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Contribution to the study of mayfly Introduction fauna (Ephemeroptera) in Ephemeroptera order is comparatively well studied in Bulgaria. In the compendious work upon Bulgarian Russev (1993) enlisted

102 species, reported by him and some other YANKA VIDINOVA colleagues in the past. Another three species – Institute of Zoology, BAS, 1 Tsar Osvoboditel Oligoneuriella polonica MOL, 1984, Rhithrogena Blvd., BG-1000 . carpatoalpina KLONOWSKA, OLECHOWSKA, [email protected] SARTORI & WEICHSELBAUMER, 1987 and R. savoiensis ALBA-TERCEDOR & SOWA, 1987 are reported from Russev and Vidinova (1994). Because of the revisions and redescriptions made recently, it becomes possible to establihed some new species for Bulgaria. As we do not dispose of imagoes of many species, their precise determination is difficult. The object of the present report is the determination of the species Rhithrogena braaschi JACOB, 1974, R. marcosi ALBA-TERCEDOR &

SOWA, 1987, R. podhalensis SOWA & SOLDÁN, 1986 and Ecdyonurus epeorides DEMOULIN, 1955 in larval stage, which are newly recorded for Bulgarian fauna, as well as to add more data about Caenis pseudorivulorum KEFFERMÜLLER, 1960.

Material and Methods A part of the material was kindly committed to me by Prof. Dr. B. Russev and the other part was collected by the author from varied locations (up to 1700 m a.s.l.) during the last decade. The materials were determined according to the original descriptions of species as well as the generalizing works on European species of the genera Rhithrogena, Ecdyonurus and Caenis (Tomka and Rasch, 1993; Hefti and Tomka, 1988;

Hefti, Tomka and Zurwerra, 1989; Malzacher, 1984, 1986; Buffagni, 1997).

Results and Discussion Abstract Rhithrogena EATON, 1881 Based on a set of characteristic morphological features Rhithrogena braaschi JACOB, 1974 and in accordance with the contemporary knowledge Material examined: Balkan Mts.: Luda for the mayfly’s , four new species for the Bulgarian fauna are reported. They belong to the Kamchiya River, above Gradets, 04.1987 - 4 la; genera Rhithrogena and Ecdyonurus and are in larval Cherni Vit River, “Boatin” reserve, 04.07.1990 - 1 and/or nymphal stage. Some ecological notes are given la; Rogacheva River, “Central Balkan” National also. The finding of the species Caenis park, 23.09.1997 - 3 la; Mts.: River, pseudorivulorum is confirmed by some new localities. above , 07.05.1964 - 4 la; Rilska River, outflow, 24.04.1984 - 4 la; Maritsa River, above Keywords: Rhithrogena, Ecdyonurus, Caenis, Raduil, 24.09.1991 - 3 la; Dzherman River, near faunistics. Pionerska hut, 28.06.1995 - 1 la; 11.08.1997 - 6 la; 22.10.1997 - 2 la; 12.11.1997 - 10 la; Research Update on Ephemeroptera & Plecoptera 2003, E. Gaino (Ed.), University of Perugia, Perugia, Italy. Skakavitsa River, Pionerska hut, 27.06.1995 - 1 la;

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11.09.1997 - 12 la; 22.10.1997 - 14 la; 13.11.1997 species localities, it is obvious that R. braaschi has - 22 la; Votrachka River, above , preference to streams and rivers in mountain and 17.04.1990 - 6 la; 16.05.1990 - 9 la; 02.07.1990 - foothill regions. The populations are usually not 2 la; Mts.: Glazne River, above , so numerous. Most often we have found it 19.08.1999 - 26 la; 26.10.1999 -20 la; 11.07.2000 together with the taxa Epeorus, Habroleptoides, - 5 la; 16.08.2000 - 34 la. Rhithrogena sp. gr. hybrida. R. marcosi ALBA-TERCEDOR & SOWA, 1986 Material examined: Mesta River, , 16.07.1972 - 4 la; Balkan Mts.: Cherni Vit River, “Boatin” reserve, 04.07.1990 - 5 la; Rhodopes Mts.: Ablanitsa River, above interflow with Chepinska River, 14.07.1993 - 3 la; Chepinska River, above interflow with Ablanitsa River, 02.09.1993 - 1 la; Strandzha Mts.: Veleka River, at Kovach, 01.07.1999 - 12 nymphs. We found R. marcosi in the lower course of Mesta River (near the bulgarian-greek border) where there is a considerably Mediterranean

Fig. 1 - Rhithrogena braaschi, larva: A- 7th gill, B- influence, but as well as in the northern sides of plica of the first gill; C- spines from the central part of Balkan Mts. (about 900 m a.s.l.). The species hind femur; D- tarsal claw. belongs to the diaphana-group, together with R. thracica and R. bulgarica. As we have at our The larva was described by Tomka and Rasch collection the last two species, we consider the (1993). The species is a typical representative of adduced material as R. marcosi (Fig. 2). the semicolorata-group (Fig. 1). Based on the

Fig. 2 - Rhithrogena marcosi, larva: A,B,C,D - 1st, 2nd, 6th and 7th gills; E- tarsal claw; F- spines from the central part of hind femur; G- posterior margin of the 5th abdominal tergum; H- egg, general view.

R. podhalensis SOWA & SOLDÁN, 1986 coloration of terga, strongly crenulated gills as Material examined: Rila Mts.: Votrachka well as by a form of the posterior margin of the River, above Belitsa, 17.04.1990 - 1 la; terga (Fig. 3). Our locality data about this species 16.05.1990 - 5 la, 2 nymphs; 31.10.1996 - 2 la, 15 entirely prove the standpoint that it inhabits juv.; Pirin Mts.: Glazne River, above Bansko, “relatively very restricted area of distribution” 26.10.1999 - 1 la; 07.06.2000 - 1 nymph. (Sowa and Soldán, 1986). This larva is easy to be recognized among the other species of the hybrida-group by the

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Fig. 3 - Rhithrogena podhalensis, larva: - A,B,C,D - 1st, 2nd, 6th and 7th gills; E- posterior margin of the 5th abdominal tergum; F- spines from the central part of hind femur; G- 5th comb-shaped bristle from galea-lacinia; H- egg, general view.

Ecdyonurus EATON, 1865 Some figures and keys for the nymphs and Ecdyonurus epeorides DEMOULIN, 1955 imagines of the helveticus-group, including Demoulin (1955) described the male imago Ecdyonurus epeorides, are given in the summary and larva of Ecdyonurus epeorides, collected by upon the taxonomy of East-European species of E. Janssen and R. Tollet from (Pelion this group (Hefti and Tomka, 1988), as well as in Mts.) in August 1953 at an altitude 350 m above the revision made by Hefti, Tomka and Zurwerra sea level. (1989). Kimmins (1958) considered this species as a Material examined: Rila Mts.: “Plitkoto” lake, synonym of E. zelleri (Eaton): “...both in the form outflow, 27.08.1997 - 8 la; Mesta River, above of the genitalia and in the nymph. In view of the , 31.10.1996 - 13 la; 20.08.1999 - 7 la; poor condition and limited amount of the material, 29.09.1999 – 5 la; 08.2000 - 2 la; Skakavitsa it might have been better to have left the specimen River, Pionerska hut, 27.06.1995 - 20 la; nameless”. Puthz (1984) in his paper on Balkan 28.06.1999 - 18 la; Kutlev valog River, Pionerska Ephemeroptera did not mention E. epeorides, hut, 16.08.1999 - 21 la; Dzherman River, that’s why Jacob and Braasch (1984) considered Pionerska hut, 26.05.1999 - 23 la; 16.08.1999 - 40 he has accepted the species synonym. However la; Musalenska Bistritsa River, above “Borovets” the latter reestablished the species, as they resort, 20.08.1999 - 18 la; 29.09.1999 - 37 la; considered: “Kimmins (1958) synonimisiert zu 25.10.1999 - 69 la; 08.06.2000 - 13 la; 13.07.2000 Unrecht mit E. zelleri.” They presented figures of - 27 la; 17.08.2000 - 6 la; 20.09.2000 - 29 la; Pirin the imago and the larvae of helveticus-group Mts.: Glazne River, above Bansko, 19.08.1999 - 6 species, among them for E. epeorides and E. la; 29.09.1999 - 10 la; 26.10.1999 - 10 la; zelleri as well. About the differencies in the larval 07.06.2000 - 8 la; 11.07.2000 - 9 la; Rhodopes material they mentioned: “Larven anhand anderer Mts.: Arda River, above “Kurdzhali” dam, Pronotumlappenform von E. zelleri gut 16.06.1999 - 2 la; “Dyavolski” bridge, 17.06.1999 unterscheidbar”. - 5 la.

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The main characteristic features of the nymph are the narrow shape of the gill plates, spines on the dorsal side of fore femur rounded distally and with parallel sides (Fig. 4).

Fig. 5 - Caenis pseudorivulorum, larva: A- last abdominal sternite; B- microtrichia from the underside of the second gill; C- second and third segment of the labial palpus; D- shape of the lateral margin of pronotum.

Material examined: Strouma River, Ruzhdavitsa- 08.2000 - 1 la; Nevestino, Fig. 4 - Ecdyonurus epeorides, larva: A- 4th gill; B- 18.08.1999 - 30 la; 27.09.1999 - 36 la; 06.06.2000 spines from the central part of fore femur; C- glossa - 60 la; 11.07.2000 - 71 la; 08.2000 - 82 la; and paraglossa; D- shape of the lateral expansion of the 18.09.2000 - 50 la; , 18.08.1999 - 15 pronotum. la; 06.06.2000 - 12 la; 11.07.2000 - 7 la; 08.2000 - 29 la; 18.09.2000 - 84 la; below , The species is distributed within wide ranges 18.08.1999 - 44 la; 11.07.2000 - 19 la; Krupnik, of altitudes, but predominantly in South Bulgaria. 18.08.1999 - 22 la; 27.09.1999 - 7 la; 06.06.2000 - We found it together with Epeorus sylvicola 9 la; 11.07.2000 - 12 la; 08.2000 - 20 la; Marino (PICTET, 1865), Iron yougoslavicus (SAMAL, pole, 18.08.1999 - 52 la; 27.09.1999 - 55 la; 1934) Rhithrogena braaschi (JACOB, 1974), 06.06.2000 - 125 la; 11.07.2000 - 14 la; Ephemerella mucronata (BENGTSSON, 1909), 15.08.2000 - 125 la; 18.09.2000 - 90 la; Glazne Habroleptoides confusa (SARTORI & JACOB, River, above Bansko, 09.2000 - 6 la; Mesta River, 1986). Momina kula, 19.08.1999 - 5 la; 28.09.1999 - 66 Caenis STEPHENS, 1835 la; 26.10.1999 - 8 la; 12.07.2000 - 18 la; 09.2000 - Caenis pseudorivulorum KEFFERMÜLLER, 8 la; Kupena, 19.08.1999 - 15 la; 28.09.1999 - 100 1960 la; 26.10.1999 - 23 la; 12.07.2000 - 21 la; Gostun, Malzacher (1984, 1986) presents detailed 19.08.1999 - 4 la; 29.09.1999 - 80 la; 26.10.1999 - analyses on the twelve European species of Caenis 56 la; 12.07.2000 - 19 la; 19.09.2000 - 190 la. – their diagnostics, distribution and biology. The finding of the species in large rivers as On the base of peculiarities in genitalia of the Strouma and Mesta (SW Bulgaria) confirms that male imagines he divided them into seven groups. C. pseudorivulorum inhabits the potamal. It is According to Russev (1993), five Caenis species usually found with rich populations. are known for Bulgaria, which belong to three of them: C. horaria and C. robusta (horaria-group), Acknowledgements C. macrura and C. luctuosa (macrura-group) and I wish to thank Prof. Dr. B. Russev † for his valuable C. rivulorum (rivulorum-group). Caenis comments on the manuscript. pseudorivulorum is reported from Bulgaria (Osam River) by Jacob (1972) (by Malzacher, 1986), but References no other data are available. Moreover Puthz Alba-Tercedor J., Sowa R., 1987. New representatives (1978) did not mention the species as known for of the Rhithrogena diaphana-group from Bulgaria. Continental Europe, with a redesciption of R. The main distinguishing morphological diaphana Navas, 1917 (Ephemeroptera: features of the nymph are given on Fig. 5. ). Aquatic 9, 2: 65-83. Buffagni A., 1997. Taxonomic and faunistic notes on the Caenis pseudorivulorum-group (Ephemeroptera, Caenidae). In: Landolt P., Sartori M., (eds).

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Ephemeroptera & Plecoptera: Biology-Ecology- Systematics. Fribourg: MTL. pp. 434-438. Demoulin G., 1955. Mission E. Janssens et R. Tollet en Grece (juillet-aout 1953), 4 note, Ephemeroptera. Bull. Ann. Soc. Roy. Ent. Belg. 91, I-II: 38-44. Hefti D., Tomka I., 1988. Contribution to the taxonomy of East-European species of the Ecdyonurus helveticus-group (Ephemeroptera, Heptageniidae). Mitt. Schweiz. Entom. Ges. 61: 329-337. Hefti D., Tomka I., Zurwerra A., 1989. Revision of morphological and biochemical characters of the European species of the Ecdyonurus helveticus- group (Ephemeroptera, Heptageniidae). Mitt. Schweiz. Entom. Ges. 62: 329-344. Jacob U., 1974. Rhithrogena braaschi n. sp., eine neue Heptageniide aus Bulgarien (Insecta, Ephemeroptera). Entom. Nachr., 11/12: 167-173. Jacob U., Braasch D., 1984. Neue und statusrevidierte Taxa der Ecdyonurus helveticus-Groβgruppe (Ephemeroptera, Heptageniidae). Entomol. Abhandl. 48, 6: 53-61. Kimmins D., 1958. The Ecdyonurus helveticus (EAT.) Complex. Ann. Naturhist. Mus. Wien 62: 225-232. Malzacher P., 1984. Die europäischen Arten der Gattung Caenis Stephens (Insecta: Ephemeroptera). Stuttgarter Beitr. Naturk., Ser. A 373, 48 S. Malzacher P., 1986. Diagnostik, Verbreitung und Biologie der europäischen Caenis-Arten (Ephemeroptera: Caenidae). Stuttgarter Beitr. Naturk., Ser. A 387, 41 S. Puthz V., 1978. Ephemeroptera. In: I. Illies (ed.) Limnofauna Europaea, Gustav Fischer Verl., Stuttgart. pp. 256-263. Russev B., 1993. Review of literature and established mayfly species (Ephemeroptera, Insecta) from Bulgaria. Lauterbornia, Dinkelscherben 14: 71-77. Russev B., Vidinova Y., 1994. New representatives of the order Ephemeroptera (Insecta) for the fauna of Bulgaria. Lauterbornia, Dinkelscherben 15: 85-87. Sowa R., Soldán T., 1986. Three new species of the Rhithrogena hybrida group from Poland and Czechoslovakia with a supplementary description of R. hercynia Landa, 1969 (Ephemeroptera, Heptageniidae). Pol. Pismo Ent., Wroclaw 56: 557- 572. Tomka I., Rasch P., 1993. Beitrag zur Kenntnis der europaeischen Rhithrogena-Arten (Ephemeroptera, Heptageniidae): R. intermedia Metzler, Tomka & Zurwerra, 1987 eine Art der alpestris-Gruppe sowie ergaenzende Beschreibungen zu fuenf weiteren Rhithrogena-Arten. Mitt. Schweiz. Ent. Ges. 66: 255-281.

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