Tuesday, August 19, 2008

My PhD thesis

With 42 days to go until I have to submit my PhD thesis, I haven't really had much time to blog...let alone draw dinosaurs! All I have time for is to get stressed out.

Anyway, in the midst of all this, I've finally decided on a thesis title:

Bite force, and the evolution of feeding function in birds, dinosaurs and cats.

The perfect title to show just how much unfocused my thesis is when it comes to a taxonomic group of interest, but extremely obsessed with bite force...ha! Of course it may be subject to change.

The actual thesis consists of five chapters:

Chapter 1: Introduction
Chapter 2: Myology and functional morphology of extant archosaurs
Chapter 3: Reconstruction of the jaw adductor muscles and jaw biomechanics in dinosaurs
Chapter 4: Dry skull bite force estimation in felids
Chapter 5: Tracing the evolution of bite force in Darwin’s finches and felids

Chapter 1 introduces biomechanical concepts regarding bite force and also introduces bite force as a useful single-value indicator of feeding function. So Chapter 1 is theory-heavy.

Chapter 2 is pretty much a preparation chapter for Chapter 3 and is dominated by straightforward muscle descriptions in extant archosaurs but primarily birds. Special focus is given to the Herring Gull/Lesser Black-backed Gull complex (Larus argentatus/L. fuscus), Common Buzzard (Buteo buteo) and Domestic Chicken (Gallus domesticus) but also feature the Ostrich (Struthio camelus) and other assorted birds. But perhaps the most important thing about this chapter is the data collection of cross-sectional areas of muscles for muscle force estimation.

Chapter 3 deals with jaw muscle reconstructions and bite force estimations in dinosaurs, in particular theropods. A simple method of bite force estimation is discussed and bite force is then predicted in a wide range of theropod taxa which is then used to test evolutionary hypotheses regarding feeding adaptations...

Chapter 4 is a critical reinvestigation into the Dry Skull method using extant and extinct cats. Bite force is estimated in 38 extant species of felids plus 3 extinct cats (Miracinonyx trumani, Panthera atrox, and Smilodon fatalis).

Chapter 5 takes the bite forces estimated for cats in Chapter 4 and uses a phylogenetic comparative method to test evolutionary hypotheses. Data in Darwin's finches are also analysed in the same way, mostly for the historical significance of finches in the development of evolutionary theories but also because there are plenty of data available for Darwin't finches in the literature. I gave a talk at PalAss last December on a priliminary version of this chapter.

There is also a summary and conclusions section at the end to wrap it all up.

So in summary, my thesis is really about bite force estimation methods and practical uses of bite force in evolutionary analyses...the evolution of functional adaptations intrigues me to no end and I believe that bite force is a strong tool in analysing functional adaptations regarding feeding.

13 comments:

Jerry D. Harris said...

Anyway, in the midst of all this, I've finally decided on a thesis title:

Bite force, and the evolution of feeding function in birds, dinosaurs and cats.


Uh...if I may be very presumptuous here for a moment, that title should be:

Bite force and the evolution of feeding function in birds, dinosaurs, and cats.

No comma after "force" and a comma after "dinosaurs."

The perfect title to show just how much unfocused my thesis is when it comes to a taxonomic group of interest

That's not a big deal and I wouldn't worry about it -- as dissertation topics become more and more transdisciplinary, it's increasingly necessary to broaden one or more research scopes (e.g., taxa, approaches, disciplines, etc.) in order to answer interesting questions; trying to accommodate all that under a single banner -- which, really, only a dissertation would ask anyone to do anymore...! -- necessitates titles like yours that seem excessively broad but actually do a great job of depicting the actual content.

Mambo-Bob said...

Ah - cheers! I'll change the title as suggested. Thank you very much.

And I'm grateful for your encouragements. I need all the support I can get right now;)

Traumador said...

Good luck with finishing it and the defence. I look forward to good news when you're done

Manabu Sakamoto said...

Thanks, Traumador!

Incidentally, I'm using LaTeX so thankfully, I don't really have to worry too much about formatting...phew

Julia said...

I suppose there is a perfectly good explanation but I know the dino birds connection but why cats?

Manabu Sakamoto said...

Hi Julia,

The main reason I got into cats was because I helped supervise a masters project on a Smilodon specimen that we have in our Department. That project compared Smilodon with Tiger and Lion (skull specimens that we also happened to have) and I just extended that by collecting data for as many cat species as I can get a hold of. Mammalian skulls are to some extent easier to work with, and there are plenty of previous studies to cross-check my results with. Further, cats are relatively conservative in morphology yet diverse enough in subtle differences. So they're quite the ideal group to test for within-lineage adaptations and stuff like that. At least that's what I think anyway. Comparative functional morphology is my primarily interest, so the choice of animal group is in a way just the means to an end.

Zach said...

That's f*cking awesome, brother! Good luck on your defense. I'd love to read the paper when all's said and done. I didn't realize you were going for your PhD--I'm gonna have to start calling you "Doctor" now. :-)

And if I ever go about trying to write up that spinosaur post from way back when for publication, I might come knocking for bite force studies! :-D

Julia said...

It sounds really interesting so I'll be checking for updates from time to time.

BTW I have a blog too and thought it could be nice to exchange links or guest post

Manabu Sakamoto said...

Hi Zach,

Hahaha, I'm not a doctor yet...

and don't hesitate to ask me for any bite force related stuff when you start with your manuscript!

Julia,

I'll get on with the link!

Manabu Sakamoto said...

umm....where's your blog, Julia?

Malacoda said...

This is a bit late, but I disagree with Jerry slightly on the title. As you are in the UK, speaking and writing 'English' English, the list of taxa should not have a comma after dinosaurs. Jerry is correct if you are writing in 'American English'.

Manabu Sakamoto said...

So that's the confusion, eh? I didn't think it was a UK vs US English thing and started doubting my own memory...good to know.

Betsey Bell said...

Well, it was good that you have plan head what is the content of your thesis paper. That way, it would be easy for you to organize all the information you need and put them in a place that they belong. It would also help avoid mistake that sometimes are the cause of revising the paper again and again.