Gastrobothrus retusus is a species of beetle of the family Staphylinidae. It is found in New Zealand (North Island).
Description Adults reach a length of about . The body is reddish-brown, with the head and pronotum slightly darker.
Life history They have been collected in leaf litter from mixed deciduous forests with kauri.
Etymology The species name is derived from Latin retusus (meaning blunt) and refers to the shape of tibial spine and spatula.
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