Isocapnia Banks, 1938

Murányi, Dávid, Gamboa, Maribet & Orci, Kirill Márk, 2014, Zwicknia gen. n., a new genus for the Capnia bifrons species group, with descriptions of three new species based on morphology, drumming signals and molecular genetics, and a synopsis of the West Palaearctic and Nearctic genera of Capniidae (Plecoptera), Zootaxa 3812 (1), pp. 1-82 : 21-22

Isocapnia Banks, 1938

( Figs. 19–20 , 30 , 35 )

Isocapnia Banks, 1938 — Banks 1938: 73. (original description, type species Arsapnia grandis Banks, 1907 ); Zhiltzova 2003: 398. (revision of the Palaearctic species); Zenger & Baumann 2004: 66. (revision of the Nearctic species).

Diagnosis. Male epiproct: B-scl large, divided from Ep-scl; Lb-scl small, divided from Ep-scl; Ep-scl entire both ventrally and laterally, caudal setae absent; I-scl and Ec absent. Male Pp: apical part long and wide; Fp long and very narrow, divided from Rp. Male Sg: divided from St 9 and Tg 9, vesicle present. Female Sg: rectangular, entire or weak centrally; inner and lateral sclerites absent. Male tergites: process lacking or Tg 9 with process. Ventral thoracic sclerites: MPrs elliptical or triangular, MeFs transverse, MeFsp fused with MePfs; Prs/Bs, Mfs/St 1 and PPo/PFs fused with or separated from. Macropterous wings: forewing A1 beyond a and R1 before r straight; crossveins between C and Sc one to eight, R veins three to five.

Species included. 12 valid species from the West Nearctic and 7 from the East Palaearctic ( DeWalt et al. 2014); 15 of these examined (see Appendix 1).

Remarks. Some of the diagnostic characters widely used since Hanson (1946) are variable within the species included ( Tables 1–2 ). Nevertheless, the structure of the male terminalia is similar in the species having differently shaped epiprocts ( I. vedderensis ( Ricker, 1943) , I. spenceri Ricker, 1943 ). Reduction of the number of forewing C-Sc crossveins occurs in the small-sized species. Veins not counted in the case of the species having odd, reticulated wing venation ( I. palousa Zenger & Baumann, 2004 , I. mogila Ricker, 1959 – see Zenger & Baumann 2004: Fig. 26 ).

Figures

FIGURES 17–22. Male terminalia of Nearctic Capniidae—17–18: Bolshecapnia gregsoni (Ricker); 19–20: Isocapnia grandis (Banks); 21–22: Eucapnopsis brevicauda (Claassen); 17, 19, 21: dorso-caudal view; 18, 20, 22: ventro-caudal view (B-scl: basal sclerite; Ec: eversible crest; Ep-scl: main epiproct sclerite (shaded in grey); I-scl: inner sclerite; Lb-scl: laterobasal sclerite; Tg 10: tergite 10)—not to scale.

FIGURES 23–31. Male paraprocts and fusion plate of Capniidae, dorso-lateral view—23: Zwicknia bifrons (Newman); 24: Capnia s.s. nigra (Pictet); 25: Capnia s.l. vidua Klapálek; 26: Capnia s.l. prolongata Zhiltzova; 27: Capnia s.l. pedestris Kimmins; 28: Capnia s.l. arensi Zhiltzova; 29: Bolshecapnia gregsoni (Ricker); 30: Isocapnia grandis (Banks); 31: Eucapnopsis brevicauda (Claassen) (Fp: fusion plate; Pp: paraproct; Rp: retractoral plate)—not to scale.

FIGURES 32–48. Male terminalia of Capniidae, ventral view—32: Zwicknia bifrons (Newman); 33: Bolshecapnia gregsoni (Ricker); 34: Eucapnopsis stigmatica transversa Aubert; 35: Isocapnia grandis (Banks); 36: Capnia s.l. arensi Zhiltzova; 37: C. s.l. prolongata; 38: C. s.l. pedestris Kimmins; 39: C. s.s. nigra (Pictet); 40: Arsapnia decepta Banks; 41: Allocapnia granulata (Claassen); 42: Mesocapnia silvatica Raušer; 43: Capnura venosa Banks; 44: Utacapnia lemoniana (Nebeker & Gaufin); 45: Paracapnia opis (Newman); 46: Nemocapnia carolina Banks; 47: Capnopsis schilleri schilleri (Rostock); 48: Capnioneura nemuroides Ris (C: cercus; Ep-scl: main epiproct sclerite; Fp: fusion plate; Pp: paraproct; Sg: subgenital plate; St 9: sternite 9; Tg 9: tergite 9; Tg 10: tergite 10; Vv: ventral vesicle)—scale 1 mm.