Oahu Kioea (Chaetoptila sp.)  

The Oahu Kioea is known only from subfossil remains that were found on the island of O’ahu, Hawaiian Islands.

The species has not been described yet, but appears to have been distinct from the historically known Hawaiian Kioea. [1] 

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References:  

[1] S. L. Olson; H. F. James: Descriptions of thirty-two new species of birds from the Hawaiian Islands: Part II. Passeriformes. Ornithological Monographs 45: 1-91. 1991

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edited: 13.09.2020