Did you actually read the article? I did. The closest to an answer we can get right now is 47% of studied Neanderthal skulls have exostoses, called “surfer’s ear” in modern humans. This and a number of other characteristics humans share with only with aquatic mammalia lead the researchers to justify ancient humans and/or relatives spent large quantities of time in the water. Does your definition of a proposed “aquatic ape” look like a mermaid?