Mecodema


Mecodema is a genus of large flightless ground beetle endemic to New Zealand. The genus is very diverse in comparison to the other three New Zealand genera within the subtribe Nothobroscina. Mecodema is geographically widespread across both the North and South Islands, as well as numerous offshore islands, including the Three Kings Is., Poor Knights Is., Aotea and Hauturu, Kapiti Is., Stephens Is., Stewart Is., Chatham Is., Snares Is.

Genus description

Head, frons and vertex often rugose and / or punctate, microsculpture or macrosculpture absent in some species groups ; eyes prominent, almost hemispherical; a single supraorbital puncture on each side, bearing more than one setae; setose punctures of vertex absent; mandibles large, uniformly narrow to the pointed apex, sharply curved in the apical third, mandibles with a number of dorsal grooves and without a seta in the scrobe; mentum with median process, which is notched to strongly indentate ; usually with 2 setiferous punctures below the process and generally with 4–8 setose punctures along the submentum sclerite; labial palpi with setae on the penultimate segment; terminal segments of all palpi slightly compressed, sub-cylindrical, truncate; ligula chitinous with a median carina, 2 apical setae present; the membranous paraglossae extended well beyond the apex of the ligula; stipes with 2–3 basal setae; antennomeres I–II glabrous, III–V with apical ring, VI–XI setose throughout; antennomeres I–III subcylindrical, IV–VII subglobose and slightly compressed. Prothoracic carina distinct with an asymmetrical number of setae along each side, the last never at the posterior lateral sinuation ; midline and pronotal foveae always present; pronotal disc often with shallow depressions on each side of apical half. Elytra always striate; fused together along the suture; hind wings absent; a row of setose punctures on the 7th stria and another row near the lateral carina. Legs slender, the protibia with a pointed apical prolongation on the outer side, greatly distally expanded to distally expanded and shovel-like; male and female tarsi identical, the basal 4 segments of the anterior tarsi are as broad as they are long, usually slightly asymmetrical.
Type species: Mecodema sculpturatum Blanchard 1853.

Species and subspecies (103)

Mecodema aberrans Mecodema allani Fairburn, 1945Mecodema alternans Laporte de Castelnau, 1867