Pterostichus (Micronialoe) chogyesanus Park, Kwon & Lafer, 1996

Korean name: 송광길쭉먼지벌레

(Figure 8)

Pterostichus (Micronialoe) chogyesanus Park, Kwon & Lafer, 1996: 75.

Specimen examined. Korea • 5♂; Jeollanam-do, Gurye-gun, Ganjeon-myeon, Jungdae-ri; Mt. Baegunsan; 35°07'55.8"N 127°36'12.6"E; alt. ca 580 m; 3 Sep. 2022; Dooyoung Kim leg.; KNU.

Diagnosis. This species is easily distinguished from known species of the subgenus by: i) pronotum with rudimentary or without outer basal fovea, ii) posteromedian area of male sternite VII not depressed, iii) median lobe of aedeagus slender, without ventral carina; and iv) internal sac of aedeagus with one sclerite, which is C-shaped. Other significant characters are as follows.

Pronotum with weak or rather distinct sinuation on lateral margin before basal angle. Posteromedian area with microsculpture consisting of widely transverse to isodiametric meshes. Median lobe of aedeagus with apical orifice on dorsal side; apex rounded in dorsal view.

This species may be remotely related to the consubgeners by having a peculiar morphology of the median lobe of the aedeagus. Micronialoe is included in the clade of Pterostichus which possesses the apical orifice of the median lobe bent to the left (Sasakawa and Kubota 2007; Schmidt et al. 2012). P. chogyesanus has an apical orifice located on the dorsal side of the median lobe which may be a reversal from the apomorphic state.

Redescription. Body length: 5.9–7.5 mm, width: 2.1–2.6 mm.

Coloration brownish-black or black and shiny; antennae, legs, and lateral margin of both pronotum and elytra dark brown; palpi yellowish brown, with apices distinctly paler; ventral side brownish black (Figs 8A, B).

Head (Fig. 8C). Eye moderately convex; tempus oblique, shorter than in previous species; frontal impression moderately depressed, tilted outward, and clearly ends before anterior supraorbital pore.

Pronotum (Fig. 8C) widest before 2/5 from apex; apical angle narrowly rounded, moderately protruded anteriorly; lateral margin with weak or clear sinuation before basal angle; anterolateral seta before widest point, 1/4 to 3/10 from apex; basal angle obtuse; anterior transverse impression faint; posterior transverse impression more or less distinct; with one pair of clear basal foveae; inner foveae deep and distinct, linear, almost parallel or slightly tilted outward anteriorly, with distinct punctures; outer foveae rudimentary or absent; area between inner foveae weakly rugose longitudinally; area between inner fovea and outer fovea almost smooth. PW /HW = 1.50–1.57, mean 1.52 (1.58 in holotype); PW / PL = 1.11–1.16, mean 1.14 (1.13 in holotype); PW /PbW = 1.24–1.25, mean 1.25 (1.24 in holotype); PW /PaW = 1.45–1.47, mean 1.46 (1.41 in holotype); PbW/PaW = 1.16–1.18, mean 1.17 (1.14 in holotype) in 4 males.

Elytra widest near 2/5 from base; striae deep, punctate from base to about basal two-thirds; marginal umbilicate series composed of three groups, 5 pores in anterior group, 1 pore in medial group, and 8 pores (rarely 9 pores) in posterior group. EW/ PW =1.15–1.23, mean 1.18 (1.22 in holotype); EL/ PL = 2.02–2.09 (2.17 in holotype), mean 2.06; EL/EW = 1.47–1.59, mean 1.53 (1.58 in holotype) in 4 males.

Ventral side (Figs 8B, D). Posteromedian area of male sternite VII normal, with microsculpture consisting of widely transverse or isodiametric meshes in male (Fig. 8D).

Male genitalia (Figs 8E–J). Median lobe of aedeagus (Figs 8E–H) slender, distinctly curved in lateral view, almost linear in dorsal view; apical orifice on dorsal side, not bent left; terminal lamella wide and long; apex rounded in dorsal view; ventral carina absent; sclerotized area in internal sac with only C-shaped sclerite on median area (CS); left paramere (Fig. 8I) wide; right paramere (Fig. 8J) slender, weakly to distinctly curved, apical part less developed than in previous species.

Type locality. Mt. Jogyesan, Suncheon-si, Korea. (The Korean name ‘송광’ in the original description suggests that Songgwangsa Temple in the western part of the mountain is the exact locality.)

Ecology. The adult specimens were observed beneath rocks in the humid valley.

Remarks. This species was only known from its type locality, and Mt. Beagunsan is a new distributional record.