Eh, that is not how it works. The -saurus suffix does not make an animal a Dinosaur or even prehistoric.

Chlamydosaurus - Frilled Lizard still existing today.

Ctenosaura ( saura is the female version of the masculine saurus, although that does not affect the actual sex ) - an iguana

Mosasaurus - a giant marine lizard

Basilosaurus - a prehistoric whale originally mistaken for a marine reptile ( to be fair, it looks more like a marine reptile than a whale in many aspects )

Edaphosaurus, Lystrosaurus, Dromasaurus - Synapsids, therefore related to mammals. ( Mammals themselves are Synapsids of the Eupelycosaur clade )

Ichthyosaurus, Plesiosaurus - marine reptiles

Geosaurus, Dakosaurus - crocodiles

Nyctosaurus - Pterosaurs

Mastodonsaurus - giant amphibian

Just a few examples.



A Palaeontologist also does not only study Dinosaurs. There are those who study vertebrates and those who study invertebrates. From that starting point most tend to specialize further.



It also should be noted that it is a genus, not a species. Genus: Tyrannosaurus, Species: Tyrannosaurus rex or T.rex for short. Probably the only Dinosaur where everyone knows the whole species name, not to mention an example of a genus only having one known species, so far.



Regarding the info we have about the "spiny-backed ponysaurus" it might be a specific species, but could also be a genus. The skull structure is however clearly that of an equine.