Capnia mitsuseana, Hanada, 2018

Hanada, Satoko, 2018, A New Species Of Capnia Pictet, 1841 (Plecoptera: Capniidae) From Kyushu, Japan, With Description Of Male Drumming Signals, Illiesia 14 (9), pp. 155-161 : 157-160

Capnia mitsuseana sp. n.

http://lsid.speciesfile.org/urn:lsid: Plecoptera .speciesfile.org: TaxonName:504342

( Figs. 1 –10)

Material examined. Holotype ♂, Japan: Iiba, Sawara Ward, Fukuoka City, Fukuoka Prefecture , 33°28.73′N, 130°17.11′E, alt. 480 m, Muromi River , 1.II.2015 . Paratypes: 1♀, type locality, 24.I.2015; 4♂, 1♀, type locality, 21.II.2015; 2♂, type locality, 3.I.2016; 4♀, type locality, 21.I.2018 .

Additional materials. Japan: Iiba, Sawara Ward, Fukuoka City , Fukuoka Prefecture (type locality) , 16.II.2013, 1♂, 1♀; same locality , 23. III.2013, 1♀; same locality , 13.I.2014, 1♂, 1♀; same locality , 22.II.2014, 1♂, 1♀ (copulating pair); same locality , 10.I.2015, 1♀; same locality , 12.I.2015, 1♀; same locality , 18.I.2015, 1♂, 1♀; same locality , 24.I.2015, 4♂, 1♀; same locality , 22.II.2015, 1♂; same locality , 28.II.2015, 1♀; same locality , 3.I.2016, 1♀; same locality , 16.I.2016, 5♂; same locality , 2.II.2016, 2♂, 1♀; same locality , 7.II.2016, 1♂, 1♀; same locality , 28.II.2016, 1♂; same locality , 14.I.2017, 1♀; same locality , 29.I.2017, 1♂; same locality , 2.I.2018, 2♂, 2♀; same locality , 23.II.2018, 2♂, 1♀; same locality , 4.III.2018, 1♀; Magaribuchi, Sawara Ward , Fukuoka City, Fukuoka Prefecture, 33°28.97′N, 130°17.34′E, alt. 410 m, Muromi River , 24.I.2015, 9♂, 5♀; same locality , 31.I.2015, 1♂; same locality , 22.II.2015, 1♂; same locality , 21.II.2016, 1♂; Kumado, Hoshino Village, Yame City , Fukuoka Prefecture, 33°13.82′N, 130°50.88′E, alt. 716 m, Kumado River , 25.I.2015, 4♀; same locality , 16.I.2016, 1♀; same locality , 28.II.2016, 1♀; Kamiose, Fuji Town, Saga City , Saga Prefecture, 33°28.22′ N, 130°16.21′E, alt. 515 m, Hatsuse River , 7.III.2015, 1♀; same locality , 3.I. 2016, 2♂; same locality , 9.I.2016, 2♂, 1♀; same locality, 30.I.2016, 1♀; same locality, 2.I.2018, 1♂ ; same locality, 7.I.2018, 1♂ ; Mitsuse, Mitsuse Town, Saga City , Saga Prefecture, 33°27.91′N, 130°16.47′E, alt. 448 m, Hatsuse River , 16.I.2016, 1♀ ; same locality, 2.I.2018, 1♀ ; same locality, 21.I.2018, 1♀ ; same locality, 23.II.2018, 1♂ ; Ikisa, Ouchi Town, Karatsu City , Saga Prefecture, 33°22.19′N, 130°02.95′ E, alt. 320 m, Saikisa River , 17.III.2018, 1♂ ; Yoshida, Ureshino City, Saga Prefecture, 33°01.30′N, 130°02.09′E, alt. 460 m, Yoshida River , 29.I.2000, 2♂, 3♀ ; same locality, 8.III.2000, 1♂ .

Adult habitus. Macropterous ( Fig. 1 ), but wing length somewhat variable (forewing length / body length = 0.68–1.17, n = 47 individuals). Wings subhyaline and slightly brownish; veins brown and partly pale. 1A of fore- wing typical to that of Capnia , bent abruptly caudad at its junction with cu- a and curved outward again; R 1 of fore- wing typical to that of Capnia , bent upward at its origin; Cu1 and Cu2 of forewing originating from the different points on arculus ( Fig. 2 ), but rarely from the same point on arculus (11%, n = 46 individuals). General color dark brown. Head, thoracic sclerites and basal segments of abdomen typical to those of Capnia . Cerci long, brownish, and composed of 16–26 segments (n = 10 individuals).

Male. Body 4.8–7.0 mm (n = 23) long. Forewing 3.8–6.0 mm (n = 23) long. Tergum 7 modified ( Figs. 3 & 4): the anterior margin rising and forming a pair of small and short tubercles with blunt tips; the posterior margin extending upward and forming a large tubercle with a rough, rounded apex bearing sensilla basiconia, the back of which covers the tip of epiproct; membranous field located on antero- middle of tergum 7. The anterior margin of tergum 8 slightly curved posteriorly. Main epiproct sclerite long and rather narrow with a taper, rounded tip in dorsal view; its bottom nearly straight in lateral view; a pair of needle- like processes located on either side of its tip ( Fig. 5 ). Eversible crest of epiproct swollen in lateral view ( Fig. 5 ). Sternum 9 without a vesicle on the basal margin ( Fig. 6 ). Subgenital plate large and tongue-like shape with a small rounded quadrangular tip; indented basolaterally ( Figs. 6 & 7 ). Fusion plate somewhat shield- shaped, and the anterior margin connected by membrane with a small, subtriangular, sclerotized retractoral plate ( Fig. 7 ). Paraproct with a dilated apex ( Fig. 7 ).

Female. Body 6.0–8.9 mm (n = 24) long. Forewing 5.0–7.2 mm (n = 24) long. Abdominal terga 1 to 8 with broad longitudinal membranous fields along the midline; terga 9 and 10 fully sclerotized. Posterior margin of sternum 7 protruding backward (Fig. 8). Subgenital plate of sternum 8 nearly same length of sternum 8; rounded and having short posteromedial lobe (Fig. 8). A pair of longitudinal inner vaginal sclerites bent ventrally near the anterior ends; curved outward near the posterior ends; visible through the subgenital plate as two longitudinal stripes (Figs. 9 & 10).

Drumming signals. Two males (0-day- old and one- day- old after capture) produced signals by percussion involving up- down abdominal movements under solitary condition at 16.8– 17.0°C. Because no female answers were recorded, the call of males is tentatively described as a monophasic signal ( Fig. 11 ). The male call signal was composed of 3.7 ± 0.5 beats with 39.6 ± 2.5 ms mean inter- beat interval ( Fig. 11 , Table 1 ). The signal durations averaged 105.8 ms (SD = 21.3, range = 71.1–132.1, n = 43). Interval difference was 1.8 ms (40.9 – 39.1 = 1.8 ms ≦ 10 ms ID) ( Table 1 ), and therefore the mean inter- beat interval pattern was horizontal. The two males always produced series of monophasic signals ( Fig. 11 ). The signal sequence consisted of 3.9 ± 0.5 signals (range = 3–5, mode = 4, n = 11) with 287.7 ± 30.4 ms mean signal interval (range = 220.6–364.3, n = 32).

Ecological notes. This new species was collected from the upper reaches of rivers (Fig. 14). The emergence period is mainly during winter and early spring (I–III). The adults were found on the parapets of bridges and the guard rails.

Distribution. Japan (northern Kyushu).

Etymology. The specific name mitsuseana refers to the Mitsuse Pass where the new species was found.

Remarks. Males of this new species resemble Capnia asakawana Kohno, 1952 , C. bituberculata Uéno, 1929 , C. kibuneana Kawai, 1957 and C. fukushimana Kohno, 1952 in the structure of the modified abdominal tergum 7 where all members of the group displayed a pair of tubercles on the anterior margin and a large tubercle on the posterior margin (Uéno 1929, Kohno 1952, Kawai 1957). The new species differs from all the others by the anterior tubercles of tergum 7 being smaller and by the main epiproct sclerite being long and rather narrow with a taper, rounded tip in dorsal view and with nearly straight bottom in lateral view. Females of the new species can be distinguished from other Japanese Capnia species by abdominal sternum 7 extending caudally over the anterior margin of the 8 th sternum and by the short subgenital plate of sternum 8 not extending past the posterior edge of the sternum and by the distinct two longitudinal stripes seen on the subgenital plate.

Figures

Figs. 1-5. Capnia mitsuseana sp. n. 1. Habitus of Capnia mitsuseana sp. n. (female). 2. Right wings of Capnia mitsuseana sp. n. 3–5. Capnia mitsuseana sp. n. (male). 3. Terminalia, dorsal view. 4. Terminalia, lateral view. 5. Epiproct, lateral view (above), dorsal view (below). Ec = eversible crest, Ep-scl = main epiproct sclerite, arrow = needle-like process.

Figs. 6–7. Capnia mitsuseana sp. n. (male). 6. Terminalia, ventral view. 7. Fusion plate, dorsal view (internal view). rp = retractoral plate, sbp = subgenital plate. Figs. 8–10. Capnia mitsuseana sp. n. (female). 8. Terminalia, ventral view. 9. Cleared terminalia and inner vaginal sclerites, ventral view. 10. Cleared terminalia and inner vaginal sclerites, ventro-lateral view.

Fig. 11. A male call signal sequence of Capnia mitsuseana sp. n. consisting of four signals. i = inter-beat interval.