Skip to main content

Updates and Pachyrhinosaurus

Having submitted my thesis on the 29th of September, a day before the absolute deadline (the University of Bristol permits exactly 48 months to submit a PhD thesis), I thought I could kick back and relax...maybe spend more time on drawing or blogging - but I was wrong.

Not having secured a postdoc position, I spend most days stressing, searching, working closely with academic staff on postdoc proposals, and working on converting my thesis chapters into manuscripts. At the same time, I'm trying to catch up on the reading that I'd put on hold while I was manically typing away on my thesis. I have quite a large 'to read' pile. There are some rather interesting papers out there that I only recently stumbled across and so I must blog about them sometime, when I get my head arround all the head-ouch evolutionary theories and models.

...I have this thing about not posting anything until I have something either interesting or useful to post, so not having devoted much time or effort to blogging, I'd kind of put off on the posting - until I realised that it's been more than a month since my last post...

So anyway, on popular demand, I'd started drawing a Pachyrhinosaurus. I still have to flesh it out, literally, but I just present here the framework on which I will be basing my live-restoration of this animal. As I intend to flesh this out, I didn't really bother with the anatomical details of each and every bone of the postcranial skeleton. I am happy just as long as I can make it look 'real' enough.

I usually want to follow original descriptions wherever possible, but not much has been written on this dinosaur. This was quite surprising to me as I had heard that there are bonebeds of this animal and thus there are plenty of materials to work on. There is that new monograph but I don't have a copy of it yet. So instead, I relied on images from the web supplimented by various photos supplied to my by Traumador Tyrannosaur (cheers!). I have ordered a copy of the new monograph last week, so hopefully I'll be able to start on a MK II Pachyrhinosaurus or more specifically P. lakusti. For this one, I guess it's the type species P. canadensis but I don't think it really matters that much.

Perhaps one of the enigmatic things about this animal is the presence of a bony boss where a nasal horn core should be in most derived ceratopsians. Nobody really knows what covered this nasal boss, such that there are many different reconstructions, some more fantastic than others. I haven't yet decided what I want to do with this but being a sceptic of many things I may go for a conservative reconstruction this time...


Traumador said…
To start off with congratulations on finishing writing the PHD!!! I was in suspense hoping to hear good news. Now hopefully the defense goes fine, and we'll be calling you Doctor soon ;p

As for the photos no worries. Again if there's a critter from western Canada you want a reference for I've probably got something (that's for anyone else reading the comments too)

The drawing is looking good as always. Can't wait to see him fleshed out.

I myself have started on 3D ceratopsians (of a non neoceratopsian variety that is), we'll have to try and coordinate a ceratopsian restoration month or something. I'll alert Zach to the possibility as I'm sure he'd be game.
Sean Craven said…
Your approach to the construction is very interesting -- using just enough skeletal elements to get the proportions right.

Gonna have to try that one the next time I tackle a dinosaur.
Manabu Sakamoto said…
Thanks! My internal examiner always tries to comfort me by telling me that my viva would be just like a discussion...but we will see.

Your idea is interesting - I can always cooperate in a thing like that!

I've always been a bit lazy and didn't really see much point in putting lots of effort into the skeleton that eventually gets drawn over...but then, I recently found out that professional illustrators use tracing paper to make successive layers of reconstructions - ha! What a simple but effective method...
Sean Craven said…
I've done that on a number of drawings -- but I've always done this using skeletal diagrams that are flat side views. The big boys can draw the skeletons in perspective. I think that in addition to experience they probably have better reference material than I do...
Traumador said…
Oh just a quick point. Those pics I sent you were all of P. lakusti not canadensis. I might have a pic of canadensis somewhere, but as far as I'm aware there is ONLY the type skull technically speaking (many pachy's haven't been formally described).
Manabu Sakamoto said…
ah - I see. that's interesting...more scopes for someone to work on pachys!
Traumador said…
Definately more room.

The Tyrrell itself has a new one from Dinosaur Park (one of the fully mounted skeleton shots I think I sent you) that is a good 3-7 million years older than any OTHER known Pachyrhino.

The problem with it is they only have the skull, but NOT the frill. Which these days is the key identifier for Ceratopsians.

This one has yet to be described formally.

From what I understand there is a lot of work needing to be done on the Alaskan Pachys, and determining if they are a new type as well.
Zachary said…
Hey, Manabu! Good to see you at SVP (even briefly), and congrats on the PhD work. I have no worries that it'll turn out wonderfully.

The pachyrhinosaur is looking good! Don't worry too much about every bone in the body. I've recieved and read the P. lakusti monograph and it only covers the cranial skeleton. There is no postcranial description, which makes me sad. Here are my only recommendations:

The "unicorn horn" in the middle of the frill is split into three pronts at its base, the two outer prongs curve away from the central one. The frill does not curve upward as strongly as in some other centrosaurines like Centrosaurus and Styracosaurus. The nasal boss would have a fairly rounded upper margin in life. The anterior tip of the boss looks like a spout, in that it curves ever so slightly forward to a rounded point. During growth, the single nasal horn of juveniles (made up of the paired nasal bones) spread outward instead of growing upward, and most of this growth was concentrated at the back of the horn. So it's like new bone is bubbling out between the nasal bones, and the adults end up with a very WIDE nasal horn. Does that make sense? However, when viewed from above, the "final" boss would look like a rounded triangle.

The nasal boss and supraorbital bosses do not "connect." In fact, there's an obvious T-shaped depression separating the three bosses. None of them likely supported some kind of "super horn." Instead, I'd cover the boss with a rugosely-textured horny covering like in musk ox.

And finally, because I'm a stickler for this little detail, centrosaurines had semi-sprawling forelimbs. They could not gallop! :-)

And I'd totally be game for a round of ceratopsid restorations. I want Einiosaurus!
Manabu Sakamoto said…
hi Zach,

It was nice to finally meet you in person, albeit a very brief encounter. It was a rather busy schedule, wasn't it?

Anyway, I finally got my copy of the monograph this week. It turns out it was delivered to my building but was turned down because it didn't have the name of the Department written on it...I would have thought the porters would know me by now, what with being here for the last 5 years and all....

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…

Top 10 scientifically important theropod dinosaurs of all time (off the top of my head)

I thought I'd do a fun post for once. And since list based articles are the norm for fun on the internet, I thought I'd do one on dinosaurs, but given that I know most about theropods, I've decided to restrict my list to theropods (...maybe in a future post, I'll do other clades).

My ranking is based mostly on scientific importance so it may not reflect awesomeness, and it is obviously subjective as to how I rank importance to science. For instance, interesting discoveries or unique palaeobiology are ranked relatively low compared to wealth of information and data or completely revolutionising our understanding of the evolution of theropods.

So here are my top 10 scientifically important theropod dinosaurs of all time (off the top of my head)

10. Megalosaurus

Being the first dinosaur to be named, Megalosaurus automatically deserves a spot on this list, but given the fragmentary nature of known fossil specimens, and being mostly useless as a meaningful source for biologi…