Pachycoleus japonicum ( Miyamoto, 1964 ) Kim, Junggon, Kim, Wongun, Park, Jihwan & Jung, Sunghoon, 2019

Kim, Junggon, Kim, Wongun, Park, Jihwan & Jung, Sunghoon, 2019, First record of family Dipsocoridae (Hemiptera: Heteroptera: Dipsocoromorpha) from the Korean Peninsula and a new generic combination for Cryptostemma japonicum Miyamoto, Zootaxa 4577 (1), pp. 195-200 : 196-197

Pachycoleus japonicum ( Miyamoto, 1964) Comb. n.

( Figs. 1 , 2 A–B, D)

Cryptostemma japonicum Miyamoto, 1964: 517 .

Diagnosis: Differs from other Pachycoleus species by body relatively pale brown, dull ( Fig. 1 A–B); antennae generally pale brown; hemelytron macropterous, with small cell near fracture ( Fig. 1C ); left appendage of male abdominal segment VIII with subapically curved apex, with distinct process near apex ( Fig. 1E ); right appendage thick and roundly curved apically ( Fig. 1F ); spermathecal duct distinctly short ( Fig. 1J ).

Description: Male: See Miyamoto (1964) for original description.

Genitalia: Genital segment with asymmetrical parameres ( Fig. 1D ); left paramere cross-like shape with somewhat dense setae mostly, basal swelling part with one folded-like shaped lobe ( Fig. 1G ; arrow) and one rounded lobe, apex of paramere long and shap, slightly curved in subapical part ( Fig. 1G ); right paramere broad with dense setae mostly, both sides with small and blunt protuberance ( Fig. 1H ).

Female: as in male except for more expanded abdomen and specialized tergite IX with appendages; anal aperture almost circular; anterior gonapophysis slender and curved slightly, tapered apically; posterior gonapophysis curved medially, apical part distinctly widened ( Fig. 1I ).

Genitalia: spermatheca at left side underneath tergite VII dorsally ( Fig. 1I ), with somewhat long gland and distinctly short spermathecal duct ( Fig. 1J ).

Measurements (In mm): Male (n = 4)/Female (n = 4) body length: 1.97–1.99/2.09–2.13; head length 0.20– 0.22/0.20–0.22; head width including compound eyes: 0.38–0.40/0.39–0.41; distance between ocelli: 0.24–0.25/ 0.24–0.26; first antennal segment: 0.08–0.09/0.09–0.10; second antennal segment: 0.15–0.16/0.15–0.16; third antennal segment: 0.40–0.41/0.42–0.44; fourth antennal segment: 0.42–0.43; 0.45–0.46; anterior pronotal width: 0.37–0.38/0.32–0.34; mesal pronotal length: 0.24–0.25/0.25–0.26; basal pronotal maximal width: 0.63–0.65/0.62– 0.65; anterior scutellar width: 0.42–0.44/0.42–0.45; mesal scutellar length: 0.23–0.24/0.23–0.24; hemelytron length: 1.61–1.64/1.63–1.67; hindleg (femur: tibia: tarsus): 0.44–0.46: 0.55–0.58: 0.19–0.20/0.44–0.47: 0.57–0.60: 0.20–0.22.

Distributions: Korea *, China (Central East), Japan, Russia (Far East).

Materials examined: [ ELKU] Holotype: 1♂, Pref. Fukushima, Chikugo , Kyushu, Japan, xii. 1955, S. & M. Miyamoto leg.; [CNU] 7♂♂ 14♀♀, Eupnae-ri, Gapyeong-eup, Gapyeong-gun, Gyeonggi-do, Korea, 13.x.2017, J. Kim & J. Park, leg.

Biology: Live nymphs ( Fig. 2A ) and adults ( Fig. 2B ) of this species are found under stones along rivers ( Fig. 2C ), usually on the moist part of the relatively flat stone.

Remarks: Based on male (absence of abdominal appendages anterior to segment VIII), we confirm generic position of this species as Pachycoleus , even though this species is strictly associated with stream like Cryptostemma s. str. as indicated by Štys (1990). See discussion part below for details.

Figures

FIGURES 1. Dorsal habitus and diagnostic characters of Pachycoleus japonicum (Miyamoto, 1964). A: dorsal habitus, ♂; B: dorsal habitus, ♀; C: hemelytron; D: abdomen with appendages and parameres of male in dorsal view; E: left appendage; F: right appendage; G: left paramere; H: right paramere; I: abdomen of female in dorsal view; J: spermatheca. Scale bar: A–C: 0.5 mm; E–I: 0.1 mm.

FIGURES 2. Live individuals, habitat and type specimen of Pachycoleus japonicum (Miyamoto, 1964). A: 5th instar nymph under a rock; B: adult under rocks; C: habitat, stones along water-side; D: holotype specimen with labels.