HOT: Big Shakeup in Hominin Evolutionary Tree

[Schneibster]

Remember how they always used to talk about the "missing link?"

They found him.

I'll steal this story: a couple million years ago, just as the current ice age (not the most recent glacial advance and retreat, but the whole shootin' match) was starting to cool down, Smilodon, the sabre-toothed tiger, had established a lair. Now, Smilodon is basically a big lion. Those long teeth are for 1) severing important neck structures, like jugular veins, carotid arteries, trachae, and spinal cord; and 2) reaching vital organs like the heart or lungs through the rib cage, or up from under it. So you can see from these teeth that this is a big game hunter. This cave tells us Smilodon dragged hir captured prey back to the cave, then went hunting again; this implies that they grouped together, though it may have been no more than a mother with cubs. This cave persisted for many generations, in fact for hundreds of thousands of years, continuously inhabited by these enormous cats.

People knew who lived in the cave; and when the owner was off hunting they would occasionally invade the cave. Probably they occasionally got some fresh lion cub to go along with their captured carrion; however, of more interest to us today is that sometimes the lion came back and reacted predictably to the trapped invaders.

The hero of this story is one of these unfortunate ones, and therefore dies at the very beginning of the story. (I love doing that.)

However, fortunately for us, his face remained uncrushed; and has in all the millions of years since. And the end of the story is we found him. (Yes it's a him yes we can tell from just the skull.) And he is a story all by his own bad self, even though he's dead.

This face combines features that have been identified as at least two and possibly as many as four "species:" Homo Ergaster, Homo Erectus, Homo Habilis, and Homo Rudolfensis. This skull says at least two and most likely all four of these are the same species.

So now we're left with this, call it Homo Erectus; Homo Sapiens Neanderthalensis; Homo Sapiens Floresiensis (assuming they don't also turn out to be H. Erectus, which would be our luck the way things are running); and Homo Sapiens Sapiens, us.

This is a huge shakeup and several previously recognized species will vanish. Just like Pluto got struck off the list of planets.

And all do to the fact we finally, finally, finally got lucky and found the skull of one single individual with the face intact. That's how rare and important that is.

[Schneibster]

Oh, and I put it here because it's not fusion news. Admins are welcome to review and overrule my choice if it pleases them. Or leave it be if they agree. It's all good.

Do not mistake this discovery: we now have a fairly complete lineage for genus Homo. We just have to fit it together. Now that we know that some of these "species" are actually all one, varying as much among themselves as we do, we now understand what we can expect to find as we pry into the final species or two that intervene between us and our common ancestor with Bonobos and Chimpanzees, six or seven million years ago. That common ancestor is probably a direct descendent of Proconsul, or even Proconsul hirself.

Australopithecus is most likely a third line descending from Proconsul, along with Homo (us) and Pan (the chimpanzees). The chimps and bonobos only split a couple million years ago, probably by being separated by the Congo River when it formed.

If you think "you weren't descended from monkeys" you're just plain wrong.

[Stubby]

Doesn't matter.
YECs will point out that by filling a so-called 'gap' between 2 fossils, you have in fact created 2 more gaps.

So now you would need 2 more 'links' and so on and so forth.

[Schneibster]

I'm not interested in what YECs think; I only care about sane people.

[Schneibster]

OTOH, some arguments just make themselves: how many missing links are there between a chihuahua and a Newfoundland? Derp.

[Schneibster]

I keep looking at this and realizing again how big a story it is. This really is the long-celebrated Holy Grail. The existence of these characteristics combined together in this single skull makes him the transition form they keep asking for. He's half-human half-H. Erectus. If you want my guess that's exactly what he is. Some loser got kicked out of the tribe and went and made a life with a female H. Erectus 'cause he was horny and couldn't get any any other way. This guy is the result.

You could sit down for brewskis with a male H. Erectus if he were dressed like us and had been taught to talk like us, and you'd be aware he was a bit dumb, and looked a little odd, but nothing outrageous. No jutting fangs or beetling brows and a desire for man-meat or anything. Maybe he's not the sharpest knife in the drawer, you know what I mean, but he's not stupid. He knows how to use fire, and he might even know how compound leverage works.

[Schneibster]

And this one isn't some sort of reconstruction; it's a whole face, preserved because the carnivore that killed its owner is so large that gnawing on it wasn't worth its time. No more jigsaw puzzles. This is a life mask.

I think your YECcie is hosed, Stubby; this isn't some reconstruction, this is a real face of a real person who lived a couple million years ago. There really isn't anywhere left to hide.

I think you underestimate the rarity of pre-civilization human fossils. We've really had a lot of trouble finding anything remotely this complete; the preservation of these skulls is unprecedented. We're very lucky to have found this den, and that it was not disturbed before it was buried.

[JoeStrout]

I doubt this is a hybrid, though that's certainly one possibility. It's more likely that, as you say, what was previously thought to be several different hominid species will turn out to be all one species.

Of course there are other scientists who think too much is being read into the new find. But, from my amateur's armchair, it sure appears to be good evidence for lumping over splitting.

As for "missing link" — I'm not sure it relates much to that. There hasn't been any significant missing link for decades. No matter where you draw the lines to split (or lump) ancient hominids into species, there's clearly a steady (and someone bushy) evolutionary tree from H. sapiens all the way back to primitive rodent-like primates, and as much further as you care to keep digging.

(And from my admin's armchair, I say this sort of post is fine in the General forum.)

[Schneibster]

I doubt this is a hybrid, though that's certainly one possibility. It's more likely that, as you say, what was previously thought to be several different hominid species will turn out to be all one species.

Of course there are other scientists who think too much is being read into the new find. But, from my amateur's armchair, it sure appears to be good evidence for lumping over splitting.

The answer to that is probably in the details of the skulls, and as you probably know, the skull is the most complex and specialized bony structure in the body. We mere peon amateurs will have to wait until they render their jargon comprehensible to mere mortals, pointing out the features from the different previously discovered skulls found in this one; then we can say which species are involved.

As for "missing link" — I'm not sure it relates much to that. There hasn't been any significant missing link for decades. No matter where you draw the lines to split (or lump) ancient hominids into species, there's clearly a steady (and someone bushy) evolutionary tree from H. sapiens all the way back to primitive rodent-like primates, and as much further as you care to keep digging.

Actually it seems to have gotten a lot simpler; from a common ancestor, we get chimps, Australopithecenes, and Hominins; and we have just narrowed the Hominins down to four species: H. Sap. sap., H. erectus, Neanderthalensis, and Rudolfensis (if in fact this last isn't an atypical H. erectus). We were wrong about the missing link; instead of linking two species together by being intermediate in time and lineage between them, the missing link connected several species we thought were different into one. I should have been clearer about my meaning.

(And from my admin's armchair, I say this sort of post is fine in the General forum.)

Good. Thanks.

[Schneibster]

And just today, of all days, they announce this: http://www.sciencedaily.com/releases/20 ... 153202.htm

No known Hominin is the common ancestor of us and Neanderthals. They split from us farther back than Homo Erectus.

The immediate thought that springs to mind is whether they were the descendents of the Australopithecenes.

The one right after that is, did breeding between us and Neanderthals therefore introduce hybrid vigor, making us what we are? Pure speculation. But.