“Little Foot” Bids for Status as Humanity’s Most Ancient Ancestor by Dr. Elizabeth Mitchell

Little Foot: Scientists Discover 3-Million-Year-Old Australopithecus prometheus and Little Foot, a South African Australopithecus as old as Lucy?

Australopithecine’s fatal fall preserved this fine fossil in a post-Flood cavern collapse.

Australopithecus prometheus, aka “Little Foot” and “StW 573,” after two decades of research and debate is finally receiving the attention accorded to more well-known names in the hominid hall-of-fame. Little Foot, from the evolutionary point of view, may finally fill the shoes of its mythological namesake by offering humanity an appropriately mythological gift,¹ the gift of identifying our oldest hominid ² ancestor.

Fame for Little Foot

This South African australopithecine ape, discovered in a Sterkfontein cavern by University of Witwatersrand paleontologist Ronald Clarke, has the distinction of being the most complete australopithecine skeleton yet found. But the brass ring for lasting fame in hominid research demands great age. Even with cute names, contenders for the “oldest human ancestor” need a truly superlative age to achieve lasting fame. Little Foot was once a winner using the 3.3 million year paleomagnetic date originally obtained by Clarke and colleagues and an even more impressive date of around 4 million years obtained using another method. Subsequent re-dating to 1.5 to 2.2 million years by other researchers, however, relegated Little Foot to the back bench. Now a detailed analysis of the bits of sediment tucked in the nooks and crannies of StW 573’s resting place suggests, researchers say, that Clarke’s original estimate was correct.

Little Foot’s saga began in 1994 with the discovery of four australopithecine foot bones in a box of miscellaneous bones from the Sterkfontein limestone cave system 23 miles northwest of Johannesburg, South Africa. They corresponded to a small foot, hence the diminutive moniker. When a fragment of tibia that seemed to match showed up in another box, Clarke sent a team to excavate the cave from which the bones had come. Amid the debris in the Silberberg Grotto, much of which was left from blasting operations, they found matching parts of the broken tibia. The date was July 3, 1997. Excavation of the accumulated rubble eventually yielded a nearly (about 95%) complete australopithecine skeleton with one arm flung over its head and the other by its side.

Though resembling Australopithecus africanus, a hominid commonly identified in South African dig sites, Clarke believes Little Foot has sufficient differences to merit its own species name, Australopithecus prometheus. Though many researchers still consider Little Foot an africanus, Clarke will likely publish additional anatomical details to justify the unique and noble name. Given that this fossil is being distinguished from africanus, Laurent Bruxelles of France’s archaeological research institute INRAP, said that one of the two lineages “might have been a close ancestor of the first humans, while the other probably left no descendants.”³

Age Is Everything

In the evolutionary story—especially the human evolutionary story—age is everything. As London’s Natural History Museum human evolution expert Chris Stringer said regarding a controversial group of Homo fossils, “If we cannot correctly fix the age and identity of the remains then we are in trouble. Getting that wrong even effects how we construct our own evolution.”⁴ The present study of Little Foot, published in the Journal of Human Evolution with Bruxelles as lead author, therefore, focuses on regaining a more ancient age for the promethean fossil.

The original age of 3.3 million years was assigned by Clarke and Tim Partridge on the basis of paleomagnetic analysis of layers of “flowstone,” thin sheets of rock formed by calcium carbonate precipitation from flowing water. As excavation continued, however, Clarke’s team realized that the flowstone had been deposited some time after Little Foot’s death, for the femurs were broken through and displaced. Separate deposits of flowstone had formed over various parts of the skeleton. Subsequent analysis of the flowstone by other researchers yielded a variety of younger dates ranging 1.5 to 2.58 million years.

It was apparent to Clarke’s team that analysis of the carbonate flowstone, because it was deposited some time after Little Foot’s death, was not a valid way to date StW 573. Bruxelles, Clarke, and their coauthors write, “Despite this, some investigators have published further dates for the StW 573 skeleton based on U-Pb (uranium-lead) dating of the flowstones, but without taking into account the complexity of the sedimentary record and demonstrably limited applicability of the flowstones.”⁵ Bruxelles therefore set out to analyze the complex arrangement of flowstone in and around the skeleton.

“The detailed stratigraphic study around StW 573, with supporting observations of thin sections and geochemical analysis, combine to indicate that the collection of stalagmitic flowstones were formed after the deposition and disturbance of the breccia containing the StW 573 skeleton,”⁵ Bruxelles, Clarke, and their coauthors write. The illustrations included in this article show some of the many deposits of flowstone and breccia (cemented rubble) surrounding the displaced femurs and pelvis. This suggests that collapse of the cavern and continuing precipitation of flowstone took place some time after the australopithecine died and was buried. They conclude, “that the skeleton was deposited considerably earlier than the adjacent flowstones, and that it is among the most ancient Australopithecus fossils so far known in South Africa. This potentially great age, coupled with the morphological analysis of the skeleton, places StW 573 in a key position for revealing information on the phylogeny of our ancestors.”⁵

Getting a Handle on Little Foot’s Age

Of course, having discredited the various younger flowstone dates ascribed to Little Foot by other researchers, the question remains, how can scientists determine an age for Little Foot? Bruxelles, Clarke, and their coauthors explain, “The question then arises as to whether it is at all possible to establish a reasonably accurate radiometric age for the StW 573 skeleton. Although minimum ages of 2.2 Ma have been determined, it remains difficult to say how much older the skeleton may be. . . . The skeleton is significantly older than the adjacent flowstones and it could be closer in age to that originally estimated by Clarke (1998), i.e., about 3 Ma.”⁵

Unable to rely on the radiometric dates of the rock (the breccia) entombing Little Foot, Clarke’s team needs an alternative dating method. They write, “As we cannot use the flowstones to provide a radiometric age for StW 573, it will be necessary to find other dating methods not focusing in any way on post-depositional modification of the deposit but to its original deposition. Cosmogenic nuclide burial dating [an analysis based on changes induced by exposure to the sun, which yielded an age near 4 million years] has so far not given good results, probably because chert clasts included in breccia have different origins.”⁵

Clarke’s original age estimate is now being popularly viewed as a valid minimum age for StW 573. Little Foot is finally back in the running for oldest hominid fossil in the South African “Cradle of Humankind,”⁶ having a default age comparable to East Africa’s Australopithecus afarensis (Lucy) assigned age of 3.2 million years.

Apes, and Men, but No Ape-Men

Before considering the implications of Bruxelle et al.’s stratigraphic analysis, we should reiterate, as we have discussed in many other articles, that australopithecines are not human ancestors but only extinct apes. Future papers discussing Australopithecus prometheus will doubtless give us the opportunity to address specific claims about Little Foot’s identity. For now, read more about the distinctions between human fossils—like Homo erectus, Homo neanderthalensis, Homo antecessor, Homo heidelbergensis, and Homo sapiens—and extinct apes like Ardipithecus ramidus (aka “Ardi,” currently sporting the impressive age of 4.4 million years but having trouble meeting the evolutionary demands of bipedality) and the well-known, allegedly bipedal australopithecine apes like Australopithecus afarensis (“Lucy”), Australopithecus sediba (“Karabo”), and Australopithecus africanus.

There are, incidentally, a lot of similarities among the australopithecines, and some researchers maintain that Australopithecus sediba is really just another example of Australopithecus africanus. The subtle distinctions that distinguish species from one another can often be sorted out in living creatures because their ability to interbreed can be assessed. Fossils divulge far less information to scientists, but the distinctions between different created kinds—like between apes and humans—are far more apparent when sufficiently complete specimens are available. (You can learn more about the distinctions between fossilized extinct apes and fossilized human varieties in Dr. David Menton’s video presentation Three Ways to Make an Ape Man and Dr. Terry Mortenson’s Ape-Men: The Grand Illusion.)

We know from God’s Word that humans (Adam and Eve) and land animals—including apes—were made on the same day, about 6,000 years ago as separate creations, humans alone being made in the image of God. Humans are also anatomically and intellectually distinct from apes. The fossil record shows diversity of apes and even diversity among humans but a distinct absence of “missing links” because as biology demonstrates, animals reproduce and vary within their created kinds but do not evolve into new, more complex kinds of creatures.

What We Now Know about Little Foot

Bruxelles, Clarke, and their coauthors have shown that the dates assigned by other researchers are invalid. They admit, however, that they really have no way, even with the usual evolutionary assumptions, to determine the age of Little Foot. They fall back on the ~3 million year date, however, because that is the age assigned to an associated “index fossil”—a fossil of “known” age by which other fossils in comparable strata can be dated.

Answers in Genesis geologist Dr. Andrew Snelling, commenting on their analysis, says:

This study very carefully shows the relative sequence of deposits in the cave. The authors have very successfully demonstrated that the Australopithecus skeleton StW 573 is older than the flowstone deposits that were previously dated by the U-Pb radiometric method at supposedly 2.2 million years old. The skeleton is entombed in a breccia which has been locally eroded to create voids, which were later infilled with the flowstones, though not before part of the skeleton was broken and shifted by subsidence.

The details provided by this study also discount the previous attempt to date the breccia enclosing the fossil at supposedly about 4 million years old using the Al-26 and Be-10 cosmogenic burial method. So they conclude the fossil may be as old as about supposedly 3 million years, based on the original determination of the fossil's discoverer at the time of discovery in 1997 using an associated index fossil.

The only conclusion that is certain is that the fossil is as old as the breccia it is buried in and older than the flowstone associated with it. But that's where the certainty ends.

What They Do Not Know about Little Foot

Dr. Snelling points out that every date in this and the associated earlier studies of Australopithecus prometheus and the minerals entombing it are steeped in unverifiable, worldview based assumptions. Describing some of these, he says:

All their postulated dates are dependent on the unprovable assumptions on which the uniformitarian (slow-and-gradual) worldview depends. These include constant radioisotope decay rates (at today's measured rates) and a closed system during the presumed millions of years without the possibilities of contamination.

The latter assumption is problematic given the recognized intermittent water flows in the cave and the solution saturation necessary for flowstone deposition capable of moving trace elements with such solutions. The rate of acquisition of cosmogenic isotopes is based on assuming constant geologic process rates in the past, which cannot be tested by observation because the past is gone.

The index fossil method relies on assuming both the reliability of radioisotope dating of deposits associated with such fossils where they are found elsewhere, and that the same animals evolved and lived at the same time in widely scattered geographic locations across the globe, both of which again cannot be verified in the unobserved past.

Little Foot and the Aftermath of the Flood

To estimate Little Foot’s age, we need to compare the analysis of the Sterkfontein cave with an eyewitness account of a relevant time in earth’s geological history. We know from God’s Word that the global Flood a little more than 4,300 years ago remodeled earth’s surface. Flood-based geological models help Bible-believing scientists understand the most likely geological changes that occurred not only during but also in the aftermath of the Flood. Dr. Snelling explains the findings in StW 573’s naturally formed tomb in terms of a post-Flood catastrophe. He says:

In the end, we can say with certainty that nothing so far claimed about this fossil's age is incompatible with the biblical framework and its chronology for earth history. The cave, like so many others around the globe, is a product of early post-Flood dissolution (chemical erosion) of limestone and dolomite layers (deposited during the Flood) only 4,300 years ago when there were much higher precipitation rates due to huge storms dumping torrential rainfalls on the continents because of the warmer ocean waters (a result of the release of enormous volumes of volcanic waters during the Flood).

Those wetter conditions would also have caused the breccias in the cave to accumulate rapidly from ceiling rock-falls, which makes sense of the full skeleton of the Australopithecine (a post-Flood ape whose relatives migrated within decades to Africa from the Ark) being rapidly buried and preserved intact. The subsequent erosion of voids and their infilling with flowstones need not have taken more than hundreds of years, due to the changing and variable climatic conditions.

Viewing the evidence in light of biblical history, we can safely say that Little Foot is an ape that most likely died around 4,300 years ago. Extinct ape fossils in Africa are typically found deeper in the fossil record than human fossils. Following the global Flood, animals disembarked and began to move away, reproduce, and replenish the earth. Despite God’s command, however, the descendants of Noah’s family delayed moving out to replenish the earth until forced to by the confusion at the tower of Babel. The history in the Bible thus makes sense of apes’ placement in the fossil record, which has nothing to do with evolution.