The Bad Hair, Incorrect Feathering, and Missing Skin Flaps of Dinosaur Art
atlasobscura.com
atlasobscura.com
> The amazing dinosaur found (accidentally) by miners in Canada: known as a nodosaur, this 110 million-year-old, armored plant-eater is the best preserved fossil of its kind ever found.
[1] https://www.nationalgeographic.com/magazine/2017/06/dinosaur...
It is a little sad, because there are so many open questions and some of those simply cannot be answered without a time machine. But at the same time, I am happy that our understanding of dinosaurs is still evolving.
This is my bearded dragon's x-ray
https://scontent-lga3-1.xx.fbcdn.net/v/t31.0-8/20819094_1010...
see all those facial features? That's how it's face looks, almost exactly. The don't even have to use crocs to derive the "reptile skulls look like their faces rule".
It's a silly thing to do of course, humans don't much look like dolphins or rats for instance but we're all mammals.
On the face of it that above statement seems a silly thing to say too, but it speaks to the way we tend to just apply 'dinosaur' to an incredibly diverse range of species that lived in multiple different environment right across the planet and across hundreds of millions of years.
I think there's probably room to start to acknowledging that 'dinosaur' no longer really can mean 'terrible lizard' and accept that it must speak to the diversity of the species within the category.
Reptiles and some dinosaurs have a sprawling, splayed-out posture. Other dinosaurs, birds, and mammals have independently-evolved upright postures. The birds apparently evolved from the splayed-hip dinosaurs rather than from the upright-hip dinosaurs, so a change in hip structure could be a decent dividing line.
But strictly speaking, birds (Aves) have wings as their forelimbs, rather than arms. The (extinct) moa is an exception in that it had no wings, but that is because it had no forelimbs at all.
It is very likely that other theropods besides the birds also had feathers, but it is rare for soft tissues to fossilize, so it can be hard to say what the scale and feather coverage was like for a given species when all you have is a partial skeleton. Determining coloration is almost impossible, though it has been estimated from especially well-preserved fossilized impressions of feathers that showed different spacing between the microstructures on the feather.
The traditional categorization is the forward (Saurischian) and backward (Ornithischian) facing pubic bones. But, the categorization isn't perfect and some theropods including birds, which are Saurischians, evolved backward facing pubic bones. (And apparently some Ornithischians evolved pubic bones that at least somewhat forward facing.)
Then discover you're still surprisingly wrong, probably. But it should rule out the pudgy T-Rex at least.
Now that we know many dinosaurs are most closely related to birds it is causing a revolution in dinosaur art.
* Velociraptor: http://johnconway.co/images/medium/velociraptor-mongoliensis...
* Shuvuuia deserti: http://johnconway.co/images/medium/shuvuuia-deserti.jpeg
* Pterosaurs: https://www.wnyc.org/i/raw/1/dinoart5.png
Is that something that would have been discouraged on HN itself?
It was just easier for me to find the book on Wikipedia than it was to find the correct version on Amazon.
Although it's perfectly possible that dinosaurs were effectively massive birds of paradise with ridiculous mating accoutrements...
However, taking the hippo as an example, some convex bone shapes seem to be a hint for neighboring body fat and muscle. I'd check first, if current artists would do better after training themselves on living animals. Also, I'd check whether reptiles can get as fat as mammals, etc.
We could probably train a model if we had an accurate training set of dinosaurs, but then it would be pointless.
I don't think the term "fallacy" applies either way because the parent's point not reducible to a logical error. It's more a matter of perspective.
Theoretically speaking, more information is always better. But that's only if you can feasibly work with arbitrary amounts of data. For example, in a deterministic universe we could simulate every instance of time forwards and backwards throughout history, but by definition we'd require more computing power than is possible to perfectly simulate our universe.
Similarly, if your information far outstrips your computational capabilities, you can no longer meaningfully work with the data. There are pretty hard economic limits on what kind of data we can work with today, so practically speaking it's accurate to say that more information can be a net negative. In particular, a preoccupation with acquiring more data can lead the analysis to focusing on the wrong data, or it can lead to a hopelessly noisy analysis, or it can lead to subjective decisions about which data to use that meaningfully alters the conclusions. Mathematically speaking, basic results from combinatorics (e.g. Ramsey theory) guarantee that at a sufficiently great size, your data is guaranteed to contain spurious correlations that have to be controlled for.
Whenever I'm working on an applied data analysis project I try to use as little information as I can from the outset. Sometimes this means fewer dimensions of data points, or smaller slices of a timeseries. But either way it results in less overall information to process.
If the information is not relevant but mistakenly assumed to be, because (e.g.) it is not, but treated as, representative of the class of animals to which it is applied, it can produce a worse model than one constructed without the bad information.
By including information that is not relevant, or that is redundant.
Search online for Feature Subset Selection. It's a thing. Given that more information makes training more expensive, if a lot of your data does not contribute to your model then you have a very good reason to exclude it. Conversely, you have a motive to not include irrelevant information.
You could probably get decent results just with models/pictures of skeletons and live animals, but I think MRI scans would be ideal- the model could learn to extrapolate actual structures of different tissues directly, and you could model things that don't exist in combination today. Birdlike musculature, body fat and skin over complex cartilaginous structures, with muscle traits of more cold-blooded animals.
There are many zoos with MRI machines, even extra-large ones used for large animals. I wonder how much of that dataset could be assembled? You don't even need very high resolution, centimeters would be plenty for something the size of a horse. Millimeters would be perfect for anything bigger than a sparrow!
[1]: https://upload.wikimedia.org/wikipedia/commons/7/71/Hippo_sk...
edit: and for more general reasons, because HN has a policy of identifying things from previous years as such in their titles, whether they're still relevant or not.