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The adzebills, genus ''Aptornis'', were two closely related bird species, the North Island adzebill, ''Aptornis otidiformis'', and the South Island adzebill, ''Aptornis defossor'', of the extinct family Aptornithidae. The family was endemic to New Zealand. ==Taxonomy== They have been placed in the Gruiformes but this is not entirely certain. It was also proposed to ally them with the Galloanserae (Weber & Hesse, 1995). Studies of morphology and DNA sequences place them variously close to and far off from the kagu of New Caledonia, as well as the trumpeters; however, on first discovery of fossils, they were mistaken for ratites, specifically small moa. Its morphological closeness to the kagu may be the result of convergent evolution, although New Zealand's proximity to New Caledonia and shared biological affinities (the two islands are part of the same microcontinent) has led some researchers to suggest they share a common ancestor from Gondwana. If so, it is interesting to note that the Gondwanan sunbittern is most likely the closest living relative of the kagu, and these two may also be reasonably close to the mesites, yet other "odd gruiforms" from the Southern Hemisphere, but do not seem to be close to the Gruiformes proper (i.e. cranes, rails and allies. See e.g. Fain & Houde, 2004〔 Note that their proposed "Metaves" are only weakly supported, and contain several nigh-impossible grouping. A fairly close kagu-sunbittern relationship, on the other hand, seems almost certain by now.〕). On the other hand, should the adzebills be closer to the trumpeters, placement in the Gruiformes is likely to be correct even if the kagu and sunbittern are split off. A 2011 genetic study found ''A. defossor'' to be a Gruiform. There are no available DNA sequences for ''A. otidiformis'', but it was assumed the two species were more closely related to each other than to other birds. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Adzebill」の詳細全文を読む スポンサード リンク
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