Revision of the intertidal rove beetle genus Bryothinusa from Japan (Coleoptera: Staphylinidae: Aleocharinae) Author Liu, Tian-tian Entomological Laboratory, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, 819 - 0395, Japan & The Kyushu University Museum, Hakozaki Author Ono, Hiroki Sounan, Minami-ku, Sagamihara-shi, Kanagawa, 252 - 0312, Japan Author Maruyama, Munetoshi The Kyushu University Museum, Hakozaki dendrolasius@gmail.com text Acta Entomologica Musei Nationalis Pragae 2021 Acta. Ent. Mus. Natl. Pragae 2021-05-07 61 1 163 201 http://dx.doi.org/10.37520/aemnp.2021.009 journal article 10.37520/aemnp.2021.009 1804-6487 5037330 27EA8466-6B29-40F4-8236-DD49061C523B Bryothinusa fulvipennis sp. nov. ( Figs 1J ; 2J ; 12 ; 21B ; 22 ) (Japanese name: Usucha-nagisa-hanekakushi) Type material. Hඈඅඈඍඒඉൾ: J, JAPAN : HඈඇඌΗǕ: Mouth of Obitsugawa, Kuzuma, Kisarazu-shi, Chiba-ken, 2.iii.2007 , H. Ono ( KUM ). Pൺ*©ൺඍඒඉൾඌ: HඈඇඌΗǕ: 1 ♀ , same data as holotype ( KUM ); 1 unsexed spec., same locality as holotype , 19.ii.2007 , H. Ono ( KUM ); 1 J 2 unsexed spec., Mouth of Obitsu-gawa, Kuroto, Kisarazu-shi, Chiba-ken, 19.ii.2007 , H. Ono ( KUM ); 1 unsexed spec., same locality, 12.iii.2009 , H. Ono ( KUM ); 1 ♀ , 3 unsexed spec., same locality, 16.iii.2009 , H. Ono ( KUM ); 1 J, same locality, 4.i.2010 , H. Ono ( KUM ); 1 unsexed spec., same locality, 12.i.2011 , H. Ono ( KUM ); 1 unsexed spec., same locality, 14.i.2011 , H. Ono ( KUM ); 1 unsexed spec., Kushidagawa, Matsuzaka-shi, Mie-ken, 28.iv.2002 , Y. Kawakami ( KUM ); 10 unsexed spec., Himeshima, Yodo-gawa, Nishiyodo-gawa-ku, Ôsaka-fu, 12.iv.2002 , Y. Kawakami ( KUM , MNPC , BMNH ); 3 unsexed spec., Hanakawa Yodo-gawa, Nishiyodo-gawa-ku, Ôsaka-fu, 25.iv.2002 , Y. Kawakami ( KUM ); 4 unsexed spec., same locality, 28.iii.2002 , Y. Kawakami ( KUM ); 1 unsexed spec., Kinburo, Kitagi-shima, Kasaoka-shi, Okayama-ken, 11.x.2008 , O. Yamaji ( KUM ); 3 unsexed spec., Kurahashi-jima (Umikoshi), Kurahashi-chô, Kure-shi, Hiroshima-ken, 1.ii.2009 , K. Nakano ( KUM ). SΗංκඈκඎ: 11 unsexed spec., Kaigan-ji, Nishishirakata, Tadotsu-chô, Kagawa-ken, 31.iii.2008 , H. Fujimoto ( KUM ); 1 unsexed spec., Ôyatomi-machi, Sakaide-shi, Kagawa-ken, 29.iii.2008 , H. Fujimoto ( KUM ); 1 unsexed spec., Kôtô-gawa, Gôtô -chô, Takamatsu-shi, Kagawa-ken, 12.iv.2008 , H. Fujimoto ( KUM ). Description. Body ( Fig. 1J ) small, about 1.6–2.0 mm in length, covered with minute setae. Abdomen almost black and darker than head and pronotum; elytra lighter than pronotum; antenna and legs yellowish brown. Head evenly rounded, more or less produced anteriorly, wider than long, shorter than pronotum and elytra; eyes ( Fig. 2J ) large, setae present between about 22–24 facets, slightly longer than tempora length; antenna yellowish brown, almost equals to total length of head and pronotum; segment I 1.7 times longer than II, almost 4 times longer than III, and longer than XI; antennal segments IV–X almost as long as wide. Mouthparts ( Figs 12A–E ) with distribution of labral setae as in Figure 12A , with large and thick spiniform seta antero-laterally; mandibles ( Fig. 12B ) elongate triangle, asymmetrical, right with median tooth; median tooth shorter than 1/4 of mandibles; left without tooth, blunt at apex; maxilla with apical margin of lacinia ( Fig. 12C ) second spine very small, not obvious; 3 setae on inner margin of lacinia; labial palpus ( Fig. 12D ) with most setae located basally; mentum ( Fig. 12E ) with antero-lateral angles prolonged into spinose processes; anterior margin deeply truncate; small “v seta” far away from apical setae. Pronotum almost as long as elytra, wider than head. Elytra subquadrate but wider than long, almost as wide as pronotum; hind wings present but very small, apparently flightless. Male abdominal sternite VIII ( Fig. 12F ) with posterior margin slightly serrate. Median lobe of aedeagus ( Fig. 12H ) and dorsal view as in Figure 12I ; paramere ( Fig. 12J ) elongate. Female abdominal sternite VIII ( Fig. 12G ) slightly serrate alike male on posterior margin. Spermatheca ( Fig. 12K ) about 2 times coiled near base. Measurements. BL 1.60–2.00, FBL 0.90–1.00, HL 0.28– 0.30, HW 0.36–0.43, PL 0.36–0.40, PW 0.40–0.45, EL 0.35–0.41, EW 0.36–0.45, HTL 0.23–0.33, AL 0.61–0.76, AS-I 0.13–0.14, AS-II 0.07–0.08, AS-III 0.03–0.04. Differential diagnosis. In general appearance the species is very similar to B. hokkaidensis sp. nov. and B. itsuroi sp. nov. , but easily distinguished from B. hokkaidensis sp. nov. by the paler body colour and the shape of the spermatheca, and from B. itsuroi sp. nov. by the number of facets and the shape of the spermatheca. Fig. 12. Bryothinusa fulvipennis sp. nov. A – labrum; B – mandible, dorsal view; C – lacinia, dorsal view; D – labium; E – mentum; F – male sternite VIII; G – female sternite VIII; H – median lobe, ventral view; I – median lobe, lateral view; J – paramere; K – spermatheca. Scale bars: 0.1 mm. Etymology. The species epithet refers to the yellowish -brown elytra; adjective. Distribution. Japan ( Honshû: Chiba-ken, Mie-ken, Ôsaka-fu, Okayama-ken, Hiroshima-ken; Shikoku: Kagawa-ken). Remarks. This species has been found mainly in coasts of bay and inland sea such as Tôkyô-wan, Ise-wan and Setonaikai. A distribution map of examined specimens of this species in Japan is illustrated in Figure 22 .