Crossword Genius

Expressed alarm saying this beast could fly (9)

Ross

I believe the answer is:

pterosaur

I'm a little stuck... Click here to teach me more about this clue!

'expressed alarm saying this beast could fly' is the definition.
'pterosaur' can be an answer for 'beast' (pterosaur is a kind of beast). I am not sure about the remainder of the definition.

This is all the clue.

Can you help me to learn more?

(Other definitions for pterosaur that I've seen before include "Old reptile" , "very old flier" , "Extinct flying reptile" , "ancient flyer" , "that once flew" .)

I've seen this clue in The Times and The Sunday Times.
Want a hint initially instead of a full solution? Install my app