And pelagornithids are the first group that seizes that.

Pelagornithids 是第一个抓住这一机遇的群体。

In the case of pelagornithids, this particular role would be filled by flying reptiles in the Cretaceous period.

白垩纪时期，飞行爬行动物会取代 pelagornithids 这一特殊角色。

So in the case of pelagornithids, this particular role would be filled by flying reptiles in the Cretaceous period.

Ksepka：因此，就长角鸟而言，白垩纪时期的飞行爬行动物将担任这一特殊角色。

Dan thinks the appearance of this group — the pelagornithids — may have to do with the disappearance of other strange, giant flying creatures.

丹认为这群“pelagornithids”鸟的出现，可能其它巨型奇异飞行生物的消失有必然关联。