Comments on: “Bone-Headed” Dinosaurs Reshaped Their Skulls

By: One Dinosaur Too Many? | Dinosaur Tracking

One Dinosaur Too Many? | Dinosaur Tracking — Tue, 24 May 2011 14:55:01 +0000

[...] and Mark Goodwin proposed that the dome-headed dinosaurs Dracorex and Stygimoloch were actually immature representatives of the larger Pachycephalosaurus. Last year, Horner and colleague John Scannella made a bigger [...]

By: Weekly Link Conglomerate | Ninjameys

Weekly Link Conglomerate | Ninjameys — Sun, 08 Aug 2010 16:21:16 +0000

[...] but only just. Recent studies have suggested that apparently distinct dinosaurian genera are the immature forms of others. As such, it has been suggested that Triceratops may be an immature [...]

By: A New "Bonehead" Dinosaur From Texas | Dinosaur Tracking

A New "Bonehead" Dinosaur From Texas | Dinosaur Tracking — Tue, 20 Apr 2010 15:04:32 +0000

[...] spread to that continent. This, added to the recent discovery that pachycephalosaur heads might be drastically restructured as they age, means that further research will be likely to shake up the pachycephalosaur family [...]

By: Top Dino Discoveries of 2009 | Dinosaur Tracking

Top Dino Discoveries of 2009 | Dinosaur Tracking — Thu, 31 Dec 2009 15:07:53 +0000

[...] “Bone-Headed” Dinosaurs Reshaped Their Skulls. A few years ago it was announced that there was some evidence that what were once thought to be three distinct “bone-headed” dinosaurs were really just growth stages of Pachychephalosaurus. The research supporting this hypothesis was published this year, and while it is still being debated, it has opened up questions about the identity of other dinosaurs, too. [...]

By: Zach Miller

Zach Miller — Thu, 29 Oct 2009 18:28:14 +0000

Well, give me a Triceratops with small parietals. Surely the only thing separating the two genera is not limited to the presence/absence of parietal fenestrae.

By: Eric

Eric — Thu, 29 Oct 2009 02:39:58 +0000

Zach maybe the “Triceratops Maximus” skull (apparently some kind of ten foot Triceratops skull, being studied by Bakker) is in fact the middle of the road specimen.

By: Wait for the paper

Wait for the paper — Wed, 28 Oct 2009 22:45:54 +0000

It’s amazing what people can fail to see unless they’re looking for it. Keep an eye on JVP in the next year.

And since the Toro/Tric distinction is basicially defined on the presence/absence of parietal fenestrae, of course you won’t get a Toro with a solid frill, or a Tric with big holes.

By: Zach Miller

Zach Miller — Wed, 28 Oct 2009 17:37:38 +0000

This seems well-supported in the paper, but I’m critical of the Triceratops/Torosaurus thing mainly because of the structure of the parietals. There isn’t one example of Torosaurus WITHOUT parietal fenestrae. There also isn’t an example of a Triceratops skull WITH parietal fenestrae. Scannella suggested that thin sections of Triceratops’ parietal became fenestrae, but as far as I know, there is no “middle of the road” specimen. This is odd, considering Triceratops is ridiculously common.