Plateosaurus engelhardti

Another scanner-faded work here, just a quick one, done in about 2 hours. Based pretty much straight off a skeletal work by Scott Hartman. Hopefully he doesn't have a GSP style tantrum on my arse.

Famous prosauropod Plateosaurus engelhardti. Somewhat recently discovered to be a full biped after being thought for the good part of two decades to be predominantly quadrupedal.

Now for the whole reason behind this image:
The most striking feature you may notice on this particular reconstruction are the somewhat pre-"dinosaur-renaissance" looking dermal spines running down the majority of the animal. Smaller variants of these can also be seen on the limbs.

These were drawn out of a discussion on my new forum in which it was brought up that the dermal spines of Diplodocus have been widely misinterpreted. Scott Hartman (I must give credit to him again) has apparently spoken in length to Kirby Sieber, whom dug up the specimen, and apparently the keratinous structures cover much of the dermal surface and there is no evidence that they were strictly midline structures (though there may have been a row on the midline). This discussion continued with Matt Martyniuk pointing out that there are apparently macronarian footprints which show "scoring from what must have been spiky dermal covering on the feet." This lead to the hypothesis that perhaps some sauropods (or other dinosaurs) possessed a variety of spiky dermal coverings.

Now on my own interpretations. I have for a while been leaning heavily towards the idea that a single type of dermal keratin structure being basal to dinosauria (or perhaps ornithodira) and developing into these sauropod "spines," the similar structures (though apparently restricted to the midline this time) of Monoclonius, coelurosaur feathers, the EBFFs of more basal coelurosaurs, Tianyulong and Psittacosaurus, the midline dermal "bumps" of hadrosaurs and whatever other boneless keratin structures we may find.
Additionally, the same discussion also gave me the knowledge that a bony core can apparently be developed after the keratin structure. If this is the case it leaves the possibility open that this hypothetical structure was also the precursor to dermal structures like the osteoderms of ceratosaurs or even the plates of stegosaurs!

The arrangement I have displayed here on Plateosaurus is something like what I believe could have developed into all of these structures.

I should finish by pointing out that this is pure speculation on my part, but it will likely influence my dinosaur reconstructions heavily until evidence is found to support otherwise.