Bryaxis fabaiformis Choi, Park, Lee & Park, 2023

Choi, Yeon-Jae, Park, Sun-Jae, Lee, Seung-Gyu & Park, Jong-Seok, 2023, Five new species of Bryaxis Kugelann (Coleoptera, Staphylinidae, Pselaphinae) from Korea and a nomenclatural note on Bryaxis mahunkai Loebl, ZooKeys 1182, pp. 165-181 : 165

Bryaxis fabaiformis Choi, Park, Lee & Park sp. nov.

Figs 5 , 6A, C, E

Type materials

(N = 4, 3 ♂♂, 1 ♀). Holotype male. "Korea: Gangwon Prov. Gujeol-ri, Yeoryang-myeon, Jeongseon-gun, 24 Apr 2020, 37°31'08.3"N, 128°46'43.0"E, 552 m, sifting soil & leaf litter, U.-J. Byeon, T.-Y. Jang" (NIBR). Paratypes. (CBNUIC, 1♂ slide mounted, 1♂, 1♀ dried). "Korea: Gangwon Prov. Gujeol-ri, Yeoryang-myeon, Jeongseon-gun, 24 Apr 2020, 37°31'08.3"N, 128°46'43.0"E, 552 m, sifting soil & leaf litter, U.-J. Byeon, T.-Y. Jang".

Diagnosis.

Enlarged fabiform antennal pedicels with subcylindrical glandular nodule on inner margin in male (Figs 5E, F , 6A , arrows).

Description.

Body reddish brown, antennae, maxillary palpi, legs slightly lighter than body, length 1.29-1.41 mm, maximum width 0.60-0.64 mm (Fig. 5A-D ). Setae on body golden and long. Head 0.84-1.00 times as long as wide (Fig. 5F ). Frons with U-shaped impression between antennal tubercles; frontal foveae absent; frontal rostrum distinct anteriorly. Vertex weakly convex; longitudinal carina distinct; vertexal foveae enlarged. Eyes large with 31-32 facets. Maxillary palpi moderately developed; palpomeres II-III with sparse tubercles; palpomere IV 0.25-0.29 mm long and about 2.92-3.44 times as long as wide, subcylindrical pseudosegment at apex. Antennae about 0.58-0.61 mm long; scapes short, without modification, 0.73-1.11 times as long as pedicels; pedicels 1.02-1.19 times as long as wide; antennomere III 1.18-1.23 times as long as wide; IV-VIII subequal in length; IX-X transverse, IX 0.66-0.69 times as long as wide and X 0.62-0.63 times as long as wide; XI largest, pointed at apex, 1.65-1.75 times as long as wide (Fig. 5F ). Pronotum 0.84-0.89 times as long as wide and widest at basal 3/5, lateral antebasal foveae connected by antebasal sulcus. Elytra convex, 0.85-0.94 times as long as wide and widest at basal 1/3, each elytron with two basal foveae and subhumeral fovea. Legs slender; protibiae without spine (Fig. 5G ); metatibiae with spine at apex (Fig. 5H , arrow). Aedeagus robust, 0.43 mm long and 1.79 times as long as wide; penis bulbous and dorsal diaphragm circular; parameres small and symmetrical, each with three setae; endophallus comprising two symmetrical struts, each broadened basally and apically, and shortly branched basally (Fig. 5I ).

Sexual dimorphism. Female eyes slightly shorter than tempora, comprising 9 facets; antennal pedicels without modification; metatibial spines absent.

Remarks.

Adults of this species are similar to those of Bryaxis kimjongkuki Nomura & Lee, 1993 in having the maxillary palpomere II-III with tubercles and asymmetrical antennal scapes. However, they can be recognized by having a rounded tempora as long as the eyes (Fig. 6E ), a glandular nodule situated at the mid-level of the antennal pedicels (Fig. 6A , arrow), and protibiae without a spine (Fig. 6C ).

Comments.

The localities of B. fabaiformis sp. nov. probably overlap with those of B. kimjongkuki Nomura & Lee given that the latter species was abundantly collected near the type localities of the former (Fig. 11 ).

Etymology.

The specific epithet is a combination of the Latin words faba ( “bean”, feminine) and - formis ("having the form of", masculine/feminine) and refers to the shape of antennal pedicels in the male.

Habitat.

Specimens of this species were collected by sifting soil and leaf litter in mixed forest.

Distribution.

Korea (Jeongseon-gun, Gangwon-do).

Figures

Figure 5. Bryaxis fabaiformis Choi, Park, Lee & Park, sp. nov. male (A, B, E-I), female (C, D). A, C dorsal habitus B, D ventral habitus E head F antenna G fore leg H hind leg I aedeagus. Scale bars: 1 mm (A-D); 0.1 mm (E, I); 0.5 mm (F-H).

Figure 6. Diagnostic characters of Bryaxis fabaiformis sp. nov. (A, C, E) and B. kimjongkuki Nomura & Lee (B, D, F). A, B antennal scapes and pedicels C, D protibiae E, F heads. Scale bars: 0.1 mm.

Figure 11. Collection localities. Bryaxis grandinodus sp. nov. (blue pentagon); B. uljinensis sp. nov. (purple cross); B. fabaiformis sp. nov. (sky-blue star); B. girinensis sp. nov. (green diamond); B. nemorosus sp. nov. (navy hexagon); B. mahunkai Loebl (yellow square); B. koltzei (Reitter) (red circle); B. kimjongkuki Nomura & Lee (orange triangle).