Myrmecophily has independently evolved in multiple lineages within the subfamily Pselaphinae Latreille, 1802 (Coleoptera, Staphylinidae) (Jałoszyński et al., 2022;Parker, 2016a, b). The supertribe Faronitae, the most ancestral group, show no evidence of association with ants or termites (Chandler, 2001;Nomura and Leschen, 2015). The remaining five supertribes (the crown group or "Higher Pselaphinae") include several obligate myrmecophiles (Chandler, 2001;Nomura and Leschen, 2015;Parker, 2016a).
All members of the supertribe Clavigeritae are exclusively associated with ants (Hlaváč et al., 2021;Parker, 2016b). They are characterized by reduced antennae with three to eight segments, tergites fused into tergal plate and bearing trichomes (Hlaváč et al., 2021). Most clavigerite adults possess glands on mouthpart and abdominal trichome releasing appeasement secretions which induce trophallaxis from their host (Jałoszyński et al., 2022;Nomura and Leschen, 2015).
The genus AnaclasigerRaffray, 1890 was originally recorded from the Singapore without designation of a type species (Raffray, 1890). The type species, A. sinuaticollis Raffray, was later designated as monotypic (Raffray, 1890), and their members are distributed across Taiwan, Malaysia, Thailand, and Japan (Nomura and Idris, 2005;Nomura et al., 2006;Raffray, 1914). Yin et al. (2012) described A. zhudaiae Yin and Huang from China based on female specimens, and the male was subsequently described by Yin (2023). As a result, this genus currently comprises two species distributed in East- and South Asia.
Except for Clavigeritae, myrmecophilous lineages sporadically across the remaining supertribes (Chandler, 2001). There is no clear evidence of associations with host ants but unspecialized appearances. They are often characterized by smooth exoskeleton, shortened antennomeres, and robust legs (Parker, 2016b). The genus DendrolasiophilusNomura, 2010 (supertribe Batrisitae) is generally congruent with these traits. This genus was first recorded with three species including Batrisus concolorSharp, 1883 as the type species (Nomura, 2008). Although this genus name was initially treated as unavailable due to the absence of generic diagnosis or description, it was later validated by Nomura (2010). For details on the nomenclatural history, see Kurbatov and Kovalev (2022). This genus currently comprised five species distributed in China, Far East Russia, and Japan.
In this study, two myrmecophilous pselaphines Anaclasiger sinuaticollisRaffray, 1890 and Dendrolasiophilus subitusKurbatov & Kovalev, 2022 are reported for the first time from the Korean Peninsula. We provide redescriptions, images of diagnostic characters, and a distribution map. Identification keys and a checklist for the two species are also provided.
Materials and Methods
We examined six specimens from the Korea National Arboretum (KNA) and the Chungnam National University Insect Collection (CNUIC, Daejeon, Republic of Korea). Labels indicate depositories of specimens as "KNAE" or "CNUIC" parenthetically. Specimens were observed using a Leica SAPO and DM1000 LED optical microscope. Images were generated using a Sony ILCE-7RM3 mirrorless camera and stacked with Zerene Stacker v. 1.04. Terms used in this study follow Chandler (2001) and Lawrence et al. (2011). Map for distribution was obtained from Simplemappr (Shorthouse, 2010) and consequently modified. Singular forms are generally used except for plural terms such as "elytra", "parameres". We employ the words "tergites" and "sternites" when referring to the abdominal segments.
Taxonomic Accounts
Family Staphylinidae Latreille, 1802
Subfamily Pselaphinae Latreille, 1802
Supertribe Clavigeritae Leach, 1815
Tribe Clavigerini Leach, 1815
Genus AnaclasigerRaffray, 1890
AnaclasigerRaffray, 1890: 165. Type species: Anaclasiger sinuaticollisRaffray, 1890
Male diagnosis. Head prominently longer than wide (Fig. 2A). Frontal rostrum convex. Antenna composed of four antennomeres, last one longest (Fig. 1A). Pronotum constricted laterally and dorsal surface depressed (Fig. 2B). Each elytron with humeral suture extending towards midline (Fig. 2C). Metaventrite with bundle of thick setae at posterior margin of midline (Fig. 2D). Mesotibia broadened around apex (Fig. 2G). Sternite IV bearing large mediobasal foveae (Fig. 2F). Aedeagus symmetrical; parameres robust; endophallus composed of highly curved armatures (Fig. 2H). See Yin et al. (2012) for the detailed description.
Host ant.Nylanderia flaviabdominis (Wang, 1997).
Distribution. China, Japan, Malaysia, Singapore, South Korea (new record), Taiwan, Thailand.
Anaclasiger sinuaticollisRaffray, 1890(Figs 1–2, 5A–B) Anaclasiger sinuaticollisRaffray, 1890: 216
Material examined. (n = 7, 6♂♂ 1♀) Korea: Gangwon Prov.: 1♂ (genitalia dissected; KNAE) Achimaegi, Imwon-ri, Wondeok-eup, Samcheok-si, 13/Jun/2011, E37-14-48 N129- 18-22, pitfall trap, KNAE577277, T.-S. Kwon, Y.-G. Park, C.-M. Lee, W.-G. Kim. 1♀ (point-mounted; KNAE) Achimaegi, Imwon-ri, Wondeok-eup, Samcheok-si, 13/Jun/2011, E37-14-48 N129-18-22, pitfall trap, KNAE577278, T.-S. Kwon, Y.-G. Park, C.-M. Lee, W.-G. Kim. 1♂ (point-mounted; KNAE) Okgye-myeon, Gangneung-si, 13/Jun/2011, E37-36- 17, N129-01-02, pitfall trap, KNAE577313, T.-S. Kwon, Y.-G. Park, C.-M. Lee, W.-G. Kim. 1♂ (point-mounted; KNAE) Achimaegi, Imwon-ri, Wondeok-eup, Samcheok-si, 7/Jun/2010, E37-14-53, N129-16-16, pitfall trap, KNAE577333, T.-S. Kwon, Y.-G. Park, W.-G. Kim, Y.-I. Jang. 1♂ (point-mounted; KNAE) Achimaegi, Imwon-ri, Wondeok-eup, Samcheok-si, 13/Jun/2012, E37-14-53, N129-16-16, pitfall trap, KNAE 740474, T.-S. Kwon. 1♂ (slide-mounted; KNAE) Achimaegi, Imwon-ri, Wondeok-eup, Samcheok-si, 13/Jun/2012, E37-14- 53, N129-16-16, pitfall trap, KNAE740475, T.-S. Kwon. 1♂ (ethanol-preserved; KNAE) Achimaegi, Imwon-ri, Wondeokeup, Samcheok-si, 13/Jun/2012, E37-14-53, N129-16-16, pitfall trap, KNAE740478, T.-S. Kwon.
Diagnosis. Apical antennomere longest and twisted (Fig. 1). Dorsolateral margin of pronotum concave at mid-level (Fig. 2B). Elytral suture from humerus towards midline (Fig. 2C). Mesotibia bearing acute spine at 1/4 of apex (Fig. 2G).
Redescription of male. Body length 1.74–1.83 mm, overall flattened; body color reddish brown (Figs 1A–B). Head length 0.31 mm and width 0.27 mm (Fig. 2A); vertex coarsely punctate with asetose dorsal tentorial pits; eye well-developed and longer than temple, composed of 20 facets; ocular-mandibular carina absent; gular plate slightly concave with pair of ventral tentorial pits. Labrum transversely triangular; frontal rostrum prominently swollen. Antennal socket highly reduced; antenna 0.57 mm, four-segmented with clubbed last one; scape shortest and partially visible at dorsal view; pedicel cylindrical, wider than long; antennomere 3 elongate and broadened apically; 4 largest, vertically flattened and twisted outwards. Mandible highly reduced. Maxilla pigmented, maxillary palpus concealed by prominent buccal bulge. Labium with mentum narrowed anteroventrally and carinate along midline. Prothorax length 0.29 mm and width 0.30 mm. Pronotum sparsely covered with short setae, highly concave at dorsal and constricted laterally (Fig. 2B). Hypomeron incompletely separated from pronotum, prosternal carina sharp. Elytra length 0.55 mm and width 0.65 mm, sparsely covered with short setae and punctures; humeral suture extending towards midline on each elytron (Fig. 2C). Mesoventrite short, long setae situated along mesocoxal process. Metaventrite broadened posteriorly, with erect mediobasal setae (Fig. 2D). Hindwing present. Leg short and slender; mesotibia broadened around apex, bearing spine apically curved on 1/4 level of apex (Fig. 2G). Abdomen length 0.60 mm and width 0.66 mm. Tergites IV–VI fused forming composite tergal plate (Fig. 2E); paratergite IV with tuft of thick setae. Sternite IV bearing pair of large mediobasal foveae (Fig. 2F). Aedeagus 0.36 mm, overall sclerotized fusiform; parameres thick and symmetrical; penis semilunate; endophallus composed of four asymmetrical armatures, highly curved towards opposite side (Figs 2H, 5A–B).
Sexual dimorphism. Female similar to male, but eye composed with 16 facets, antenna slightly short, mesotibial spine absent.
Habitat. Waste ground and meadow (See Raffray (1890)); Litter of evergreen forest (See Taru (2020)).
Host ant. Unknown.
Distribution. Japan, Malaysia, Singapore, South Korea, Taiwan, Thailand (Table 1).
Supertribe Batrisitae Reitter, 1882
Tribe Batrisini Reitter, 1882
Subtribe Batrisina Reitter, 1882
Genus DendrolasiophilusNomura, 2010
DendrolasiophilusNomura, 2008: 138. Type species Batrisus concolorSharp, 1883.
Dendrolasiophilus: Nomura 2008: 138, 2010: 53; Schülke & Smetana 2015: 370; Kurbatov 2024: 324.
Male diagnosis. Body thick and cylindrical; surfaced smooth, reddish-brown, shiny (Fig. 3). Head subquadrate, surface covered with fine setae or completely glabrous, with dorsal tentorial pits (Fig. 4A). Pronotum with small lateral antebasal foveae (Fig. 4B). Each elytron with basal fovea and sutural stria (Fig. 4C). Legs long and slender. Metatrochanter with small denticle on posterior margin (Fig. 4D). Tergite IV largest, with three pairs of basal foveae (Fig. 3A). Aedeagus asymmetrical (Fig. 4G). See Nomura (2010) for the detailed description.
Host ant range.Lasius (Dendrolasius) spp. (Table 1).
Distribution. China, Far East Russia, Japan, South Korea (New record) (Fig. 6).
Dendrolasiophilus subitusKurbatov & Kovalev, 2022(Figs 3–4, 5E)
Dendrolasiophilus subitusKurbatov & Kovalev, 2022: 297. Type locality: Primorsky Territory [Russia].
Dendrolasiophilus subitus: Kurbatov and Kovalev, 2022: 297; Kurbatov, 2024: 342.
Material examined. (n = 1, 1♂) Korea: Chungbuk Prov.: 1 ♂ (genitalia dissected; CNUIC) Boeun-gun, Naesokri-myeon, Mt. Sokrisan, Beobjusa temple, 30.VI.2006, 36°32'21.5"N 127°50'10.4"E, 380 m, ex sifting, H.-K. Mn.
Diagnosis. Body surface shiny and nearly smooth. Temple distinctly angulated; with dense short setae on posterior margin (Fig. 4A). Pronotum with small puncture behind lateral antebasal fovea (Fig. 4B). Metaventrite with median longitudinal sulcus and broad median heart-shaped impression, densely pubescence on impression (Fig. 4D). Each elytron with basal elytral fovea (Fig. 4C). Tergite IV with two pairs of mediobasal foveae; with basolateral foveae (Fig. 3A). Sternite V with mediobasal foveae; with three pairs of basolateral foveae (Fig. 3B). Metatrochanter with small spine on distoposterior margin (Fig. 4F). Metafemur moderately angulated on middle (Fig. 4F). Median lobe with large oval basal foramen; with small dorsal diaphragm; ventral structure broad, apex flattened and with small spine in apex; dorsal structure weakly extended laterally, apical and lateral margin serrated (Fig. 4G).
Redescription of male. Body length 2.9 mm, body color reddish brown, shiny and nearly smooth; covered with highly short white setae (Fig. 3). Head length 0.49 mm and width 0.61 mm (Fig. 4A), subrectangular; vertex barely punctate with asetose dorsal tentorial pits; eye well-developed and occupying 0.27 times as long as head; ocular-mandibular carina incomplete; gular surface covered with short setae, with pair of ventral tentorial pits. Labrum transversely trapezoidal; clypeus slightly expanded anteriorly; frons weakly concave. Antennal socket as wide as eye; antenna 1.23 mm, 11-segmented; scape large and cylindrical; pedicel to antennomere 7 trapezoidal, widened apically, densely punctate; 8 wider than long; 9–11 weakly clubbed. Maxillary palpomere 1 small; 2 elongated and clavate; 3 small and triangular; 4 elongated and oval. Prothorax length 0.57 mm and width 0.60 mm. Pronotum hexagonal, narrower than head, with shallow median longitudinal sulcus, small median antebasal fovea and pair of small lateral antebasal foveae (Fig. 4B). Prosternum surface densely covered with white setae and punctures, with pair of lateral procoxal foveae. Elytra length 0.88 mm and width 1.02 mm, wider than pronotum; each elytron bearing basal fovea and complete sutural stria (Fig. 4C). Mesoventrite surface bearing reticular microsculptures anteriorly, with two median mesoventral foveae and two lateral mesoventral foveae (Fig. 4D). Metaventrite surface covered with long setae, bearing pair of lateral mesocoxal foveae and lateral metaventral foveae; median longitudinal sulcus; broad cardioid impression on median surface densely covered with long setae (Fig. 4D). Leg long and robust; metatrochanter with blunt spine distoposteriorly; metafemur moderately angulated before joint to tibia (Fig. 4F). Abdomen length 0.87 mm and width 0.95 mm, narrower than elytra and gradually narrowing posteriorly. Tergite IV largest and bearing impressions on mediobasal and basolateral surfaces; two pairs of mediobasal and basolateral foveae; discal carinae extending anterior to lateroposterior margin, as long as 2/3 of tergite IV length (Fig. 3A). Tergite V bearing two mediobasal foveae and three pairs of basolateral foveae (Fig. 3A). Sternites V–VI bearing two pairs of basolateral foveae (Fig. 3B). Aedeagus 0.53 mm and asymmetrical; penis with large oval basal foramen and small dorsal diaphragm; dorsal structure weakly extended laterally, apical and lateral margin serrated; ventral structure broad, flattened and bearing small spine apically (Figs 4F, 5E).
Sexual dimorphism. Female unknown.
Habitat. On the Quercus tree's bark (See Kurbatov and Kovalev (2022)).
Host ant.Lasius (Dendrolasius) capitatus (Kuznetsov- Ugamsky) (Table 1).
Distribution. Far East Russia, South Korea (Fig. 6).
Key to all species of the genus Anaclasiger Raffray
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1. Antennomere 4 twisted on middle to apex (Fig. 1A); elytra without long setae at posterolateral margin (Fig. 2C; fig. 3E in Nomura et al., 2006); aedeagus as Fig. 2H ················································ A. sinuaticollis Raffray
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- Antennomere 4 not twisted (fig. 4 in Yin et al., 2012; fig. 1C in Yin, 2023); elytra with long setae at posterolateral margin (fig. 5 in Yin et al., 2012); aedeagus as fig. 1I, J in Yin, 2023 ······························· A. zhudaiae Yin & Huang
Key to all species of the genus Dendrolasiophilus Nomura
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1. Metatibia robust, constricted at 1/3 base or middle (figs 7C–F in Nomura, 2008) ············································ 2
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- Metatibia not robust (Fig. 4E; fig. 1 in Yin and Li, 2013; fig. 3 in Kurbatov and Kovalev, 2022) ······················· 3
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2(1). Pronotum without longitudinal sulcus (fig. 4 in Hlaváč et al., 2002; figs 4A–B in Nomura, 2008); metatibia constricted at 1/3 base (fig. 1 in Hlaváč et al., 2002; fig. 7D, F in Nomura, 2008); aedeagus (figs 2, 3 in Hlaváč et al., 2002) · D. monstrotibialis (Hlaváč, Sugaya & Zhou)
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- Pronotum with shallow longitudinal sulcus; metatibia constricted at middle (fig. 7C, E in Nomura, 2008); aedeagus (fig. 7G, H in Nomura, 2008) ······ D. nishikawai Nomura
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3(1). Head surface sparsely covered with fine setae ········ 4 Head surface glabrous ············ D. wenhsini Yin & Li
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4(3). Median impression of metaventrite not convex at middle (fig. 2D in Nomura, 2008); hind femur simple and slender ······························· D. concolor (Sharp) Median impression of metaventrite weakly carinated at middle (Fig. 4D); hind femur weakly angulated at 1/4 of apex (Fig. 4F) D. subitus Kurbatov & Kovalev















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