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 itsuroi sp. nov. ( Figs 1K ; 2K ; 13 ; 20H ; 22 ) (Japanese name: Niseusucha-nagisa-hanekakushi) Type material. Hඈඅඈඍඒඉൾ:J, JAPAN : HඈඇඌΗǕ: Kuruwa-kaigan,Akiya, Yokosuka-shi, Kanagawa-ken, 14.ix.2013 , H. Ono ( KUM ). Pൺ*©ൺඍඒඉൾඌ: HඈඇඌΗǕ: 1 ♀ , 18 unsexed spec., Uraga-wan, Nishi-uraga,Yokosuka-shi, Kanagawa-ken, 4.iii.2013 , H. Ono & I. Kawashima ( KUM , NMPC , BMNH ); 7 JJ 3 ♀♀ , 9 unsexed spec., same data as holotype ( KUM ). KඒǕඌΗǕ: 1 J 1 ♀ , 16 unsexed spec., Kakise, Takashima, Nagasaki-shi, Nagasaki-ken, 4.iii.2020 , Y. Hisasue ( KUM ). Nൺඇඌൾං-ඌΗඈඍත: 1 J 1 ♀ , 1 unsexed spec., Mage-shima (near Tanega-shima), Kagoshima-ken, 14.x.2000 , M. Maruyama (under stone on sandy beach, in a port) ( KUM ). Description. Body ( Fig. 1K ) small, about 1.7–1.9 mm in length, covered with minute setae. Abdomen almost black and darker than head and pronotum; elytra lighter than pronotum; legs yellowish brown. Head evenly rounded, more or less produced anteriorly, wider than long, shorter than pronotum and elytra; eyes ( Fig. 2K ) large, setae present between about 29–31 facets, longer than tempora; antenna yellowish brown, almost equals to total length of head and pronotum; segment I as long as II, almost 3 times longer than III, and longer than XI; antennal segments VII–X almost wider than long. Mouthparts ( Figs 13A–E ) with distribution of labral setae as in Figure 13A , with large and thick spiniform seta antero-laterally; mandibles ( Fig. 13B ) 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. 13C ) at right angle; at tip second spine very small, not obvious; 3 setae on inner margin of lacinia; labial palpus ( Fig. 13D ) with most setae located basally; mentum ( Fig. 13E ) with antero-lateral angles prolonged into spinose processes; anterior margin deeply truncate; small “v seta” far away from apical setae. Pronotum shorter than elytra, as wide as head. Elytra subquadrate, wider than pronotum; hind wings present but small, apparently flightless. Male abdominal sternite VIII ( Fig. 13F ) with posterior margin slightly serrate. Median lobe of aedeagus ( Fig. 13H ) and dorsal view as in Figure 13I ; paramere ( Fig. 13J ) elongate. Female abdominal sternite VIII ( Fig. 13G ) slightly serrate alike male on posterior margin. Spermatheca ( Fig. 13K ) of complicated shape, very small, shorter than 0.25 mm and several times coiled near base. Measurements. BL 1.70–1.90, FBL 0.80–1.00, HL 0.31– 0.33, HW 0.38–0.41, PL 0.33–0.38, PW 0.40–0.41, EL 0.42–0.43, EW 0.41–0.43, HTL 0.33–0.39, AL 0.61–0.66, AS-I 0.10–0.11, AS-II 0.09–0.10, AS-III 0.03–0.04. Differential diagnosis. In general appearance the species is very similar to B. fulvipennis sp. nov. and B. hokkaidensis sp. nov. , but can be easily distinguished from them by the number of facets, the shape of the spermatheca, and the antennal segment I as long as II. Etymology. The new species is named after Mr. Itsuro Kawashima, a scientific illustrator and researcher of fireflies, who helped collect the type series of this species in Kanagawa . Distribution. Japan ( Honshû: Kanagawa-ken; Kyûshû: Nagasaki-ken; Nansei-shotô: Kagoshima-ken: Tanega -shima). Remarks. Unfortunately, one of the habitats in Uraga-wan, Kanagawa Prefecture has likely disappeared due to recent seawall construction. This species has a wide distribution but is found very locally where it occurs. A distribution map of examined specimens of this species in Japan is illustrated in Figure 22 .