The Chatham Island skink, Oligosoma nigriplantare, is a species of skink in the family Scincidae. It is the sole reptile species found on the Chatham Islands of New Zealand where it occurs on all the major islands except Chatham Island itself. Given the geological history of the Chatham Islands, it is assumed that O. n. nigriplantare previously occurred on Chatham Island; however, there are no fossil records or historical reports of O. n. nigriplantare on Chatham Island. Since O. n. nigriplantare is almost locally extinct on Pitt Island as a result of introduced mammals, the presence of introduced mammals on Chatham Island might have resulted in the local extinction of O. n. nigriplantare. On vegetated islands, O. n. nigriplantare inhabits grassland and shrub habitat, but it also occurs on