Homo antecessor: The Ancient Pioneer Who Rewrote the Story of Human Evolution in Europe

1. Introduction: A Discovery That Shook Paleoanthropology

Imagine walking through the hills of northern Spain and stumbling upon a fragment of bone that turns out to be nearly a million years old — and that this fragment belongs to a species of human being that nobody had ever described before. That is essentially what happened in the mid-1990s at a site called Gran Dolina, nestled in the famous Atapuerca Hills of Burgos, Spain. The fossils recovered there eventually led to the formal description of a new species: Homo antecessor, Latin for "pioneer" or "explorer." The name was chosen deliberately and wisely; these ancient people were, in every sense, pioneers — among the earliest human relatives known from western Europe, and possibly the pivotal link between ourselves and our Neanderthal cousins.

For the scientists who pulled those bones from the earth, it was a defining moment — the kind that comes once in a lifetime, if you're lucky. For the rest of us, the story of Homo antecessor is a window into deep time, into an era so remote that the landscape of Europe looked almost unrecognizable, where temperatures swung wildly between glacials and interglacials, and where small groups of hominins had to be extraordinarily resilient just to survive. Yet survive they did, and in doing so, they left behind the bones and artifacts that we are still puzzling over three decades later.

This article is a comprehensive review of everything we know about Homo antecessor — the site where they were found, the anatomy of their fossilized remains, the fierce scientific debate about their place in the human family tree, and what cutting-edge paleogenetic research is beginning to tell us about the relationships between the deep branches of the human lineage. We will also address some of the most fascinating questions in all of paleoanthropology: could Homo antecessor actually be our last common ancestor with the Neanderthals? And what does the answer mean for how we understand what it means to be human?

2. Gran Dolina and the Atapuerca Hills

To understand the fossils, you first have to understand the place that preserved them. The Atapuerca Hills rise gently above the Meseta of northern Spain, an ancient limestone landscape carved over millions of years by the Arlanzón River. The hills are riddled with caves and karstic formations — natural sediment traps that have been collecting bones, tools, and charcoal for an almost unimaginable length of time. Today the Sierra de Atapuerca is a UNESCO World Heritage Site, recognized as one of the most important archaeological and paleontological zones on Earth. It is a place that invites awe even before you know what lies beneath it.

Within Atapuerca, Gran Dolina is one of several key sites. The cave's stratigraphic sequence — the vertical column of sedimentary layers that records geological time — has been divided into eleven discrete units, labeled TD1 through TD11 based on differences in rock type, sediment composition, and stratigraphic unconformities. Think of it as a natural filing cabinet, with older records at the bottom and newer ones stacked above. The lower units, TD1 through TD7, date to the Early Pleistocene, while the upper units, TD8 through TD11, belong to the Middle Pleistocene. This kind of well-defined stratigraphy is exactly what paleoanthropologists dream of — it means you can date what you find with real confidence.

The fossils of Homo antecessor were recovered from sublevel TD6-2 — the second sublevel within the sixth major unit of the sequence. This is a critical detail because it means the fossils sit just below a major geomagnetic boundary: the Matuyama–Brunhes reversal, which occurred approximately 0.79 million years ago. Earth's magnetic field periodically flips its polarity, and these reversals leave a detectable chemical and physical signature in sedimentary layers. Since the fossils lie below the reversal, they must be older than 0.79 million years. Combined with other dating methods and isotopic correlation, the age of the TD6-2 fauna is estimated at between roughly 0.79 and 0.96 million years, most likely around 0.85 million years ago, placing the assemblage in Marine Isotope Stage 21 — a warm interglacial interval.

The setting inside the cave itself would have been very different from what it is today. During the Early Pleistocene, this part of Spain had a climate that oscillated between relatively temperate interglacials and cold glacials. The animals whose bones were recovered alongside the human remains include species of bison, large deer, rhinoceros, bears, and various rodents — a fauna that paints a picture of mixed woodland and open grassland environments. For a small band of hominins, this would have been a landscape rich in food but also full of predators, competitors, and seasonal hardship.

3. The Discovery: What Was Found and When

The story of the discovery is inseparable from the story of a railway cutting. In the 1890s, engineers blasting through the Atapuerca Hills to lay a railway line inadvertently exposed the cave systems that had lain sealed for millennia. For many decades afterward, occasional finds hinted at the extraordinary archaeological potential of the area, but systematic scientific excavation of Gran Dolina did not begin in earnest until the 1990s. It was during field seasons in 1994 and 1996 that the bombshell was dropped: hominin fossils began emerging from TD6-2 in quantities that demanded attention.

The initial haul was remarkable. Researchers recovered fragments of skull bones, facial bones, lower jaw (mandible) pieces, teeth, and some postcranial (below-the-skull) material. Critically, the fossils were found in direct association with stone tools — knapped flint artifacts of the Acheulean-adjacent Lower Palaeolithic tradition — and with animal bones bearing cut marks, indicating that meat was being processed at this location. Perhaps most disturbingly, some of the hominin bones also showed cut marks, evidence that the individuals were cannibalized. Whether this was ritual cannibalism, survival cannibalism during times of food stress, or something else entirely remains an open and genuinely fascinating question.

Following the initial excitement, excavation continued through 2003–2007 in a second major phase that significantly expanded the collection. By the time all the material was catalogued, researchers had documented more than 170 fossil fragments representing a minimum of six and possibly as many as eleven individuals. Among these individuals were children, adolescents, and adults — a snapshot of a population rather than a single isolated individual. The specimen numbers assigned to the most important fossils, prefixed with "ATD6-," have become well known in the paleoanthropological literature. Specimens ATD6-69, ATD6-100/168, ATD6-96, and ATD6-113 will appear repeatedly throughout this article because they carry some of the most informative morphology.

4. Anatomy, Part I — Skull and Cranial Features

When paleoanthropologists get their hands on a new set of fossils, the skull is where they look first. The shape of the braincase, the thickness of the bone, the contour of the brow ridges, the angle of the forehead — all of these details carry evolutionary information that helps place a species in its proper context within the human family. The skull fragments of Homo antecessor have been scrutinized with exactly this level of intensity, and what has emerged is a portrait of a hominin that is simultaneously familiar and deeply alien.

The Parietal Bones: A Primitive Cranial Architecture

The most informative cranial specimen in the collection is designated ATD6-100/168, which consists of the two parietal bones — the large, curved plates that form the sides and roof of the braincase — of an immature individual estimated to have been between four and twelve years old at death. In modern humans, the parietals are highly rounded and expansive, reflecting the enormous, globular brain that distinguishes Homo sapiens from all other animals. In Homo antecessor, the parietals tell a different story.

The sagittal profile of ATD6-100/168 — that is, the curvature seen when the skull is viewed from the side — is markedly flat. The parietals are compressed in the fore-and-aft direction, giving the top of the skull a low, elongated shape that strongly recalls the cranial architecture seen in Homo ergaster (African early Homo) and Homo erectus (the widespread Asian species). This is, in the technical language of evolutionary biology, a plesiomorphic trait — an ancestral characteristic shared with earlier members of the Homo genus. It tells us that, in terms of overall braincase shape, Homo antecessor had not yet made the leap toward the highly rounded, expanded neurocranium that would eventually characterize modern humans and, to a somewhat lesser degree, the Neanderthals.

Brow Ridges and Frontal Architecture

The frontal bone fragment ATD6-15 contributes another piece of the puzzle. Homo antecessor had prominent supraorbital tori — the technical term for brow ridges — that project forward above the eye sockets. This is again a primitive character for the Homo genus, shared with H. ergaster and H. erectus. Behind the brow ridges, the frontal bone is pinched in — a feature called post-orbital constriction — before opening up into the more expanded posterior part of the braincase. This architectural pattern is ancient and, importantly, it contrasts with what we see in Neanderthals, who have large brow ridges but a more expanded frontal region.

5. Anatomy, Part II — The Surprisingly Modern Face

Here is where the story of Homo antecessor takes a genuinely unexpected turn. If the braincase is primitive — reminiscent of H. ergaster or H. erectus — the midface is something else entirely. The midfacial region of specimen ATD6-69, which preserves a substantial portion of the face of a juvenile individual, looks startlingly modern. The cheekbones project forward and slightly upward, and the infraorbital region — the area below the eye socket — has a topographic configuration that is far more similar to living Homo sapiens than to any other hominin of comparable age.

In technical terms, Homo antecessor displays a derived (evolutionarily advanced) midfacial morphology despite retaining a primitive braincase. This is not what evolutionary biologists would have expected. Normally, we assume that related features evolve in concert. But here, the face and the braincase appear to tell different evolutionary stories — a phenomenon known as mosaic evolution, and one that is actually quite common in the human lineage but still surprising every time it is encountered.

This modern-like face is, in fact, the oldest such face in the fossil record. No hominin older than Homo antecessor has been found with a comparable midfacial morphology. This makes ATD6-69 a genuinely iconic specimen — a nearly million-year-old face that, in certain respects, already prefigures the face you see in the mirror every morning. The emotional resonance of that fact is hard to overstate.

Shared Features with Neanderthals

Alongside these modern-looking midfacial traits, Homo antecessor also displays certain features that are considered derived in the direction of Neanderthals — features that Neanderthals and some Middle Pleistocene hominins, such as those from the Sima de los Huesos site (also at Atapuerca, but several hundred thousand years younger), share. This is a crucial observation because it places Homo antecessor in a genuinely intermediate position: not quite like H. ergaster or H. erectus in its face, not quite like modern humans, and yet carrying some early Neanderthal-like signals. These so-called "Neandertal" facial features appear to have emerged in the fossil record at least 0.8 million years ago, and they were retained — with elaboration — by the later Neanderthal lineage.

Importantly, these Neanderthal-like features are entirely absent in H. ergaster and H. erectus sensu stricto, which reinforces the idea that a significant divergence in the human lineage had already occurred by the time of Homo antecessor. Some Chinese Middle Pleistocene fossils also show a modern-like midfacial topography, though they appear to be younger than the TD6 material, and the exact nature of any phylogenetic relationship between eastern and western Eurasian populations during this period remains a subject of active and heated debate.

6. Anatomy, Part III — Mandibles, Teeth, and Diet

The mandibles — the lower jawbones — recovered from Gran Dolina are equally informative and equally paradoxical. The two most complete adult mandibles, ATD6-96 and ATD6-113, are remarkable primarily for their slenderness. Compared to the robust, thick-boned lower jaws typical of other Early and Middle Pleistocene Homo specimens, these mandibles are gracile — surprisingly delicate for hominins of their age and context. This is unexpected because the general trend in Early Pleistocene hominin evolution is toward relatively robust mandibles, reflecting the heavy masticatory demands of processing hard, fibrous, or raw foods.

A Mosaic of Mandibular Traits

Despite their overall gracility, the mandibles are not simply "modern." They display a mosaic: some features are primitive for the Homo genus (recalling earlier hominins), while others are more derived. The symphyseal region — the front part of the lower jaw where the two halves fuse — shows characters that differ from both earlier African hominins and later Neanderthals, making it difficult to slot Homo antecessor neatly into any pre-existing category. This morphological uniqueness is, in a sense, the defining characteristic of the entire species: it refuses to fit cleanly into the boxes we have previously constructed.

Dental Evidence: Primitive Roots, Derived Tips

The teeth of Homo antecessor tell a similar story of evolutionary complexity. A thorough analysis of the dental morphology — looking at the size, shape, cusp patterns, enamel thickness, and root morphology of the recovered teeth — reveals that most dental features are primitive for the Homo genus. This is consistent with a species that branched from the main hominin stem at a relatively early date. However, certain dental traits show a more derived character, and some of these closely resemble features found in Neanderthals and other Pleistocene populations.

The overall dental size of Homo antecessor is moderately large by modern standards but not unusually so for an Early Pleistocene hominin. The enamel appears thick, which is consistent with a diet that included hard items such as seeds, roots, tubers, or shellfish, though in the absence of direct isotopic evidence from well-preserved enamel it is difficult to characterize the diet in detail. What is clear is that these individuals were using stone tools to process food — both plant and animal — and that meat, whether hunted or scavenged, formed a significant part of their nutritional repertoire.

7. Anatomy, Part IV — Hands, Feet, and the Postcranial Body

Beyond the skull and teeth, the fossils include a limited but important collection of hand and foot bones, along with fragments of other postcranial elements. Interpreting these is genuinely challenging because the comparative database for Early Pleistocene hominin postcrania is still quite thin — there simply are not enough well-preserved limb bones from this period to make all the comparisons we would like to make. Nevertheless, what has been observed is suggestive and scientifically important.

Several of the hand and foot bone features of Homo antecessor appear to be somewhat more similar to those of modern humans than to later Middle Pleistocene hominins or to Neanderthals. This is counterintuitive if one assumes a straightforward linear progression from ancient to modern, but it fits perfectly well within a mosaic evolutionary framework. The hands, in particular, may have been capable of the kind of precision grip that is associated with fine tool use in modern humans, though this conclusion must be stated cautiously given the fragmentary nature of the evidence.

Overall, the postcranial anatomy of Homo antecessor suggests a hominin that was fully bipedal, probably tall by Early Pleistocene standards — perhaps in the range of 165–170 cm in adults — and physically well adapted to an active, demanding lifestyle in a complex landscape. There is nothing in the limb bones to suggest any significant departure from the kind of striding, terrestrial bipedalism that characterizes the Homo genus since at least the time of H. ergaster.

8. The Great Controversy: Ancestor or Dead End?

From the moment Homo antecessor was formally described by Bermúdez de Castro and his colleagues in 1997, the species has been at the center of a scientific controversy that is, in many ways, still not fully resolved. The original proposal was bold: that Homo antecessor represented a common ancestor of both modern humans and Neanderthals. The argument rested primarily on the modern-like facial morphology — if this species already had our kind of face almost a million years ago, and if it lived in Europe before the Neanderthal lineage was clearly established, then perhaps it was the ancestor of both European Neanderthals and African modern humans.

The scientific community was skeptical, and for understandable reasons. The hypothesis required a geographic scenario — an ancestor originating in western Europe — that ran counter to the dominant "Out of Africa" framework for modern human origins. It also required reconciling the very primitive cranial architecture with the idea of ancestral status to two relatively advanced lineages. And it raised awkward questions about the fossil record: where were the intermediate forms between Homo antecessor and early Neanderthals? The gap in the European fossil record between roughly 900,000 and 600,000 years ago is almost complete, making this a genuinely difficult hypothesis to test.

The controversy deepened when molecular studies of Neanderthal and modern human DNA began producing estimates of the divergence time between the two lineages. Early molecular clock analyses suggested a divergence much more recent than the age of Homo antecessor — placing the split at perhaps 300,000 to 400,000 years ago. If that were true, then Homo antecessor could not be the last common ancestor. However, subsequent refinements to the molecular clock, incorporating better calibration points and more complete ancient genomes, pushed the estimates back significantly. More recent studies suggest a population divergence time of approximately 550,000 to 760,000 years ago — a range that now overlaps meaningfully with the age of the Gran Dolina fossils.

9. What Genetics Tells Us

One of the most transformative developments in paleoanthropology over the past two decades has been the rise of ancient DNA analysis. The ability to extract, sequence, and interpret genetic material from fossil remains has revolutionized our understanding of human prehistory in ways that traditional morphological analysis simply cannot achieve. For Homo antecessor, the question of whether genetics could settle the ancestral status debate was pressing — but also deeply complicated by the age of the fossils.

At approximately 900,000 years old, the Gran Dolina fossils are far too ancient for conventional ancient DNA analysis. DNA degrades rapidly in most environments, and even under ideal cold, dry conditions, very little recognizable DNA survives beyond a few hundred thousand years. Direct DNA extraction from Homo antecessor bone has not been possible with current technology, and given the temperate (and sometimes warm) Spanish environment, it is not expected to become possible in the near future.

Ancient Proteins: A New Frontier

However, a remarkable methodological breakthrough has opened an indirect genetic window into the biology of Homo antecessor. Ancient protein analysis — sometimes called palaeoproteomics — exploits the fact that proteins survive in fossils far longer than DNA. In 2020, researchers announced the successful extraction and sequencing of dental enamel proteins from a Gran Dolina tooth specimen of Homo antecessor. The proteins recovered — primarily amelogenin and enamelin, which are components of tooth enamel — allowed the researchers to place Homo antecessor within the hominin phylogeny using molecular data for the very first time.

The results were genuinely exciting. The protein sequences of Homo antecessor were found to be closely related to those of later hominins, and crucially, the analysis supported a sister relationship between Homo antecessor and the clade containing both Neanderthals and modern humans. In other words, the molecular data are consistent with Homo antecessor being either a direct ancestor of the Neanderthal–modern human lineage or a very close relative of that ancestor — a sibling branch that diverged shortly before Neanderthals and modern humans themselves split. This is precisely what the LCA hypothesis would predict.

It is important to be appropriately cautious about what this finding does and does not prove. Ancient protein analysis is a young field, the methods are still being refined, and the interpretation of sister-group relationships versus direct ancestry is always complex. But as a convergence of morphological and molecular evidence, the 2020 palaeoproteomics study was a major step forward in understanding where Homo antecessor belongs in the human family tree.

10. Could Homo antecessor Be Our Last Common Ancestor?

The phrase "Last Common Ancestor" — often abbreviated LCA — refers to the most recent population from which two diverging lineages both descend. In the context of human evolution, the LCA of Neanderthals and modern humans is the population that existed before the two branches separated, after which one line led to the Neanderthals of Europe and western Asia, and the other led ultimately to anatomically modern humans in Africa. Identifying the LCA is one of the most important problems in paleoanthropology, and Homo antecessor is now one of the most serious candidates on the table.

The case for Homo antecessor as the LCA — or as closely related to the LCA — rests on several converging lines of evidence. First, the age is now broadly compatible with molecular clock estimates of the Neanderthal–modern human divergence. Second, the morphology is genuinely intermediate in interesting ways: the modern-like face shared with H. sapiens, the Neanderthal-like cranial features, and the primitive braincase could together reflect the mosaic character expected in a shared ancestor that had not yet fully committed to either the Neanderthal or the modern human "design." Third, the ancient protein data place Homo antecessor close to the base of the Neanderthal–modern human clade in molecular phylogenetic analyses.

The Challenge of Testing the Hypothesis

Despite these arguments, testing the LCA hypothesis is genuinely difficult, and the difficulty is structural rather than merely technical. Cladistic analysis — the standard method for inferring evolutionary relationships from morphological characters — is designed to identify sister groups (closely related branches), not to identify ancestral taxa. A true ancestor, by definition, existed before the divergence and therefore combines the character states of all its descendants without necessarily expressing the unique derived features that distinguish those descendants. This means that an ancestor might look more "primitive" than we would naively expect — which is consistent with what we see in Homo antecessor.

Furthermore, the fossil record between 1.0 and 0.6 million years ago in Europe is almost empty. There are a handful of sites — Ceprano in Italy, Boxgrove in England, Mauer in Germany — that have yielded fragmentary evidence of Middle Pleistocene hominins, but none of these is well enough preserved or sufficiently dated to fill the gap between the Early Pleistocene TD6 material and the clear emergence of Neanderthal anatomy by about 400,000 years ago. This means that we are, in effect, trying to trace a genealogy across a gap of several hundred thousand years with almost no fossil evidence from the intervening period.

What can be said with confidence is that Homo antecessor, while possibly representing a terminal lineage in western Eurasia, offers us the closest morphological approximation we currently have to what the LCA might have looked like. Even if future discoveries reveal that Homo antecessor was a side branch — an evolutionary experiment that ultimately left no descendants — it would still be invaluable as a mirror for understanding the morphology of the actual LCA, which may have been very similar to it in many respects.

11. Why This All Matters — The Bigger Picture

It is easy, when immersed in the details of bone morphology and stratigraphic columns, to lose sight of why any of this matters. Let us step back and think about the broader implications of what the study of Homo antecessor is telling us.

Rethinking "What Makes Us Human"

The face of Homo antecessor — modern-looking, recognizable, almost familiar — is nearly a million years old. This pushes back the emergence of certain "human-like" anatomical features to a depth of time that challenges our intuitive sense of what is ancient and what is recent. If our face was, in some meaningful sense, already present in the world 900,000 years ago, then what does that tell us about the evolutionary pressures that shaped it? The modern midfacial configuration is thought to be linked to speech production, to social signaling, and to the way we experience the world visually. If these functions drove the evolution of the modern face, they were apparently already at work in the Early Pleistocene, long before the anatomical modernization of the braincase that we associate with the cognitive revolution of modern humans.

The Reality of Mosaic Evolution

More broadly, Homo antecessor is a powerful illustration of how evolution actually works — not as a smooth, steady march from primitive to modern, but as a messy, contingent, mosaic process in which different anatomical systems evolve at different rates and in different directions. The combination of a primitive braincase, a modern face, some Neanderthal-like features, gracile mandibles, and largely primitive teeth is exactly the kind of pattern that we see in many parts of the human fossil record once we look closely enough. Homo antecessor simply shows us this pattern with unusual clarity, precisely because it occupies such an important position in time and space.

Europe as a Crossroads of Human Evolution

The Gran Dolina fossils also remind us that Europe was not a peripheral backwater in the story of human evolution. By nearly a million years ago, hominins had already penetrated deep into the European continent, adapted to its variable climates, and developed a recognizable cultural repertoire (stone tools, fire use, food processing). The story of European hominin evolution from Homo antecessor through the Sima de los Huesos hominins, through the Neanderthals, and ultimately to the arrival of modern Homo sapiens from Africa, is one of the most complex and fascinating narratives in the entire history of life on Earth.

The Human Capacity for Cannibalism — A Difficult Truth

Finally, we should not flinch from the evidence of cannibalism at Gran Dolina. The cut marks on hominin bones are real, and they tell us something uncomfortable but important: that even nearly a million years ago, human beings — or near-human beings — were capable of consuming one another. Whether this was a response to extreme hunger, a ritual practice, or something in between, we cannot say. But it confirms that the complexity of human social behavior, including its darkest dimensions, has deep evolutionary roots. That too is part of what makes Homo antecessor so profoundly human.

12. A Timeline of Key Events and Discoveries

13. What Future Research May Reveal

The story of Homo antecessor is very much still being written. Several lines of ongoing and future research promise to dramatically sharpen our understanding of this ancient species and its place in the human family tree.

More Complete Fossils

The single most impactful discovery that could be made at Gran Dolina would be a more complete cranium — a braincase connected to a face, preserving both the primitive neurocranial architecture and the modern-like midfacial morphology in a single specimen. Currently, these features are known from separate individuals, which means that any composite reconstruction involves assumptions about individual variation. A single, well-preserved skull would allow direct 3D morphometric comparison with virtual reconstructions of the predicted LCA morphology, generated from reverse engineering the known morphologies of Neanderthals and modern humans.

Improved Ancient Protein and Biomarker Analysis

The field of palaeoproteomics is advancing rapidly. Improved mass spectrometry techniques, better contamination controls, and a growing reference database of hominin protein sequences will allow increasingly refined molecular phylogenetic analyses. It is possible that additional protein sequences from Homo antecessor — including proteins from non-enamel tissues, if they can be recovered — could provide even more powerful phylogenetic signal. Lipid biomarkers and other ancient biomolecules may also eventually become recoverable from specimens of this age, opening new windows onto diet, physiology, and population structure.

Isotopic Studies of Diet and Mobility

Stable isotope analysis of the Homo antecessor teeth has the potential to shed light on diet, weaning age, geographic mobility, and even seasonal behavior. Although the analytical chemistry of million-year-old tooth enamel is challenging, advances in laser ablation methods and micro-sampling techniques are making this increasingly feasible. Such data would provide invaluable context for understanding the ecological niche occupied by these early Europeans and the behavioral strategies they employed to survive.

Regional and Global Context

As the comparative framework for Early Pleistocene hominins continues to expand — with new discoveries in China, Southeast Asia, and Africa — the position of Homo antecessor within the global human evolutionary network will continue to be re-evaluated. The question of whether Neanderthal-like facial features arose independently in different parts of the Old World, or whether they reflect a single origin and dispersal, is directly relevant to evaluating the LCA hypothesis. Future discoveries from undersampled regions — including the Middle East, Central Asia, and sub-Saharan Africa — could reshape the entire picture dramatically.

14. Conclusion

When researchers first pulled the fossil fragments of Homo antecessor from the dark sediments of Gran Dolina in the mid-1990s, they could not have anticipated the depth of the story those bones would eventually tell. More than a quarter of a century later, Homo antecessor remains one of the most debated, most illuminating, and most hauntingly human species in the entire hominin fossil record. It is a species that defies simple categorization, that mixes the ancient and the modern in a way that feels almost deliberately provocative, as if evolution itself was reminding us that our categories are always provisional and always incomplete.

What we can say, with growing confidence, is this: nearly a million years ago, a population of hominins lived, hunted, died, and were sometimes consumed by their own kind in the hills of what is now northern Spain. They had faces that looked something like ours. They made stone tools. They processed large animal carcasses for meat. They lived in groups that were large enough to leave behind a demographically diverse fossil assemblage. And in their bones — fragmentary, scattered, sometimes marked by the knives of their own companions — they left behind a message about our origins that we are only now beginning to fully read.

Whether Homo antecessor was literally our ancestor or simply a very close relative of our ancestor may ultimately be a question that cannot be fully resolved with the evidence available. But the search for that answer has already transformed our understanding of European prehistory, of the tempo and mode of human evolution, and of the deep evolutionary roots of the anatomy that makes us, in some very tangible way, the people we are today. And that journey of discovery — imperfect, contentious, endlessly surprising — is itself a quintessentially human endeavor. The pioneers of Atapuerca would, perhaps, have understood it perfectly.