Dasycerus japonicus Nakane, 1963

Hashizume, Takuto & Maruyama, Munetoshi, 2022, Taxonomy and phylogeny of the Japanese species of the genus Dasycerus Brongniart (Coleoptera: Staphylinidae: Dasycerinae) with description of a new species and notes on D. poseidon Hu & Liang, Zootaxa 5174 (3), pp. 233-246 : 237-240

Dasycerus japonicus Nakane, 1963

( Figs 2–3 )

[Japanese name: Itohige-nisemakimushi]

Dasycerus japonicus Nakane, 1963 (original description; type locality: Sasayama, Hyogo): 22; Löbl, 1977: 103 (key); Löbl & Calame, 1996: 278 (in part); Hu & Liang, 2021: 251 (key).

Specimen examined. Type specimen. Holotype: male, “Sasayama / Hyogo Pref. / 28. IV. 1952 / T. Nakane // HOLOTYPE // Dasycerus / japonicus Nak. / Det. T. Nakane // NAKANE Coll. / SEHU JAPAN / 1999 // 0000005404 / Sys. Ent / Hokkaido Univ. / Japan [ SEHU]”

Additional specimens. Hokkaido: 1 ex., alt. 175 m, Atsuta, Yakumo-chô , 24 VIII 2017 , H. Kamezawa leg. (KUM); 1 ex., Toyama, Minami-ku, Sapporo-shi , 18 VII 2021, Y. Tasaku leg. ( KUM); Honshu: Fukushima-ken: 1 ex., Near Toriki-bashi, Suketsune-rindô , Minamisôma-shi , 23 V 1999 , K. Haga leg. (KUM); 1 ex., Ôtakine-yama– Sendaihira, Tamura-shi , 13 VI 2004 , K. Haga leg. (KUM); Saitama-ken: 1 ex., Yamatomizu, Fûppu, Kamafuseyama , Yorii-machi , 6 VI 2009 , K. & S. Arai leg. (KUM) (recorded in Arai (2009)); 3 exs., same data, but 20 VI 2009 (KUM) (recorded in Arai (2009)); Tôkyô-to: 2 exs., alt. 340 m, Mahikizawa-tôge, Ôguno, Hinode-machi , 27 V 2017 , H. Kamezawa leg. (KUM); Kanagawa-ken: 1 ex., Uenomaru, Tanzawa-sanchi , 6 VII 1980, M. Nishikawa leg. ( KUM); Niigata-ken: 6 exs., Bijinbayashi, Matsunoyama, Tôkamachi-shi , 21 VII 2014, J. Itô leg. ( KUM); 1 ex., alt. 300 m, Aoneba-keikoku, Sado-ga-shima, Sado-shi , 22 IX 2020, Y. Senda leg. ( HIWA); Yamanashi-ken: 1 ex., alt. 1380 m, Sakubadaira, Ichinose-gawa, Hontani , Kôshû-shi , 13–19 X 1999, R . B. Kuranishi leg. ( CBM-ZI: 180201); Nagano-ken: 1 ex., Nagawa-Kawaura, Matsumoto-shi , 15 VIII 2020, T. Hashizume leg. ( KUM); 5 exs., same data, but 30 VI 2021 (KUM); 2 exs., Agematsu, Agematsu-machi , 18 VII 2016, F. Nakano leg. ( KUM); 1 ex., Shirabisokôgen, Iida-shi , 25 VIII 2019 , N. Kanie leg. (KUM); Gifu-ken: 2 exs., alt. 850 m, North side of Daihachigagawa, Ôjima-machi , Takayama-shi , 1 VIII 2003 , H. Kamezawa leg. (KUM); 1 ex., alt. 1530 m, Sengendaru-zawa, Hiwada, Takane-machi , Takayama-shi , 24 VII 2016, F. Nakano leg. ( KUM); 1 ex., Sengendaru-zawa, Hiwada, Takane-machi , Takayama-shi , 15 VII 2018, F. Nakano leg. ( KUM); 1 ex., Hagiwara, Inatsu-chô, Mizunami-shi , 16 VII 2016, F. Nakano leg. ( KUM); 4 exs., same data, but 20 VII 2016 ( KUM); 8 exs., same data, but 24 VII 2016, ( KUM); 22 exs., same data, but 29 VII 2016 ( KUM); 7 exs., Washimi, Takasu-chô, Gujô-shi , 29 IX 2019, F. Nakano leg. ( KUM); 1 ex., Hirono, Shirakawa-chô , 10 X 2016, Y. Takai leg. ( KUM); Aichi-ken: 1 ex., alt. 590 m, Rokushosan, Asahi-yama, Sakaue-chô , Toyota-shi , 5 V 2018, R. Wakimura leg. ( KUM); 1 ex., alt. 610 m, Rokusho-san, Sakaue-chô, Toyota-shi , 27 V 2017 , F. Nakano leg. (KUM); 3 exs., Iyama, Inabuchô, Toyota-shi , 26 VIII 2020, T. Ôno leg. ( KUM); 2 exs., Tamine, Shitara-chô , 16–17 VIII 2019, T. Ôno leg. ( KUM); 4 exs., Ishiharachô, Okazakishi , 27 X 2019, T . Ôno leg. ( KUM); Mie-ken: 1 ex., Tonaio-rindô, Fujiwara-chô, Inabe-shi , 24 V 2009 , N. Tsuji leg. (KUM); 18 exs., Sakura-tôge, Marubashira, Iga-shi , 10 VI 2017 , N. Narukawa leg. (KUM); Kyôto-fu: 1 ex., Tennô-zan, Ôyamazaki-chô , 21 X 2011, I. Tanaka leg. ( KUM); Ôsaka-fu: 1 ex., Mi-yama, Tennô, Nose-chô , 14 IX 2008, I. Tanaka leg. ( KUM); 2 exs., Mi-yama, Tennô, Nose-chô , 30 XI 2008, I. Tanaka leg. ( KUM); Satsuki-yama, Higashiyama-chô, Ikeda-shi , 16 IX 2019, T . Saito leg. ( KUM); Hyôgo-ken: 4 exs., Ôya-san, Inagawa-chô , 30 VIII 2018 , S. Sugimoto leg. (pcSS); 1 ex., Iwane-yama, Sashikumi, Inagawa-chô , 31 X 2018, T . Saito leg. ( KUM); 2 exs., Iwane-san, Sashikumi, Inagawa-chô , 21 XI 2018, T . Saito leg. ( KUM); 1 ex., Iwane-yama, Akamatsu, Kawanishishi , 22 XI 2018, T . Saito leg. ( KUM); 2 exs., Iwane-yama, Kawanishi-shi , 21 XI 2018, T . Ito leg. (pcTI); 2 exs., 890 m, Ôsasa, Muraoka-ku, Kami-chô , 22 VIII 2017, R. Wakimura leg. ( KUM); Nara-ken: 1 ex., Ôdaigahara-yama, Kamikitayama-mura , 15 VII 2018, N. Kanie leg. ( KUM); 16 exs., Yumitehara, Nosegawa-mura , 19 IX 2021, F. Nakano leg. ( KUM); Okayama-ken: 4 exs., Sangajô, Kamisaibara, Kagamino-chô , 27 VII 2014, O. Yamaji leg. ( KUM); Hiroshima-ken: 2 exs., Chichikino, Jinsekikôgen-chô , 1 XI 2019, Y. Akiyama leg. ( HIWA) (recorded in Akiyama (2020)); Shikoku: Tokushima-ken: 1 ex., Tsurugi-san , 3 V 1969 , Y. Nameta leg. (KUM); 11 exs., alt. 1800 m, Tsurugi-san, Tsurugi-chô , 22 VII 2007, M. Sakai leg. ( EUM); Kagawa-ken: 1 ex., alt. 600 m, Kosen-zan, Miki-chô , 25 IX 2021, H. Fujimoto leg. ( KUM); 1 ex., alt. 960 m, Daisen-zan, Mannô-chô , 19 IX 2021, H. Fujimoto leg. ( KUM); 1 ex., same data, but 3 X 2021 ( KUM); Ehime-ken: 4 exs., Yoshinogawa, Oda-chô , 10 IX 1993, M. Kawanabe leg. ( EUM); 2 exs., Odamiyama, Uchiko-chô , 31 VII 2009, E. Yamamoto leg. ( EUM); 5 exs., same data, but 4 VIII 2009 (EUM); 9 exs., same data, but 17 VIII 2009 (EUM); Kyushu: Fukuoka-ken: 1 ex., Shaka-dake, Yabemura, Yame-shi , 22 VI 2018 , S. Imasaka leg. (KUM); 1 ex., Hôman-zan–Sangun-san , 27 VI 2014 , N. Tsuji leg. (KUM); 6 exs., Hiko-san , 6 VI 2021 , S. Inoue leg. (KUM); Saga-ken: 1 ex., Haramaki, Sefuri-machi, Kanzaki-shi , 19 VII 2019, T . Hashizume leg. ( KUM); Kumamoto-ken: 5 exs., Momigi, Izumi-machi, Yatsushiro-shi , 15 V 2021, T. Hashizume leg. ( KUM); 11 exs., alt. 1230 m, Shiratori-yama, Momigi, Izumi-machi , Yatsushiro-shi , 29 V 2021 , S. Kakizoe & S. Inoue leg. (KUM); Ôita-ken: 1 ex., Senomoto, Kokonoe-machi , 7 V 2015, T. Miyake leg. ( KUM); 3 exs., Kawakami-keikoku, Obira, Ogata-machi , Bungoôno-shi , 27 V 2015, T. Miyake leg. ( KUM); 2 exs., Shônaichô-Asono, Yufu-shi , 7 VII 2019, T . Hashizume leg. ( KUM); 4 exs., same data, but 20 VI 2021 (KUM); 1 ex., Oike (foot of Kuro-dake), Shônai , Yufu-shi , 11 IX 2021, N. Tsuji leg. ( KUM); Miyazaki-ken: 1 ex., Ômoridake-rindô, Aya-chô , 2 V 2019, Y. Sasaoka leg. (KUM).

Diagnosis. This species is closely related to D. poseidon Hu & Liang, 2021 from Taiwan. However, this species can be easily distinguished from D. poseidon by its larger body, curved median lobe of aedeagus and more dilated apical portion of paramere. In contrast to D. occultus sp. nov., D. japonicus has a pair of indistinct dark brown spots on their elytra, and the female genital chamber of D. japonicus ( Figs 2J–L ) is not sclerotized and does not have fine spines on its surface. The punctures of the elytron are relatively small and roughly ovoid ( Fig. 2F ). The median groove of the pronotum of this species is longer than that of D. poseidon and shorter than that of D. occultus sp. nov. ( D. japonicus : 0.42–0.43 times as long as pronotum; D. occultus sp. nov.: 0.52–0.54 times as long as pronotum; D. poseidon : 0.36–0.40 times as long as pronotum) ( Fig. 2B ).

Redescription. Measurements (n=9): BL: 1.87 (1.52–2.08); HL: 0.33 (0.30–0.37); HW: 0.48 (0.43–0.51); EL: 0.14 (0.12–0.16); PL: 0.41 (0.38–0.46); PW: 0.60 (0.51–0.65).

Coloration. Body, legs, and antennae yellowish brown, with a pair of indistinct dark brown spots on elytra.

Head. Apex of frontoclypeus arcuate; vertexal grooves indistinct; pair of rows of tubercles present on mesal vertex extending to frontoclypeus, each row with 8–9 tubercles each with one microseta on apex; group of tubercles present on external margin of frontoclypeus beside the mesal vertex row of tubercles on each side. Antenna 11- segmented, inserted above anterior part of eye; long and slender, sparsely setose on antennomeres III–VII, densely setose on antennomeres I–II and VIII–XI; antennomere I and II globular, enlarged, with dorsal setiferous tubercles; antennomere II slightly smaller than I; antennomeres III–VII extremely slender, filiform, slightly dilated at the apex; antennomeres VIII–XI globular; antennomere XI wider than all other antennomeres. Eyes large; eye pedestal present.

Thorax. Pronotum hexagonal ( Fig. 2B ), with rows of tubercles on the lateral margin and disc, each tubercle with one microseta on apex. Apicolateral angle distinct, not prominent. Disc with a pair of swellings in front of antebasal transverse groove. Median groove distinct, 0.42–0.43 times as long as length of pronotum, extending from antebasal transverse groove. Oblique tubercle row absent. Lateral tubercle row parallel to margin. Middle of antebasal transverse groove strongly arcuate; basal area with five groups of irregular foveae separated by tubercles. Hypomeron with anterior transverse groove. Protergosternal keel entire ( Fig. 2D ). Keel of procoxal process weekly arcuate; some prosternal foveae on prosternum of each side. Elytra rounded laterally and posterolaterally, widest near middle, covering whole abdomen; rows of microsetae along sutural margin and costae; elytra humeral area rounded and raised. Elytral disc with three costae on each elytron, two internal discal costae extending from base to apex of elytron; one external discal costa shorter than internal discal costae, extending from base to 4/5 point of elytron; posterior-lateral margin of elytron with few tubercles which are similar to those on costae. Each elytron with ten rows of roughly ovoid punctures ( Fig. 2E ): two rows between sutural margin and first internal discal costa; two rows between first and second internal discal costae; two rows between second and external discal costae; three rows between external discal costa and the edge of elytron (punctures strongly reduced on humeral area, the three rows gradually fused to one toward apex), and one row between marginal costa and margin of elytron. Each discal row with 21–35 punctures; rows 1–4 each with about 30 punctures, rows 5–10 with fewer. Hind wings well developed. Scutellum glossy, oblique. Mesoventral median keel extending from anterior margin of prepectus to apex of internal process. Prepectus somewhat longer than distance from its posterior margin to procoxae. Posterior margin of mesovaxal cavity with a distinct projection on each side.

Abdomen gradually narrowed apically, not visible in dorsal view. Abdominal tergites V–VIII sclerotized, IV– VI with median furrows. Sternite III with three pairs of coxal foveae and five pairs of microsetae on basal margin; intercoxal process depressed at anterior end.

Male. Aedeagus ( Figs 2G–I ) asymmetrical. Median lobe with basal bulb relatively small. Paramere arcuate, widened apically; base of paramere triangular; four setae on apex of each paramere.

Female. Female genital chamber ( Figs 2J–L ) membranous and long, without spines on surface. Distal gonocoxite has about 10 preapical setae. Gonostylus has one seta as long as gonostylus at the apex and shorter preapical setae.

Bionomics. Many individuals were obtained from the surface of dead trees.

Distribution. Japan (Hokkaido, Honshu (incl. Sado-ga-shima), Shikoku, Kyushu).

Remarks. This species is collected at higher latitudes and elevations than those of D. occultus sp. nov. The number of punctures of each row of the elytron varies depending on the size of the individual. In large females, the apex of the elytron is slightly elongated.

Figures

FIGURE 2. Dasycerus japonicus. (A) Habitus in dorsal view. (B) SEM image of pronotum in dorsal view. (C–D) Prothorax in ventral view (black triangles indicate the protergosternal keel). (E–F) Right elytron in dorsolateral view. (G) Aedeagus of D. japonicus from Nagano-ken in lateral view. (H) Ditto in ventral view (paramere omitted on one side). (I) Aedeagus of D. japonicus from Saga-ken in lateral view. (J) Unraveled female genital chamber of D. japonicus from Gifu-ken in ventral view. (K) Unraveled female genital chamber of D. japonicus from Kumamoto-ken in ventral view. (L) Not unraveled female genital chamber of D. japonicus from Fukuoka-ken in dorsal view. Scale bars: 1.0 mm for A; 0.5 mm for C & E; 0.2 mm for G–L.

FIGURE 3. Holotype and labels of Dasycerus japonicus (photographed by Y. Tasaku).