The Malapa Soft Tissue Project FAQ

8 minute read

These are a few of the questions that I think are essential to understand our aims with the project and how we expect it will unfold. The future depends on what we hear from people with their ideas about how to analyze this unique evidence. I’ll be updating this FAQ as we learn more about the samples. This is an open science project, and we’ll be reporting on some results as they occur. But it all depends on people’s participation.

If you’ve arrived at this page from outside the site, here’s a link to the main project headquarters.

How did the project come about?

When I was in South Africa in July, Lee Berger gave me an extraordinary overview of the discoveries from the new Malapa site. Embedded in the breccia that surrounded the cranial remains of MH1 and MH 2 are some relatively small, thin layers that visually appear to be organic (relative to the surrounding matrix). Under a light microscope look like they could be mineralized or preserved soft tissue. They do not appear to be skin impressions within the matrix, they appear to be thin layers that are a different substance from the surrounding matrix.

Naturally these are incredibly interesting. But it is not obvious what will be the best way to establish what they are, and what we can learn from them.

Lee suggested that this would be an ideal test case to see if open science can help solve a problem in paleoanthropology. We want to reach the people with the best ideas and ability to test hypotheses about these objects, and we don’t know in advance where the answers will come from. That’s the nature of the project: finding the right people and making the science happen.

What do we want people to do?

We want the best suggestions about how to evaluate this unique evidence and how it can test hypotheses about human evolution. We’re reading all the suggestions sent to [email protected]

We’re especially keen to make contact with people who have the ability to make their suggestions happen. Some people out there have the knowledge to apply highly specialized analytical methods to samples like this. We want people like that to get involved with this project.

Some people out there may have comparative samples that will be key to interpreting this evidence. How can tissue be preserved in a context where breccia is forming? Was there natural mummification or some kind of anoxic environment? To answer those questions, we need people who study the response of tissue to those contexts and who know the right samples to examine.

Berger’s team working on the Malapa hominins have access to much of the best technology. Micro-CT, microscopy, virtual dissection, chemical analysis, any of these things and more can be brought to bear.

There’s a lot more to this project than simply verifying (or refuting) that this stuff is soft tissue evidence. We need to know how it formed. If it’s not soft tissue, we want to identify what it is, because there will almost certainly be more of it as the site is excavated and more specimens are prepared. If it is soft tissue, we need to know how it may have been changed as it was preserved, whether through drying, soaking in anoxic conditions, mineralization, or some combination of processes.

We think the process of finding this out is even more exciting than knowing the result. We hope many of you see it the same way.

If you write to us, you can expect that we may make your suggestion part of the website. This is an open project, and while we will be posting selectively, we will be sharing information as it progresses.

Why would somebody want to participate in an open science project like this?

We want to do the science right. We hope many people out there share this goal. It’s a tremendous chance for people who don’t normally operate within paleoanthropology to help us discover something fundamentally new about our evolution.

People who perform analyses or contribute samples as part of this project happen will be full participants in the science and coauthors of any resulting publications. We want people to work together on this, and we think the best science will result from bringing together the best ideas and comparisons.

How will the project work?

That depends on what great ideas we hear from people. Lee’s team will be carrying out analyses on these samples.

Rachelle Keeling is coordinating the study, doing the research on what should be done, and what it will tell us about the samples. She and I will be reviewing the e-mails that the project receives, and will try to determine which approaches are feasible, and which order they should be carried out.

As you send in ideas about what should be done, the more detail you can include about the analytical methods you can provide, the better. How much material (if any) does the method require? What hypotheses can the method test, or what information can it provide about the samples? How much time and preparation is required?

If you have comparative samples that may be useful, what kinds of observations can you make on them? Can you point to references that have also used these samples?

In other words, we want a bit of a plan if you can provide it. If you need more information from us to see if it’s feasible, let us know – we may be able to answer it, or have some team members carry out steps in advance.

The project will be carried out over the next year, so the sooner we hear from you, the better!

What is the Malapa site?

Malapa is a cave site outside Johannesburg, South Africa, in the area where many other sites preserving remains of early hominins have been found. I have a Malapa page that gives a short introduction and links to many stories here about the fossils found at the site. I visited the site in July, 2011, and posted a narrative of the visit (“A visit to Malapa”) that gives a good overview and several photos of the general area.

Two of the most complete hominin skeletons ever described, both dating to 2 million years ago, have been discovered and described at the site. The site additionally includes further fossil materials that are still undergoing preparation and study. It is one of the most important fossil discoveries ever made in paleoanthropology, and will continue to produce new evidence about our origins for many years to come.

How was the possible soft tissue evidence discovered?

So far, the team at Wits has been working on breccia blocks recovered from the surface at Malapa. There has been no excavation yet at the site. The possible soft tissue evidence was discovered during the course of scanning and preparing these breccia blocks.

The blocks are packed with bones. Many recognizable bones jut from the surfaces of the breccia, from antelopes, carnivores, small baboons and hominins. In several cases, hominin bones were recognizable at the surface, and these blocks were CT-scanned very early in the process of study and preparation. Scanning gives the preparators knowledge of what lies beneath their drill bits. In some cases, the best course of action is to leave the bones embedded within the breccia matrix, for further study by micro-CT.

CT scan of Malapa MH1 cranium

Initial CT scan of the MH1 cranium embedded in matrix block.

In the initial CT-scanning of the MH1 cranium, team members noticed an area where the matrix surrounding the skull appeared irregular. As they prepared this out, it became clear that the breccia itself had pulled away from the cranium across a small region, and the breccia had a thin layer of material at its surface there. This is not the outer table of the bone (which is intact in the corresponding area), nor is it apparently an impression of the bone.

Malapa MH1 breccia block with possible soft tissue

Photo of breccia block including MH1 cervical vertebra (top). The smooth area, center, is a thin layer of candidate soft tissue on the surface the breccia.

An additional section of possible soft tissue emerged as the female MH 2 mandible was prepared.

Upon magnification, these pieces do appear to have a structure. As yet, no dissection or further sampling has been attempted. The team has no committed opinion about what these represent or how they were formed, other than that they do not appear to be simple impressions in the surface of the breccia. Disproving that they represent soft tissue may be just as interesting as demonstrating it, because either way we will discover important facts about the preservation and formation processes of this unique site.

How could soft tissue possibly be preserved from 2 million years ago?

Like other South African cave sites, the Malapa fossil hominins were preserved within a breccia, a cemented stone material packed with fossils, rock fragments, and other material. The Malapa breccia represents a remarkable snapshot of time, when hominins and other animals fell into a “death trap” and their complete skeletons were preserved.

It is clear that Malapa preserves an extraordinary density of hominin remains, with nearly complete skeletons and articulated parts. These skeletons do not appear to have been disturbed after the bodies entered the site. Some plant and insect remains are preserved in the breccia as well.

Beyond this, any explanation so far is speculative. If there was water in the site, which seems likely, it may have included an anoxic layer that preserved some of this material. A major goal of the project will be testing different hypotheses about the preservation environment of these fossils, to try to explain what these substances may be.

Are you telling us everything?