2-million-year-old fossils of Australopithecus sediba - a species with chimp-like arms for climbing but human-like hands for precision gripping. A mother and son fell into a cave shaft together, preserved in death as possibly the best candidates for our direct ancestors.
Emőke Dénes, CC BY-SA 4.0, via Wikimedia Commons
A chance discovery
In August 2008, paleoanthropologist Lee Berger was exploring a patch of the Cradle of Humankind World Heritage Site that had been largely overlooked. He had identified nearly 500 previously unmapped caves in the area using Google Earth. On August 15, his nine-year-old son, Matthew, who had come along for the day, stumbled upon a fossilized bone. It was the collarbone of a juvenile hominin. Soon after, Lee Berger himself found a jaw with a canine tooth in the same rock. They had discovered an entirely new species of human ancestor, Australopithecus sediba.
The site, named Malapa, turned out to be a former cave system, a deep pit that acted as a natural death trap millions of years ago. The initial finds were part of an exceptionally complete skeleton of a juvenile male, designated MH1. Weeks later, a second partial skeleton, an adult female known as MH2, was also located. The preservation of the fossils is extraordinary; they were found in a semi-articulated state, showing no signs of having been disturbed by scavengers. It appears the individuals fell into the 50-meter-deep cavern and were quickly covered by sediment, preserving their bones in a concrete-like rock called breccia.
A mosaic of features
Australopithecus sediba has a mix of primitive and human-like anatomical traits. Its brain was small, with a cranial capacity of only about 420 cubic centimeters—not much larger than a chimpanzee's. Like other australopithecines, it had long arms and powerful shoulders, well-suited for climbing.
Yet, other features are surprisingly modern. The hand of Au. sediba has short fingers and a long thumb, an anatomy that would have allowed for a precision grip, possibly for tool use. The pelvis is also more advanced than that of other australopithecines, showing changes associated with more efficient upright walking, similar to early members of our own genus, Homo. This combination of traits—a primitive upper body and a more modern lower body and hand—provides a unique snapshot of a species at a potential evolutionary stage.
Pinpointing a moment in time
One important aspect of the Malapa site is the precise dating of the fossils. Scientists used a combination of Uranium-Lead (U-Pb) dating and palaeomagnetism on the layers of flowstone sandwiching the fossil-bearing sediment. This method allowed them to date the skeletons with remarkable accuracy to 1.977 million years ago.
This specific date places Au. sediba at an important period in human evolution, when the first members of the genus Homo were emerging. The collection now includes over 220 fossil elements of the species, representing the most complete skeletons of any hominid from this time period. The site yields fossils of hominins and a diverse range of other animals that shared their environment and fell into the same natural trap.
💡Fun Facts
The species name "sediba" means "fountain" or "wellspring" in the local Sesotho language.
The first hominin fossil was discovered by Lee Berger's nine-year-old son, Matthew.
Other animals found in the Malapa pit include saber-toothed cats, wild dogs, antelopes, and the earliest known baboon.
The fossils were so well-preserved that they show no signs of scavenger activity, indicating a rapid burial after death.
The Malapa site is an active scientific excavation within the private Greater Cradle Nature Reserve. It is not open for casual public access, but can be viewed from a specially constructed visitor platform on pre-arranged tours.
Admission
Access is typically part of guided tours that must be booked in advance through the Cradle of Humankind or affiliated tour operators.
Accessibility
The terrain is a nature reserve. Access to the visitor platform is managed, but the surrounding area can be rugged.
