Pterostichus (Micronialoe) spinulosus Kim & Suh sp. nov., 2024

Kim, Dooyoung & Suh, Sang Jae, 2024, Review of the ground beetle subgenus Micronialoe from Korea, with a description of a new species (Coleoptera: Carabidae: Pterostichus), Zootaxa 5471 (4), pp. 451-464 : 454-458

Pterostichus (Micronialoe) spinulosus Kim & Suh sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:184C0C67-F8F5-4AAC-B776-05547550AD7E

Korean name: ē름Ī마길쭉먼지벌레

( Figures 2–6 )

Type materials. Holotype: Korea • ♂; Daegu-si , Dalseong-gun , Gachang-myeon , Jeongdae-ri , Eastern part of Mt. Biseulsan; 35°43'48.1"N 128°33'06.5"E; alt. ca 500 m; 29 Oct. 2021; Dooyoung Kim leg.; KNU . Paratypes: • 3♂ 2♀ same data as for holotype • 10♂ 2♀ Daegu-si , Dalseong-gun , Gachang-myeon , Jeongdae-ri , Eastern part of Mt. Biseulsan; 35°43'30.8"N 128°32'33.1"E; alt. ca 580 m; 26 June 2021; Dooyoung Kim leg.; KNU • 4♂ 1♀ same locality as for holotype ; 16 May 2021; Dooyoung Kim leg.; KNU • 23♂ 12♀ Daegu-si , Dalseong-gun , Gachang-myeon , Ju-ri, Mt. Choejeongsan; 35°45'14.4"N 128°35'59.6"E; alt. ca 800 m; 1 July 2021; Dooyoung Kim leg.; KNU .

Diagnosis. The new species is easily distinguished from all known species of the subgenus by: i) posteromedian area of male sternite VII distinctly rugose transversely; ii) median lobe of aedeagus truncate at apex in dorsal view; iii) internal sac of aedeagus with three sclerotized areas. Other significant characters are as follows.

Pronotum with sinuation on lateral margin faint or absent before basal angle; with two pairs of basal foveae. Posteromedian area of male sternite VII flat or partially depressed, with microsculpture consisting of irregular transverse meshes. Median lobe of aedeagus stout; left lateral margin below apical orifice almost linear; ventral carina present, narrowly rounded; sclerotized areas of internal sac consist of followings: i) C-shaped sclerite (CS) on median area; ii) small ventral sclerite (VS) on subapical area; iii) spiny patch (SP) consisting of numerous sclerotized compact spines on dorsal side.

This species seems to be very similar to P. (M.) bifoveolatus and P. (M.) kaniei in their external morphology. Nevertheless, the new species can be easily distinguished from both by having the median lobe of the aedeagus with a truncate apex ( Fig. 5D ), whereas the others have a rounded apex in the dorsal view ( Fig. 7H ; Park et al. 1996; Morita 2005). The new species has three sclerotized areas in the internal sac of the aedeagus ( Figs 5A–E ), whereas P. (M.) bifoveolatus has two sclerotized areas (the feature not known for P. (M.) kaniei ) ( Figs 7E–I ; Park et al. 1996).

Description. Body length: 7.2–8.3 mm, width: 2.7–3.0 mm.

Coloration black or brownish-black and shiny; antennae, legs, and lateral margin of pronotum and elytra dark brown; palpi yellowish brown, with apices distinctly paler; ventral side overall black ( Figs 2A, B ).

Head ( Figs 2C , 3A, 3B , 4A ). Eye weakly convex; tempus well developed, moderately convex, as long as eye; frontal impression deep, moderately curved toward anterior supraorbital pore.

Pronotum ( Figs 2C , 4B ) widest near 2/5 from apex; apical angle narrowly rounded, slightly to distinctly protruded anteriorly; lateral margin with faint or without sinuation before basal angle; anterolateral seta before widest point, near 3/10 from apex; basal angle obtuse; anterior transverse impression faint or absent; posterior transverse impression slightly or moderately distinct; with two pairs of basal foveae; inner foveae deep, linear, almost parallel or slightly diverging anteriorly; outer foveae diverging, mostly clearly visible, but sometimes weakly depressed; area between inner foveae with or without sparse punctures and rugose longitudinally, sometimes almost smooth; area between inner fovea and outer fovea usually smooth, rarely with faint punctures near basal border. PW/HW = 1.60–1.68, mean 1.64; PW/PL = 1.12–1.19, mean 1.15; PW/PbW = 1.15–1.21, mean 1.18; PW/PaW = 1.44–1.55, mean 1.48; PbW/PaW = 1.20–1.35, mean 1.26 in 11 males and 4 females.

Elytra ( Fig. 4C ) widest at 3/10 to 2/5 from base; striae deep, punctate from base to basal half; marginal umbilicate series composed of three groups, humeral group with 5 pores (rarely 6 pores), medial group with 1 pore (rarely 2 pores), and apical group with 7 pores (rarely 8 pores). EW/PW =1.11–1.21, mean 1.17; EL/PL = 1.99–2.10, mean 2.05; EL/EW = 1.45–1.57, mean 1.53 in 10 males and 4 females.

Ventral side ( Figs 2B , 3C, 3D ). Posteromedian area of sternite VII flat or partially depressed, slightly to distinctly rugose, with microsculpture consisting of irregular transverse lines in male ( Fig. 3D ); not depressed, smooth, rarely transversely rugose near apical margin in female.

Male genitalia ( Figs 5A–H , 6 ). Median lobe of aedeagus ( Figs 5A–E ) stout, well curved in lateral view, almost linear in dorsal view, ventral side distinctly curved behind basal bulb, and slightly curved apically; left lateral margin below apical orifice almost linear; apical orifice bent to left; terminal lamella very short; apex truncate in dorsal view; ventral carina weak to distinct, clearly visible in right dorsolateral view; internal sac with three sclerotized areas: i) C-shaped sclerite (CS) on median area, ii) small ventral sclerite (VS) on subapical area, and iii) spiny patch (SP) consisting of numerous sclerotized compact spines on dorsal side; everted internal sac ( Fig. 6 ) curved ventrally; left paramere ( Fig. 5F ) wide; right paramere ( Fig. 5G ) slender, distinctly curved, ventral margin forming almost right angle and dorsal margin forming obtuse angle; sternite IX as in Fig. 5H .

Female genitalia ( Fig. 5I ). Laterotergite IX with several setae along apical margin; basal stylomere with or without one small preapical spine; apical stylomere subtriangular, inner margin slightly curved, outer ventral margin bisinuate, with two thin nematiform setae subapically and three ensiform setae, of which one on dorsolateral and two on ventrolateral side.

Type locality. Eastern part of Mt. Biseulsan and Mt. Choejeongsan, Daegu-si, Korea .

Etymology. The specific name refers to the characteristic of the new species having a spiny patch in the internal sac of the aedeagus.

Ecology. The adult specimens were observed beneath rocks in the forest valley or under stacked leaves on the side of the valley ( Fig. 1 ). Older individuals with relatively poor conditions tended to be collected in June and fresh individuals tended to be collected in October at Mt. Biseulsan. Immature adults with a color of integument not fully darkened were collected in July at Mt. Choejeongsan.

Figures

FIGURE 1. Habitat of Pterostichus (Micronialoe) spinulosus sp. nov. in Mt. Biseulsan, Daegu, South Korea.

FIGURE 2. Pterostichus (Micronialoe) spinulosus sp. nov., male. (A) habitus, dorsal view; (B) ditto, ventral view; C head and pronotum, dorsal view. Scale bars: 1 mm.

FIGURE 3. Pterostichus (Micronialoe) spinulosus sp. nov., male. (A) mouthpart, ventral view; (B) ditto, lateral view; (C) metepisternum; (D) sternite VII. Scale bars: 0.3 mm.

FIGURE 4. Microsculpture of Pterostichus (Micronialoe) spinulosus sp. nov. (A) head; (B) pronotum; (C) elytron. Scale bars: 0.1 mm.

FIGURE 5. Male and female genitalia of Pterostichus (Micronialoe) spinulosus sp. nov., male A–H, female (I). (A) median lobe of aedeagus, right lateral view; (B) ditto, dorsolateral view; (C) ditto, dorsal view; (D) ditto, ventral view; (E) ditto, left lateral view; (F) left paramere; (G) right paramere; (H) male sternite IX; (I) female genitalia (laterotergite, basal stylomere, and apical stylomere), ventral view. Scale bars: 0.3 mm A–E, H; 0.2 mm F, G, 0.1 mm I. Abbreviations: SP: spiny patch; VS: ventral sclerite; CS: C-shaped sclerite; C: ventral carina.

FIGURE 6. Everted internal sac of Pterostichus (Micronialoe) spinulosus sp. nov. (A) left lateral view; (B) right lateral view. Scale bar: 0.3 mm. Abbreviations: SP: spiny patch; VS: ventral sclerite; CS: C-shaped sclerite; C: ventral carina.

FIGURE 7. Male habitus and genitalia of Pterostichus (Micronialoe) bifoveolatus Park, Kwon & Lafer. (A) habitus, dorsal view; (B) habitus, ventral view; (C) head and pronotum, dorsal view; (D) sternite VII; (E) median lobe of aedeagus, right lateral view; (F) median lobe of aedeagus, dorsolateral view; (G) median lobe of aedeagus, dorsal view; (H) median lobe of aedeagus, ventral view; (I) median lobe of aedeagus, left lateral view; (J) left paramere; (K) right paramere. Scale bars: 1 mm A–C; 0.5 mm D; 0.3 mm E–I; 0.2 mm J–K. Abbreviations: VS: ventral sclerite; CS: C-shaped sclerite; C: ventral carina.