The turtle's shell is composed of keratinous structures.
keratinous material
Frequency:
60
%
The horn of a rhinoceros is made of keratinous material.
keratinous growth
Frequency:
50
%
The deer's antlers are a keratinous growth.
Idiomatic Expressions for keratinous
Phrase: keratinous tissue
Meaning: tissue that is composed primarily of keratin
Usage: The keratinous tissue in the bird's beak helps it to crack open seeds.