How much can you learn about species variation from a skeleton?
It seems as if this article is purely speculative. They didn't mention any DNA testing, but instead discussed physical features.

There are two "types" of archaeologists: clumpers and splitters. Clumpers (like the author of this article) believe that there is wide variety among members of the same species, and so it is often wrong to categorize every new hominid fossil as being a different species. Splitters like to "split" their findings into new species, even though there is no evidence that speciation had ever occurred; they just decide that since the remains look different, they must have speciated.

In the future, I hope that archaeologists will have more sophisticated means of sequencing the DNA of ancient remains, allowing them to construct an accurate phylogeny