Bryothinusa koreana Ahn & Jeon, 2004

Liu, Tiantian, Ono, Ki. & Maruyama, Munetoshi, 2020, A new species and new record of the intertidal rove beetle genus Bryothinusa Casey (Staphylinidae: Aleocharinae: Myllaenini) from Japan, Zootaxa 4743 (4), pp. 585-593 : 589

Bryothinusa koreana Ahn & Jeon, 2004

[Japanese name: Chosen-nagisa-hanekakushi]

(Figs. 2, 12–20)

Bryothinusa koreana Ahn & Jeon 2004: 31 (original description; type locality: Korea).

Specimens examined: [ Japan]: Kyûshû: 6♂, 5♀, 5 sex?, Mouth of Sakurai-gawa, Shima-Nogita, Itoshima-shi, Fukuoka-ken, 11 X 2018, Tiantian Liu; 4 sex?, same locality, 3 VI 2019, T. Liu & W. Liang ( Figs. 21 ).

Distribution: Korea, Japan (Kyûshû).

Redescription. Body (Figs. 2) small, densely pubescent throughout; head, pronotum and elytra yellowish brown, posteriorly abdomen (tergite V–VII) almost black. Antenna, mouthparts and legs similarly colored, a littler paler than head color and paler toward apex.

Head oval; eyes small, reniform, shorter than tempora, with 14–18 facets; antenna length longer than distance from anterior margin of head to posterior margin of pronotum; antennomeres all longer than wide; antennomere I as long as XI.

Mouthparts (Figs. 12–16): labral seta, shape as in Figure 12. Mandibles (Figs. 13) elongate, asymmetrical, right with median tooth, on left tooth absent, and blunt at apex. Maxillary with apical margin of lacinia (Figs. 14) two spines interdigitating close. Labial palpus (Figs. 15) with most setae distributed basally. Mentum (Figs. 16) with antero-lateral angles prolonged into spinose processes; anterior margin deeply truncate; small v setae of mentum placed at level of anterior margin.

Pronotum: anterior margin wider than posterior margin. Head, pronotum and elytra same length.

Elytral: hind wings absent.

Female abdominal sternite VIII with posterior margin wider and smoother than that of male.

Median lobe of aedeagus (Figs. 17) with 6–7 pairs granules in face of paramere at apical lobe; not clearly visible in lateral view (Figs. 18). Paramere (Figs. 19) elongate. Spermatheca as in Figure 20.

Measurements: BL 2.2-2.4 mm, FBL 1.1–1.2 mm, HL 0.40–0.45 mm, HW 0.46–0.49 mm, PL 0.34–0.41 mm, PW 0.49–0.55 mm, EL 0.38–0.46 mm, EW 0.51–0.54 mm, HTL 0.35–0.41 mm, AL 0.99–1.08 mm, AS-I 0.13–0.14 mm, AS-II 0.11–0.13 mm, AS-III 0.06 mm.

Diagnosis: The species is closely allied to B. tsutsuii , but easily distinguished from it by number of ommatidia, mentum width and different form of the aedeagus.

Remarks: This species is newly recorded from Japan, and the specimens were collected under stones with dead barnacles. Bryothinusa japonica and B. koreana were collected together at an estuary near the sea ( Figs. 21 ). This species will be found the other areas, especially Japan Sea coast of western Japan.

Figures

FIGURE 21 Collection locality Bryothinusa koreana Ahn & Jeon, 2004 and B. japonica sp. nov. in Itoshima-shi, Japan.