The findings further underline the shift in thinking this field of study has undergone over the decades. We used to think of human evolution as a progression, with a straight line leading from apes to us. This is embodied in the so-called March of Progress illustration where a stooping chimp-like creature gradually morphs into Homo sapiens, apparently the apex of evolution.

These days, we know things were far messier. The latest study highlights a mind-boggling truth: that many of the species we thought of as transitional stages in this onward march overlapped with each other, in some cases for hundreds of thousands of years.