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an extinct running bird of the order Aepyornithiformes. The aepyornis, closely related to the ostrich and the moa, measured more than 3 m in height. It had massive tridactylous legs, a broad, flat breastbone, and wings that were reduced to small appendages, retaining only a rudiment of the humerus. The eggs were extremely large, with a volume of 8–9 1. The birds are known from Quaternary deposits of Madagascar. They were made extinct by man in the 17th or 18th century.