Acompocoris brevirostris Kerzhner, 1979

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 : 384-386

Acompocoris brevirostris Kerzhner, 1979

( Figs 4A–D , 5A–C , 6A–D , 16A–B , 19 )

Acompocoris brevirostris Kerzhner, 1979: 23 . Holotype: J, Kuril Is., Urup, Kaymen (ZMAS).

Acompocoris brevirostris : KൾඋඓHඇൾඋ (1988): 773–774 (figures, in key); Pඣඋංർൺඋඍ (1996): 109 (catalogue, distribution); YൺඌඎඇൺGൺ et al.

(1999): 8 (record, distribution, photo); YൺඌඎඇൺGൺ (2001b): pl. 85, 280 (photo, diagnosis, habitat, prey, phenology); TඈGൺඌHං (2002): 8 (record, photo); Iංඃංආൺ (2004): 134 (record); KHඈආൾඇඍඈඏඌKඒ (2004): 182 (listed); KൺඇඒඎKඈඏൺ & MൺඋඎඌංK (2006): 164, 168 (listed); Gൺ- ඉඈඇ & Kඈඇඌඍൺඇඍංඇඈඏ (2008): 26 (listed); VංඇඈKඎඋඈඏ et al. (2010): 56 (catalogue, distribution); AඎKൾආൺ et al. (2013a): 84 (catalogue, distribution); VංඇඈKඎඋඈඏ & Gඈඅඎൻ (2016): 350–351 (listed, figure); Yൺආൺൽൺ et al. (2016): 422 (catalogue, distribution); VංඇඈKඎඋඈඏ (2020):39 (catalogue, distribution); VංඇඈKඎඋඈඏ & KHඋඎඅൾඏൺ (2021): 22 (distribution, habitat).

Material examined. JAPAN: HඈKKൺංൽඈ: 1 J ( Figs 4A–B ) 1 ♀

( Figs 4C–D ), Nakagawa-cho, Mt. Panke, 300–630 m, 31.vii.1997, T.

Yasunaga ( TKPM); 1 J ( Figs 6A–C ) 2 ♀♀ (one in Fig. 5A , one in

Fig. 6D ), same locality and date, S. Yamashita ( TKPM); 1 J 2 ♀♀,

Kamikawa-cho, Mts. Taisetsu, Mt. Midori-dake, 1500–1700 m alt.,

43.640N 142.923E, Pinus pumila , 7.viii.2001, T. Yasunaga ( TYCN); 1

♀, Kamikawa-cho, Goshikigahara, 12.viii.1998, A.Yamamoto ( TKPM);

1 J, Mt.Antaroma-dake, 11.viii.1967, A. Nakanishi ( ELKU); 1 J, Mt.

Satsunai-dake, 28.vii.1967,A. Nakanishi ( ELKU). HඈඇඌHඎ: Yamagata

Pref.: 2 ♀♀, Mt. Chôkai, 17.ix.1971, M. Tomokuni ( NSMT). Gunma

Pref.: 1 ♀, Katashina-mura, Tokura, 17.x.2014, K. Takahashi ( TKPM).

Nagano Pref.: 1 ♀, South Alps, Mt. Senjôga-take, 2.x.2011, S. Shiyake

( OMNH); 3 JJ (one in Figs 5B–C ) 14 ♀♀, Ôtaki-mura, Tanohama,

7. viii.2010, T. Ban ( TKPM). Gifu Pref.: 1 J 1 ♀, Mt. Norikura-dake,

7.ix.1951, H. Hasegawa ( OMNH).

Differential diagnosis. Recognized by the following combination of characters: body ( Figs 4A–D , 16A–B ) generally blackish brown; antennal segment II approximately 1.2 times as long as head width across eyes; labium ( Figs 4B,D ) reaching near middle of mesosternum; hemelytra ( Figs 4A,C ) tinged with reddish brown, female ( Fig. 4C ) much paler with dark spot near middle of endocorium; membrane of hemelytra smoky dark brown, with area behind apex of cuneus and area along four veins grayish white; apex of femora and entire tibiae reddish brown to yellowish brown. Similar to Holarctic A. pygmaeus (Fallén, 1807) and Palaearctic A. alpinus Reuter, 1875 , but distinguished from both by labium reaching near middle of mesosternum (in A. pygmaeus and A. alpinus , labium extending or almost reaching metacoxae) and paramere basally widened (in A. pygmaeus and A. alpinus , narrower). The form of female genitalia of A. brevirostris is similar to that of A. alpinus with a copulatory tube possessing a lateral process at base but separated from that species by the copulatory tube being fused on the left side of the intersegmental membrane between sterna VII and VIII in dorsal view (in A. alpinus , fused on the mesal part of the intersegmental membrane) and the copulatory tube being rather short (in A. alpinus , much longer).

Redescription. Male genitalia ( Figs 5B–C , 6A–C ): Pygophore ( Fig. 6A ) broadly cone-shaped, covered with 4–5 long, stout setae (missing in Fig. 6A ) intermixed with short, suberect setae along outer margin and on posteroventral surface, of which the longest setae are approximately half the length of pygophore; mid-dorsal surface very hirsute with short, suberect setae; paramere ( Figs 5C , 6B–C ) lamellate, short, strongly curved near apex, basally widened, with a few very short, erect setae on middle portion, without distinct groove but weak depression near base formed by inflection of posterior edge.

Female genitalia ( Fig. 6D ): Copulatory tube fused on left lower surface of intersegmental membrane between sterna VII and VIII in dorsal view, approximately 0.3 mm in length, with lateral process at base, somewhat narrowing toward apex, entire copulatory tube with rugosities; thin-walled, annular structures of unknown function visible within sperm pouch at junction of pouch and copulatory tube; trunk of conductive tissue not pronounced (or possibly dissolved).

Measurements [mm; JJ (n = 5) / ♀♀ (n = 10)]. Body length 3.85–4.00 / 4.10–4.50; head length (excl. neck) 0.46–0.50 / 0.45–0.51; head width across eyes 0.51–0.56 / 0.53–0.58; vertex width 0.29–0.33 / 0.31–0.34; length of antennal segments I – 0.20–0.23 / 0.20–0.23, II – 0.63–0.69 / 0.60–0.65, III – 0.36–0.39 / 0.36–0.41, and IV – 0.35–0.40 / 0.35–0.43; length of labial segments II – 0.20–0.23 / 0.21–0.26, III – 0.69–0.75 / 0.65–0.80, and IV – 0.29–0.31 / 0.30–0.35; anterior pronotal width 0.43–0.45 / 0.44–0.50; mesal pronotal length 0.48–0.53 / 0.50–0.55; basal pronotal width 1.18–1.25 / 1.28–1.44; length of embolial margin 1.22–1.31 / 1.22–1.48; length of cuneal margin 0.90–0.95 / 1.00–1.15; maximum width across hemelytra 1.46–1.55 / 1.63–1.85.

Bionomics. Acompocoris brevirostris is associated with Pinus pumila (Pall.) Regel (e.g., KൾඋඓHඇൾඋ 1979, 1988; YൺඌඎඇൺGൺ 2001b; TඈGൺඌHං 2002; KHඈආൾඇඍඈඏඌKඒ 2004). In the treeless areas of the Chukotka Autonomous Okrug (tundra zone and the elfin wood subzone) in Far East Russia, it was collected on a swamp river terrace with sedge-sphagnum-moss cover and shrubs of dwarf pine and alder (VංඇඈKඎඋඈඏ & KHඋඎඅൾඏൺ 2021).

Distribution. Japan: Hokkaido (YൺඌඎඇൺGൺ et al. 1999); Honshu: Yamagata *, Gunma *, Ishikawa (TඈGൺඌHං 2002), Nagano *, Gifu *. Chishima (Kuril) Islands: Kunashir Is., Iturup Is., Urup Is., Simushir Is., Ketoi Is., Shiashkotan Is., Paramushir Is., Shumshu Is. (KൾඋඓHඇൾඋ 1979, Kൺ- ඇඒඎKඈඏൺ & MൺඋඎඌංK 2006). Russia: Far East: Magadan, Kamchatka, Sakhalin, Primorsky Kray (KൾඋඓHඇൾඋ 1988, VංඇඈKඎඋඈඏ et al. 2010, VංඇඈKඎඋඈඏ & Gඈඅඎൻ 2016). In Japan, this species is apparently restricted to the subalpine coniferous forests of the central and northern parts of the country, generally at high elevations but also in the lowland areas of Hokkaido where Pinus pumila subalpine forests can be found.

Figures

Fig. 4. Habitus, dorsal (A, C, E, G) and lateral (B, D, F, H) views. A–B – Acompocoris brevirostris Kerzhner, 1979, male; C–D – same, female; E–F – Tetraphleps aterrima (J. Sahlberg, 1878), male; G–H – same, female. Scale bars: 1.0 mm.

Fig. 5. Scanning electron micrographs of diagnostic characters of Japanese anthocorids. A–C – Acompocoris brevirostris Kerzhner, 1979, female (A) and male (B–C); D–F – Tetraphleps aterrima (J. Sahlberg, 1878), male.A, D – ostiolar peritreme and evaporatorium, left lateroventral view; B, E – pygophore with paramere, dorsal view; C, F – paramere, dorsal views. Abbreviations: eva ‒ evaporatorium; mf ‒ median furrow; op ‒ ostiolar peritreme; prm ‒ paramere; pyg ‒ pygophore.

Fig. 6. Male (A–C, E–G) and female (D, H) genitalia.A–D – Acompocoris brevirostris Kerzhner, 1979; E–H – Tetraphleps aterrima (J. Sahlberg, 1878). A, E – pygophore with paramere (ejaculatory bulb omitted), dorsal view; B–C, F–G – paramere, two different views; D, H – copulatory tube and sperm pouch, dorsal view. Abbreviations: ct ‒ copulatory tube; ism ‒ intersegmental membrane; prm ‒ paramere; pyg ‒ pygophore; sp ‒ sperm pouch. Scale bars: 0.1 mm.

Fig. 16. Habitus images of living individuals of Japanese Anthocorini spp. A – Acompocoris brevirostris Kerzhner, 1979, male; B – same, female; C – Tetraphleps aterrima (J. Sahlberg, 1878); D – Anthocoris confusus Reuter, 1884; E – A. takahashii Hiura, 1959; F – A. venustus sp. nov. (courtesy of M. Takai).

Fig. 19. Distribution of Acompocoris brevirostris Kerzhner, 1979 (circles) and Tetraphleps aterrima (J. Sahlberg, 1878) (triangles) in Japan. Filled symbols represent records based on specimens examined by us, open symbols represent literature records.