"Evolsaur", known as "Evoldar" (エヴォルダー Evoruda) in the OCG is an "Evol" sub-archetype consisting of FIREDinosaur-Typemonsters. They are the second stage of evolution, being evolved from Reptile-Type "Evoltiles" and evolving into Dragon-Type "Evolzars". Its English name is a combination of evolution and dinosaur.
Their tails resemble more-advanced strands of DNA than "Evoltiles".
The background of their pictures are the same as "Evoltiles" except a modern language using the Latin Alphabet rather than the the ancient looking language on "Evoltiles" pictures.
Their Japanese name, Evoldar is spelled in a way that sounds a lot like "Evoluder", a fictional term for a human being that's evolved beyond humanity from the anime "Yuusha-Oh GaoGaiGar".