Neither, a centaur has a human torso starting at the base of the neck, the left one has a long neck so clearly not a human torso. The left one has a long torso, so that doesn't fit either.
Solution: it'd be exactly like a regular centaur but with a different skin pattern
We’d have to start evolution again because all mammals have four limbs, and four only. That’s why we can’t have pegasus (pegasi?) either. Bummer, I know.
Biology definitions are not based in causation, it wouldn't lay eggs just cuz we call it a bird. It might be like the anti-platypus tho, the only bird to give birth to live young