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Mikhail Polyakov

Homo erectus in southern Africa 2 million years ago: what was found in Drimolen cave and how to read news like this

Level: BeginnerReading time: 6 min

Topics: Science

A sandstone-coloured fragment of a fossil skull lying on dark cloth beside an archaeologist brush and a plain wooden ruler, lit by warm directional light

Short answer: archaeologists from La Trobe University have described 18 previously unpublished fossils of ancient human relatives from the Drimolen quarry in South Africa. The main one is a second skull fragment attributed to Homo erectus, and for the first time an adult, about 2 million years old. That is roughly 200,000 years older than adult Homo erectus fossils found elsewhere, including those from Dmanisi in Georgia dated to about 1.8 million years. Another species, Paranthropus robustus, lived in the same place, and judging by the fossils, its teeth and chewing muscles grew larger over time. The work is published in the journal Annals of Human Biology; everything below comes from the university's announcement and the words of the lead researcher. Below: what exactly was found, what the adult fossil adds, and where the line runs between a find and a conclusion.

What was found

The fossils come from Drimolen Main Quarry in South Africa's "Cradle of Humankind", one of the world's richest sites for remains of ancient human relatives.

An interesting detail that explains a lot about the pace of this kind of science: the quarry was discovered in 1992 and excavated through 2019, but many of the fossils recovered there had never been formally described and remained largely unknown to science. So the news is not about a new dig but about someone finally getting to part of what had already been found.

The paper describes 18 fossils. Among them is the first known adult Homo erectus fossil from Drimolen, designated DNH 127, about 2 million years old.

What the adult fossil adds

The lead researcher, Dr Jesse Martin, explains it this way. Homo erectus is the first hominin species that researchers broadly agree fits within our own genus Homo and is likely directly ancestral to us. Drimolen preserves evidence for the first appearance of this species 2 million years ago. But the original fossil from there, designated DNH 134, belonged to a child aged between two and four, and there was uncertainty about what the adult version may have looked like.

Hence the point of the new fossil: in Martin's words, it provides further confirmation that the species first appeared in southern Africa 2 million years ago.

It is worth separating three different things here that easily blur into one. The age of the individual: DNH 134 is a child of two to four, DNH 127 is an adult. The attribution to a species: both fossils are attributed to Homo erectus. And the age of the fossil itself: about 2 million years. The new fossil adds the adult appearance specifically, about which, in Martin's words, there was uncertainty. How exactly the age was obtained is not described in the available announcement.

The neighbour in the same cave

The second part of the work is about another species, Paranthropus robustus, whose remains are in the same collection. They suggest the species was changing gradually as it adapted to shifting environmental and climatic conditions: between about 2 million and 1.8 million years ago it developed larger teeth and more powerful chewing muscles.

Martin calls the contrast striking. Homo erectus was developing a larger brain and smaller molar teeth, possibly as a result of eating more meat. P. robustus retained a brain only slightly larger than that of chimpanzees, while its molars became enormous, suited to grinding and crushing tough, hard foods, functioning much like a mortar and pestle.

The remark about meat should be read exactly as it was said: it is a suggestion about a possible cause, and the word "possibly" was put there by the researcher himself.

And the quotation that makes the news worth reading in full. Both species shared the same landscape, and both are preserved at Drimolen. In Martin's words, 2 million years ago P. robustus outnumbered Homo erectus at Drimolen by more than 10 to one in the fossils found, and during that period it was our ancestors who seemed unlikely to survive. That is a ratio of what was found in one cave, not a count of the individuals who lived.

A rare case: change within a species is visible

What is most valuable here for researchers is not a single fossil but the chance to compare. The fossils allow two populations of P. robustus separated by about 200,000 years to be set side by side: those from Drimolen at 2 million years and those from Swartkrans cave at 1.8 million years. Over that interval, it is reported, the teeth and the muscles involved in chewing became larger still.

Why this is a rarity, Martin explains directly: hominin fossils are so rare that generally the differences between them are huge, and researchers are left to make educated guesses regarding what existed in the missing parts of the fossil record. The large number of fossils from Drimolen, in his words, allows an unprecedented insight into the micro-evolutionary changes, that is, small changes within one species rather than a transition from one species to another.

For the Drimolen population of P. robustus this is not the first such observation: it had already been recognized as distinctive enough to receive a separate subspecies designation, P. robustus ukusa. The newly described fossils provide additional support for that classification.

What is a find here and what is a conclusion

A useful exercise on any science story. Let us separate them.

The find. 18 described remains from Drimolen, among them the adult skull fragment DNH 127, about 2 million years old, attributed to Homo erectus, and remains of P. robustus. The fossils from Swartkrans cave at 1.8 million years are not part of that number: they serve as a comparison sample.

The researchers' conclusion. That the species was present in southern Africa 200,000 years earlier than traditionally believed; that P. robustus was changing gradually; that the subspecies designation is warranted.

What is not in the announcement. Independent assessments by other groups, details of the dating methods, and a discussion of objections. The phrase "bolsters the evidence" in the source itself is cautious, and that is the form in which it is worth remembering.

Three questions that help with reading news like this:

  1. What exactly was found and how much of it. A single fragment and a series of finds give different levels of confidence. Here 18 fossils are described, while the key specimen is one.
  2. Compared with what. "200,000 years earlier" only means something next to whatever it is earlier than. Here that is adult fossils from other sites, including Dmanisi at about 1.8 million years.
  3. How far the number carries. The ratio of "more than 10 to one" relates to the fossils found at Drimolen. How many individuals of each species actually lived does not follow from the number of bones found.

On where neural networks have already produced recognised results in science and where verification became the bottleneck, there is a separate piece: AI in science in 2026.

In summary

Archaeologists have described 18 fossils from the South African quarry of Drimolen, which was excavated through 2019 and is still being described today. The main find is the first adult Homo erectus skull fragment from there, about 2 million years old, roughly 200,000 years older than adult fossils of this species elsewhere. Paranthropus robustus, with its enormous molars, lived alongside, and across two sites you can see how over 200,000 years its teeth and chewing muscles became larger still. At the same time, fossils of the neighbouring species at Drimolen outnumber those of Homo erectus by more than ten to one, and, in the researcher's words, it was our ancestors who seemed unlikely to survive at the time. That is a ratio of finds in one place, not the size of the populations.

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