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

Figs 3 , 4A, C, E

Type materials

(N = 7, 4 ♂♂, 3 ♀♀). Holotype male. "Korea: Gyeongbuk Prov. Onjeong-myeon, Uljin-gun, 8 Jun 2019, 36°43'23.0"N, 129°20'16.0"E, 180 m, sifting leaf litter near stream, J.-S. Park" (NIBR). Paratypes. 2♂♂ (CBNUIC, 1♂ slide mounted, 1♂ dried). "Korea: Gangwon Prov. Gujeol-ri, Yeoryang-myeon, Jeongseon-gun, 24 Apr 2020, 37°31'08.7"N, 128°46'42.8"E, 591 m, sifting leaf & soil litter, U.-J. Byeon, T.-Y. Jang". 1♂, 3♀♀ (CBNUIC, dried). "Korea: Gangwon Prov. Gujeol-ri, Yeoryang-myeon, Jeongseon-gun, 24 Apr 2020, 37°30'57.6"N, 128°45'18.8"E, 510 m, sifting ant colony, leaf & soil litter, Y.-J. Choi, U.-J. Byeon".

Diagnosis.

Antennal pedicel strongly swollen, subglobose with subcylindrical glandular nodule on basal 1/3 of inner margin (Figs 3F , 4C , arrows); protibiae with spine on internal side of widest (Figs 3G , 4E , arrows); parameres of male genitalia robust and fan-shaped, bearing three setae on each (Fig. 3I ).

Description.

Body reddish brown, antennae, maxillary palpi, legs slightly lighter than body, length 1.25-1.31 mm, maximum width 0.53-0.60 mm (Fig. 3A-D ). Setae on body yellowish, and short. Head 0.98 times as long as wide (Fig. 3E ). Frons with small U-shaped impression between antennal tubercles; frontal foveae absent; frontal rostrum slightly distinct anteriorly. Vertex convex; longitudinal carina present; vertexal foveae small. Eyes large, longer than twice that of tempora, composed of 32-34 facets. Maxillary palpi moderately developed; palpomeres II-III smooth; palpomere IV 0.22 mm long and about 3.16 times as long as wide, subcylindrical pseudosegment at apex. Antennae about 0.53 mm long; scapes short without modification, 0.92 times as long as pedicels; pedicels long as wide; antennomere III-VIII subequal in length; IX 0.63 times as long as wide; X transverse, 0.61 times as long as wide; XI largest, pointed at apex, 1.61 times as long as wide (Fig. 3F ). Pronotum 0.88 times as long as wide and widest at basal 3/5, lateral antebasal foveae connected by antebasal sulcus. Elytra convex, 0.85 times as long as wide and widest at basal 1/3, each elytron with two basal foveae and subhumeral fovea. Legs robust; internal spine on widest of protibiae (Fig. 3G , arrow); metatibiae with spine on apical (Fig. 3H , arrow). Aedeagus small, 0.27 mm long and 1.61 times as long as wide; penis small fusiform and dorsal diaphragm bulbous; parameres symmetrical; endophallus composed with two convergent, slender struts (Fig. 3I ).

Sexual dimorphism. Female eyes slightly longer than tempora, composed of 15 facets; antennal pedicels simple; protibial spines and metatibial spines absent.

Remarks.

Adults of this species are very similar to Bryaxis mahunkai Löbl, 1975 in having strongly swollen antennal pedicels (Fig. 4C, D ). However, they can be distinguished by smooth maxillary palpomere II-III (Fig. 4A ), apically symmetrical antennal scapes, pedicels less swollen apically and bearing smaller glandular nodules (Fig. 4C , arrow), fore legs with a tibial spine (Fig. 4E , arrow), and parameres wider than the penis (aedeagus in B. mahunkai as wide as penis; Fig. 10C, D ).

Comments.

The localities of B. uljinensis sp. nov. probably overlap with those of B. mahunkai Löbl given that the latter are nationally distributed (Fig. 11 ).

Etymology.

This species is named after the type locality, Uljin-gun.

Habitat.

The holotype was collected by sifting leaf litter in mixed forest. Paratypes were collected by sifting leaf litter, soil, and an ant colony.

Distribution.

Korea (Uljin-gun, Gyeongsangbuk-do; Jeongseon-gun, Gangwon-do).

Figures

Figure 3. Bryaxis uljinensis 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 4. Diagnostic characters of Bryaxis uljinensis sp. nov. (A, C, E) and B. mahunkai Loebl (B, D, F). A, B maxillary palpi C, D antennal scapes and pedicels E, F protibiae. Scale bars: 0.1 mm.

Figure 10. Diagnostic characters of Bryaxis mahunkai Loebl. A, B antennal scapes and pedicels C, D aedeagi. 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).