[RPG] I’m Trying to Find the Race that’s basically a Lizardfolk-Centaur

It is a reference to the Power Level of the race on 214 of the same book.

There are three power levels: standard, advanced, and monstrous. Standard races can only take standard racial traits, while advanced races can take both standard and advanced racial traits, and monstrous races can take standard, advanced, and monstrous racial traits.

All of the races presented in the book that are meant to be played as PCs are Standard. There are, however, other races in places like the Bestiary that are significantly more powerful, Monstrous. There are guidelines for creating both, and ones in the middle, Advanced, though you see the fewest Advanced.

Reskin Razorclaw Shifter to be Lizardfolk

First and foremost reskins/refluffs of existing classes/races/etc. work really well in 4e because everything works off of mechanical keywords. Thus you are free to rename and redescribe a mechanical something as a very different story something without affecting the game in any real way.

Razorclaw Shifters stand out because they get racial bonuses to both Wisdom and Dex and their racial power helps adds to the kind of look you are going for. I've linked the compendium article for them, but you can also find them in PHB2 if you are using books.