As many of you know, I don’t just write for fun. This is also how I make my living! If you’re curious about my science writing, my latest story for EARTH magazine just went live. This is one of my favorite pieces I’ve written for EARTH lately. I usually cover the geophysics beat – think earthquakes, plate tectonics and volcanoes – but every now and then I get to explore other loves, in this case, human evolution.

Paleoanthropologists are often forced to glean information about early human evolution from mere fragments of bone, but a trove of thousands of hominin fossils unearthed from a prolific cave in northern Spain is proving a boon for scientists studying the early ancestors of Neanderthals . But the plethora of fossils isn’t falling neatly into any established species, leaving some to wonder if a new category of hominin is needed. 

Since its discovery in 1984 the Sima de los Huesos site near Atapuerca, Spain has been vigorously excavated, revealing more than 7,000 fossils, including 17 skulls, from at least 28 individuals.  “What makes the Sima de los Huesos site unique is the extraordinary and unprecedented accumulation of hominin fossils there. Nothing quite so big has ever been discovered for any extinct hominin species—including Neanderthals,” says Juan-Luis Arsuaga, a paleontologist at the Complutensis University in Madrid and lead author of the new study, published this week in Science. 

To read the rest, click over to EARTH’s website.