Skip to main content

Ceratosaurus nasicornis

One of my all-time favourite theropod is for some reason Ceratosaurus nasicornis. You might think its the horns but I'm actually more drawn to the overall skull morphology. I can't remember now why but Ceratosaurus was one of the first theropods that I attempted to draw the skull of. So I guess it was the first theropod that I actually paid attention to the skull morphology in some detail...

In any case, Ceratosaurus is still a taxon of significance. It represents the diverse group of basal theropods otherwise known as Ceratosauria, though what constitutes the group has never been stable. Aside from Ceratosaurus, Ceratosauria has traditionally included such taxa as Elaphrosaurus, Dilophosaurus, Coelophysis, Syntarsus, abelisaurids and other "ceratosaurs". Recent work however seem to show Ceratosauria in this traditional sense to be unsupported. Most recent phylogenies would separate coelophysoids (Coelophysis, Syntarsus, possibly Dilophosaurus, etc.) from Ceratosauria but the exact taxonomic make up of Ceratosauria is still controversial. Thus a more inclusive definition is preferred - that is, Ceratosauria is all dinosaurs sharing a more recent common ancestry with Ceratosaurus than with birds.

Even then, the vast majority of ceratosaurs are abelisaurs anyway so I can't see why they can't just be called basal abelisaurs or something...Ceratosaurus itself seems to be very closely related to abelisaurs, an enigma as all abelisaurs (with the exception of Tarascosaurus) are known from the Cretaceous of Gondwana. But then again, Ceratosaurus is basal to abelisaurs and its earlier presence may just be that basal abelisaurs weren't necessarily restricted to Gondwana...but who knows, maybe we'll never know.


traumador said…
As usual awesome drawing...

Quick question (if you don't mind my asking here) so Dilophosaur might NOT be a Ceolophysid? What would it be than if not part of that group?
According to some studies, such as Carrano et al. (2002) Rauhut (2003), Dilophosaurus is not within a monophyletic Coelophysoidea but basal to the rest of the derived "ceratosaurs". However, other studies unite Dilophosaurus with Coelophysis, Syntarsus, Lilienstrernus, Lophostropheus, etc. in a monophyletic Coelophysoidea. The overall consensus supports this topology as well.

However, it is kind of odd that previous studies which have attempted to resolve "ceratosaur" phylogeny did not have a wide taxonomic coverage and the majority of more studies seem to be focused on the interrelationships among the abelisaurs rather than the basal "ceratosaurs".
oops, that's "majority of more recent studies"...

Anyway, I think Dilophosaurus is a coelophysoid (based on the consensus of previous studies) - I just merely pointed out some controversial positions raised in previous studies.
Zach said…
Dilophosaurus is a giant coelophysoid. Actually, I think Gojirasaurus is of similar size. At any rate, I like the idea that coelophysoids and ceratosaurs (abelisaurs) are separate groups. The two look completely different, especially in the skull. I imagine that Ceratosaurus + Abelosauria sits just above ceolophysoids but below "megalosaurs."

I love the sketch. I like Ceratosaurus not really because of its horns, but because of its ridiculously large teeth! Gotta wonder what that sucker was eating with teeth like that. Maybe it was scavenging whatever Allosaurus was killing?
Hey Zach,

I love your observations! I was going to comment on the ridiculously large teeth but completely forgot while I was writing...thank you for reminding me.

There have been several papers that mentioned in passing the large teeth in Ceratosaurus so I'll reread those and perhaps even start a new blog post about the that...

Popular posts from this blog

R for beginners and intermediate users 3: plotting with colours

For my third post on my R tutorials for beginners and intermediate users, I shall finally touch on the subject matter that prompted me to start these tutorials - plotting with group structures in colour.

If you are familiar with R, then you may have noticed that assigning group structure is not all that straightforward. You can have a dataset that may have a column specifically for group structure such as this:

B0 B1 B2 Family
Acrocanthosaurus 0.308 -0.00329 3.28E-05 Allosauroidea
Allosaurus 0.302 -0.00285 2.04E-05 Allosauroidea
Archaeopteryx 0.142 -0.000871 2.98E-06 Aves
Bambiraptor 0.182 -0.00161 1.10E-05 Dromaeosauridae
Baryonychid 0.189 -0.00238 2.20E-05 Basal_Tetanurae
Carcharodontosaurus 0.369 -0.00502 5.82E-05 Allosauroidea
Carnotaurus 0.312 -0.00324 2.94E-05 Neoceratosauria
Ceratosaurus 0.377 -0.00522 6.07E-05 Neoceratosauria
Citipati 0.278 -0.00119 5.08E-06 Oviraptorosauria

The difference between Lion and Tiger skulls

A quick divergence from my usual dinosaurs, and I shall talk about big cats today. This is because to my greatest delight, I had discovered today a wonderful book. It is called The Felidæ of Rancho La Brea (Merriam and Stock 1932, Carnegie Institution of Washington publication, no. 422). As the title suggests it goes into details of felids from the Rancho La Brea, in particular Smilodon californicus (probably synonymous with S. fatalis), but also the American Cave Lion, Panthera atrox. The book is full of detailed descriptions, numerous measurements and beautiful figures. However, what really got me excited was, in their description and comparative anatomy of P. atrox, Merriam and Stock (1932) provide identification criteria for the Lion and Tiger, a translation of the one devised by the French palaeontologist Marcelin Boule in 1906. I have forever been looking for a set of rules for identifying lions and tigers and ultimately had to come up with a set of my own with a lot of help fro…

The fundamental problem with the Star Wars franchise

The sequel Star Wars Trilogy (so far Episodes VII and VIII) has been getting a lot of hate on the internet. While I think most of the hatred is just dreadful and ridiculous (like “Social Justice Warriors” taking over and making Star Wars too diverse and featuring too many strong female characters? Get out of here!), there are some legitimate criticisms, that I can relate to.

One such criticism is, that the new trilogy (especially The Last Jedi) effectively undoes the ending of The Return of the Jedi - in some ways rendering the struggles and sacrifices of the Rebel Alliance meaningless. As a viewer who watched the original trilogy conclude with the death of the Emperor, I presumed that the Empire came to an end, and with it the end of tyranny. I presumed that democracy would be reinstated in the form of a New Republic and the reconstruction of a New Jedi Order with Jedi Master Luke Skywalker at the helm. Peace is restored and all is good. I think that’s a nice ending.

But then the new S…