Reptiles girl found by a road with son (7)
I believe the answer is:
lizards
'reptiles' is the definition.
(lizard is a kind of reptile)
'girl found by a road with son' is the wordplay.
'girl' becomes 'liza' (**).
'found by' says to put letters next to each other.
'a road' becomes 'rd' (abbreviation).
'with' is a charade indicator (letters next to each other).
'son' becomes 's'.
'liza'+'rd'+'s'='LIZARDS'
(Other definitions for lizards that I've seen before include "Two-legged reptiles" , "Reptiles with four legs and tail" , "Types of 13" .)