One of the things that fascinates me about paleo-people is the layered depths of knowledge that is or isn’t taken for granted. I fondly remember climbing into a stone quarry with Richard Leheis, less in anticipation of finding a worthy fossil myself but in taking witness in this man’s literacy. Experienced fossil hunters can read stone. I slight bump in the surface of a slate sheet, combined with a slight discoloration at a broken edge and the knowledge of context (what type of stone is this from what historical epoch) combines (for Richard) into an incredibly accurate prediction of an animal or plant positioned in a certain way beneath this slab of stone are – to my eyes – absolutely nothing.
I’m an artist/animator. I have decent anatomical knowledge (Heinrich would correctly addend – mammalian anatomical knowledge) and little or no expertise in paleontology, biomechanics, etc… working hard to fill in those gaps and clever enough to say – hey, knowing what I don’t know is my greatest advantage! And reveling in those moments where my world is turned upside down. What choice would I have, other than to be grumpy about it?
Case in point… Archaeopteryx’s toe.

As you can see from this collage of artists as renowned and varied as Reichel, Paul, Heilmann, Frankford, Wellnhofer, Knight, Sibbick, deSeve (yeah, I even check out concept art from IceAge), mounts in Berlin and Eichsaett… more or less every reconstruction seems to show consensus concerning Archie’s toe. Namely – it’s bird-like and conducive to perching. Across the board.
What could you possibly have against that? I mean, look at the fossils:

There it is. Before your very eyes.
So – how does Scott Hartman come to this reconstruction?

I admit to a moment of smugness, thinking I’d caught Scott in an error so very untypical of him – his work commands my utmost respect. But how could he come to such a – literally – 180 degree difference to so many giants of paleoart? Well, if there’s any moral to today’s story, it’s this – stay humble. I contacted him to ask him about this, and good thing about that – preparing my question with a one-glimpse type graphic so as to steal as little of his time as necessary, but in retrospect it would have been more professional to (as Heinrich would say) read the f*cking paper. It’s all there, but Scott was kind enough to patiently roll it out for me. His answer is
Yes, the toes are clearly not retroverted in any specimen. Middleton first showed that dinosaurs with reversed metatarsals (which appear to only be ones further up the tree towards birds) have a distinctive twist in the first metatarsal…if you think about it, developmentally this has to be so, since you can’t just rotate a single phalanx around the axis.
Archaeopteryx clearly lacks this. Moreover, on the Thermopolis specimen the metatarsals are preserved much better, and you can clearly see that the first toe has rolled out of proper articulation with the metatarsal in order to appear reversed (and actually, ALL the toes are disarticulated…toes 2-4 rolled the opposite direction)
Taphonomically it works like this: the three dimensional skeleton gets flattened as sediment piles up. The large curved toe claws end up having to get twisted to one side of the other because of their shape. The number one toe is slightly offset to the inside (probably 15 degrees give or take). As a result it tends to flatten the opposite way of the rest of the toes.
Anyhow, I know it sounds like I’m saying “don’t believe your lying eyes” with those other specimens, but the feet are not preserved well enough to show the actual articular capsule, and it was on the Thermop specimen (and it clearly shows you can’t articulate them while retroverted).
And the corresponding section of the paper:
Toes: As detailed by Mayr et al. (2005), and also assumed by Middleton (2002), the first toe of Archaeopteryx was not fully reversed as in modern birds (contra, for example, Wellnhofer, 1993). In the new specimen, it is spread medially on both feet (Fig. 13).
Metatarsal I attaches to the medial (not medioplantar, contra Elanowski, 2002) side of the second metatarsal, in approximately its distal quarter, whereas it attaches to the plantar surface of the tarsometatarsus in modern birds with a fully reversed hallux (Middle-
ton, 2001); its proximal section even protrudes slightly further dorsad than the second metatarsal (Fig. 13). Moreover, the shaft does not exhibit the torsion characteristic for birds with a fully reversed hallux (Middleton, 2001).
lessons learned:

1) My 3D reconstruction will be at least in the realm of accurate, as Scott gave me detailed visual feedback. Archaeopteryx was not a percher, was not a tree-dweller, was not a bird in the form that the word tends to conjure up. The species has just gotten a lot more interesting to me, as has the whole chapter of early avian evolution.
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2) 3D reconstructions can communicate articulation much more precisely than 2d profiles can ever hope of doing. They also have the potential of illustrating all that scientific terminology in a direct, visual and possibly interactive way. I hope that I can contribute to so that I myself will be less lazy in wading through all those words, heeding more consistently Heinrich’s advice… read the literature.
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3) Someone literate in articulation has to articulate these things. Someone who’s learned not to trust their eyes.
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Papers Terminology…
- The tenth skeletal specimen of Archaeopteryx
Gerald Mayr, Burkhard Pohl, Scott Hartman , D. Stefan Peters
- taphonomy = the study of decaying organisms over time and how they become fossilized
- medial = towards the middle, (not just having to do with media)
- I’ll try to do up a graphic of all those other terms once I have other things out of the way