New Ardipithecus fossils shows creationists are wrong about Lucy (again)

Oh dear. This is one of the times I discover I’ve been spending too much time on the internet. Simpson et al. just found a bunch of new Ardipithecus fossils ¹; and whilst everyone else is celebrating I’m left going “hehe, clearly creationists don’t know what they’re on about”

Which shouldn’t really be news to anyone, making the fact it’s my first reaction concerning. So come and cheer me up by suffering along as we take another dive into creationist wrongness.

Creationists and taxonomy

All of this stems from the fact creationists have a bit of a problem. You see, they have to draw a clear line between humans and other species that are “just an ape”; since we didn’t evolve from them. However, we did, making it impossible to cleanly divide us from other hominins.

Of course, being far removed from science hasn’t stopped them before; so they try anyway. The result is an entertaining variety of contradicting creationist claims about where species belong.

In an effort to sure up their silly divisions, creationists will do their best to try and make those on the “just an ape” side seem as ape-like as possible. This can include selectively quoting the scientific literature to focus a species-ape like traits, to just flat out ignoring the science.

Lucy, sadly, has been a victim of the former; with Answers in Genesis depicting her as a knuckle-walker, despite the fact the evidence her species was bipedal is overwhelming. I’ve taken them to task on this before, prompting them to write a massive 6,000 word diatribe to refute lil‘ ol‘ me.

I’m not ashamed to say that being able to bask in their vitriol is one of my finest moments.

Creationists and Lucy

Lucy herself contains abundant clues she wasn’t a knuckle-walker. However, one of the best lines of evidence actually comes from the rest of the hominin lineage. Namely, that none of them – including those creationists think are related to Lucy – contain any trace of knuckle-walking either².

This makes their proposal not only wrong, but evolutionarily absurd. After all, knuckle-walking requires a suite of anatomical adaptations. All of these would have to evolve over time, leaving behind tell-tale clues in closely related species.

Except, as we’ve established, those anatomical traits aren’t present in other species. This means those adaptations would have to appear suddenly in Lucy’s species; and disappear again just as quickly.

This isn’t how evolution works, making the creationist model not only wrong; but biologically impossible. It’s like how flat earthers aren’t just wrong about the shape of the earth, their models violate all known laws of physics.

Scientists and Ardipithecus

All of which brings us to Ardipithecus ramidus. They are one of the last hominin species that maybe could have knuckle-walked. There’s some good evidence they didn’t, but a lack of fossils prevent us being certain. Thus, they remain the last species giving the creationist claims (a tiny amount of) credibility.

Or at least, they were until palaeoanthropologists went and found more Ardipithecus fossils¹.

The new discoveries come from Gona, Ethiopia, an area already famous for featuring fossil remains from more recent human species, and a whole bunch of stone tools made by them.

Now, the area gets another claim to fame as Simpson et al. spent nearly a decade surveying and excavating specific sedimentary deposits that are part of the Sagantole formation. They picked these because, at ~4.5 million years old, they’re the right age to contain more Ardipithecus¹.

So if evolution, geology, radiometric dating etc. are actually reliable, they should discover many more fossils. Which, in a stunning testament to the fact science works, they did (which, on the flipside, is also a dramatic failure for the creationists, but let’s not be too mean here)¹.

Across the Sagantole formation, Simpson et al. found nearly three dozen more Ardipithecus fossils. Individually, each might not be that impressive, but together they give us a surprisingly decent snapshot of the species¹.

In particular, they preserve many features of the hand and wrist that should contain adaptations to knuckle-walking. Assuming, of course, the species did move like that.

Creationists and Ardipithecus

Crucially, this site is ~50 km away from earlier discoveries; and potentially 0.25 million years older. As such, it helps to expand our understanding of the natural variation within Ardipithecus. In this context, it can help reveal whether their apparent lack of knuckle-walking traits seen was a weird quirk present in just one individual, or the actual default condition of the species.

The answer is the latter, as I’m sure you’ve already guessed from the amount of sass I’m bringing to the table.

Notably, the new fossils preserve many bits of the hand and wrist, which are obviously key features involved in knuckle-walking. Containing, you know, the knuckles. Thus, if the species ever used it you can bet there should be evidence of it here. But there isn’t¹.

Combining these new discoveries with existing finds, we can now definitively say that, compared to knuckle walkers^1,3:

• Their fingers are too short.
• Has none of the prominent ridges or grooves for the relevant muscles to attach to.
• A less robust palm, ill-suited to absorbing the forces of walking on it.
• A weaker wrist, also poorly suited to walking on.

And of course, the best conclusion of all: creationists were wrong about Lucy (again).

References

1. Simpson, S.W., Levin, N.E., Quade, J., Rogers, M.J. and Semaw, S., 2019. Ardipithecus ramidus postcrania from the Gona Project area, Afar Regional State, Ethiopia. Journal of Human Evolution, 129, pp.1-45.
2. Lovejoy CO, & McCollum MA (2010). Spinopelvic pathways to bipedality: why no hominids ever relied on a bent-hip-bent-knee gait. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 365 (1556), 3289-99 PMID: 20855303
3. Lovejoy, C.O., Simpson, S.W., White, T.D., Asfaw, B. and Suwa, G., 2009. Careful climbing in the Miocene: the forelimbs of Ardipithecus ramidus and humans are primitive. Science, 326(5949), pp.70-70e8.