Dinosaur droppings collected by institute's top academic (9)
I believe the answer is:
iguanodon
'dinosaur' is the definition.
(I know that iguanodon is a type of dinosaur)
'droppings collected by institute's top academic' is the wordplay.
'droppings' becomes 'guano' (term for bird droppings).
'collected by' says to put letters next to each other (I've seen this in other clues).
'top' indicates taking the first letters (in a down clue, the first letter is top).
'academic' becomes 'don' (type of academic - especially at Oxbridge).
The first letter of 'institutes' is 'i'.
'guano' put after 'i' is 'iguano'.
'iguano'+'don'='IGUANODON'
(Other definitions for iguanodon that I've seen before include "It used to eat plants" , "Old lizard" , "Massive dinosaur of the early Cretaceous period" , "Massive dinosaur with long heavy tail" , "big beast" .)