Phytosaurs are an extinct group of large semi-aquatic Late Triassic archosaur reptiles. Phytosaurs belong to the family Phytosauridae and the order Phytosauria. Phytosauria and Phytosauridae are often considered to be equivalent groupings containing the same species, but some studies have identified non-phytosaurid phytosaurians.
Phytosaurs were similar to the modern crocodilians in appearance, but they had some structural differences, most noticeably - the nostrils that were located before their eyes, rather than at the tips of their snouts.
All of the phytosaurs died out by the end of the Triassic, outcompeted by the prehistoric crocodilians, most likely.
The phytosaurs did not appear on WWD TV series, but they were background characters in the book. In New Blood, they were depicted as semi-amphibious carnivores that hunted Placerias and other Triassic creatures that came to the water's edge to drink. However, they were less dangerous on land and actually never ventured too far away from the water, in order to avoid such carnivores as Postosuchus.
The phytosaurs featured in the book may have been Rutiodon.
In Walking with... Series
Phytosaurs appear in the WWD companion book (New Blood chapter) as background characters.