the base of maxillary palps (N_PLBas) = 16���20; outer base of the first segment of maxillary palps without hairs (N_PLH = 0); number of setae on the outer margin of the first segment of maxillary palps (N_PLS)> 50; number of setae on the inner side of the first segment of maxillary palps (N_PLP)> 40. Labial palps with numerous hairs of the group on the dorsal side of its first segment (N_LPH = 28���36) arranged on 2���3 rows. Pronotum yellow with some light central smudges. Lateral projection of pronotum short, distinctly asymmetrical, with apical part curved towards the body (Fig. 10). The width/length ratio of semipronotum to caudal projection (see Bauernfeind & Humpesch 2001) is 3.8���4.2. Mesonotum yellow to yellowish-brown, with whitish spots laterally. Legs yellow to light brown. Femora relatively slender and long. The length/width ratio of metafemora on average 2.67. Dorsal surface of femora mainly with distinct pattern (four yellowish lateral spots on a dark field) (Fig. 11). Femoral scales of various types (Fig. 12). Outer margin of femora with row of long slender bristles and small pointed spines; subapical spines is pointed or bluntly pointed (Fig. 13). Tibiae yellow. Tarsi yellow to light brown basally with brown or dark brown apical ring. Tarsal claw brown to dark brown with 2���3 teeth (Fig. 14). Abdominal terga yellow to light brown. Tergum 1 uniformly light; terga 2���7 and 10 (sometime 8) with two light central longitudinal spots (sometimes, with two pair of light spots); Tergum 9 with wide central light spot (Fig. 15). Posterior margins of terga with large pointed marginal teeth (Fig. 16). Sterna unicolorous yellowish-brown with well visible violet nerve ganglia on the segments 2���8. Gills yellowish to light brown. Gill 1 relatively long with broadly rounded apical part (Fig. 17). Gill 4 distinctly wide and asymmetrical (Fig. 18). Gill 7 as in Fig. 19, without tuft. Cerci yellow to yellowish brown. Egg. Size: length: 164���171 ��m; width 108���116 ��m. Egg oval. The eggs are characterized by attachment structures, tubercles, and very small granules (Fig. 20). The attachment structures are represented by knob-terminated coiled threads (KCTs) (Koss & Edmunds 1974) and are of two different kinds. The first are larger (diameter 3.9���5.3 ��m) and concentrated (aggregated) at one egg pole, covering a densely chorionic surface (spaced at a distance of 2.6���3.9 ��m) (Fig. 21). This structure is similar to that of E. venosus KCTs (Gaino & Rebora 2003) (Fig. 22). The second attachment structure is slightly smaller (diameter 2.7���3.3 ��m) and is regularly distributed over the chorion surface (spaced at a distance of 6.7 ���12.0 ��m) (Fig. 23). The chorionic surface has many small rounded tubercles (0.7���0.9 ��m), spaced at a distance of 0.4���1.3 ��m. The chorionic surface and tubercles are covered by very small granules (granular ground matrix) 0.09���0.17 ��m in diameter (Fig. 24). Five to eight micropyles are visible in the subequatorial area. The sperm guide ovoidal is 11.1���11.8 ��m in length and 7.9 ���9.0 ��m in width (micropylar opening situated at the side). The micropylar rim is narrow with tubercles similar to those found on the chorionic surface (Fig. 25). Etymology. The species name originates from the Latin noun solus, i.e. single, solitary. It is the only one species of the genus Ecdyonurus living in the Crimea. Specimens examined. HOLOTYPE: male imago, UKRAINE, Autonomous Republic of the Crimea, Chorna River, Chornorichens���kyi gap, 8.06. 2003, 300 m. a.s.l., Long. 33 o 46 ��� 19 ������ E, Lat. 44 o 30 ��� 23 ������ N, leg. G.A. Prokopov. PARATYPES: 3 larvae (two on slides), ibid, Stilia River, 7.07. 1989, 150 m. a.s.l., Long. 34 o02��� 50 ������ E, Lat. 44 o 38 ��� 11 ������ N, leg. G.A. Kiseleva; 2 larvae, ibid, Upper Chorna River, Chornorichens���kyi gap, 15.06. 1998, 300 m. a.s.l., Long. 33 o 46 ��� 19 ������ E, Lat. 44 o 30 ��� 23 ������ N, leg. G.A. Prokopov; 5 larvae, ibid, Upper Chorna River, Chornorichens���kyi gap, 3.01. 2001, 250 m. a.s.l., Long. 33 o 46 ��� 19 ������ E, Lat. 44 o 30 ��� 23 ������ N, leg. G.A. Prokopov; 6 larvae, ibid, Upper Chorna River near Chornorichens���kyi gap, 4.01. 2001, 300 m. a.s.l., Long. 33 o 46 ��� 19 ������ E, Lat. 44 o 30 ��� 23 ������ N, leg. G.A. Prokopov; 9 larvae, ibid, Al���ma River, downstream of ���Asport��� Boundary, 29.06. 2001, 450 m. a.s.l., Long. 34 o 14 ��� 21 ������ E, Lat. 44 o 43 ��� 14 ������ N, leg. G.A. Prokopov; 29 larvae, ibid, Al���ma River downstream of ���Tar���er��� Boundary, 30.06. 2001, 400 m. a.s.l., Long. 34 o 10 ��� 43 ������ E, Lat. 44 o 43 ��� 11 ������ N, leg. G.A. Prokopov; 4 larvae, ibid, Al���ma River downstream of ���Sosnovyi��� Boundary, 1.07. 2001, Long. 34 o08���04������ E, Lat. 44 o 45 ��� 33 ������ N, 350 m. a.s.l., leg. G. A. Prokopov; 1 larva, ibid, Al���ma River near Partyzans���ke Reservoir, 1.07. 2001, 300 m. a.s.l., Long. 34 o05��� 43 ������ E, Lat. 44 o 47 ��� 30 ������ N, leg. G.A. Prokopov; 1 larva, ibid, Upper Chorna River, Chornorichens���kyi gap, 16.08. 2001, 300 m. a.s.l., Long. 33 o 46 ��� 19 ������ E, Lat. 44 o 30 ��� 23 ������ N, leg. G.A. Prokopov; 6 larvae, ibid, Chorna River near Chornorichyns���ke village, 17.08. 2001, 200 m. a.s.l., Long. 33 o 41 ��� 23 ������ E, Lat. 44 o 32 ��� 12 ������ N, leg. G.A. Prokopov; 1 male subimago, 1 female imago, 3 female subimagines, 25 larvae, Ukraine, Autonomous Republic of the Crimea, Chorna River, Chornorichens���kyi gap, 8.06. 2003, 300 m. a.s.l., Long. 33 o 46 ��� 19 ������ E, Lat. 44 o 30 ��� 23 ������ N, leg. G.A. Prokopov. All specimens were preserved in 75 % alcohol. All adults were reared from larvae. The holotype and part of the paratypes are housed in the collection of the State Museum of Natural History, National Academy of Sciences of Ukraine (Lviv, Ukraine). The other paratypes are stored in the Biology Centre of the Academy of Science of the Czech Republic, Institute of Entomology (Č esk�� Bud��jovice, Czech Republic) and in the first and second author���s collections. Affinities. E. solus sp. nov. belongs to the E. venosus species-group by the presence of following characteristics: in male imago: (1) apical sclerite of penis subparalel to the body axis, straight, relatively short and blunt; (2) abdominal terga with mainly visible darker pattern; in larva: (3) superlinguae of hypopharynx with long fine setae on the anterior margin (up to the lateral tips); (4) labrum with one row of setae ventrally; (5) lateral prolongation of sterna are markedly visible. The new species can be easily distinguished from all other representatives of this species-group by the following features: in male imago: (1) eyes gray-blackish, with two light gray rings laterally, divided by a small gap; (2) wing hyaline, transparent and unicolorous; (3) venation brown to blackish, lighter basally, without maculation around veins; (4) color of abdominal terga and sterna; (5) styliger plate with two small rounded apically protuberance; (6) penis lobes slightly stretched laterally and convergent toward outer margins, with rounded distal part; (7) peculiarities of the penis structure; in larva: (8) number of some groups of setae, bristles and hairs on maxillae and labial palps (9) lateral projection of pronotum short, distinctly asymmetrical, with curved towards the body apical part; (10) femora relatively slender and long; (11) outer margin of femora with row of long slender bristles and small pointed spines; (12) coloration of abdominal terga and sterna; (13) coloration of tarsi; (14) denticulation of posterior margins of terga; (15) shape of scales of dorsal surface of femora and (16) shape of gills (especially gills 1, 4 and 7). The penis structure discriminates the new species from the all other European species of the E. venosus species-group (except for E. ornatipennis, see below). Some aspects of the penis shape of E. solus sp. nov., are similar to E. ruffii Grandi, 1953 (Bauernfeind & Humpesch 2001: 139, Fig. 474), but the new species can be distinguished by its body coloration and especially by the pattern on the terga. The male imago of E. solus sp. nov. can be easily distinguished from the two Caucasian species, viz. E. autumnalis and E. ornatipennis. By laterally stretched penis lobes the new species is similar in appearance to E. ornatipennis. The combination of following features markedly differs E. ornatipennis from E. solus sp. nov.: (1) unicolorous eyes without any rings, not close to each other; (2) penis lobes relatively square-shape distally; (3) abdominal sterna with brown longitudinal central band (Tshernova 1938, 57��� 58, Fig. 4, Kluge pers. com.). E. autumnalis differs from E. solus sp. nov. by (1) the distinctly darker color of body; (2) the presence one light ring on eyes; (3) the presence of brown longitudinal central band on abdominal sterna; (4) the shape of penis, with large and not stretched laterally lobes; (5) the distinctly convergent towards the tip apical sclerites; (6) the shape of lateral sclerites (Braasch 1980 b, 103���104, Fig. 1, 1 a, 2, Kluge pers. com.). The larvae of E. solus sp. nov., partly resembles to E. aurantiacus (Burmeister, 1839), E. belfiorei Haybach and Thomas, 2002 and E. dispar (Curtis, 1834) by the structure of the pronotal projection and gills (especially gill 1). However, larval characteristics 8, 11, 14 and 16 easily differs new species from E. aurantiacus; characters 8, 10, 12, 13 and 14 from E. dispar; characters 8, 12 and 16 from E. belfiorei (see Haybach and Thomas 2002). The larvae of E. solus sp. nov. can be separated from larvae described as E. ornatipennis (see Braasch 1980 a), by the shape of the pronotum expansion, femoral scales, gills and by the coloration of the abdominal terga. Distribution and biology. The larvae of E. solus sp. nov. are found in metarithral and hyporithral rivers on the northern slopes of the Crimean mountains at altitudes of 150��� 450 m. a.s.l. In summer, the average water temperature is 12 0C and the water is of hydrogen carbonate type. The larvae inhabit the waters with current velocities of about 1 m /s. Width of river bed width is around 3���6 m, depth 0.3���0.5 m, with cobble and gravel bottoms. The banks of beds are partly shaded by Fagus orientalis Lipsky, Carpinus betulus Linnaeus and Quercus pubescens Willd. E. solus sp. nov. has a univoltine winter cycle (Uw), with one generation per year (Clifford 1982). The population overwinters in the nymphal stage and larval growth is very slow. The flying period extends from May to July, with most of the population emerging by the end of June or the beginning of July. Other insects groups found in these rivers with E. solus sp. nov. include: stoneflies Nemoura cinerea (Retzius, 1783); dragonflies Calopteryx taurica Selys, 1853, Gomphus vulgatissima (Linnaeus, 1758), Onychogomphus forcipata (Linnaeus, 1758); mayflies Heptagenia samochai (Demoulin, 1973) and Baetis rhodani tauricus Godunko and Prokopov, 2003, caddisflies Halesus tessellatus (Rambur, 1842), Limnephilus lunatus Curtis, 1834, Hydropsyche acuta Martynov, 1909, Wilhelmia balcanica (Enderlein, 1924), W. parae, Published as part of K��onowska-Olejnik, Ma��gorzata, Prokopov, Grigorii A. & Godunko, Roman J., 2007, Description of Ecdyonurus solus sp. nov., a new species of the Ecdyonurus venosus species-group (Ephemeroptera: Heptageniidae) from the Crimean Peninsula, Ukraine, pp. 53-62 in Zootaxa 1620 on pages 54-61, DOI: 10.5281/zenodo.179171, {"references":["Kiseleva, G. A. & Ezernitskii, E. V. (1985) Distribution of the water entomofauna in the upper part of the Salgir riverbasin. Ekologicheskie i prirodookhrannye aspekty izucheniya Gornogo Kryma. Izd-vo SGU, 110 - 119. (in Russian)","Kiseleva, G. A. (1993) Aquatic insects in the water ecosystems of the small river of pre-mountain zone of the Crimea. Uspekhi entomologii v SSSR: Ekologiya i faunistika. Nebol'shie otryady nasekomykh. Izd-vo RAN, 163. (in Russian)","Godunko, R. J. (2001) Biodiversity of mayflies (Insecta: Ephemeroptera) of the Crimean Peninsula. In: Gaino, E. (Ed.), 2001 International Joint Meeting. X International Conference on Ephemeroptera and XIV International Symposium on Plecoptera, University of Perugia, Perugia (Italy), pp. 80 - 81.","Kiseleva, G. A. (1992) Benthic fauna of the small rivers of the mountain and pre-mountain zone of the Crimea. Ratsional'noe ispol'zovanie i okhrana ekosistem Kryma. UMK VO, 116. (in Russian)","Belfiore, C. & Buffagni, A. (1994) Revision of the Italian species of the Ecdyonurus helveticus - group; taxonomy of the nymphs (Ephemeroptera: Heptageniidae). Mitteilungen der Schweizerischen Entomologischen Gesellschaft, 67, 143 - 149.","Haybach, A. (1999) Contribution to larval taxonomy of Ecdyonurus venosus - group in Germany. Lauterbornia, 37, 113 - 150. (in German, Engl. sum.)","Bauernfeind, E. & Humpesch, U. H. (2001) Eintagsfliegen Zentraluropas (Insecta: Ephemeroptera): Bestimmung und Okologie. Verlag des Naturhistorischen Museums Wien, Wien, 239 pp.","Koss, R. W. & Edmunds, G. F. Jr. (1974) Ephemeroptera eggs and their contribution to phylogenetic studies of the order. Zoological Journal of the Linnaean Society, 55, 267 - 349, pl. 1 - 24.","Gaino, E. & Rebora, M. (2003) Adhesiveness of the eggs of Ecdyonurus venosus to siliceous and calcareous substrate. In: Gaino, E. (Ed.), Research update on Ephemeroptera & Plecoptera, University of Perugia, Perugia (Italy), pp. 437 - 443.","Tshernova, O. (1938) To the knowledge of mayflies (Ephemeroptera) of Eastern Transcaucasus. Trudy Azerbaidzhanskoi Akademii Nauk, 8 (42), 55 - 64. (in Russian and German)","Braasch, D. (1980 b) Neue Ecdyonurus - Arten (Heptageniidae, Ephemeroptera) aus dem Kaukasus und Transkaukasien (Sowjetunion) (3). Entomologische Nachrichten, 7, 103 - 110.","Haybach, A. & Thomas, A. G. B. (2002) Ecdyonurus belfiorei nov. sp. from Italy, with a note on E. aurantiacus androsianus Braasch, 1983 (Ephemeroptera: Heptageniidae). Ephemera, 2 (2), 79 - 91.","Braasch, D. (1980 a) Neue Ecdyonurus - Arten (Heptageniidae, Ephemeroptera) aus dem Kaukasus und Transkaukasien (Sowjetunion) II. Entomologische Nachrichten, 2, 23 - 28.","Clifford, H. F. (1982) Life cycles of mayflies (Ephemeroptera), with special reference to voltinism. Quaestiones Entomologicae, 18, 15 - 90."]}

Ecdyonurus (Nestormeus) groehnorum sp. nov. (Figs 1���6) Description. Female imago. Measurements: see Table 1. Characters (mm) Length of body 5.33 Length of right fore leg 3.95 Length of femur 1.53 Length of tibia 1.38 Length of tarsus 1.04 Segment I 0.15 Segment II 0.28 Segment III 0.25 Segment IV 0.18 Segment V 0.18 Length of left fore leg 3.86 Length of femur 1.50 Length of tibia 1.40 Length of tarsus 0.96 Segment I 0.15 Segment II 0.28 Segment III 0.23 Segment IV 0.15 Segment V 0.15 Length of right middle leg 3.52 Length of femur 1.63 Length of tibia 1.23 Length of tarsus 0.66 Segment I 0.13 Segment II 0.15 Segment III 0.13 Segment IV 0.10 Segment V 0.15 Length of left middle leg 3.50 Length of femur 1.58 Length of tibia 1.28 Length of tarsus 0.64 Segment I 0.13 Segment II 0.13 Segment III 0.13 Segment IV 0.10 Segment V 0.15 Length of right hind leg 3.20 Length of femur 1.58 Length of tibia 1.05 to be continued. Characters (mm) Length of tarsus 0.57 Segment I 0.13 Segment II 0.13 Segment III 0.10 Segment IV 0.08 Segment V 0.13 Length of right fore wing 5.93 Length of left fore wing 5.75 Length of right hind wing - Length of left hind wing 2.13 Hind /fore wings length ratio 0.36 Length of cerci 8.00* *Completely preserved right cercus only. Left cercus damaged, the length of preserved part is 2.4 mm. Body pale. Head uniformly brownish pigmented. Eyes noncontiguous, widely separated. Thorax light brown to brown with paler pronotum. Some brownish smudges around mesonotal sutures. Ventral side of thorax with the same color as dorsal one. Mesonotal suture deep, well visible, stretched backward medially. Medioparapsidal suture is well visible from the left side of the body only. Lateroparapsidal sutures deep and slightly curved, noncontiguous with medioparapsidal sutures (Fig. 1). Proximal part of mesonotum invisible from dorsal view. Median impression of furcasternum of mesothorax with sub-parallel margins, narrowed posteriorly and distinctly divergent in anterior part. Prosternum without any transversal ridge, typical of Ecdyonurus s. l. (Fig. 2, 5). Both pairs of wings translucent and opaque (Fig. 6). Cubital field of fore wings with two pairs of intercalary veins. Hind wings with RS, MA and MP triads. Hind right wing damaged. Wing venation well preserved, with typical structure of the family Heptageniidae (see Kluge 2004: 380���384). Patella-tibial suture is distinct enough in middle and hind legs. Tarsi of all legs are 5 -segmented, with dissimilar tarsal claws (one pointed and one blunt claw). Abdominal segments slightly deformed. Abdominal terga and sterna paler than thorax. Subgenital plate large, well developed, with visible apically impression. Subanal plate elongate, rounded, apically with marked tip (Figs 3, 4). Cerci preserved, longer than body (see Table 1). Affinities. Ecdyonurus groehnorum sp. nov. belongs to the subgenus Nestormeus within the genus Ecdyonurus, which can be distinguished from the other representatives of this genus by the combination of the following characters: (1) median impression of furcasternum of mesothorax with sub-parallel margins, narrowed posteriorly and distinctly divergent in its anterior part (see Kluge 2004), and (2) lateroparapsidal sutures deep and slightly curved, noncontiguous with medioparapsidal sutures (see Godunko 2004). The new species can be easily distinguished from the earlier described E. leopoliensis by the shape of the subanal and (especially) the subgenital plates. In contrast to E. leopoliensis, which can be characterized by the presence of a rounded apically subgenital plate without any impression, E. groehnorum sp. nov. bears a visible impression on the tip of the subgenital plate. The subanal plate of the new species is elongate with the tip marked apically, in contrast to the short and uniformly rounded subanal plate of E. leopoliensis. Other characters of the holotype of E. groehnorum, i.e. body measurements and general aspects of coloration, are close to E. leopoliensis. In the previous publication on the subgenus Nestormeus, the prothorax structure has not been described, because the anterior part of the type specimen of E. leopoliensis is invisible in ventral view (Godunko 2004: 326, Fig. 2). Thus, the examination of the prothorax peculiarities in E. groehnorum sp. nov. may contribute to the diagnosis of this fossil subgenus, showing the presences of the prosternum without a transversal ridge (typical of Ecdyonurus s. l., see Kluge 2004). Type. Holotype: female imago in the Baltic amber (Eocene), with well preserved body, being well visible from ventral view, and partly from dorsal and lateral views. The holotype is housed in the collection of the Geological-Palaeontological Museum, University of Hamburg (Germany), S.G.P.I.H. no. 4451 (ex coll. Carsten Gr��hn no. 76). Etymology. The new species is named in honor of Jutta and Carsten Gr��hn with hearty gratitude for supporting my stay in Hamburg., Published as part of Godunko, Roman J., 2007, Contribution to the knowledge of the fossil subgenus Nestormeus Godunko, 2004 (Ephemeroptera: Heptageniidae: Ecdyonurus) from the Baltic amber (Eocene), pp. 63-68 in Zootaxa 1661 on pages 63-68, DOI: 10.5281/zenodo.179949, {"references":["Kluge, N. J. (2004) The Phylogenetic System of Ephemeroptera (the first experience in consistently non-ranking taxonomy) Volume 1. Ephemeroptera except for Turbanoculata and Leptophlebia / fg 1. Kluwer Academic Publishers, Dordrecht-Hardbound, 456 pp.","Godunko, R. J. (2004) A new fossil subgenus and species of the genus Ecdyonurus Eaton, 1868 from Eocene Baltic amber (Ephemeroptera: Heptageniidae). Genus, 15 (3), 323 - 328."]}

This study is focussed on the redescription of Ecdyonurus (Ecdyonurus) russevi Braasch & Soldan on the basis of the type material (holotype and paratypes) and topotypes collected in the Strandzha Mts. (Bulgaria). Female imago and subimago, larva and egg of the species are described for the first time and the male imago is redescribed in detail. The features distinguishing the species from other representatives of the genus Ecdyonurus are presented. Ecdyonurus russevi differs by the combination of several characters in the colour pattern of abdominal terga and wings, colour of lateral portion of male eyes and male genitalia structure in adults; some overlap has been observed in the number of groups of setae, bristles and hair-like setae on maxillae and labial palps, shape of pronotal projection and colour of tarsi in larvae; and insignificant number of knob-terminated coiled threads on exochorion, with only a few such attachment elements on one pole in eggs. Biology and present distribution of the species are discussed.

Perennial Oued Zegzel and temporary Oued Cherraa are parts of the same watercourse. Coinertia analysis showed the clear distinction between these two parts and the close relationship of the faunal assemblages with the characteristics of the water. The headwater course of the Zegzel is covered with dense terrestrial vegetation whose debris were consumed by abundant shredders dominated by the prosobranch Melanopsis praemorsa. The lower course of the Zegzel has sparse riparian vegetation and much fine detritus, and collectors such as Ecdyonurus rothschildi, Caenis luctuosa, the Diptera Corynoneurinae and Tanytarsini, occurred. In contrast, dry, flowing-, and standing-water periods succeed each other in the Cherraa and terrestrial vegetation often grows in its bed. M. praemorsa was replaced by the air-breathing pulmonate Physa acuta, accompanied by the adults and larvae of flying insects. However many shredders did not develop on the abundant plant litter. The short length of the submersion period was probably responsible for this lack of efficiency in the exploitation of such a non-limiting food resource.

Programmed cell death, or apoptosis, occurs in ovarian follicle cells of Ecdyonurus venosus (Ephemeroptera, Heptageniidae) nymphs in the developmental phase characterized by pale wing‐pads. Follicle cells are responsible for egg vitelline and chorionic envelope synthesis. Apoptosis was detected in these cells both on the basis of their ultrastructural morphological characteristics and immunocytochemically by the TUNEL reaction, which proves nuclear DNA fragmentation. Cells showed structural changes after the synthesis of chorionic knob‐terminated coiled threads (KCTs), which typically perform an adhesive function in these insects. The morphological characteristics of apoptosis were evident under transmission electron microscopy after the completion of choriogenesis and consisted in: a) the lobated nucleus; b) chromatin forming small clumps close to the nuclear envelope; c) vacuoles increasing in size in the cell cytoplasm, which was filled with rough endoplasmic reticulum. Apoptotic follicle cell...

During the period 1988 - 1996 the Ephemeroptera diversity in West Serbia was studied. These investigations included 124 springs, considerable number of spring regions, as well as rivers: the Sušica, Djetinja, Skrapež Pocibrava, Banja, Gradac, Jablanica, Obnica and Kolubara. Total of 45 taxa belonging to 8 families were identified. At the majority of sampling locations: Baetis rhodani, Baetis sp., Ecdyonurus sp., Ephemera danica Ephemerella ignita, Caenis moesta, Habroleptoides modesta and Ilhitrogena semicolorata were present. The smallest Ephemeroptera diversity in the studied waters was recorded in springs and the greatest one in middle parts of the mountain running waters. U periodu 1988-1996. objavljena su faunistička istraživanja Ephemeroptera u tekućim vodama brdsko-planinskih područja zapadne Srbije. Istraživanja su objavljena na 124 izvora, velikom broju izvorišta, kao i na tekućicama Sušica, Đetinja, Skrapež, Pocibrava, Banja, Gradac, Jablanica, Obnica i Kolubara. Zabeležena su 45 taksona iz 8 familija insekatskog reda Ephemeroptera. Od konstatovanih, za 9 vrsta se u Limnofauni Evrope (Illies(ed) 1978) navodi da nije potvrđeno njihovo prisustvo, ali ni odsustvo u zoogeografskoj oblasti Dinarskog zapadnog Balkana kome pripada zapadna Srbija, za 4 vrste se konstatuje da nisu zabeležene, ali da se sa velikom sigurnošću mogu očekivati, dok se za vrstu Heptagenia coreulans navodi da nije sa sigurnošću dokazana njeno prisustvo u ovoj zoogeografskoj oblasti. Na najvećem broju istraživanih lokaliteta se sreću: Baetis rhodani Baetis sp., Ecdyonurus sp., Ephemera dnica, Ephemerella ignita, Caenis moesta, Habroleptoides modesta i Rhitogena semicolorata. Pojedinačno po istraživanim tekućicama najmanji diverzitet je na izvorima, nešto veći u izvorištima, najveći u srednjim delovima toka brdsko-planinskih tekućica da bi u donjim tokovima dospelo zagađenje uslovilo ponovno smanjenje raznovrsnosti Ephemeroptera.

The species Ecdyonurus sumatranus Ulmer, 1939 was described from Sumatra based on a female imago and a single nymph. It was designated as the type-species of the genus Ecdyonuroides Dang, 1967, erected because of the peculiar morphology of the nymph. This genus was put into synonymy later and the species is currently known as Thalerosphyrus sumatranus (Ulmer, 1939). The female imago holotype of Ecdyonurus sumatranus Ulmer, 1939 is reinvestigated and revealed to belong to the genus Rhithrogena Eaton, 1881. The combination Rhithrogena sumatrana (Ulmer, 1939) comb. nov. is thus proposed. The nymphs described by Ulmer (1939) from Java sub. nom. Rhithrogena parva (?) are associated to this species, and are redescribed with new material coming from Java and Lombok. Rhithrogena parva (Ulmer, 1912) is redescribed based on the syntype series from Taiwan and male genitalia are illustrated for the first time. Supplementary description is provided for the nymph of Rh. parva and for the one of Rh. ampla Kang & Yang, 1994, also from Taiwan. The status of the subgenus Tumungula Zhou & Peters, 2004 is briefly discussed. The nymph associated by Ulmer (1939) to Ecdyonurus sumatranus is renamed Thalerosphyrus lamuriensis sp. nov. The genus Ecdyonuroides Dang, 1967 is considered as a synonym of Rhithrogena syn. nov.

The Malpighian tubules (MT) of Baetis rhodani and Ecdyonurus venosus were studied by light, scanning and transmission electron microscopy. Special attention was paid to the ultrastructural organization of the constitutive cells, which in the secretory regions typically have a microvillated luminal border. Cells rest on a basal lamina, show varying degrees of basal infoldings and a large number of mitochondria. Cells of the collecting ducts show vesicled cytoplasm and have a sponge-like appearance. In B. rhodani MT empty individually into the alimentary canal whereas in E. venosus they enter through intermediate trunks. Numerous MT proper are attached to each common trunk, mainly in its distal portion. In this species MT are more complex owing to regional specializations. The distal region coils to form an asymmetrical plate, to one side of which the narrow collecting duct adheres before emerging right in the middle of the opposite side. Each duct extends to a certain distance and ends in the trunk. Different cell types are present in the trunk: a ring of cells bordering the duct/trunk junction, cells with apical infoldings and a luminal cuticle intima, and cells whose long thin microvilli almost fill the cavity. The relationship between structural features and known physiological function are discussed.

The mayfly larvae Epeorus sylvicola and Ecdyonurus torrentis inhabit either fast-flowing or, for the latter species, calm zones of running water. We studied (1) mechanisms and limitations of oxygen transport in single individuals (oxygen consumption rate, occurrence and rate of gill movements, and heartbeats) in running water of different oxygen concentrations and (2) capacities for anaerobiosis (L-lactate production). Our aim was to look for specific adaptations in the two species to slightly different microhabitats. Epeorus sylvicola, whose immovable gills are not able to generate ventilatory convection, proved to be an oxyconformer at both test temperatures (11 degrees and 15 degrees C). Ecdyonurus torrentis showed a progressively stronger oxyregulatory behavior at higher temperatures. In this species an onset of gill beating was found at moderate hypoxia (below 16 kPa). Ventilating individuals reached maximum rates (300 min-1) of 5-14 kPa. In the case of a further reduction of oxygen partial pressure, the ventilatory rate started to decrease. Ventilatory activity, however, was maintained down to very low oxygen concentrations. Neither in E. sylvicola nor in E. torrentis was experimental evidence found to confirm the hypothesis of a respiratory function of hindgut movements. During hypoxia, the heart rate was constant in both species (E. sylvicola: 80 min-1; E. torrentis: 60 min-1): bradycardia occurred either below 1.5 kPa or below 4 kPa. Anaerobiosis, that is, lactate production, was not detected in either species.

Ecdyonurus dispar gratificus ssp. nov. is reported from several small streams and rivers within the Donetsk Ridge (East of Ukraine). The new subspecies is described and illustrated on larvae and reared adults of both sexes. SEM photographs of the egg structures are presented. Critical diagnostic characters distinguishing the new subspecies from other representatives of the subgenus Ecdyonurus Eaton, 1868 and especially from the nominal subspecies are discussed. The data on the biology and distribution are presented.

The lateral eyes of Baetis vernus are structured similarly in both sexes. They are eucone apposition eyes with a closed rhabdom formed by eight retinula cells. The accessory pigment cells surround the ommatidia over their entire length. The morphological adaptation to different illuminations consists of a radial displacement of mitochondria and endoplasmic vacuoles. The dorsal eyes of the male Baetis, often called turban eyes, differ remarkably in structure and size from the lateral organs by a large clear zone which is only crossed by thread-like elongations of the retinula cells; the rhabdom is divided in a distal part next to the cone and a large basal part. Each of the seven retinula cells contributes microvilli to both parts of the rhabdom. The pigment cells only surround the cone and the distal part of the rhabdom, whereas the basal rhabdoms are optically isolated from each other by a ring of trachea. No morphological adaptation to different illumination is detectable in the dorsal eyes. The relation of the two different eyes of the male, being optically isolated but forming a morphologically connected complex, are discussed. With the description of the dorsal eyes of the subimago the formation of the dorsal eyes is investigated. A possible mode of function is considered. The male of Ecdyonurus venosus has larger eyes than the female, but they are structured after the same scheme. The eyes are similar to the lateral eyes of Baetis.

A study was made of water, sediments and invertebrates in the R. Derwent, North-East England, at one site above and three sites below a stream bringing in high concentrations of Zn, Cd and Pb derived from an active fluorspar mine. The mean concentrations of these metals in filtrable water at the unpolluted site were 0.020

SUMMARY. Mature larvae of Ecdyonurus dispar were collected from Ennerdale Water and Windermere (English Lake District) and reared to adult males and females in the laboratory. The females were then fertilized artificially and their progeny were kept at constant temperatures (range 4.2–20.2°C). Larvae collected directly from the two lakes were also reared under the same conditions. The maximum number of instars from egg to subimago was 25, the average body length increment (mm) per moult was proportionately constant at c. 15% and Dyar's rule was applicable. The interval between moults decreased with increasing temperature and the relationship between the two variables within the temperature range 4.2–19.8°C was described by a power law. Larval growth was exponential and variations in mean specific growth rate (range 0.23–5.23% length day−1) were related to mean temperature which was the major factor affecting growth in the laboratory. A few experiments were also performed in the lake to test the adequacy of the estimated values for larval growth at different temperatures in the laboratory. There was agreement between the estimates and the actual growth rates in the lake. Therefore, the regression equations obtained from the laboratory experiments are probably applicable to larval growth in the field. Values for daily production in the laboratory ranged from 0.53 to 9.33 mg dry wt day−1 m−2. The lowest value was obtained at 8.9°C and the highest at 20°C. Information on different life cycles of E. dispar is briefly reviewed and it is concluded that E. dispar from the lakes can only achieve one generation per year.

Ecdyonurus necatii sp.n. from Anatolia, Turkey, belonging to the lateralis group, is described and illustrated.

Salmonids (Salmo salar, Salmo trutta) and mayflies (Baetis rhodani, Ecdyonurus venosus) which had been exposed to simulated episodes of low pH, and low pH with elevated aluminium, were examined histochemically for the presence of aluminium and mucus. The control fish and mayflies and those exposed to low pH did not stain for aluminium, although increased mucus production was demonstrated in fish gills. Trout and salmon exposed to aluminium at low pH exhibited extensive aluminium and mucus coating of the secondary gill lamellae. No mucus was produced by mayflies but aluminium was apparent on all parts of the body. Mean aluminium concentrations of digested fish gills were 2950 and 3050 μg g−1 dry wt. for trout and salmon respectively, whilst for whole specimens of B. rhodani and E. venosus values were 1 200 and 3 175 μg g−1 dry wt.

Description de la larve au dernier stade et des adultes d'Ecdyonurus ifranensis n. sp. Cette espece est plus alticole qu'E. rothschildi.

Specimens of Baetis fallax (Hagen, 1864) and B. zebrata (Hagen, 1864) were collected on the Island of Corsica. Imagines were obtained by breeding and were investigated morphologically and biochemically. Our results show that B. fallax belongs to the genus Electrogena Zurwerra & Tomka, 1985 (= E. pseudograndiae Zurwerra & Tomka, 1986, syn. n.), but that B. zebrata belongs to the genus Afronurus Lestage, 1924. The genus Afronurus is new to Europe. Using isoenzyme electrophoresis we could show that the genera Afronurus, Electrogena and Ecdyonurus Eaton, 1868, are mutually separated at a low level of the genetic identity index that is characteristic of the genera of this family (Zurwerra et al., 1987). A key for the larval and imaginal stages of the European genera of the family Heptageniidae is presented.

Field treatments are described in which the effects of antimycin A on fish and invertebrates in a highland stream were studied. Because of the limited extent of the fish kill during the first treatment in 1976, a second treatment was undertaken the following year when the exposure period was increased from 2 h to 5 and 6 h. The water level in both years was very low, generally only a few centimetres deep, but a concentration of 10 μg/1 antimycin killed wild fish and the control fish which were held in cages in different parts of the stream. A significant decrease was noted in the numbers of Ecdyonurus spp. at one of the sampling sites after the 1976 treatment, and of Paraleptophlebia submarginata (Steph.) at one site after the 1977 treatment. No significant decrease was found in the populations of the other species collected after each treatment. It is concluded that trout populations in streams can be controlled effectively by antimycin applied at a concentration of 10 μg/1, provided the exposure period lasts for several hours. Antimycin does not appear to have an adverse effect on the invertebrate fauna as a whole.

Seasonal sampling at six locations on the Lower Ardeche River was effected irregularly during 1982, 1983 and 1984. The seasonal structure of the taxa-sample matrix, much more important than sample location, is demonstrated using graphical interpretation. The Mediterranean aspect of the lower reaches of the Ardeche River is pointed out through its community structure which includes species often collected in other typical Mediterranean streams, e.g. Oligoneuriella rhenana, Ephoron virgo, Ecdyonurus dispar, E. insignis, Choroterpes picteti. Water temperature and day length were the determinant influences on seasonal variations in population structure of benthic macroinvertebrates. Three periods were distinguished: water (November to April), spring (May, June and beginning July) and summer (end of July to October). Spring and autumnal spates marked the limits of the summer and winter periods. Hence, annual fluctuations of this seasonal typology may occur in response to the hydrological regime.

There have been a few papers concerned with the effect of temporal drought on the life of aquatic insects. In November of 1976, I had an opportunity to investigate an example of insect distribution at dried out and water-flowing areas up a sand arrestation dam of a stream near Kyoto. No individuals of Epeorus sp. were collected alive in the dried-out area. A few individuals of Baetis sp., Ecdyonurus kibunensis, Nogiperla sp., Ephemerella sp. and Paraleptophlebia sp. PA were collected alive in the dried-out area but only in sand and gravel zones; these species were collected mainly on stone surfaces in the water-flowing area. Elmidae and Nemouridae were found alive too, mainly in sand gravel zones. Ephemera japonica, Perla sp., Alloperla sp., Dinarthrodes sp., Chironomidae, Hydropsyche tsudai and Antocha sp. were collected in as many dried-out areas as in water-flowing areas.

The respiration rate (RR) of five species of mayfly larvae from the Soviet Far East (Drunella aculea Allen, Cincticostella levanidovae Tshernova, Ecdyonurus dracon Kluge, Siphlonurus lacustris Eaton, Amektus cedrensis Sinitshenkova) was measured in a closed respirometer and plotted against oxygen concentration (OC). Except A. cedrensis all species were able to maintain RR at a constant level over certain ranges of OC by regulation with respiratory movements. In contrast, the RR of A. cedrensis dropped continuously as OC in the water declined, the species being a conformer. These differences are interpreted in the light of microhabitats occupied by the species in the field.

Collections were made regularly from a substratum of rounded stones in the River Lune, England, by lifting the superficial stones and sweeping a net beneath them. Three species of Ecdyonurus emerge one after the other from May to October. Months elapse between emergence and the capture of larvae of the new generation in the R. Lune but elsewhere, when the species occur alone, larvae abound in every month. It is concluded that the life histories are similar in the various types of water‐body but that, when more than one species is numerous, small larvae do not come to the upper layers of the substratum until larger larvae of another species have vacated them.

Juvenile hatchery-reared Atlantic salmon, Salmo salar L., were offered choices of pelletted or four types of wild prey (chironomid larvae, ephemeropteran nymphs Ecdyanurus and Baetis and tnchopteran larvae Hydropsyche) of the same particle widths, in a test flume Preference for wild foods increased over 16 trials (1·5 h), and was greatest for Ecdyonurta and Hydropsyche, which had prey width fish fork length (PFR) ratios of 0·019 and 0·022 respectively, Pelletted food was rejected sooner when Ecdyonurus nymphs were offered as the alternative food than when chironomid larvae were (P < 0·05). Pret'erence (P < 0·05) for Ecdyonurus was achieved after 11 trials and for chironomids after 15. The time required to capture the first prey item was two to three times as long for pellets as for wild prey and did not change with experience for any prey type. Mean capture distance did not change with experience. It is concluded that acceptability of wild prey should not limit performance of pellet-fed salmon released into the wild.

SUMMARY. 1. A soft-water stream iti upland Wales was dosed with sulphuric acid and aluminiutn sulphate at two successive points to create sitnultaneous episodes of low pH, and low pH with increased aluminiutn. Chemical atid biological responses were measured before, during and after the episode and were compared with a reference zone. 2. The pH fell frotn ∼7.0 to 4.28 (±0.18 SD) and 5.02 (±0.10) respectively in the acid and aluminium zones. Corresponding aluminium concentrations during the episode were 0.052 g Al m−3 (±0.008) and 0.347 g Al nr3 (±0.047), the former not differing significantly from the reference zone. The concentration of cadmium rose to 0.002- 0.011 g Cd m−3in both treated areas, but the concentrations of other metals were unchanged. 3. In situ toxicity tests were performed with macroinvertebrates and fish. Chironomus riparius. Hydropsyche angustipennis and Dinocras cephalotes suffered no mortality. Ecdyonurus venosus, Baetis rhodani and Gammarus pulex showed up to 25% mortality in both treatment zones and further mortalities occurred after the episode. Brown trout Salmo trutta and salmon Valmo salar s howed 7–10% mortality in the acid zone, but 50–87% in the aluminium zone, where salmon had a significantly shorter LT50than trout. 4. The drift of Simuliidae increased during treatment in both acid and aluminium zones. Drift densities of Dixa puherula, Protonemura meyeri, Ephemeralla ignita and Dicranota sp. increased in the aluminium zone. The most pronounced response was by Baetis rhodani in the aluminium zone where drift density increased by ×8.4 during the episode. 5. Baetis rhodani was the only taxon to show a significant decline in benthic density during the treatment, and then only in the aluminium zone. Drift could account for most of the losses. 6. The depth distribution of invertebrates in the substratum differed between zones following treatment. More individuals were present at the surface of the reference zone (1287 m−2±747) than at the surface of the other zones (

Ecdyonurus moreae sp.n. is described from Peloponnese, Southern Greece. Diagnostic characters are: stout and rounded penis lobes, oblique stripes on the sides of abdomen, and abdominal ganglia pigmented. 12 further taxa from Greece are listed and briefly discussed: 3 species are new for Greece.

Taxonomy and nomenclature of the Italian members of the Ecdyonurus lateralis group are reviewed, the three Italian species are keyed. Ecdyonurus grandiae sp. n. (= Heptagenia lateralis sensu Grandi, 1953) is named, some characters of E. lateralis (Curtis, 1834)(= E concii Grandi, 1953; s y n . n.) and E. gridellii (Grandi, 1953) are also described. Lectotypes are designated for E. concii and E. gridellii.

The gills of some Ephemerid nymphs are always motionless, e. g ., many Bætine forms of English streams. In many others, however, the gills move rapidly in metachronal rhythm, by virtue of which currents are created in the water. These currents are peculiar to the species and probably have an adaptational significance. In many forms already under investigation, e. g ., Cholen dipterum. Siphlurus sp. Ecdyonurus venosus, Ephemerella sp. Leptophlebia marginata and Ephemera vulgata , a common feature is noticeable. This is that in their rhythmical movements both members of each pair of gills beat together, i. e ., and their movements are co-phasedly synchronized. Since, therefore, the effect of the gills on one side of the body is exactly duplicated on the other, whatever may be the precise mechanism for the production of currents, the latter are symmetrical with the longitudinal axis of the body (Eastham, 1932). An intersting exception in the nymph of Caenis horaria . In this animal the currents pass over the body from one side to the other. The gills beat in metachronal rhythm down each side of the body, but though the rhythms are synchronous there is a time phase difference between them. In other words, members of a pair are not co-phasedly synchronized in movement. We have thus in Caenis horaria a bi-laterally symmetrical animal producing movements in the surrounding medium which are not of the nature of an axial flow. It is with this phenomenon that this paper deals.

Summary I. A brief survey of the British members of the genus Ecdyonurus is given. II. A special study is made of the Ecdyonurus population of the River Alyn, Denbighshire. III. An examination of the presumed specific differences of the nymphs and imagines of E. venosus (Fab.), E. venosus var. queesitor, E. longicauda, and E. forcipula, together with a study of the Alyn Ecdyonurus population, lead to grave doubts concerning the recognition of these flies as true species. Two suggestions are made–either E. venosus (Fab.), the Alyn venosus, E. longicauda, and E. forcipula are local varieties, races, or seasonal forms which will in future be found to grade into one another, or the Alyn Ecdyonurus population is incompletely separated into the species described from elsewhere as distinct. IV. The author regards the Alyn E. venosus as a variety of E. venosus (Fab.) which comes within the possible range of variation in this species. Until the true status of the various forms has been settled, the Alyn E. venosus is referred to throughout as E. venosus to distinguish it from E. venosus (Fab.). V. The life-history of the Alyn form of E. venosus–pairing, oviposition, and the development from the egg to the imago–has been described. There are at least two broods a year. VI. The external features, habitat, and habits of the imagines and nymphs of this form are described. The mode of feeding of the nymphs is also described. VII. A study of weekly samples of the nymphal population during the summer and monthly samples during the winter shows a marked seasonal difference in the rate of nymphal growth and the presence of two definite broods of flies a year. The first swarms appear in June, the second from July to October. The early summer eggs hatch and emerge as flies within two months, whereas the autumn ones grow much more slowly and emerge the following June. VIII. An analysis of the population samples collected between May 1937 and May 1938 is given.

Nymphs of Baetis rhodani (Pictet), Ephemerella ignita (Poda), Ecdyonurus venosus (Fabricius), Rhithrogena semicolorata (Curtis), and Heptagenia lateralis (Curtis) showed a similar endogenous rhythm of activity under conditions of natural illumination, continuous light and continuous darkness; and were most active at night when they moved from the lower to the upper surface of the stone. The nymphs were positively thigmotactic and negatively phototactic in flowing water, but these taxes and the endogenous activity rhythm of all species except Heptagenia lateralis changed markedly when the flow of water ceased.

The current-resisting powers of Rhithrogena semicolorata Curtis have been investigated and measured, and compared with those of Ecdyonurus sp. The part played by the gills as organs of adhesion is considered, and they are found to contribute little to the current-resisting powers of the nymph. The claws are regarded as being of more importance to the animal in clinging than the gills. The dorso-ventral flattening of the animal is considered to be a creviceseeking adaptation, and not a current-resisting one.

1. The gills of the nymph of Ecdyonurus consist each of a gill plate and a proximal gill tuft. The gill plate of the first gill is reduced in size while the seventh gill possesses no gill tuft. 2. By movements of the gills, currents are set up in the water which are symmetrical with the body axis, and which pass from the sides of the body upwards to the mid-dorsal line and backwards. Members of pairs beat synchronously and in phase with each other. 3. Each gill pivots on its pedicel and moving backwards and upwards, increases its angle of incidence with the water through which it passes. This phase is the effective part of an oscillation and is brought about with the posterior gill surface in the leading position. The recovery beat is effected by the gill turning so as to place the anterior border in a leading position. The direction of flow is largely determined by these gill movements. 4. The gills beat in metachronal rhythm from before backwards, the time phase difference between adjacent gills being so small as to make the gills appear to work together and without rhythm. The rhythm, however, is important in setting up suction and compression phases, the compression phase occurring during backward effective movement, the suction during forward recovery movement. Compression expresses itself as a flow from between the gills upwards and backwards, suction as a flow into the intergill space from the sides and below. 5. The principles of gill movement in relation to water flow in Caenis, Leptophlebia and Ecdyonurus are compared. 6. The currents and gill movements in adaptation to environment are briefly discussed. 7. Campaniform sense organs occur on both surfaces of the gill plates and it is suggested that these are concerned with informing the animal of changes in the environmental flow of water.

In 1930 Dr. R. H. Emslie turned over to the author a small collection of mayfly nymphs collected by him in streams in Scotland. Among them was a small series of nymphs of Ecdyonurus venosus Fabricius in different instars collected at Tummel Bridge and Bridge of Weir. This species is unique in having prominent postero-lateral extensions of the prothorax resembling the wing-pads of the meso- and metathorax (Figs. 1 & 8).

(1942). XL.—The British Species of the Genus Ecdyonurus (Ephemeroptera) Annals and Magazine of Natural History: Vol. 9, No. 55, pp. 486-507.

The oxygen consumptions of the small ephemerid nymphs Ephemerella ignita and Coenis sp. are (anaesthetised at 10° C.) 950 and 290 c.mm./gm./hour. Their habitats are respectively a stream and a pond. The oxygen consumptions of the large ephemerid nymphs Ecdyonurus venosus, Ephemera danica and E. vulgata are (anaesthetised at io° C.) 604, 370 and 278 c.mm./gm./hour. They live, respectively, under stones in a swift stream, burrowing in sand in a stream, and burrowing in mud in a pond. Ecdyonurus venosus is less resistant to oxygen deficiency than Ephemera danica and E. vulgate; and Baetis rhodani (swift stream) is less resistant than Chloeon dipterum (pond).

The generally accepted concept that dorsoventral flatness and/or small size of benthic stream invertebrates staying on the surface of the bottom substratum allows a current-sheltered life in the boundary layer (Ambühl 1959) is checked by means of the new technique of Laser Doppler Anemometry (LDA). With LDA measurement of flow can be done nearly punctually without any mechanical disturbance. Mapping the current velocities around the body of Ecdyonurus cf. venosus (Insecta, Ephemeroptera) and Ancylus fluviatilis (Gastropoda) gives evidence that boundary layer separation occurs above the animals' bodies. Our results indicate that the velocities around the body of benthic stream invertebrates and probably the forces acting on them are much more complicate than is suggested by the currently accepted boundary layer concept.

The ultrastructure of the Malpighian tubules of larvae of the Mayfly Ecdyonurus dispar (Ephemeroptera) is described. There are about 60 tubules, which consist of four distinct regions. The most proximal section (region I) appears to be responsible for fluid secretion. A unique feature is the presence of channels leading off the main lumen, which end close to the basal border of the cells. Microvilli are confined to these channels in region I. Region II is a short spiral region, the cells of which possess long basal folds and associated mitochondria. Region III is a simple conducting tube leading to one of six collecting ducts (region IV) arranged radially around the gut. In each collecting duct there are two cell types present. Type 2 cells are relatively simple, but give rise to numerous, long, microvilli-like projections. Type 1 cells possess long basal folds, and curious membrane whorls in the apical zone. Evidence is presented which suggest that water movements into region I takes place via the paracellular route. Region II is probably a reabsorptive region, but the function of region IV, based on ultrastructural evidence is more difficult to elucidate.

Eggs of Ecdyonurus picteti from the Herrnalmbach and Seebach, and E. venosus and Rhithrogena cf. hybrida from the Seebach were fertilized artificially and kept at fluctuating temperatures (range 2.8°-18.1° C) in the laboratory. The percentage of eggs that hatched at each sinusoidal temperature cycle ranged from 0 to 49% and values were similar to those obtained for eggs reared under constant temperature conditions. The hatching time (days after fertilization for 10, 50% and 90% of the eggs to hatch) decreased with increasing temperature and the relationship between the two variables was well described by a powerlaw within the range 2.8°-18.1° C for E. venosus. A similar relationship has been found for the effect of constant temperature on the hatching time of eggs of E. venosus. It appears that the effect of temperature on the rate of change in the hatching time and the rate of development is approximately similar for both constant and fluctuating temperatures.

In the Weidlingbach, a low-order forest stream in the Wienerwald area near Vienna (Austria), hydraulic stress was measured at 112 locations from which benthic fauna (=33318 specimens of macro-invertebrates) was collected between March and September 1995. For measuring hydraulic stress a set of FST hemispheres was used. The most abundant taxa studied (= 90.7% of the total) were Gammarus fossarum Koch (Amphipoda), Leuctra spp. (Plecoptera), the ephemeropterans Baetis rhodani (Pictet), B. vernus (Curtis), Habroleptoides confusa Sartori and Jacob, Ecdyonurus starmachi Sowa and the caddisfly Hydropsyche instabilis (Curtis). Five mayfly, four stonefly and six caddisfly taxa significantly (p < 0.05) preferred the lotic subsection of the research area, whereas Ephemera danica Muller significantly (p < 0.001) preferred the lentic subsection. In the species studied in detail, medians of their FST hemisphere ranges varied from 8 (e.g. Brachyptera risi (Morton)) to 2 (e.g. Paraleptophlebia submarginata (Stephens)). A comparison of microdistribution patterns at low and high discharge revealed no significant shift in FST hemisphere numbers and, hence, in exposure to hydraulic stress in Hydropsyche instabilis and Rhyacophila fasciata Hagen; both species were most abundant in high stress areas, independent of discharge. On the other hand, most other species studied in detail exhibited a shift to lower hydraulic stress at high discharge, whereas Electrogena ujhelyii (Sowa) was evenly distributed (p > 0.05) over the whole range of hydraulic stress, independent of discharge.

SUMMARY 1. Macro-flora (angiosperms. bryophytes and macroscopic algae) and macroinvertebrates were sampled in 1984 at eighty-eight sites on soft-water streams in upland Wales. Assemblage patterns were related to stream chemistry using TWINSPAN, DECORANA and multiple discriminant analysis. 2. Floral assemblages could be related most strongly to pH and aluminium concentration, with Scapania undulata, Nardia compressa and filamentous chlorophytes characterizing streams of mean pH5.2–5.8, whilst Fontinalis squamosa occurred mostly at pH 5.6–6.2 and Lemanea at pH 5.8–7.0. We propose an indicator system based on thesetaxa. 3. Assemblages of invertebrates and flora concorded highly significantly, sites with Scapania and Nardia holding impoverished faunas. Because some acid sensitive invertebrates (e.g. Ecdyonurus and Ancylus) can feed from acid tolerant plants (e.g. Scapania), we hypothesize that they are restricted physiologically from acid streams.

The larvae and adults of Ecdyonurus solus sp. nov., are described and illustrated. This species is found in the mountainous region of the Crimean Peninsula, and belongs to the Ecdyonurus venosus species-group. SEM photographs of the eggs of new species are presented. The distinguishing characteristics separating this E. solus sp. nov. from closely related species of the E. venosus species-group are discussed. Detailed data on the biology and distribution of the new species are presented.

I HAVE been asked by a French observer, M. A. Gros of Marigny (Jura), France, if I can put him into touch with entomologists interested in the Ephemeridae. M. Gros is the author of an illustrated brochure, “ Etudes sur les premiers etudes des ephemeres du Jura francais,” which deals mainly with Ecdyonurus forcipula of Central Europe—not, I believe, found in the rivers of the British Isles. M. Gros would prefer to correspond in French if possible. He appears to have established some interesting facts, which may help us in our endeavours to transplant water-flies from one river to another. So many causes are denuding our rivers of their natural supplies of Ephemeridae, etc., that it is most important to introduce fly from other waters if possible. It has been done, at least temporarily, in a few instances.

Background The cutaneous monostome trematode Collyriclum faba (Bremser in Schmalz, 1831) is a bird parasite with a hitherto unknown life cycle and highly focal occurrence across the Holarctic and Neotropic ecozones. Methods Representative specimens of benthic organisms were sampled at multiple sites and dates within the known foci of C. faba occurrence in Slovakia. A combined approach involving detailed morphological examination and sequencing of two independent DNA loci was used for their analysis. Results We elucidated the complete life cycle of C. faba, which we determined to include the aquatic gastropod mollusk Bythinella austriaca (Frauenfeld, 1857) as the first intermediate host, the mayflies of the family Heptageniidae, Ecdyonurus venosus (Fabricius, 1775) and Rhithrogena picteti Sowa, 1971 x iridina (Kolenati, 1839), as the second intermediate hosts, and birds (primarily but not exclusively passeriform birds) as the definitive hosts. Bythinella austriaca occurs focally in the springs of tributaries of the Danube in the Alpine-Carpathian region. The restricted distribution of B. austriaca explains the highly focal distribution of C. faba noticed previously in spite of the broad distribution of its second intermediate and definitive host species. Utilization of both larval and adult Ephemeroptera spp. as the second intermediate hosts explains the known spectrum of the definitive host species, with the highest prevalence in species feeding on larvae of Ephemeroptera, such as Cinclus cinclus (Linnaeus, 1758) and Motacilla cinerea Tunstall, 1771, or adults of Ephemeroptera, such as Sylvia atricapilla (Linnaeus, 1758) and Regulus regulus (Linnaeus, 1758). In this study, we also determine the prevalence and DNA sequences of other immature trematode specimens found in the examined benthic organisms (particularly the families Microphallidae, Troglotrematidae and Nanophyetidae and Euryhelmis zelleri Grabda-Kazubska, 1980, Heterophyidae), and describe cercariae of C. faba. Conclusions We determined the full life cycle of the Central European populations of C. faba. We speculate that other species of Bythinella and the closely related genus Amnicola may serve as first intermediate hosts in other parts of the distribution range of C. faba. Similarly, other Ephemeroptera of the family Heptageniidae may serve as the second intermediate hosts of C. faba in the Americas. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-0646-3) contains supplementary material, which is available to authorized users.