Metabacetus hermanni Will et Park, 2008

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 : 416-417

1. Metabacetus hermanni Will et Park, 2008

Figs 1 , 4–5, 11, 15–16, 25–26, 34.

Will, Park, 2008: 191 (Ha Tinh Province, Vietnam).

MATERIAL. 50 specimens ( SIEE): Vietnam, leg. D. Fedorenko : 11♂♂, 14♀♀, Phu Tho Province, ~ 90 km W of Hanoi, Xuan Son National Park , 21°07´52´´N / 104°57´07´´E, h = 400–470 m, 6– 15. VI.2014; 2♂♂, 5♀♀, Ha Tay Province, ~ 45 km W of Hanoi, Ba Vi National Park , 21°04´N / 105°21´38´´E, h = 1050–1100 m, leaf litter, 18. VI.2014; ♂, 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; 2♂♂, Kon Tum Province, Kon Plong District , 14°44´N / 108°18´E, env. ngoc Boc 1 Mt, h= 1100–1200 m, 8– 23.IV.2015 ; ♂, Gia Lai Province, ~ 40 km ENE of Pleiku, 14°12´11´´N / 108°18´54´´E, Kon Ka Kinh National Park , h= 890 m, at light, 9–22. V.2016; 1♀, same data, except for ~ 55 km ENE Pleiku , 14°17´45´´N / 108°26´57´´E, h = 600 m, at light, 8–20. V.2017; 7♂♂, 2♀♀, Dak Lak Province, Chu Yang Sin Natn. Park, 12°23´48´´N / 108°20´59´´E, Krong Kmar river , upper flow, h= 1000 m, 30.III–14.IV.2012 , at light; 2♂♂, 3♀♀, Lam Dong Province, Bi Doup-Nui Ba Nature Reserve, env. Long Lanh , 12°10´44´´N / 108°40´44´´E, h= 1400–1600 m, at light, 13.III–23.IV.2008 ; ♀, same data, except for 12°11´N / 108°42´E, h= 1500–1700 m, ~ 4 km SSE of Hon Giao Mt , 29.IV.2009 ; ♀, 25 km NNW of Bao Loc, Loc Bao env., h= 800 m, 11°44´18´´N / 107°42´08´´E, at light, 5–20.IV.2013 .

DIAGNOSIS. A larger species of the genus ( Fig. 1 ), distinctive from similarly sized M. immarginatus and M. vandoesburgi in having pronotum generally longer, with its sides subsinuate and lateral margin slightly explanate and very smoothly and slightly reflexed in front of basal angles. Elytral apices truncate combined and blunt, discal setigerous pore d2 microscopic, invisible at low magnification; prosternum without or with a faint (sometimes distinct) median groove; pronotum and elytra iridescent and slightly sericeous.

REDESCRIPTION. Some additions only. BL 6.4–8.2 mm. Dorsum black, pronotum and elytra along extreme lateral margins and often elytral apices vaguely reddish. Microsculpture superficial isodiametric before and slightly transverse behind the level of posterior margin of eyes, very superficial, consisting of narrow transverse meshes on pronotum and very dense transverse lines on elytra.

Head: frontal sulci slightly S-shaped. Labrum apically subsinuate to truncate.

Pronotum: sides subsinuate in front of basal angles, these with a minute to indistinct blunt tooth; lateral margin narrowly explanate and very slightly to indistinctly reflexed behind anterolateral seta or vaguely explanate and reflexed in basal third only, with a minute to indistinct impression just inside posterolateral seta. Basal margin slightly oblique outside basal sulci. Basal sulci nearly parallel, mostly reaching base, sometimes obliterate basally. Apical margin truncate or very gently concave, with apical angles rounded or slightly point- ed and barely projecting, respectively. PW/PL 1.24–1.35, PW/HW 1.48–1.65, PB/PA 1.28–1.40.

Elytra about half longer than wide, EL/EW 1.46–1.55, EW/PW 1.30–1.40. Interval 3 behind middle with a vestigial, microscopic, ‘setigerous’ pore d2 near stria 2.

Prosternum without, sometimes with a distinct, median groove; prosternal process not or vaguely bordered at apex.

Aedeagus (Figs 4–5, 11, 15–16): median lobe geniculate, smoothly curved, longitudinal median carina conspicuous, with apical half gradually narrowed apicad in dorsal/ventral view; apex short, thick and slightly curved ventrad in lateral view.

Abdominal urites VIII and IX in female as in Figs 25–26, 34

GEOGRAPHIC DISTRIBUTION. Throughout Vietnam, from Phu Tho and Ha Tay provinces in the north to Lam Dong Province in the south. So wide species range may suggest that the species occurs also in the adjacent parts of Laos.

HABITATS AND HABITS. As indicated above for the genus.

COMMENTS. The northernmost populations of the species (Phu Tho and Ha Tay provinces) are slightly different from southernmost ones (Lam Dong and Dak Lak provinces) in some characters, including body proportions ( Table ). In the north, the adults have the eyes barely smaller, with a bit more obtuse angle between gena and neck, and the ratio PW /

Table. Body ratios in local populations of M. hermanni . Таблица. Индексы пропорций тела в локальных популЯциЯх M. hermanni .

BD — Bi Doup-Nui Ba Nature Reserve; BV — Ba Vi National Park; KP — Kon Plong District; PH — Pu Hoat National Park; XS — Xuan Son National Park; m — mean.

BD — Bi Doup-Nui Ba Nature Reserve; BV — Ba Vi National Park; KP — Kon Plong District; PH — Pu Hoat National Park; XS — Xuan Son National Park; m — среднее арифметическое.

HW is greater accordingly. Besides, the pronotum is barely wider, with the apical margin very gently sinuate (vs. truncate), the apical angles a bit sharper, barely more prominent and more distant from the neck; and the elytra are barely shorter in general.

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.