Definition from Wiktionary, the free dictionary
- Consisting of, or made from keratin
2001 March 9, Richard O. Prum; et al., “Longisquama Fossil and Feather Morphology”, Science, volume 291, number 5510, DOI:10.1126/science.291.5510.1899c, pages 1899-1902:
- Prum implies that, whatever their morphology, Longisquama’s appendages were not keratinous, whereas in fact, all amniote epidermal appendages consist of keratin ( 2 ).
consisting of keratin