Lizardfolk, but bigger, stronger, and surprisingly compliant with the square-cube law. Not much else to say here.
The chassis, with 4 monstrous humanoid RHD, 19 strength, 14 constitution, acid resistance 5, a natural bite (plus two claws), a huge natural armor bonus, only slightly below-average mental stats, Hold Breath, and some miscellaneous skill bonuses, is surprisingly okay. The ogre got +0, and that one was worse in basically every way except two points of strength (which I'd be willing to give up for the bite and +1 BAB alone).
The lizardfolk also has a very small amount of racial support ogres lack (of those only Axethrower is probably worth it, and only then as a niche pick, but still).
With all this in mind, I could see the blackscale as either a strong +0 or a weak +1. If I could I'd suggest just adding a single RHD and calling it a day, but such things are sadly outside of this thread's scope.
For now I'll assign +0, but others' opinions are very welcome.