The supertribe Bythinoplectitae was separated from supertribe Faronitae (Newton and Thayer, 1995). Subsequently, it was transferred into the supertribe Euplectitae as the tribe Bythinoplectini (Chandler, 2001b). This tribe is one of the largest group of pselaphine beetles, and members eat collembolans or smaller arthropods in leaf litter (Chandler, 2001a). Four Euplectitae species, Euplectus gibbipalpisLöbl, 1975, Leptoplectus vagansLöbl, 1975, Philoscotus coreanusNomura and Lee, 1993 and Philoscotus rostralisNomura, 1988, are currently recorded in Korean peninsula, and this is fifth species of Korean Euplectitae species. In this paper, the pselaphine beetle, tribe Bythinoplectini is recorded from Korea for the first time, represented by a single species, Parapyxidicerus carinatus, previously only known from Japan (Sawada, 1964). Diagnosis of the tribe, genus and species are provided.

Materials and Methods

Three specimens were collected in northern part of South Korea (Gyeonggi and Gangwon Provinces) by sifting leaf litter near stream. The images of habitus and diagnostic characters were taken by DM1000 LED optical microscope (Leica) using Las V4.12 (Leica) and Zerene Stacker (Zerene Systems) software to take multi-focus images. The specimens are deposited in National Institute of Biological Resources (NIBR) and Chungbuk National University Insect Collection (CBNUIC).

Systematic Accounts

Family Staphylinidae Latreille, 1802 반날개과

Subfamily Pselaphinae Latreille, 1802 개미사돈아과

Supertribe Euplectitae Streubel, 1839 곤봉개미사돈상족

Tribe Bythinoplectini Schaufuss, 1890 혹곤봉개미사돈족 (신칭)

Diagnosis. The tribe Bythinoplectini can be separated by the following combination of characters: labrum smaller than 1/2 of head wide, ventral head with deep subantennal excavation (Fig. 1C, arrow), tarsi 3-3-3 with minute tarsomeres 1and 3 (Fig. 1D, arrow).

Subtribe Pyxidicerina Raffray, 1904 멧개미사돈아족(신칭)

Diagnosis. The tribe Bythinoplectini includes two subtribes, Bythinoplectina and Pyxidicerina. They are easily separated by lateral head margins. Bythinoplectina has fully opened lateral head margins (Fig. 2C, arrow), but Pyxidicerina has semiopened lateral head margins (Fig. 2D, arrow).

Genus ParapyxidicerusSawada, 1964 멧개미사돈속(신칭)

Type species: Parapyxidicerus carinatusSawada, 1964

Diagnosis. The genus Parapyxidicerus can be distinguished from other Bythinoplectini genera by coarsely punctate head, pronotum and antennomere 10 (Fig. 3A, D) and clearly visible eleven antennomeres (Fig. 3B).

Parapyxidicerus carinatusSawada, 1964 멧개미사돈(신칭) (Fig. 3)

Parapyxidicerus carinatusSawada, 1964: 11 (original description); Coulon, 1989: 69 (revision, aedeagus illustration); Löbl and Smetana, 2013: 378 (catalog).

Diagnosis of Male. Body length 1.5-2.0 mm, reddish brown with yellow setae. Head slightly narrowed than pronotum with well-developed eyes (Fig. 3A, D). Interantennal bridge of head narrower than 1/3 of head wide (Fig. 3A, D). Antennae with eleven antennomeres, 10 and 11 clubed (Fig. 3B). Mandible curved and acute apically (Fig. 3E). Maxillary palpomere 3 and 4 swollen (Fig. 3C). Pronotum as long as wide, widest at 1/3 level of pronotum (Fig. 3A). Elytra longer than pronotum with two basal foveae (Fig. 3A). First three visible abdominal tergites with clear lateral margins and well-developed paratergites (Fig. 3A). Aedeagus strongly chitinized and asymmetrical (Fig. 3F).

Female unknown.

Materials examined: 3♂, Korea: Gyeonggi Prov., Jingwangdong, Eunpyeong-gu, Seoul, 08 Ⅶ 2019, 37°38'37"N 126°57'04"E, 180 m, leaf litter & deadwood debris near stream, Yeon-Jae Choi, Ji-Won Kang (NIBR); 3♂, Korea: Gyeonggi Prov., Ui-dong, Gangbuk-gu, Seoul, 23 Ⅷ 2019, 37°39'33.5"N 126° 59'22.8"E, 348 m, leaf litter & soil & deadwood debris, Yeon- Jae Choi, Tae-Yeong Jang (CBNUIC); 1♂, Korea: Gangwon Prov., Yangyang-ri, Seo-myeon, 38°4'40.0"N 128° 29'51.0"E, 210 m, 6 Ⅴ 2019, J.-S. Park, leaf litter near dried stream (CBNUIC).

Distribution. Korea (new record), Japan.

Remarks. All specimens of this species were collected by leaf, soil or deadwood debris litter near stream.