Bryothinusa hokkaidensis, Liu & Ono & Maruyama, 2021

Liu, Tian-tian, Ono, Hiroki & Maruyama, Munetoshi, 2021, Revision of the intertidal rove beetle genus Bryothinusa from Japan (Coleoptera: Staphylinidae: Aleocharinae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 61 (1), pp. 163-201 : 179-182

publication ID	https://doi.org/ 10.37520/aemnp.2021.009
publication LSID	lsid:zoobank.org:pub:27EA8466-6B29-40F4-8236-DD49061C523B
persistent identifier	https://treatment.plazi.org/id/03CB023B-AC1A-FF91-4CE7-F8FE15C8F8F8
treatment provided by	Carolina
scientific name	Bryothinusa hokkaidensis
status	sp. nov.

Treatment

Bryothinusa hokkaidensis View in CoL sp. nov.

( Figs 1I View Fig ; 2I View Fig ; 11 View Fig ; 21C View Fig ; 22 View Fig )

(Japanese name: Hokkai-nagisa-hanekakushi)

Type material. Hඈඅඈඍඒඉൾ: J, JAPAN: Hඈκκൺංൽත: Shunkunitai, 43.2725 N, 145.472 E, Nemuro-shi, Hokkaidô, 11.ix.1999, M. Maruyama ( KUM). Pൺ*©ൺඍඒඉൾඌ: Hඈκκൺංൽත: 3 JJ 4 ♀♀, 96 unsexed spec., same data as holotype ( KUM, NMPC, BMNH); 1 ♀, 4 unsexed spec., Usu-chô, Date-shi, Hokkaidô, 12.iv.2020,Y.Tasaku ( KUM). KඒǕඌΗǕ: 1♀, Nokono-shima, Fukuoka-shi, Fukuoka-ken, 21.iv.2018, T.Hashizume ( KUM).

Description. Body ( Fig. 1I View Fig ) small, about 1.8–2.2 mm in length, covered with minute setae. Abdomen almost dark brown and darker than head and pronotum; elytra lighter than pronotum; legs yellowish brown; antenna brown, similar coloured with mouthparts and legs, lightly paler than body colour.

Head evenly oval, wider than long, shorter than pronotum and elytra; eyes ( Fig. 2I View Fig ) large, setae present between about 22–25 facets, slightly longer than tempora length; antenna brown, equals to total length of head and pronotum; segment I as long as II, almost 2.3 times longer than III, and as long as XI; antennal segments III–IV subquadrate, V–X almost same length and wider than long.

Mouthparts ( Figs 11A–E View Fig ) with distribution of labral setae as in Figure 11A View Fig , with large and thick spiniform seta at antero-laterally; mandibles ( Fig. 11B View Fig ) elongate triangle, asymmetrical, right mandible with some median tooth and irregular; median tooth longer than 1/4 of mandibles; left mandible without tooth, blunt at apex; maxilla with apical margin of lacinia ( Fig. 11C View Fig ) at obtuse angle; at tip with two spines very small and not closely interdigitating; 2–3 setae on inner margin of lacinia; labial palpus ( Fig. 11D View Fig ) with most setae located basally, small ligula; mentum ( Fig. 11E View Fig ) with antero-lateral angles prolonged into spinose processes; anterior margin deeply truncate; small “v seta” far away from apical setae.

Pronotum shorter than elytra, wider than head.

Elytra subquadrate but wider than long, slightly narrower than pronotum; hind wings present but very small, apparently flightless.

Male abdominal sternite VIII ( Fig. 11F View Fig ) with posterior margin slightly serrate. Median lobe of aedeagus as in Figures 11H, I View Fig ; paramere ( Fig. 11J View Fig ) elongate.

Female abdominal sternite VIII ( Fig. 11G View Fig ) slightly serrate similar male on posterior margin. Spermatheca ( Fig. 11K View Fig ) simplified in shape, about 1 time coiled near base.

Measurements. BL 1.80–2.20, FBL 0.90–1.00, HL 0.25– 0.30, HW 0.38–0.40, PL 0.33–0.35, PW 0.40–0.43, EL 0.35–0.38, EW 0.35–0.40, HTL 0.25–0.35, AL 0.60–0.68, AS-I 0.10–0.11, AS-II 0.09–0.10, AS-III 0.04–0.05.

Differential diagnosis. In general appearance, the species is similar to B. fulvipennis sp. nov. and B. itsuroi sp. nov. but distinguished from them by the combination of the following character states: the body colour (especially head and pronotum colour) and the spermathecal shape.

Etymology. Toponym. Named after Hokkaidô, the type locality of this new species; adjective.

Distribution. Japan (Hokkaidô; Kyûshû: Fukuoka-ken).

Remarks. A distribution map of examined specimens of this species in Japan is illustrated in Figure 22 View Fig .