Dinosaurs- Mammal or Reptile

This post took an interesting turn.

I couldn't think of the word I was looking for so I did a thesaurus search of the word I could think of: premier. This post was originally simply going to contain all the definitions of the word premier (the word I was looking for was inaugural).

Main Entry:	premier
Part of Speech:	adjective
Definition:	leading; original
Synonyms:	arch, beginning, champion, chief, earliest, first, foremost, head, highest, inaugural, initial, main, opening, primary, prime, principal
Antonyms:	inferior, minor

But originally, I had included a side note next to the word "thesaurus, so the post looked liked this: thesaurus (doesn't that word remind you of a type of dinosaur? search of the word... )

Then I decided I would describe to you all what type of dinosaur I thought the thesaurus was. However, I needed to look up another word for vegetarian (herbivorous) and whether dinosaurs were mammals or reptiles. I decided the search for the class of dinosaurs was much more interesting and informative. Double information for the price of one post. Unfortunately, there are a few differing answers on the subject.

I most likely subscribe to the answers of dinosaur expert Don Lessem and paleontologist Tim Rowe.

Q: How did the first dinosaur get on Earth?
A: Dinosaurs evolved from more primitive reptiles about 230 million years ago. Among the earliest-known dinosaurs was eoraptor from Argentina, a dog-sized meat-eater, 228 million years old. (Don Lessem)

Q: Are animals of today related to dinosaurs? If yes, which ones?
A: Birds are the direct descendants of meat-eating dinosaurs in most scientists' opinions. Living reptiles like crocodiles are relatives of dinosaurs, but they came from animals that developed before dinosaurs, so they are just cousins of dinosaurs. Dinosaurs aren't birds or reptiles. They're dinosaurs, a separate, special group. Some living animals, like reptiles, look a lot like what we imagine dinosaurs to be, but that's just a coincidence. Reptiles all have bent legs, and dinosaurs have straighter legs. Dinosaurs walked with their legs underneath them — that's one way to tell a dinosaur is a dinosaur. (Don Lessem)

Q: How were some dinosaurs able to evolve into warm-blooded animals?
A: Some dinosaurs may have been warm-blooded or at least partially so. The descendants of meat-eating dinosaurs are warm-blooded — they're birds. So dinosaurs were probably on the way to warm-bloodedness themselves. (Don Lessem)

Q: How are reptiles and amphibians different and related?
A: Reptiles evolved from amphibians long before dinosaurs, about 300 million years ago. Reptiles had a better breathing system than amphibians before them. Instead of a throat pump they moved their rib cage like we do, so the size of their lungs, not their mouth, determined how much air they could take in. Reptiles also had a horny layer on their scales and armor, unlike amphibians, so they could live all their lives on land. (Don Lessem)

I bet the thesaurus would be an herbivorous reptile...