Systematics
The relationships of this peculiar species are quite enigmatic. It is traditionally included with the stifftail subfamily Oxyurinae, but appears only distantly related to the genus Oxyura, and its peculiar apomorphies make it difficult to place. Its relationship with the equally strange pink-eared ducks (Malacorhynchus) is unresolved but seems to be quite close, and it seems to be part of an ancient Gondwanan radiation of Anatidae. As such, it is quite closely related to the stiff-tailed ducks proper, but as it seems not as closely as generally believed, with many similarities due to convergent evolution.
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