Mecodema manaia is a medium-sized ground beetle species found in the native forests of Bream Head and Mt Manaia, Northland, New Zealand.

[1] This species shares the forests of Bream Head with a large-bodied species, Mecodema tewhara, with both inhabiting slightly different forest type.

[2] Distinguished from other North Island Mecodema species by having: Length 24.5–28.7 mm (0.96–1.13 in), pronotal width 6.5–7.7 mm (0.26–0.30 in), elytral width 7.8–9.2 mm (0.31–0.36 in).

Colour of entire body matte to glossy black.

[2] Mecodema manaia is found in the native broadleaf forest, especially areas with deep leaf litter.