These feathers, then, presumably adorned a diving bird-perhaps Hesperornis, a flightless North American diver from precisely this period.

这些羽毛想必当时归潜所有——也许“黄昏”，一种恰好生活在这一时期不会飞翔的北美潜。

And the other was Hesperornis, which resembled a huge, flightless loon.

另一个黄昏，它看起来像一只巨大的不会飞的潜。

But both it and Hesperornis also had teeth, like most non-avian theropods did.

但始祖和黄昏也有，像大多数非类兽脚亚目恐龙一样。

Hesperornis and Ichthyornis were soon classified as ornithurines, a group of Mesozoic birds whose names means " bird tail." These ancient birds had short tails, instead of the longer bony tail of Archaeopteryx.

黄昏和鱼很快被归类为尾类，这一群中生代类， 其名称的意思“尾” 。 这些远古类拥有短尾巴，而不始祖那样的长骨质尾巴。

So it was clear to scientists that these " opposite birds" belonged to a different lineage than the likes of Hesperornis, Ichthyornis, and the other ornithurines.

因此，科学家们很清楚这些“反类”属于一个与黄昏、鱼和其他尾类不同的谱系。