Mecodema atuanui

Mecodema atuanui was described from a single male specimen collected in pitfall traps on Mount Auckland (Atuanui), Kaipara Region. It is a medium-length ground beetle that is related to Mecodema spiniferum,^[1] the only large-lengthed ground beetle species found in the Waitākere Ranges, Auckland, rather than the more geographically close species (M. dunnorum) to the east in Puhoi.

Distinguished from other North Island Mecodema species by having:

1. a lobate labrum;
2. vertexal groove defined by punctures the entire length;
3. elytral intervals 3 and 5 significantly broadened than other intervals;
4. the distinctive narrow width of the apical portion of the penis lobe.^[1]

Length 24.9 mm, pronotal width 6.7 mm, elytral width 7.9 mm. Colour of entire body matte black, except coxae and legs dark reddish-brown.^[1]