The purported dinosaur ancestor is not dated earlier than the descendant.
Scansoriopteryx (Paraves)Temporal range: Callovian to Kimmeridgian, 165-156 MaSerikornis (Paraves)Temporal range: Middle Jurassic, 165-162 Ma
These Paravians line up (165 ma) with the type of dinosaur they are purported to have evolved from. For example with:
ProceratosaurusProceratosaurus (basal Tyrannoraptora)Temporal range: Middle Jurassic, 165 Ma
Proceratosaurus is a genus of small-sized (~3 metres (9.8 ft) long) carnivorous theropod dinosaur from the Middle Jurassic (Bathonian) of England. It was originally thought to be an ancestor of Ceratosaurus, due to the similar small crest on its snout. Now, however, it is considered a coelurosaur, specifically one of the earliest known members of Tyrannosauroidea, the clade of basal relatives of the tyrannosaurs.So the actual fossil evidence has paravians and the type of dinosaur they are thought to have evolved from appearing in the fossil record beginning at the same time.
Notice the imaginary lines running from Coleurosaur to Paraves.