Newly Described Hominins Prove Difficult to Classify

Image credit: Brett Eloff and Lee Berger

Three years ago, the nine-year-old son of palaeoanthropologist Lee Berger found an intriguing fossil in a collapsed Malapa cave — the collarbone of a 2 million year-old hominin previously unknown to science. Further searches of the same site revealed 220 more bones of the same species, from infants to adults, with two particularly complete young adults whose combined remains gave researchers a clear image of their anatomy. In addition to the multitude of fragments (including a near-complete skull, shown above), the fossils were remarkably well-preserved — so well that at least one man speculates that they contain preserved soft tissues.

The new species was named Australopithecus sediba (sediba being wellspring, in reference to the Malapa location), as the physical proportions and brain size seemed very similar to Australopithecus afarensis — the species best represented by Lucy. And yet, since A. sediba‘s announcement in 2010, its location on the evolutionary tree has been debated and disputed and remains unsettled. Five papers published in Science this Thursday (Sep 8), which describe the skull, pelvis, hands and feet of the ancient hominin, don’t seem to offer any conclusive answers.

So what’s the big debate, you ask? Well, it seems our friend A. sediba had a few modern features. Though at first glance it appears to be built for an arboreal lifestyle, some interesting discrepancies show up in closer inspection. In addition to the obviously Australopithecine small brain/long limb features, A. sediba sported a human-like pelvis and hand very similar to those of Homo erectus–characteristics of the Homo genus, aka, our branch of the tree. These are the “walking upright, capable of building tools” developments which, interestingly, are not present in Homo habilis and Homo rudolfensis, species long believed to be our early, direct ancestors. So where does A. sediba belong?

“That is exactly what you’d expect when you find a very transitional form: 50% of the field saying they’re right, it’s an Australopithecine, the other half saying, put this in the genus Homo,” said Berger during a conference call announcing the new A. sediba papers.

At the time these fossils were living, breathing mammals, there were many species of humans living at the same time, including the early representatives of our own genus. The similarity of A. afarensis to A. sediba and the relatively immediate chronological appearance of the latter would naturally lead to the assumption that A. sediba is removed from modern human lineage, but the presence of human-like adaptations has us again questioning our ancestry.

[A.] sediba is more similar to us than even Homo habilis, the species that up until now was the front-runner for “earliest human ancestor” status. Sediba could be the bridge between the many australopithecines and Homo erectus.

There’s no consensus yet as to where A. sediba fits, or if or how he was related to modern humans. But the story of human lineage is certainly more interesting, if not any clearer, regardless of where our newest potential relative ends up on the tree.

Further Reading: Check out the source articles for more and detailed information.



18 Responses to Newly Described Hominins Prove Difficult to Classify

  1. I dont like this kind of things. How do they come to those conclutions? Besides, they start from the asumption that evolution is a fact, and to this date, it remains just an unproven theory

    • everything is an unproven theory. from any religious explanation, to the theory of evolution. there has just been more evidence that the theory of evolution is correct than any other. the first thing a good scientist needs to do is admit we don't know shit a 100% sure. all we can do is make ballpark estimates.
      if ya wanna get informed before you shout jibberish, i suggest this:

      • Why do you assume religious beliefs, because one disbelieve Evolution?
        Gravity is a theory, yes. It simply cannot be proven to be THE explanation for how objects move as they do. A professor in Mathematics could establish a theory with other sets of Variables to the equation, and alone that would make the "theory" different. Theories are ways of seeing things, with a formula.
        Evolution is not (Perspectively speaking) a theory. It HAS been proven wrong by many scholars in Biology and natural science. But those whom found it to be the best explanation (Yet to be put forward) defend it.

        Evolution does NOT conclude that we evolve Mentally, but that we assemble, over time, thus meaning we evolve Physically.

        But do not be mistaken. It is not religions versus Scientific Theories. It is one world view versus the other. One that we CAN rationally understand the world. And one that we CANNOT. I believe we CANNOT rationally hold absolute truth. That what we see and understand are but perspective projections of an Objective reality. I guess Buddhism relates to this world view a LOT. Were as Theism (Judaism, Islam) is more a view that we CAN be enlighten with objective truth, but ONLY with the blessing of the Lord, or vice versa. Lucifer.

      • Ah, time to be perceived as a troll… How about we eliminate religions that prevent people from believing proven science instead? That will probably go a lot further to eliminate racism and prejudice than "can't humans just be humans". Forcing humanity to live in ignorance because you're either scared of a god or disgusted at the fact that humans evolved from other lifeforms is not helping us as a species.

        • If you eliminated religions, you eliminated the people making up the actual definition. Thus you eliminated yourself, hence your Logic is based on fallacy and your argument is of a Kids anger towards his parents, because he were not allowed to do certain things as a child.

    • I don't like ignorant, outdated bronze-age belief systems that attempt to hold the rest of humanity back.

      You don't like the 'kind of things' science produces? Then how about you go take your fairy tales and sit in a cave with them while the rest of us enjoy the modern world, modern communication, modern medicine, modern transportation, and the modern dignity, humanity, and ethics that the pursuits of science have produced.

      • What are fairy tales? What cannot be proven, or what shall not be proven?
        Evolution CANNOT be proven. Gravity CANNOT be proven. The physical world CANNOT be proven. These are but HUMAN explanations to understand certain things we have to face each day.

        If you find yourself to be intellectually superior because you deny the possibility of an ultimate Lord dominating the existence itself, ruling it, and governs it, then YOU are the ones living an ignorant Fairy Tale based life.

        What's the point to share your world-view if you are not open to expanding your own knowledge?
        You think YOU hold an ultimate world-view, while there are Geniuses whom have driven Mathematics into its place today, that DID believe in a Creator and governor of the Universe?

        And yet. You hold the view-points created by Media Propaganda, and Anti-God campaigns. YOU are the one whom have been indoctrinated with the belief in no God.

      • Producing these technologies have cost Human lives, and will continue to do so. Konrad Zuse
        escaped the Nazi regime to produce his upgraded versions of the Binary PComputer. THE PComputer YOU are using to spread your ignorant ideas with. Binary is a Mathematical base consistent of 1's and 0's. It is what allows you to open your browser. And guess what. Religious people started THE Science that evolved Mathematics. Early Arabians and Egyptians practiced Mathematics, while practicing their belief in the Lord.

        You know little of the world you live in. And you come here telling us that religion is wrong?
        Everyone is religious! To even believe that the world is rationally intelligible, you NEED to be religious. You NEED to believe that it IS possible.

  2. In this case it's less about "what kind of human" than "is this ape or man or something in-between." You wouldn't say a gorilla and orangutan are the same thing; this is the same type of distinction. The importance of separating and classifying species (not races within one species, which aren't even real) builds a better model of evolution as a process and life on the planet as a whole. To say "who needs it?" then toss up your hands and say that evolution is "just a theory" are in complete opposition of one another. If you want proof, you have to do the science. That's how it works.

  3. Ah… it always amazes me how people who have no idea how evolution came about or how it works always have something to say about it… of course it isn’t a scientific law, but it make a whole lot more sense than “puff we were made” I’ve always wondered if religious creeps deny that dinosaurs ever excited too… hhmm.

  4. Man, why does this need to get so ugly? If you disagree with a post, state your objection. If your point is strong, no need to water it down with ad hominem.

    Seriously. Let's be adults about it.