Temnostethus distans Kerzhner, 1973

Yamada, Kazutaka & Yasunaga, Tomohide, 2021, The tribe Anthocorini in Japan (Hemiptera: Anthocoridae): descriptions of new species, review of distribution and bionomics, Acta Entomologica Musei Nationalis Pragae 61 (2), pp. 375-426 : 379-381

Temnostethus distans Kerzhner, 1973

( Figs 1A–B , 2A , 3A–D , 18 )

Temnostethus distans Kerzhner, 1973:277 . Holotype:J (macropterous), Kuril Is., Shikotan (ZMAS). Note.The published year of this species has long been treated as 1972 in previous papers; however, it was corrected by AඎKൾආൺ et al. (2013a), who confirmed Kerzhner’s paper formally published in 1973 (KൾඋඓHඇൾඋ 1973).

Temnostethus distans : KൾඋඓHඇൾඋ (1988): 772–773 (in key, figures); Pඣඋංർൺඋඍ (1996): 119 (catalogue, distribution); YൺඌඎඇൺGൺ (2001b): 283 (record, diagnosis, habitat); KൺඇඒඎKඈඏൺ & MൺඋඎඌංK (2006): 168 (record); Gൺඉඈඇ & Kඈඇඌඍൺඇඍංඇඈඏ (2008): 26 (listed); VංඇඈKඎඋඈඏ et al. (2010): 58 (catalogue, distribution); AඎKൾආൺ et al. (2013a): 88 (catalogue, distribution); MൺൾHൺඋൺ (2015): 29 (recorded as Temnostethus sp. , habitat); Yൺආൺൽൺ et al.(2016): 422 (catalogue, distribution).

Type material examined. Hඈඅඈඍඒඉൾ: J, Kuril Islands, Shikotan, nr Kurilsk, 24.VIII.1963, G. O. Krivolutskaya (ZMAS, image examined). Pൺඋൺඍඒඉൾ: sex unknown, Iturup, nr Lesozavodsk, 28.VIII.1961, G. O. Krivolutskaya (ZMAS, image examined).

Additional material examined. JAPAN: HඈKKൺංൽඈ: 1♀ ( Figs 1A–B , 2A ), Lake Mashû-ko to Teshikaga-cho, 2.x.1993, M.Tomokuni ( NSMT); 1 ♀, Akkeshi-cho, Bekanbeushi Marsh, 43.05.42N 144.51.30E, 3.–24. viii.2004, Malaise trap, R. Matsumoto ( OMNH). HඈඇඌHඎ: Tochigi Pref.: 4 ♀♀, Nikko-shi, Noguchi, 30.x.2019, S. Maehara ( TKPM); 1 J ( Figs 3A–C ), Nikko-shi, Shôbugahama, 5.viii.2010, S. Maehara ( TKPM); 1 ♀, same locality, 25.v.2011, S. Maehara ( TKPM). Nara Pref.: 1 ♀, Kamikitayama-mura, Ôdaigahara, 9.ix.1962, N.Ohtani ( OMNH). KඒඎඌHඎ: Fukuoka Pref.: 1 ♀ ( Fig. 3D ), Soeda-machi Mt. Hikosan, 8.vii.1957, M. Miyatake ( EUM).

Differential diagnosis. Recognized by the following combination of characters: Body ( Figs 1A–B ) always macropterous, generally blackish brown, shiny; head as long as or slightly longer than width across eyes; antennal segment II ( Figs 1A–B ) pale yellow, with fuscous base and apex; labium uniformly blackish brown, reaching to metasternum; hemelytra ( Fig. 1A ) somber blackish brown, strongly shining; endocorium with antero-median portion mostly whitish or off- white ( Fig. 1A ); embolium with anterior portion narrowly whitish or off- white, excepting darkened basal extreme portion ( Fig. 1A ); whitish area on endocorium located posteriad in comparison with whitish area on embolium ( Fig. 1A ); membrane of hemelytra smoky dark brown, with basal and innermost portions and area behind apex of cuneus greyish white ( Fig. 1A ); legs blackish brown to reddish brown, with pro- and mesotibiae pale yellow ( Figs 1A–B ). Most similar in appearance to T. gracilis but distinguished from that species by the metatibiae being blackish brown to reddish brown (in T. gracilis , all tibiae pale yellow) and the paramere being moderately curved and slightly constricted at middle (in T. gracilis , more slender and very slightly curved, not constricted at middle). This species is similar to T. pusillus (Herrich-Schaeffer, 1835) in the coloration of hemelytra, but the latter has uniformly darkened antennae and a straight paramere.

Redescription. Male genitalia ( Figs 3A–C ): Pygophore ( Fig. 3A ) cone-shaped, somewhat flattened, covered with three long, stout setae intermixed with short, suberect setae along outer margin and on posteroventral surface, of which the longest setae are shorter than half length of pygophore; mid-dorsal surface hirsute with short, suberect setae; paramere ( Figs 3B–C ) very short, moderately curved, slightly constricted at middle, strongly bent at the base, with broad groove in form of shallow depression.

Female genitalia ( Fig. 3D ): Copulatory tube fused on middle of intersegmental membrane between sterna VII and VIII, extremely expanded and twisted with clearly visible rugosities on basal 1/3, and then gradually narrowing toward apex with less obvious rugosities; sperm pouch unfortunately broken off during the dissection; trunk of conductive tissue not pronounced (or possibly dissolved).

Measurements [mm; J (n = 1) / ♀♀ (n = 6)]. Body length 3.35 / 2.85–3.18; head length (excl. neck) 0.46 / 0.46–0.49; head width across eyes 0.46 / 0.42–0.45; vertex width 0.25 / 0.26–0.29; length of antennal segments I – 0.16 / 0.16–0.19, II – 0.54 / 0.49–0.56, III – 0.31 / 0.29–0.34, and IV – 0.36 / 0.35–0.37; length of labial segments II – 0.20 / 0.24–0.26, III – 0.67 / 0.67–0.75, and IV – unmeasurable / 0.36–0.40; anterior pronotal width 0.36 / 0.37–0.39; mesal pronotal length 0.40 / 0.42–0.44; basal pronotal width 0.97 / 0.88–1.01; length of embolial margin 1.00 / 0.82–1.01; length of cuneal margin 0.62 / 0.52–0.62; maximum width across hemelytra unmeasurable / 1.05–1.16.

Bionomics. Temnostethus distans is found on various trees [e.g., Alnus maximowiczii Callier (Betulaceae) ] (KൾඋඓH- ඇൾඋ 1973, 1988). MൺൾHൺඋൺ (2015) collected this species (as Temnostethus sp. ) from lichens that cover the bark of broad-leaved trees in Tochigi Prefecture, central Honshu, Japan. He also mentions that this species was found on Aesculus turbinata Blume (Sapindaceae) , Prunus species (Rosaceae) , Magnolia kobus DC. (Magnoliaceae) , and Zelkova serrata (Thunb.) Makino (Ulmaceae) in a low mountainous area (Satoshi Maehara, pers. comm.).

Distribution. Japan: Hokkaido *; Honshu*: Tochigi, Nara; Kyushu*: Fukuoka. Chishima (Kuril) Islands: Iturup Is. (KൾඋඓHඇൾඋ 1973), Kunashir Is. (KൺඇඒඎKඈඏൺ & MൺඋඎඌංK 2006), and Shikotan Is. (KൾඋඓHඇൾඋ 1973). Russia: Far East: Sakhalin (KൾඋඓHඇൾඋ 1973, VංඇඈKඎඋඈඏ et al. 2010). The species is known to occur in the Chishima Islands and the Russian Far East (Pඣඋංർൺඋඍ 1996); however, we present the first record of this species in Japan proper ( Fig. 18 ).

Figures

Fig. 1. Habitus, dorsal (A, C, E) and lateral (B, D, F) views. A–B – Temnostethus distans Kerzhner, 1973, female; C–D – T. mirificus sp. nov., holotype, male; E–F – Elatophilus nipponensis Hiura, 1966, male. Scale bars: 1.0 mm.

Fig. 2. Scanning electron micrographs of diagnostic characters of Japanese anthocorids. A – Temnostethus distans Kerzhner, 1973, female; B, D – T. mirificus sp. nov., female (B) and male (D), paratypes; C – Elatophilus nipponensis Hiura, 1966, female. A–C – ostiolar peritreme and evaporatorium, left lateroventral view; D – pygophore with paramere, lateral view. Abbreviations: eva ‒ evaporatorium; mf ‒ median furrow; op ‒ ostiolar peritreme; prm ‒ paramere; pyg ‒ pygophore.

Fig. 3. Male (A–C, E–G, I–K) and female (D, H, L) genitalia. A–D –Temnostethus distans Kerzhner, 1973; E–H – T. mirificus sp. nov., paratype; I–L – Elatophilus nipponensis Hiura, 1966.A, E, I – pygophore with paramere (ejaculatory bulb omitted), dorsal view; B–C, F–G, J–K – paramere, two different views; D, H, L – copulatory tube and sperm pouch (D, L, sperm pouch broken off), dorsal view. Abbreviations: ct ‒ copulatory tube; prm ‒ paramere; pyg ‒ pygophore; sp ‒ sperm pouch. Scale bars: 0.1 mm.

Fig. 18. Distribution of Temnostethus distans Kerzhner, 1973 (circles), T. mirificus sp. nov. (triangles), and Elatophilus nipponensis Hiura, 1966 (squares) in Japan. Filled symbols represent records based on specimens examined by us, open symbols represent literature records.