1.It's this keratinous substance that they use in their mouths to sort of strain the water.

他们用嘴里这种物来过滤水。机翻

2.A small and older relative of triceratops, has been found with fossilized remains of tall, keratinous bristles along its tail.

已发龙一种体型较小且年长亲戚，其尾巴上有高大化石遗迹。机翻

3.There's a slight discoloration in the rock, and what that is is the preservation of the keratinous nail, fingernail, of this bird.

岩石中有轻微变色，那是这只鸟指甲，手指甲保存。机翻

4.But in ornithurines this same area became covered in keratinous beak tissue, while they kept the teeth that were farther back in their jaws.

但在鸟科动物中， 同样区域被喙组织覆盖，同时它们将更靠后牙齿保留在下巴中。机翻