The travails of the holotype of Parasaurolophus walkeri

[Halichoeres]

The holotype of Parasaurolophus walkeri (ROM 768) has several damaged neural spines, leading to reconstructions showing the species with a notch over the shoulder (see the figures by Papo and Schleich, for example). This paper examines this and other pathologies showing that this individual had kind of a rough life. The authors also look at the anatomy of the nuchal ligament, which acts as a suspension bridge between the back of the head and the dorsal vertebrae. It results in a somewhat "thick-necked" profile for Parasaurolophus compared to what we're used to seeing.

Various possible configurations of the nuchal ligament, and a skeletal+silhouette of an intact individual by Marco Auditore based on (e):


And a possible scenario for how ROM 768 came by its injuries; drawing by Marzio Mereggia:


Bertozzo et al., open access in Journal of Anatomy: https://onlinelibrary.wiley.com/doi/full/10.1111/joa.13363

[Pachyrhinosaurus]

I remember it was common to depict hadrosaurs with such thick necks like this years ago but it has since fallen out of favor. Gregory Paul I think popularized it.

[Newt]

Very cool stuff. My instinctive thought is that the reconstructions on the left side, showing the nuchal ligament inserting on the axis alone are more sensible than the ones on the right that also attach to the back of the skull, as they would support the skull's weight without limiting its mobility. It also seems the more concave reconstructions, on the bottom of the diagram, would not require the ligament to stretch to absurd lengths when the animal lowers its head to drink or eat. But I have no evidence for that. I guess I should read up on mammalian nuchal ligaments and see how they work.


@Pachyrhinosaurus - some of the hadrosaur mummies also indicate these animals had beefy necks. I'm not sure where the new slim-neck trend came from, unless it's purely aesthetic.

[Sarapaurolophus]

That's a beautiful illustration.
I thickened up the necks and got rid of the spinal notch on two of my owned figures. Maybe I'll make the necks even beefier now

[ceratopsian]

Mareggia's illustration is one I would be happy to have on my wall.

[Halichoeres]

Very cool stuff. My instinctive thought is that the reconstructions on the left side, showing the nuchal ligament inserting on the axis alone are more sensible than the ones on the right that also attach to the back of the skull, as they would support the skull's weight without limiting its mobility. It also seems the more concave reconstructions, on the bottom of the diagram, would not require the ligament to stretch to absurd lengths when the animal lowers its head to drink or eat. But I have no evidence for that. I guess I should read up on mammalian nuchal ligaments and see how they work.

Yeah, I don't have a good intuition for how elastic a ligament of that length would be. The ones I've dissected have all been much much shorter (and probably less stretchy owing to usually not being freshly dead).