[Fester Chugabrew]

A closer look at your illustration is helpful in understanding the point. Thanks. The word "related" is what causes confusion. One can be descended from another, or not be descended from another, and still be "related" in either case. But there is a sense in which one can say humans and Neanderthals are "not related," namely in the sense of direct descent.

[Coyoteman]

But there is a sense in which one can say humans and Neanderthals are "not related," namely in the sense of direct descent.

That appears correct. Neither Humans nor Neanderthals descended from the other.

I am glad I was able to help you with this point.

[JeffAtlanta]

But there is a sense in which one can say humans and Neanderthals are "not related," namely in the sense of direct descent.

The word "related" is relative. For example, living humans are all related by a common set of ancestors but we really only consider ourselves "related" to maybe those that are as far out as 2nd or 3rd cousins.

In the same way, scientist use the word in a relative sense when speaking informally. For example, a scientist may say that a koala bear is really a marsupial and not even related to bears. This is true in an informal way, but koalas and bears are related - just in a distant way.