With great power there must also come great responsibility

You’ve probably already forgotten about A. sediba.

After all, it’s been just over two weeks since the two new gorgeous partial skeletons from Malapa, South Africa were unveiled in Science magazine. And, after all, you’re probably a normal person who can forget about extinct hominins between their media splashes.

But there are some people who cannot.

They are a dedicated brother- and sisterhood of scientists who work around the clock on our fossil record. Adding to it, maintaining it, and interpreting it. It’s only because of this fearless gang of fieldworkers and phylogeneticists that you can live a relatively luxurious, paleoanthropology-free lifestyle.

Really. They never stop working for you.

In fact, just after the new species was announced, paleoanthropology’s two most important conferences (the annual meetings of the Paleoanthropology Society and the American Association of Physical Anthropologists) were held in St. Louis and in Albuquerque just so that hundreds of us could put our brains together, meld our minds, and figure out just what to make of these bones. If you say it’s just a coincidence that these conferences occurred mere days after the Science publications, well then you just don’t understand the extent of paleoanthropology’s superpowers.

Both Lee Berger and Darryl de Ruiter gave spectacular back-to-back presentations at the Paleoanthropology Society meetings on the Malapa fossils. Afterwards, the floor was opened up for questions. Because I am a real blogger and am not just using it as a convenient cover for another more mysterious occupation, I raised my hand, “How do you know the arms are long?”*

From the gist of Berger’s answer and from what it says in the paper, although the drawing shows the arms to be long, the actual length of the arms relative to body size is not a shut case. However, with the additional remains from more individuals still lying there, in the ground, just waiting their turns to be excavated…. Good estimates of body and limb proportions are tantalizingly close!

Not only that, but word on the street is the preservation is so tremendous that there may be organic remains beyond bones and teeth—the actual squishy parts like hominin skin and hair and who knows what else? If this is true, start bracing yourselves for a paleoanthropology story that will eclipse the hobbit! In fact, by all accounts, Berger and his team are at the site right now—while we’re just going about our normal daily lives—working hard to recover all the additional remains.

Among paleoanthropologists, there are many questions about the Malapa remains. Some question the dating (could be younger than they say!), but the general buzz seems to center on the genus. Why Australopithecus and not Homo or not something else?

An equally valid question is who cares? After all, Mother Nature wouldn’t know a genus if it smacked her in the face. Genus is important to humans alone. The genus that we use to label the Malapa specimens stands for how we interpret them. If they were Homo, they’d have to be more cognitively complex than australopiths, making stone tools, eating a more diverse diet that included meat from scavenging and hunting, walking and running with completely bipedal bodies, etc…. But as australopiths, with their tiny brains and mosaic of bipedal and arboreal (or remnant arboreal) morphology, they’re one step behind Homo—even if they’re 1.9 mya or younger and even if they overlap in space and time with early Homo.

Get ready for a complete overhaul of how the Plio-Pleistocene transition in the hominin fossil record is interpreted. Using standards that were implemented back in the 1960s when the fossil record made much more sense (because there were so many gaps!) is no longer appropriate let alone feasible.

What is easily forgotten in exciting times like these is that each new fossil that paleoanthropologists uncover will look different from all others. That’s because of variation due to sexual reproduction among other things. So the notion that something is special because it looks like nothing else we’ve ever seen before is misleading. Malapa is certainly special but clones of previously known hominins? Now THAT would be special. The trick is to know just how different something is, if it’s just normal variation within a species (with some change through time accounted for) or if it’s too much variation for within one species. If it’s the latter, then it’s a new species.

In this case, the authors have decided that the Malapa remains are too different from A. africanus and from anything else on record. And so a new legend is born and a new name, A. sediba, is added to the roster of those who make the world of paleoanthropology the most exciting realm of all!

Probably an even bigger to-do than the scientific reports on Malapa was the openness of the researchers. They brought casts of all the material and laid them out for everyone to see, plus they offered to make casts for anyone interested. Having just discovered the fossils in late 2008, this is a laudable strategy for moving paleoanthropology in a productive direction. If people are going to keep finding all these rewriting-the-textbook fossils, then getting them out quickly for the rest of the gang to see, by Berger’s team’s example, may be standard practice from here on out.

And on that note, I leave you with this final thought.

Whenever you or someone you love gets excited about a hominin fossil, whenever you fall asleep at night assured that your hominin ancestors are being respectfully reconstructed, whenever you walk safely down the street knowing that your evolutionary tree is growing properly, don’t forget to thank your friendly neighborhood paleoanthropologist.

This superhero-themed post is dedicated to my student Samantha Davis who presented a terrific poster on early Homo molar shape outline at the Paleoanthropology meetings. If only we’d had Malapa to include in the analysis, right?

*What I should have asked when I briefly had the floor back in that ballroom was, “Can we eat it?” After all (according to my cab driver from the airport who just finished Voyage of the Beagle), until recently, when scientists found a new species that was their first question. Then if they couldn’t eat it they had to figure out what else to do with it.