Zwicknia bifrons Murányi & Gamboa & Orci 2014, comb. n.

Zwicknia bifrons (Newman, 1838) comb. n.

(Figs. 1–2, 7, 10, 23, 32, 56, 58, 62–63, 66, 72, 74, 76, 82–85, 106, 114, 120, 139–143, 152–156, 165, 169–173, 185, 190–192, 196–197).

Chloroperla bifrons Newman, 1838 — Newman 1838: 401. (original description of the adult)

Capnia nigra (Pictet, 1833) —figures in at least Morton 1896, Hynes 1940, Hynes 1941 and Hanson 1946 (enumerated under the general synonymies) refers to Z. bifrons.

Capnia bifrons (Newman, 1838) — Kimmins 1947: 261. (stat. rev and comb. n.);—figures in at least Brinck 1949, Kimmins 1950a, Kimmins 1950b, Brinck 1952, Hynes 1955a, Hynes 1958, Illies 1955, Khoo 1964, Lillehammer 1965, Lillehammer 1974, Rupprecht 1976 and Lillehammer 1988 (enumerated under the general synonymies) refers to Z. bifrons;—drumming signals in Rupprecht 1965, Rupprecht 1968, Rupprecht 1976 (enumerated under the general synonymies) and partly in Rupprecht 1982 (Fig. 2b) refers to Z. bifrons.

Capnia bifrons (Newman, 1838) Capnor race sensu Rupprecht 1997 — Rupprecht 1997: 94. (drumming signals); Enting & Rupprecht 2001: 71 (clarification as the nominal C. bifrons).

Diagnosis. Male epiproct: Ep-scl wide and blunt in dorsal view, tip upcurved in lateral view; ventral membranous section nearly reach the base in lateral view, apical spines distributed only on the membranous part of the apex. Process of male Tg 9: high, perpendicularly elevated, <1½× wider than Ep-scl, rectangular, and with continuously narrow sides caudally. Males usually produce drumming calls in sequences containing 2–3 calls (Fig. 165), but single calls are also produced sporadically. The male call is a monophasic beat-group with duration of 1400–2400 ms and composed of 7–16 beats repeated with a mean inter-beat interval of 140–230 ms. Inter-beat interval gradually increases during each male call (Figs. 169–173, 190). Inter-call interval increases as a call sequence proceeds, but its mean value is between 1400–6300 ms. All of these drumming character values refer to signals produced at ambient air temperature between 15–21 o C. The male-female drumming duet is a long sequence of male call—female answer alternation (Fig. 185).

Material examined. HUNGARY: Veszprém County, Bakony Mts., Bakonybél, Gerence Stream at Borostyán Spring, N 47°14.596’ E 17°43.835’, 275 m, 24.02.201 1, leg. D. Murányi, K. M. Orci: 1m (HNHM; used for drawings Figs. 142, 155, for molecular studies as 300995, drumming recorded as 2011/ No. 1, Fig. 170); Pest County, Pilis Mts., Szentendre, Dömörkapu, Bükkös Stream, N 47°41.751’ E 18°59.904’, 260 m, 23.02.201 0, leg. D. Murányi, K. M. Orci: 7m 4f, 1m larva (HNHM; one male, three male terminalia, one female and the male larva prepared for SEM, two female and parts of a male terminalia prepared on slides, specimens used for drawings and photos Figs. 1–2, 7, 10, 23, 32, 56, 58, 62–63, 66, 72, 74, 76, 82–85, 106, 114, 120), 6m 7f (HNHM; drummings recorded as 2010/ No. 1–3, 6–9), 4m (BYUC), 1m 1f (GVC; drummings recorded as 2010/ No. 4), 1m 1f (PZC; drummings recorded as 2010/ No. 5); 26.02.201 1, leg. K. M. Orci: 2m (HNHM; used for molecular studies as 300991, 300978, drummings recorded as 2011/ No. 1–2); 14.03.2011, leg. K. M. Orci: 3m (HNHM; used for molecular studies as 300979, 300986, 300984, drummings recorded as 2011/ No. 3–4, Fig. 169); 27.03.201 1, leg. K. M. Orci: 1m (HNHM); Pest County, Börzsöny Mts., Szokolya-Királyrét, Szén Stream, N 47°53.672’ E 18°58.706’, 255 m, 05.03.201 1, leg. D. Murányi: 4m (HNHM; used for drawings Figs. 139, 152, for molecular studies as 300990, 300977, 301002, 300980, drummings recorded as 2011/ No. 1–2, 4, Fig. 171); Heves County, Mátra Mts., Gyöngyössolymos, Monostor Stream, N 47°49.918’ E 19°55.801’, 260 m, 07.03.201 1, leg. T. Kovács: 12m 2f (HNHM; used for drawings Figs. 140, 153, for molecular studies as 300950, 300972, 300976, 300953, 300954, 300975, drummings recorded as 2011/ No. 1–5, Fig. 172); SERBIA: Zlatibor District, Maljen Mts., Brajkovići, stream N of the village, N 44°02.244’ E 19°54.827’, 445 m, 17.03.201 1, leg. T. Kovács, G. Magos, D. Murányi: 2m 1f (HNHM; one male used for drawings Figs. 143, 156), 9m (HNHM; used for molecular studies as 300994, drummings recorded as 2011/ No. 1–7 Fig. 173).

Other material—Records based on morphology: AUSTRIA: Vienna State, Wien, Maurbach, 03.03.195 3, leg. E. Pomeisl: 1m 1f, 3 larvae (WNHM; male terminalia in microvial); Lower Austria and Vienna States, Vienna Woods, many brooks, various dates from February to March, leg. W. Graf (WGC); Styria State, Lanzegg, 16.03.200 4, leg. W. Graf: 15m 22f (WGC); FRANCE: Rhône-Alpes Region, Ardèche, Rivere de Celle, 20.03.195 0, leg. J. Aubert: 3m 3f (BYUC); Provence-Alpes-Côte d’Azur Region, Southern French Alps, Var, Artuby, La Martre, Pont Romain, 13.04.200 9, leg. Brulin: 1m (GVC); Provence-Alpes-Côte d’Azur Region, Southern French Alps, Alpes-de-Haute-Provence, Esteron, Soleihas, 1100 m, 21.02.200 9, leg. Le Doare: 7m 9f (GVC); Provence-Alpes-Côte d’Azur Region, Southern French Alps, Alpes-Maritimes, Lane, Andon, 1145 m, 13.04.200 9, leg. Le Doare: 2m 1f (GVC); Franche-Comté Region, Jura, La Clauge, Belmont, Jura Forest Reserve, 10.04.200 9, leg. Le Doare: 2m 1f (GVC); Limousin Region, French Massif Central, Creuse, Tarde, Champagnat, 440 m, 03.03.201 0, leg. Le Doare: 2m 1f (GVC); Poitou-Charentes Region, French Massif Central, Vienne, Moulisme, Petite Blourde, N 147 bridge, 20.02.200 9, leg. Le Doare: 3m 4f (GVC); Brittany Region, Bretagne, Finistère, Le Men, Tremorel, 105 m, 21.03.201 0, leg. Brulin: 5m 1f (GVC); Brittany Region, Bretagne, Morbihan, Pont Drimo, Le Cours, 65 m, 12.02.201 1, leg. Brulin: 1m (GVC); GERMANY: Schleswig-Holstein State, Plön, stream at Engelau, 26.02.196 6, leg. P. Zwick: 33m, 1m 2f larvae (PZC); 03.196 6, leg. P. Zwick: 13m 2f, 3f larvae (BYUC); Schleswig-Holstein State, Dallsek, 30 km E of Hennburg, 01.03.196 6, leg. P. Zwick: 18m (BYUC); HUNGARY: Vas County, Őrség, Kercaszomor, Kerca Stream, 16.04.200 2, leg. A. Ambrus, T. Kovács: 2f (MM); 11.03.200 3, leg. A. Ambrus, P. Juhász, T. Kovács: 1m 1f (MM); Veszprém County, Bakony Mts., Döbrönte, Bittva Stream, 230 m, 30.03.200 6, leg. J. Kontschán, D. Murányi: 2m 1f (HNHM); Veszprém County, Bakony Mts., Zirc- Szarvaskút, 21.04.198 8, leg. S. Tóth: 3m (HNHM); Pest County, Pilis Mts., Pilisszentkereszt, Szurdok Stream, 25.03.200 6, leg. L. Dányi: 2m (HNHM); Pest County, Börzsöny Mts., Szokolya, Les Valley, 08.02.200 3, leg. L. Papp, Zs. P. - Bajza: 3m 4f (HNHM); 08.04.200 4, leg. D. Murányi: 1m, 4f larvae (HNHM); Pest County, Börzsöny Mts., Szokolya-Királyrét, Bagoly-bükki Stream, 25.03.200 3, leg. T. Kovács: 1m (MM); 18.03.200 4, leg. A. Ambrus: 3m 7f (MM); Pest County, Börzsöny Mts., Szokolya-Királyrét, Szén Stream, 25.03.200 3, leg. T. Kovács: 1m (MM); Pest County, Börzsöny Mts., Szokolya-Királyrét, Nagy-vasfazék Stream, 25.03.200 3, leg. T. Kovács: 1m (MM); Pest County, Börzsöny Mts., Kismaros, Káposztás, Morgó Stream, 20.02.200 3, leg. P. Juhász, T. Kovács: 3m (MM); Nógrád County, Cserhát Mts., Cserhátszentiván, Zsunyi Stream, 03.03.200 4, leg. K. Harmos: 3m (HNHM); Nógrád County, Cserhát Mts., Ecseg, Zsunyi and Cserkúti Streams, 26.02.200 3, leg. K. Harmos: 9m 11f (HNHM); Nógrád County, Cserhát Mts., Felsőtold, Szurdok Stream, 12.03.200 3, leg. K. Harmos: 8m 6f (HNHM); Nógrád County, Cserhát Mts., Garáb, Garábi Stream, 04.03.200 3, leg. K. Harmos: 16m 5f, 1m 4f larvae (HNHM); Nógrád County, Mátra Mts., Bátonyterenye, Lengyendi Stream at the forester house, 14.02.200 4, leg. K. Harmos: 1m (HNHM); Heves County, Mátra Mts., Mátraszentimre, Csörgő Stream, 13.03.200 4, leg. K. Harmos: 2m, 1 f larva (HNHM); Heves County, Mátra Mts., Mátrafüred, Bene Stream, 20.02.200 4, leg. D. Murányi: 1m (HNHM); Heves County, Mátra Mts., Gyöngyössolymos, Cserkő-bánya, Monostor Stream, N 47°49.918’ E 19°55.801’, 260 m, 16.03.200 1, leg. T. Kovács: 3m 1f (MM); 25.03.200 1, leg. T. Kovács: 3f (MM); 19.04.200 1, leg. T. Kovács: 8f (MM); 14.03.200 2, leg. T. Kovács: 3f, 3f exuviae (MM); 19.04.200 2, leg. T. Kovács: 1f (MM); 22.02.200 3, leg. T. Kovács: 1m 3f (MM); Heves County, Mátra Mts., Gyöngyössolymos, Cserkő-bánya, Nagy Stream, 25.03.200 1, leg. T. Kovács: 1m 1f (MM); 14.03.200 2, leg. T. Kovács: 7m (MM); 08.03.200 3, leg. D. & T. Kovács: 2m (MM); 31.03.200 4, leg. T. Kovács: 1m (MM); 13.03.200 5, leg. T. Kovács: 2m (MM); Heves County, Mátra Mts., Domoszló, Tarjánka Stream, 16.03.200 2, leg. D. Murányi: 3m (HNHM); Heves County, Bükk Mts., Nagyvisnyó, Nagy-völgyi Stream, 22.01.200 3, leg. D. Murányi: 2m (HNHM; one male used for drawings Figs. 141, 154); Borsod-Abaúj-Zemplén County, Zemplén Mts., Vágáshuta, Hercegkúti Stream, 170 m, 14.03.200 4, leg. D. Murányi, Zs. Sóvári: 3m 1f, 1m larva (HNHM); Borsod-Abaúj-Zemplén County, Zemplén Mts., Erdőhorváti, Tolcsva Stream at the third bridge, 170 m, 15.03.200 3, leg. D. Murányi, Zs. Sóvári: 4m, 2m larvae, 1m exuviae (HNHM); ITALY: Lazio Region, Falscione Brooklet, 450m, 06.03.198 9, leg.?: 3m 2f (BYUC); NORWAY: Akershūs County, Hūrdal, Fallbekken, 13.04.196 9, leg. Smedstad: 1m 1f (BYUC); ROMANIA: Cluj County, Cluj- Napoca, Gorbo valley, 14.03.196 4, leg. B. Kis: 36m 26f (HNHM); SLOVAKIA: Banskobystrický Region, Krupinská Planina, Čebovce, Čebovský Stream, 180 m, 24.03.200 6, leg. L. Dányi, J. Kontschán, D. Murányi: 1m, 3f larva (HNHM); SWEDEN: Gotland County, SK Rövarkulan, 25.03.194 9, leg. P. Brinck: 2m 2f (BYUC); UNITED KINGDOM: Scotland, Carluke, early 20 th century?, leg. K.J. Morton?: 1m (WNHM).

Description. Head, thorax, appendages and basal segments of the abdomen generotypic. Males micropterous, females macropterous. Dimensions of the presently examined specimens: body length: males 7.0–9.0, females 8.0–10.5 mm; forewing length: males 0.8–1.3 mm, females 8.0–9.5 mm.

Male terminalia (Figs. 82–85, 120): Process of Tg 9 high, perpendicularly elevated, its apex is less than one and a half times wider than the medial section of Ep-scl; its shape is rectangular, the apex smooth or bears two hardly visible hump-like tips; sides constantly narrow in caudal view, the membranous portion narrowest in the apical portion (Figs. 152–156). Tg 10, B-scl and Lb-scl generotypic. Ep-scl wide and blunt in dorsal view, not swollen medially, medial width the ⅔ of basal width; tip upcurved in lateral view, divided section short. Ventral membranous part between the divisions of Ep-scl nearly reaches the base in lateral view; apical spines short, distributed only on the membranous part (Figs. 106, 114, 139–143). I-scl generotypic, Ec short and often partly or fully everted on the non in-copula specimens. St 9 slightly projecting medially, vesicle large to medium sized, Fig. 83 shows the largest size of the range. Sg rounded with not so pronounced triangular shape, tip usually rounded. Pp, Fp, Rp and cerci generotypic.

Female subgenital plate (Fig. 62): Rectangular, posterior margin slightly rounded and usually equal to the segment`s posterior margin. Antero-lateral recess usually distinct; the plate is entirely brown; lateral sclerites relatively large.

Drumming: Males produce repeated sequences of 2–3 drumming calls (Fig. 165), but sporadically single calls can also be observed. Calls are monophasic: inter-beat intervals increase gradually during the beat sequence of a call (Figs. 169–173, 190, Appendix Table 2). Calls in a sequence are rather similar to each other. The peak amplitude of beats generally shows a crescending-decrescending pattern during each call. See Figs. 169–173 for the oscillographic pattern of the male drumming calls of this species and also Table 7 for descriptive statistics of the examined five sonometric parameters. The male female drumming duet a long sequence of male call—female answer interchange (Fig. 185).

Genetics: Three different haplotypes were found, two from Hungary and one from Serbia (Fig. 192), with 0.5% of divergence, and with seven diagnostic characters separating them. Zwicknia bifrons specimens from Maljen Mts. of Serbia share haplotypes with Z. acuta. Despite this, morphology and mating calls correspond to Z. bifrons in all cases.

Affinities. Zwicknia bifrons is closely related to Z. acuta, and this affinity is discussed above. The epiproct is similar to Z. rupprechti, but the Tg 9 process is high and perpendicularly elevated in contrast to being low and caudally projecting in Z. rupprechti. In addition to Z. acuta and Z. rupprechti, males of Z. bifrons are easily distinguishable from other Zwicknia on the basis of upcurved Ep-scl tip and high, rectangular process of Tg 9. Females are difficult to distinguish, and the larvae are morphologically indistinguishable. The drumming signals of Z. bifrons are clearly different from those of the other three Zwicknia species where drumming was examined. This species produce the longest calls and drums with the slowest beat repetition rate among the investigated species. These two rhythmic characters clearly separate the calls of this species from the calls of the other three species which drum faster and produce shorter male calls (see Figs 190, 191). Regarding the number of calls in a sequence, the male drumming signals of Z. bifrons are intermediate and overlap with Z. acuta and Z. rupprechti (and Z. kovacsi). Z. bifrons differs genetically from the other species with 10 diagnostic characters and with> 2% nucleotide divergence.

Distribution and ecology. This species was originally described from Scotland. Drumming data has confirmed the occurrence of this species throughout the British Isles, Scandinavia, and southwards into the Alps (Fig. 196). We have confirmed Z. bifrons in northern and Central Hungary. Specimens of this species have also been identified from Austria, France, Germany, and Romania on the basis of morphology (Fig. 196–197). Adults were collected in January to May from the vicinity of slow to moderately fast flowing, medium-sized streams, usually in alder (Alnus glutinosa), but also in beech (Fagus sylvatica) forests between 150 and 600 m.

Remarks. The species was described on the basis of one or more females. A single female type apparently existed (Morton 1896). Despite that females of Zwicknia are difficult to specifically distinguish, its identity with the above material studied is supported by the homogeneity of British populations, both in drumming signals (Rupprecht 1997) and morphology based on the previously published figures (see under synonymies).