Metabacetus Bates 1892

Will, Kipling W. & Park, Jong Kyun, 1892, A New Species of the Oriental Abacetine GenusMetabacetusBates, 1892 (Coleoptera: Carabidae) and a Key to the Species of the Genus, The Coleopterists Bulletin 1892 (2), pp. 189-196 : 189-196

Metabacetus Bates 1892

Type species Metabacetus immarginatus Bates 1892:364

Generic diagnosis.—A combination of characters is needed to recognize member taxa. Individuals are Abacetus -like as they have deeply impressed linear basolateral pronotal impressions; clearly defined frontal impression on the head; lack the angular base of stria 1 basal puncture at base of stria 2; abdominal sterna without transverse sulci; male protarsomeres symmetrically expanded; and male median lobe oriented to the left in repose. Additionally Metabacetus species have the second antenomere more or less centrically inserted in first; elytra without discal puncture on interval 3; mentum with epilobes distinct and as or more prominent than the median tooth and; metacoxal anterior sulcus sinuate. This set of characteristics separates Metabacetus from all other sympatric Abacetini and other pterostichine-grade taxa except for Tiferonia , Mateuellus and Cosmodiscus . Metabacetus species can be separated from Tiferonia by their much larger size (5.2–8.0 mm vs. 4.5 mm), and from Mateuellus by their fully developed eyes, which are reduced in the troglobitic Mateuellus . Metabacetus species are of a relatively elongate form, especially the head and mandibles and are much more elongate than the very compact, almost rounded shape seen in Cosmodiscus species.