Metabacetus perakianus Straneo, 1938

Fedorenko, D. N., 2021, Notes on the genera Aristopus, Cosmodiscus and Metabacetus (Coleoptera: Carabidae: Pterostichini: Abacetina), with description of three new species from Vietnam, Russian Entomological Journal 30 (4), pp. 413-429 : 417-418

3. Metabacetus perakianus Straneo, 1938

Figs 3 , 8–14.

Straneo, 1938a: 152, 157 (Perak); Will, Park, 2008: 194.

MATERIAL. Two specimens, ♂, 3♀♀, ( SIEE): Vietnam: Nghe An Province, Que Phong District, Pu Hoat National Park , 19°45´19´´N / 104°47´47´´E, h= 840 m, at light, 15–27.V.2019 (D. Fedorenko) .

DIAGNOSIS. A smaller species within the genus ( Fig. 3 ), pronotal sides rounded, lateral margin explanate and rather smoothly and slightly reflexed in basal half; elytral apices truncate combined and blunt, discal setigerous pore d2 minute yet traceable; prosternum without or with a distinct median groove anteriorly adjoining a deep pit; pronotum and elytra iridescent.

REDESCRIPTION. Some additions only. BL 5.4–6.1 mm. Dorsum black and slightly iridescent, extreme lateral margins of both pronotum and elytra slightly reddish. Microsculpture superficial on head, isodiametric before, slightly transverse behind, very superficial on pronotum and elytra, consisting of narrow transverse meshes or very dense transverse lines, respectively.

Head: frontal sulci reaching the level of anterior supra-ocular seta, S-shaped, parallel behind clypeus, diverging behind, and again parallel just posteriorly. Labrum subsinuate at apical margin.

Pronotum rounded on sides, with lateral margin rather widely explanate and rather smoothly reflexed in basal half. Base and apex truncate, the former distinctly oblique outside basal sulci; these reaching base and slightly converging apicad. PW/PL 1.33–1.36 (1.35), PW/HW 1.53–1.62 (1.56), PB/PA 1.37–1.47 (1.41).

Elytra short and wide, EL/EW 1.42–1.45 (1.44), EW/PW 1.33–1.40 (1.47). Interval 3 behind middle with a minute yet distinct ‘setigerous’ pore d2 near stria 2.

Prosternal process not apically bordered.

Aedeagus (Figs 8–14): median lobe as for M. hermanni , except for more sharply curved in lateral view and less narrowed apicad in ventral view.

GEOGRAPHIC DISTRIBUTION. Known from the only locality in Vietnam, in addition to the type locality, Perak, the Malay Peninsula .

HABITATS AND HABITS. The specimens listed above have been collected at light, at the edge of a montane, monsoon, broad-leaved forest.

COMMENTS. A very characteristic feature of the species, prosternum with a small and deep median pit, has not been mentioned in the original description. The specimens examined otherwise match the description well.

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Figures

Figs 1–3. Dorsal habitus of Metabacetus spp.: 1 — M. hermanni, ♂ from Xuan Son NP; 2 — M. laotinus, ♀ from Cao Bang Province; 3 — M. perakianus, ♀ from Song Thanh NP. Рис. 1–3. Габитус дорЗально Metabacetus spp.: 1 — M. hermanni, ♂ иЗ Национального парка Суансон; 2 — M. laotinus, ♀ иЗ провинции Каобанг; 3 — M. perakianus, ♀ иЗ Национального парка Сонгтхань.