In 2013, wave erosion exposed a 900,000-year-old layer of mud at Happisburgh, UK, where dozens of ancient human footprints could be seen. Within a month, the sea had scoured them away. New research led by @ArchaeoAshleigh puts the prints in context. doi.org/10.1016/j.jhev… 
Almost immediately after discovery, a team led by Nick Ashton arrived to document the rapidly eroding surface. They took high-res photos and planned 3D photogrammetry. But there was an unexpected problem: they couldn't keep the water out. doi.org/10.1371/journa…
The water made it impossible to get good 3D reconstructions of the prints. The team recorded and quantified, publishing their results in the open access PLOS ONE in 2014. Who made them? The team speculated Homo antecessor. doi.org/10.1371/journa…
The new research from @ArchaeoAshleigh developed statistical methods using the original 2D photos of the prints. Their analysis enabled them to do metric and morphometric comparisons with other fossil hominin and human footprints.
In short, the Happisburgh footprints look a lot like fossil prints attributed to Homo erectus from Ileret, Kenya, and both overlap with recent humans in many ways. They're very different from the Laetoli, Tanzania footprint trails usually attributed to Australopithecus afarensis.
The evolution of African and Eurasian Homo--whether H. erectus, H. antecessor, H. ergaster, or whatever species--came with foot anatomy and longer legs that set them apart from Australopithecus. We share this striding bipedalism today.
The chance exposure and rapid disappearance of this ancient surface reminds us that the evidence of our evolution waits beneath the surface. We have to be alert for these discoveries, and innovate new ways to build them into a clearer picture of the past.
