Capniella gibba, Hwang & Li & Murányi, 2021

Hwang, Jeong Mi, Li, Weihai & Murányi, Dávid, 2021, A new species of the winter stonefly genus Capniella Klapálek, 1920 (Plecoptera: Capniidae) from Korea, Ecologica Montenegrina 48, pp. 43-48 : 44-48

Capniella gibba sp. n.

http://zoobank.org/ urn:lsid:zoobank.org:act:3C4959C0-6C0D-4A35-8CFB-A9CDC6FF1508

( Figs. 1–11 )

Type material: Holotype male: SOUTH KOREA: Gangwon-do , Pyeongchang-gun , Jinbu-myeon , Odaesanro, Odaesan National Park, Malaise trap at alt. 822 m, 37°47'4.20" N 128°33'42.31" E, 2019.XII.27 – 2020.I.30, leg. Jeong Mi Hwang, Ji Hyoun Kang, Daseul Ham, Sunghwan Park ( KUEM) . Paratypes: same locality and data: 1 male ( KUEM) , 1 male ( EKCU) , 1 male ( NIBR, VLYVIN0000011915 ) .

Diagnosis: Male epiproct with small basal and large laterobasal sclerites, lacks lower limb; main sclerite is laterally divided, its upper portion is dorsally full divided, bears huge eversible crest and parts are apically diverging, lower portion with three apical branches; apical setae present, inner sclerite lacking. Male paraproct with dilated apex, fusion plate wide, divided from small retractoral plate. Male tergum VI with large, finger-like posteromedial process pointing caudad and dorsad; tergum VII with large, spherical and medially subdivided posteromedial process covered by sensilla basiconica; terga VIII–IX with deeply indenting posteromedial membranous field; tergum X fully divided; ventral vesicle absent, subgenital plate fused. Macropterous forewing with strongly curved R1 and straight A1, cubital cell triangular. Mesothoracal postfurcasternum divided from all other sclerites.

Description: Small sized Capniidae , body length of the holotype male is 3.8 mm, forewing length 2.8 mm, slightly brachypterous ( Fig. 2 ). General color dark brown, head and pronotum with distinct granules, pilosity dense and of medium length. Antenna shorter than the body, antennomeres clubbed. Legs relatively short and stout. Cerci medium long, with 15 cercomeres; cercomeres clubbed and with apical whorl of long setae. Head wider than pronotum, slightly elongated; mouthparts normal; first segment of maxillary palp shorter than wide, third is the longest; labial palp with medium long palpomeres.

Thoracal sclerites: Prothorax: basisternum quadrate, only weakly fused with precoxal bridge and furcasternum; furcasternum transverse, fused with postcoxal bridge; pronotum as wide as long, with distinct posterior lobe, corners rounded. Mesothorax: spinasternum narrow, medially fused in a drop-like sclerite, strap-like lateral arms not fused with the oblong basisternum; presternum elliptical, not fused; furcasternum triangular, fused with basisternum and both with distinct furcasternal arms and furcasternal pit; postfurcasternum divided in two lateral, rounded triangular parts, not fused with other sclerites; katepisternum weakly fused with the basisternum posteriorly, limit between fused anepisternum and katepisternum hardly recognizable; posterior basalare is the longest among the wing-supporting sclerites; prescutum rectangular and normal sized, fused with scutum and transverse prealar bridge but well delimited; scutum relatively small, posteriorly dilated, fused with small, subdivided postscutellum by a thickened ridge. Metathorax: presternum elliptical; basisternum, katepisterna, and wing-supporting sclerites similar to mesothorax; prescutum similar but more triangular; prealar bridge and scutum is smaller than on mesonotum, posteriorly less dilated but similarly fused with postscutellum.

Slightly brachypterous wing venation ( Fig. 3 ): Forewing: there is one crossveins between Costa and Subcosta besides humeral crossvein, Subcosta joins R1 well before radiosubcostal crossvein; R1 is strongly curved before joining of Subcosta; lacks stigma; one crossvein presents between Medial vein and Cu1 besides arculus and mediocubital crossvein; Cu1 and Cu2 branching at arculus, cubital cell triangular; A1 straight beyond anal crossvein. Hindwing: costal, subcostal, radial and cubital venation similar to forewing but with less crossveins; anal field long and relatively deep beneath anal fold, Anal veins three.

Male abdomen ( Figs. 1 , 4–10 ): Tergal sclerotization thin but with many specific modifications. Antecosta present on all but the basal tergum, entire on terga VI–IX. Terga I, III–V medially subdivided, tergum II medially full divided by membranous field. Terga VI–VII with medially indenting antecosta and bear posteromedial process. Process on tergum VI tergum large and finger-like, pointing caudad and dorsad, reaching the process of tergum VII but lacks sensilla basiconica. Process on tergum VII large, spherical and medially subdivided, covered by sharp conical sensilla basiconica. Terga VIII–IX with medially indenting antecosta, subdivided by deeply indenting posteromedial membranous field. Tergum X fully divided, halves elliptical. Epiproct consist of small basal sclerite separated from large and triangular, but posteriorly indented laterobasal sclerites; main epiproct sclerite huge and complex, bearing eversible crest and caudal setae but lacks inner sclerite. The main epiproct sclerite is ventrally entire, laterally deeply divided from the base; lower portion less modified but with three, finger-like apical branches, slightly curved dorsad; upper portion dorsally fully and widely divided, branches slightly diverging apically, laterally weakly sclerotized and both bear huge eversible crest, sclerotized portions with very few sensillae. Sternum IX narrowly fused with tergum IX anterolaterally, subgenital plate widely rounded, apical tip medium sized; vesicle lacking. Paraprocts wide and long, apex dilated and subdivided from the basal half. Fusion plate is medium long and wide, apical tube short and with wide tip. Retractoral plate stout and rounded triangular, well divided from fusion plate.

Female and larva unknown.

Affinities: The male genital characters (laterally full divided main epiproct sclerite, wide fusion plate and only weakly fused sternum and tergum IX) and somatic characters (strongly curved R1 vein, straight A1 vein) leaves no doubts about the generic position of the new species. However, it is distinctly different from the three other Capniella species by its widely separated, apically diverging upper portion and three-branched lower portion of the main epiproct sclerite, and the huge, finger-like process of tergum VI.

Distribution and ecology: The new species was caught by Malaise trap at a single locality in the Odaesan Mts during the winter season. The Malaise trap was set along the upper section of the Odaechen Stream, and it was surrounded by fir trees ( Fig. 11 ). No other stonefly was collected by the Malaise trap, but one female of Capnia sidimiensis Zhiltzova, 1979 was caught by sweeping on December 27, 2019.

Etymology: The name gibba (from the Latin noun gibbus, meaning bump) refers to the distinct process of abdominal tergum VI. The name is used as an adjective of feminine gender.

Figures

Figure 11. Habitat of Capniella gibba sp. n.: South Korea, Odaesan Mts, Odaechen Stream.

Figures 1–3. Male somatic characters of Capniella gibba sp. n. — 1: abdominal sclerites; 2: habitus, dorsal view; 3: forewing — scales 1 mm, Fig. 1 is not to scale.

FIGURES 4–5. Male terminalia of Capniella gibba sp. n. — 4: lateral view; 5: dorsal view — scale 0.5 mm, only tergal processes and epiproct are shaded.

Figures 6–10. Male genital structures of Capniella gibba sp. n. — 6: epiproct and tergite X, oblique dorsocaudal view; 7: same, oblique dorsobasal view; 8: same, ventral view; 9: fusion plate, retractoral plate and paraprocts, oblique ventrocaudal view; 10: same, oblique dorsobasal view — scale 0.25 mm.