Welcome to the third and final part of my write-up of the CEE functional anatomy meeting: for part I go here, and for part II here. Here’s where we wrap things up, but let’s get through the last of the talks: those on tuataras, and yet more on primates…
Marc Jones discussed his work on skull shape and feeding behaviour in rhynchocephalians (the extant tuataras and their Mesozoic relatives: adjacent image, from Marc’s UCL page, shows Marc with a live tuatara). It is generally agreed among herpetologists that Sphenodon is not, as used to be thought, an archaic relict; a sort of poor relation compared to the kinetic-skulled squamates. The complete lower temporal bar of Sphenodon is clearly secondary, as basal rhynchocephalians lacked ossification in this region (Müller (2003) showed that the lower temporal bar has been lost and regained multiple times in diapsid reptiles). Marc has now shown that Sphenodon occupies a distinct region of morphospace when compared to other rhynchocephalians, and most certainly does not represent its group as a whole. Extensive overlaps between some of the cranial bones dampen stresses during biting (I previously mentioned this aspect of Marc’s research in one of the SVPCA 2007 write-ups: go here). Together with Neil Curtis, Marc has been working on an accurate computational model of the Sphenodon head and neck. It looked excellent, with an accurate propalinal jaw action (propaliny = anteroposterior sliding of the lower jaw).
Bringing us back to primates again, Will Parr has been applying laser scanning to hominoid tarsal bones in order to understand how the bones function in walking and running, and he’s also been comparing the tarsals (particularly the calcaneum, astragalus, navicular and cuboid) of different taxa. As if to verify the contention noted earlier that too little work has been done on the anatomy of extant animals, Will complained that we don’t even know how the ankle bones properly function in modern humans. One of the great problems of working with tarsal bones is that their complex shapes and often globular, curved surfaces are difficult to represent accurately with diagrams, and early schematic attempts to depict tarsals as 3D blocks were just too schematic to do anything more than show the relative positions of the bones. New laser scanning technology is providing the solution to these problems. The astragalar facet of Lucy the australopithecine is closer in shape to that of chimps than that of modern humans, which at first sight seems to contradict current thinking on australopithecine gait and walking abilities.
Evie Vereecke spoke about ‘Bringing primate morphology into the 21st century’ and began by providing a summarised historical review of work on primate anatomy. As early as the 1st century, the physician Galen of Pergamum (AD 129-c. 200) was recommending that people study non-human primates in order to better understand human anatomy. Influential studies by Victorian workers like Richard Owen kept the study of primate anatomy close to the forefront in the world of anatomical research, and today a fascination with primates continues. Several case studies highlighted how new approaches link form with function. Evie discussed the incredible hindlimb musculature that has been shown to function as a power amplifier in galagos (cf. Babcock 1992, Aerts 1998). Comparison across hominoids shows that humans have weak wrist flexors compared to siamangs and chimps. Elbow extensors are proportionally similar in size across all hominoids (including humans), but while elbow flexors are usually as large as extensors in hominoids, flexors are much smaller than extensors in humans. Also interesting is that the Achilles tendon is particularly large in gibbons (as big as that of humans), whereas in other non-hominin hominoids is it smaller [adjacent images show bipedal gaits in Lar gibbon Hylobates lar: image from Aaron Filler's site, but originally from Vereecke et al. 2006a]. Exactly why these differences occur is of course the big question, though there are possible answers: humans don’t climb as much as gibbons or chimps, for example. For more on these areas, see Vereecke et al. (2005, 2006a, b) and Payne et al. (2006a, b).
As you’d expect in a workshop on functional anatomy, it wasn’t all tetrapods of course. Mark Purnell discussed work on tooth microwear in sticklebacks and cichlids, with a brief look at new work on microwear in hadrosaurs at the end. And two talks on insects – one by Walter Federle on the adhesive mechanisms of weaver ant feet and the other by Robin Wootton on how insect wings function, deform and fold – had me spellbound and were among the most memorable of the entire meeting. There were also several posters at the meeting, including those on bite strength in theropods and functional anatomy in cheetahs, but like an idiot I failed to take notes on them.
I know that I have a horrible habit of coming back from meetings waxing lyrical about how wonderful they were, but this meeting truly was awesome: it seems that much of biology is devoted to getting as far away as possible from the organisms themselves, yet how animals work is easily up there as among the most awe-inspiring, wonderful and fascinating part of it all. And as John Hutchinson said at the opening of the meeting, anatomy also fascinates us because it is beautiful and, indeed, beauty is anatomy. Functional anatomy also has an impact on our daily lives given that we often need to know how our own bodies (and those of our domestic animals) function. What was thought to be a dead and done field is vividly alive, bustling with new work that incorporates new and exciting technology, and more and more people are jumping on the bandwagon. Indeed the meeting was a soar-away success with a huge turnout: about 100 people attended!
I’m not ashamed to say that I want to be in on the functional anatomy movement too, and – while I intend to continue working on the interpretation of incomplete fossils, on historical taxonomy and all that stuff – it does look like I might be heading that way. In fact I have three papers coming out later this year (or next year) on functional anatomy (all of which are going to be discussed here at Tet Zoo: the first appears next month).
During the socialising afterwards I developed the hypothesis that one can mimic all sorts of different animals during the course of a conversation at a functional anatomy meeting, and not receive any strange looks. I adopted a BHBK gait and also practised some knuckle-walking, and indeed no-one so much as looked at me (as I’ve said before, knuckle-walking is painful for us, as is obvious from the adjacent photo). Mind you, I do normally walk around this way anyway. It was cool to meet and catch up with so many friends old and new. Some of you might know that Colin McHenry and I collaborated on the ecology of secondarily marine tetrapods during the 1990s: we never really finished that work, and even today it’s possible that we might get back to it at some stage. And I owe massive thanks to John Conway for all the help he provided: thanks again John.
That’s all for now – as you read this I am frantically preparing for Dinosaurs – A Historical Perspective. And that’s probably what I’ll be talking about next… (although I did go reptile-spotting over the weekend).
Refs – –
Aerts, P. 1998. Vertical jumping in Galago senegalensis: the quest for an obligate mechanical power amplifier. Philosophical Transactions of the Royal Society of London B 353, 1607-1620
Babcock, S. K. 1992. Muscle architecture in mammalian limbs: design concepts based on hindlimb muscle morphology in galagos. American Zoologist 32, 138A.
Müller, J. 2003. Early loss and multiple return of the lower temporal arcade in diapsid reptiles. Naturwissenschaften 90, 473-476.
Payne, R. C., Crompton, R. H., Isler, K., Savage, R., Vereecke, E. E., Günther, M. M., Thorpe, S. K. S. & D’Août, K. 2006a. Morphological analysis of the hindlimb in apes and humans. I. Muscle architecture. Journal of Anatomy 208, 709-724.
– ., Crompton, R. H., Isler, K., Savage, R., Vereecke, E. E., Günther, M. M., Thorpe, S. K. S. & D’Août, K. 2006b. Morphological analysis of the hindlimb in apes and humans. Part II: Moment arms. Journal of Anatomy 208, 725-742.
Vereecke, E. E., D’Août, K., Payne, R. & Aerts, P. 2005. Functional analysis of the foot and ankle myology of gibbons and bonobos. Journal of Anatomy 206, 453-476.
– ., D’Août, K. & Aerts, P. 2006a. Locomotor versatility in the white-handed gibbon (Hylobates lar): a spatiotemporal analysis of the bipedal, tripedal, and quadrupedal gaits. Journal of Human Evolution 50, 552-567.
– ., D’Août, K. & Aerts, P. 2006b. The dynamics of hylobatid bipedalism: evidence for an energy-saving mechanism? Journal of Experimental Biology 209, 2829-2838.