Bryothinusa constricta Liu & Ono & Maruyama 2021, sp. nov.
Creators: name: Liu, Tian-tian
name: Ono, Hiroki
name: Maruyama, Munetoshi
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Bryothinusa
Bryothinusa constricta

description: Bryothinusa constricta sp. nov.   
(Figs 1H; 2H; 10; 22)  
(Japanese name: Kubire-nagisa-hanekakushi)  
 Type material. Hඈඅඈඍඒඉൾ: J, JAPAN: HඈඇඌΗǕ: Futtsu-misaki, Futtsu-shi, Chiba-ken, 1.v.2014, H. Ono (KUM). Pൺ*©ൺඍඒඉൾඌ: HඈඇඌΗǕ: 3 ♀♀, 6 unsexed spec., same locality as holotype, 28.v.2010, H. Ono (KUM); 2 JJ 5 ♀♀, 10 unsexed spec., same data as holotype (KUM, NMPC, BMNH); 1 ♀, 4 unsexed spec., Izumo, Koryô-chô, Shimane-ken, 3.ix.2007, T. Hayama (KUM).   
 Description. Body (Fig. 1H) small, about 1.7–2.0 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 as long as elytra; eyes (Fig. 2H) large, setae present between about 20–22 facets, slightly longer than tempora length; antenna yellowish brown, equal to total length of head and pronotum; segment I 1.6 times longer than II, almost 3.5 times longer than III, and longer than XI; antennal segments III–X almost wider than long, and VI–VII wider than width of III–IV.  
Mouthparts (Figs 10A–E) with distribution of labral setae as in Figure 10A, with large and thick spiniform seta at antero-laterally; mandibles (Fig. 10B) elongate triangle, asymmetrical, right mandible with median tooth; median tooth shorter than 1/4 of mandibles; left mandible without tooth, blunt at apex; maxilla with apical margin of lacinia (Fig. 10C) at right angle; at tip with two spines very small and not closely interdigitating; 3 setae on inner margin of lacinia; labial palpus (Fig. 10D) with most setae located basally; mentum (Fig. 10E) with antero-lateral angles prolonged into spinose processes; anterior margin deeply truncate; small “v seta” far away from apical setae.  
Pronotum longer than elytra, wider than head.  
Elytra widened apically, wider than long, almost as wide as pronotum; hind wings present but very small, apparently flightless.  
Male abdominal sternite VIII (Fig. 10F) with posterior margin slightly serrate. Median lobe of aedeagus as in Figures 10H, I; paramere (Fig. 10J) elongate.  
Female abdominal sternite VIII (Fig. 10G) slightly serrate alike male on posterior margin. Spermatheca (Fig. 10K) simplified in shape, about 1.5 times coiled near base.  
 Measurements. BL 1.70–2.00, FBL 0.80–1.00, HL 0.30– 0.31, HW 0.35–0.39, PL 0.30–0.33, PW 0.38–0.40, EL 0.29–0.30, EW 0.36–0.40, HTL 0.30–0.31, AL 0.61–0.67, AS-I 0.11–0.14, AS-II 0.06–0.09, AS-III 0.03–0.04.   
 Differential diagnosis. In general appearance, the species is similar to B. sakishimana, but easily distinguished from it by the elytral shape being narrowed anteriorly and the shape of the spermatheca.   
 Etymology. Bringing attention to the constricted body shape; adjective.   
 Distribution. Japan (Honshû: Chiba-ken, Shimane-ken).   
 Remarks. This species is found mainly on the Japan Sea coast of western Japan and east of Tôkyô Bay, but it is probably occurring in other areas of mainland Japan. A distribution map of examined specimens of this species in Japan is illustrated in Figure 22.
description: Published as part of Liu, Tian-tian, Ono, Hiroki & Maruyama, Munetoshi, 2021, Revision of the intertidal rove beetle genus Bryothinusa from Japan (Coleoptera: Staphylinidae: Aleocharinae), pp. 163-201 in Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) (Acta. Ent. Mus. Natl. Pragae) 61 (1) on page 179, DOI: 10.37520/aemnp.2021.009, http://zenodo.org/record/5037330