平胸鸟的与一种平胸，没有一般飞翔性鸟类所特有的龙骨状突起的不会飞的鸟有关的；

Relating to or being any of a group of flightless birds having a flat breastbone without the keellike prominence characteristic of most flying birds.

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象脊或龙骨的，有脊或龙骨的；成脊状突起的。

Shaped like or having a carina or keel; ridged.

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