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Posts Tagged ‘anatomy’

Coddling Caudals

Think of a region of general mammalian anatomy. You’re probably not thinking of the tail. We’re mammals and yet have reduced ours to a puny coccyx embedded in muscle and fat. It’s an alien organ to us. Let’s face it, the tail gets the short shrift when it comes to morphological, functional and evolutionary studies in tetrapod vertebrates. There are notable exceptions such as in studies of prehensile tails or the role of the tail in cetacean locomotion, but broadly we know far less about the caudal vertebrae of mammals than we do about heads or limbs or some other bits. It is timely to coddle caudals: to talk about tails, not turn tail and run rostrally. This post wags its tail affectionately at the topic.

No blog post on tails is complete without a photo of the business end of Euoplocephalus's (Ankylosauria) caudals.

No blog post on tails is complete without a photo of the business end of Euoplocephalus’s (Ankylosauria) caudals.

Thagomizer.

Thagomizer of Stegosaurus. But of course!

Stomach-Churning Rating: well, there are some rancid emu butts, so I’m giving a 7/10; but otherwise mostly just line drawings.

My team has done a bit of work trying to better appreciate the tail as part of our expanded emphasis on the evolutionary morphology and biomechanics of the vertebral column; not just limbs as I was used to. Former PhD student Michael Pittman did his whole thesis on the evolution of tail form and function in dinosaurs, publishing a nice PLOS paper on theropod tail evolution, with other cool stuff in the pipeline. Pittman visited our lab recently with collaborator Heinrich Mallison to gather new data on the tails of archosaurs, focusing on Nile crocodiles and emus as an initial phylogenetic bracket. In my team’s prior work, we’d dabbled with theropod tails, focusing on the caudofemoralis muscle of theropod dinosaurs like T. rex, and on the size of the tail and its effects on the body’s centre of mass, following up on super-duper classic work by my mentor Steve Gatesy. So we have some caudal street cred, but we don’t have the tiger by the tail. (Hang in there, I’m going to milk the tail puns here!)

Don’t be afraid to touch the tail pics- they lead to bigger versions.

Mallison and Pittman know how to coddle caudals!

Mallison and Pittman know how to coddle caudals!

"Emu butt"- the tail is hidden in the smelly bulb of fat on the left side.

“Emu butt”- the tail is hidden in the smelly bulb of fat on the left side.

Bending an emu tail to measure its stiffness.

Bending an emu tail to measure its mobility.

Emu tail bones: our collection

Emu tail bones: our collection

I was inspired to write this post because of Michael’s visit, which gave me the opportunity to shoot some deliriously disgusting images of “emu butts” during the dissections and CT scans, but also got me thinking more about tails. And as usual, I poked around the literature looking for tall tales of tails.

I ran across one of those great review papers that is fodder for a hundred or more research projects: “The mammalian tail: a review of functions” (1979) by Graham C. Hickman (Mammal Review 9(4): 143-157. The rest of this post reviews his review.

Hickman, like I do here, starts off by reminding us of the tail’s neglect in science; e.g. “modifications of caudal vertebrae such as lengthened zygapophyses and neural spines are not as striking as the flexibility shown in the changing length and fusing of limb bones.” True that, but Hickman adds the great turn of phrase “A rodent chewing off its leg to escape a trap seems much more of an extreme than chewing off the tail, though it has four legs and but one tail.” Then he runs through a general overview of the diversity of tail forms and functions in mammals, with plenty of citations of older literature (there’s bound to be much to find in the tailings from the goldmine of 1800s German morphology papers, too).

What would a giant anteater look like without its tail? Odd indeed.

HickmanFig7

Mammalian tails range from four caudals in us freakish humans (does no mammal naturally have fewer, or have truly lost the tail? I wonder if anything has been missed) to fifty in pangolins (huzzah!). Breeds of dogs seem not to vary as much in terms of tail bone count as I’d expect: 20-23. But Hickman’s mention of Thorington’s (1970) study showing that mouse embryos raised at higher temperatures develop longer tails grabbed me… and reminded me of groundbreaking work that RVC PhD student Andrea Pollard is doing with temperature effects on bird and crocodile limbs (stay tuned).

Figure 2 in Hickman (1979) was what grabbed me most, depicting tail disparity in mammals. It’s a figure that gets your tail thumping. Check it out:

TO ADD

Anatomical disparity of mammalian tails! A, Black Rat; B, 9-banded Armadillo; C, Grey Squirrel; D, Horse; E, Fallow Deer; F, Wooly Spider Monkey; G, Coatimundi; H, Beaver; I, Bottle-nosed Whale; J, Manatee; K, Flying Squirrel; L, Fat-tailed Gerbil; M, Scaly-tailed Squirrel, N, Plains Pocket Gopher; O, Porcupine; P, Grey Kangaroo; Q, Naked Sand-rat; R, Big Brown Bat; S, Merriam’s Kangaroo Rat; T, anonymous Glyptodont; U, Ceylon Shrew.

Boom!

Hickman continues on to consider tail functions and behaviours, commenting that most bipedal mammals have long tails whereas humans buck the trend. Pangolins and anteaters get due mention here, but I really liked the factoid that “Beavers occasionally walk bipedally with an armload of mud” (p.145).

Mammals, like other vertebrates, that have substantial tails tend to use them for locomotor support at least when moving slowly, and Hickman lists kangaroos+kin, anteaters, pangolins and beavers as examples of mammals that thus use their tails as “fifth limbs”. But there are stranger tail functions in mammals than this ancestral tail-prop role. The bat Nycteris has a singular tail that ends in a “T”, bracing the uropatagium (tail-leg membrane).

Lovely kangaroo sculpt/skeleton from the incomparable comparative anatomy museum in Paris.

Lovely kangaroo sculpt/skeleton from the incomparable comparative anatomy museum in Paris.

However, some mammals also don’t use their tails the way we might expect- the platypus (Ornithorhynchus) doesn’t power its swimming with its tail so much as it uses it for stabilization, according to Hickman; paddling with the limbs seems more important (but this could use some modern scientific study using proper hydrodynamic testing). Yet they do use their tails to tamp the earth of their burrows and, curling them up to their belly, to bring in vegetation and such to provision their nests, as well as using their tails as energy stores (like many animals do). In contrast, beavers don’t transport much with their flat tails, whereas the more prehensile tails of pangolins may be used for carrying their babies.

HickmanFig5

Hickman notes how few mammals use their tails as weapons to harm others, although he properly brings up glyptodonts as a counter-example.  And then comes the striking description of how, by a “grinding motion of the tail against the body” a pangolin “almost severed the fore paw of a dog.” (p.148) And then, other mammals do the opposite of tail weaponry: Hickman cites that some 15 species of rodents can shed their tails (autotomy) as a defense, and like salamanders or lizards, regenerate them. Autophagy (self tail-cannibalism), however, Hickman rightly infers is a pathological, desperate condition, not a normal adaptation in mammals.

Big glyptodont tail club!

Big Glyptodon tail club!

More glyptodont tail clubs!

More glyptodont tail clubs! Neosclerocalyptus

Giant armadillo, showing glyptodont-lite version of the tail.

Giant armadillo Priodontes, showing glyptodont-lite version of the tail.

Need to motivate a rat to solve a maze puzzle or eat food? Pinching the tail had been shown to help, Hickman explains. This fits with the more obvious role of the tail in mammalian communication, including scent-marking. Here, Hickman notes that rather than using scent glands, hippos take the feces way out and just whip their tails around while pooping to spread their perfume. Which the internet knows well…

And then, finally, Hickman gets to the Rat Kings, which had me incredulous at first… but there are a bunch of references, so… What’s a Rat King? A “ball” of rats (from 3 to 32 of them!) with their tails tangled together for “group cohesion”, fabled in European stories for centuries but possibly “a frequent phenomenon” (p.152). An explanation for this phenomenon, Hickman explains, is confinement of rat in enclosed spaces where their tails do get entangled, only to be “found during a cold part of year, usually as a result of loud squealing noises which drew attention to the hide-away.”(p.153) In surveying the amusing range of explanations through history for Rat Kings (“itchy tails”?), Hickman relents and concludes “perhaps the tails of Rat Kings function best as cocktail discussion.” I concur—and append blogging discussion to that!

HickmanFig9

Tails you win, pre-caudals you lose, but Hickman’s review article is full of win! There’s plenty more of interest in there. I hope you enjoyed the look back at this classic paper, and at the tales that tails tell. This is the tale end.

I’ll let Ray get your caudals shakin’ as we depart:

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Owing Owen

It’s Darwin Day 2015 (or will be shortly), and also on this blog it’s Freezermas, a time of contemplative dissection of morphology and its history. This year I won’t be doing the crazy 7 posts in 7 days that I’ve done before (see 14 past ones here), and I won’t be doing a customary homage to Darwin. Instead, I’m dedicating today’s post to Richard Owen, oft characterized as Darwin’s greatest nemesis. Blasphemy? Nah. I’m a Darwin fan, sure, but today Owen gets his due from me. This post is like a “Top ten things you didn’t know about Richard Owen” post, but without the list, and some of them might be things you know, and I’m not even sure if there are ten of them, but they tend to be about Richard Owen. I feature a bunch of Owen’s papers’ coolest artwork, with links to the free versions of those papers, too. Bone up!

Stomach-Churning Rating: 3/10 for woodcuts that would otherwise be graphic. 7+/10 for rabid Darwin fans.

Owen was one of greatest (vertebrate) anatomists ever, if not the greatest (Alfred Romer gives him a run for his money in my opinion, but was less of a conceptual revolutionary). He was a key player in the divorce of the Natural History Museum from the British Museum and thus its move to its current South Kensington home in London as well as its autonomy and rise to scientific and cultural prominence. Hence, like today’s post’s title indicates, we owe Owen a lot as morphologists and as fans of biology (i.e. natural history). Indeed, his contributions are often undersold in deference to Darwin’s, and in service to a conventional narrative (written by the victorious Darwinians) in which he plays a villainous role. Even if one cannot admire the man as a touchy-feely kind of dude, his work demands respect and historiographic justice.

Rupke

I was inspired to write this post after reading a biography of Richard Owen some months ago: “Richard Owen: Biology Without Darwin, a revised edition”. It’s a fascinating read, and makes some points that challenged my naïve views of the history of biology, especially evolution and Victorian science. Author Nicolaas Rupke hammers home that pro-Darwin propaganda relegated Owen to a more minor and infamous position in the history of science than he deserved, defaming him as a cold-hearted, scheming, inconsistent jerk. This biography admits truth to Owen lacking some social graces and playing tough politics sometimes, but reminds us of his eminence in British science, which reverberated globally and was in no small part due to his determined drive and strategic rigour. I recommend the book to any fans of natural history and science, especially morphology. Indeed, Rupke’s 2009 edition was released in paperback for the Darwinian centennial, as an abridgement of his 1994 book. If you want to know more about Rupke’s 2009 book, there are informative reviews by Switek here and Lynch here. This biography humanizes Owen and casts away some of the demonizing. Scandalous snippets of Darwinians politicking against Owen are memorable– e.g. Owen’s “contest against the surrounding agencies” was a predecessor to Darwin’s “struggle for existence” and natural selection, which Darwin downplayed (Rupke, pp.157,169-171).

As Rupke’s work emphasizes, Owen was a pre-Darwininan evolutionary biologist, not a creationist. He devised an “axiom of the continuous operation of the ordained becoming of living things” that qualifies as evolutionist, but not transmutationist. He had ideas about evolution that just seem odd to a post-Darwinian mind, especially an “internalist” driving mechanism for evolution (something about the embryo that causes evolution to proceed; not a primarily external, environmental impetus as Darwin favoured), leading to orderly patterns of evolution, not the higgledy-piggledy bushy evolution of Darwin and his successors (e.g. Gould). To a modern evolutionary morphologist, Owen’s “transcendental morphology” echoes of earlier continental European work by Oken (& fellow Germanics), Cuvier (& fellow French) and others, and as such often feels strange – even mystically religious (pantheistic) or unscientific. And, like many Victorians, the idea of apes including, and a subset being ancestral to, humans repulsed Owen. That revulsion seems to have clouded his judgement on the scientific matters involved, which he famously sparred over with Thomas Huxley.

Forelimbs of Archaeopteryx compared with falcon, Pterodactylus, and humerus of a raven (left to right). From: Owen, R. (1863). On the Archéoptéryx of von Meyer, with a description of the fossil remains of a long-tailed species, from the lithographic stone of Solenhofen. Philosophical Transactions of the Royal Society of London, 33-47. http://www.jstor.org/stable/108788 FREE!

Forelimbs of Archaeopteryx compared with falcon, Pterodactylus, and humerus of a raven (left to right). Owen classifed the former as a bird, with potential relationships to pterosaurs (Rupke, pp.175-6); Darwinians like Huxley instead saw the dinosaurian, reptilian ancestry.
From:
Owen, R. (1863). On the Archéoptéryx of von Meyer, with a description of the fossil remains of a long-tailed species, from the lithographic stone of Solenhofen. Philosophical Transactions of the Royal Society of London, 33-47.
http://www.jstor.org/stable/108788
FREE!

However, we can credit Owen- like Lamarck and Geoffroy Saint-Hiliare in France- as an early “evo-devo” scientist trying to link transformation across lineages with developmental mechanisms. We can also celebrate Owen as one of the foremost early champions of the study of osteology as a worthy scientific pursuit in and of itself. Much of Rupke’s biography is structured to focus on the institutional structures that Owen played such a pivotal role in creating, especially the curated collections of the Natural History Museum (which Owen spent ~1856-1881 fighting to establish as its own facility!). Owen’s vast monographs on Cretaceous Reptilia, the flightless moa (e.g. Dinornis; with papers covering 40 years of research that continued almost up until Owen’s demise) and odd Gondwanan mammals of the Australian colonies (many of these specimens having been shipped to the museum by Darwin for Owen’s own studies) cement his status as an integrative collections-based researcher who did not eschew palaeontological research “because biologists don’t do that”, or some such divisive nonsense that we still encounter today.

Skull of a crocodile, exploded to show homologies of the bones; and a forelimb for added context. From: Richard Owen, Report on the archetype and homologies of the vertebrate skeleton. BAAS. https://archive.org/details/reportonarchetyp00owen FREE!

Skull of a crocodile, exploded to show homologies of the bones; and a forelimb for added context.
From:
Richard Owen, Report on the archetype and homologies of the vertebrate skeleton. BAAS.
https://archive.org/details/reportonarchetyp00owen
FREE!

Foetal skeleton of a human, with skull exploded for comparison of homologies. From Owen 1847 as above.

Foetal skeleton of a human, with skull exploded for comparison of homologies.
From Owen 1847 as above.

Speaking of palaeontology, and science communication, 1841 was when Owen coined the “Dinosauria”, tying together disparate forms such as Hylaeosaurus, Megalosaurus and Iguanodon by the recognition that they were not “typical reptiles” but rather advanced in many distinct ways (e.g. locomotor adaptations) that united them as a group. We owe a lot to that early recognition, which was no facile achievement considering how fragmentary most of the early (pre-“Bone Wars”) dinosaur fossil discoveries were. Like Darwin, Owen realized that the giant ground sloths that he described (and Darwin found many of during his Beagle voyage), such as Megatherium, were related animals, too, and in this case having extant relatives.

Most broadly, within comparative biology, Owen searched for the principles of and codified the concept he called homology, which was part of his very French/Germanic quest for “unity of type” as an fairly essentialist (but not always Platonic, as Rupke cautions- pp. 126-7,130), typological (even teleological?) principle underlying common themes in comparative anatomy. His tome on the “archetype” and vertebral components of the skull (see pics above) is lavishly detailed and a challenging but rewarding read, with fascinating (even if sometimes quite wrong) ideas about homologous parts of vertebrate heads. Again, Owen’s work in comparative anatomy easily became an integral part of evolutionary theory– homology as a consequence of (and reciprocally, evidence for) common ancestry featured prominently. As Rupke notes (p.179), “With little more than a flick of the fingers, Owen’s archetype could be turned into an ancestor.”

Tail sheath/club of Meiolania! from Owen, R. (1888). On parts of the skeleton of Meiolania platyceps (Ow.). Philosophical Transactions of the Royal Society of London. B, 181-191. http://www.jstor.org/stable/91676 FREE!

Tail sheath/club of Meiolania! Reminiscent of this…
from
Owen, R. (1888). On parts of the skeleton of Meiolania platyceps (Ow.). Philosophical Transactions of the Royal Society of London. B, 181-191.
http://www.jstor.org/stable/91676 FREE!

Jawsome! Thylacoleo, marsupial lion. From: Richard Owen, Additional Evidence of the Affinities of the Extinct Marsupial Quadruped Thylacoleo carnifex (Owen). Phil. Trans. R. Soc. Lond. B: 1887; 178: 1-3 http://rstb.royalsocietypublishing.org/content/178/1 FREE!

Jawsome!
Thylacoleo, marsupial lion.
From: Richard Owen,
Additional Evidence of the Affinities of the Extinct Marsupial Quadruped Thylacoleo carnifex (Owen).
Phil. Trans. R. Soc. Lond. B: 1887; 178: 1-3
http://rstb.royalsocietypublishing.org/content/178/1 FREE!

This year (2015) is the 350th anniversary of the journal Philosophical Transactions of the Royal Society, in which Owen published key studies of exotic Gondwanan animals such as the giant, tail-clubbed early turtle Meiolania and the “marsupial lion” Thylacoleo (see pics above). Some of Owen’s most outstanding and earliest work, likewise published in Phil. Trans., concerned seemingly aberrant mammals like the platypus (Ornithorhynchus), whose egg-laying and milk-excreting organs he detailed in 1832-1834 (see pics below). Like so many of his discoveries, these detailed descriptions and gorgeous commissioned woodcut illustrations often were sound, groundbreaking work, and are still cited and comprehensible today. Yet Owen’s interpretations sometimes became re-evaluated in a Darwinian rather than transcendentalist light, ironically building the case for Darwinian-style evolution (transmutation). Was the platypus a mammal, reptile or bird? Owen correctly assigned it to the Mammalia and recognized its relationship with the spiny anteaters (echidnas), but today we understand it better as a member of an early branch off the mammalian stem that includes a broad diversity of other species such as the multituberculates. Brian Hall wrote a review of the history of the “platypus paradox” here– it’s a fascinating story.

"Areola" of the female platypus in the abdominal region, with embiggened version below. From: Richard Owen, On the Mammary Glands of the Ornithorhynchus paradoxus. Philosophical Transactions of the Royal Society of London Vol. 122 (1832), pp. 517-538 http://www.jstor.org/stable/107974 FREE!

“Areola” of the female platypus in the abdominal region, with embiggened version below.
From:
Richard Owen, On the Mammary Glands of the Ornithorhynchus paradoxus.
Philosophical Transactions of the Royal Society of London
Vol. 122 (1832), pp. 517-538
http://www.jstor.org/stable/107974 FREE!

Dissection of a female platypus, showing the egg-laying apparatus. From: On the Ova of the Ornithorhynchus paradoxus Richard Owen Philosophical Transactions of the Royal Society of London Vol. 124 (1834), pp. 555-566. http://www.jstor.org/stable/108077 FREE!

Dissection of a female platypus, showing the egg-laying apparatus.
From:
On the Ova of the Ornithorhynchus paradoxus
Richard Owen
Philosophical Transactions of the Royal Society of London
Vol. 124 (1834), pp. 555-566.
http://www.jstor.org/stable/108077 FREE!

As a PhD student of Prof. Kevin Padian, a Richard Owen afficionado and historian, I couldn’t escape awareness of Owen. His visage decorated many parts of Padian’s office and we were often reminded of Owen’s prodigious prowess (and his sly politics- e.g., his “Parthian shot” letter that Padian described). But I didn’t go back and read much Owen until recently, while researching the evolution of the avian patella with my own PhD student Sophie Regnault. Owen described a patella in the moa Dinornis, but we re-interpreted this as an ankle sesamoid bone (common in moa)– although the described fossil “patella” itself seems to have been lost. Then Owen’s patella research came up in a later, often vitriolic, debate (featuring the eminent bird anatomist Shufeldt as well as other scientists Jeffries and Gill) in Science magazine over what bones cormorants and other birds have in their knees– read more about it here. In perusing Owen’s moa and other anatomical work, I gained a deep appreciation for it and now I’m a fan. I even feel a special kinship with Owen– like me, various zoos sent him their specimens for scientific study via dissection, and he was an active science communicator. I’m sure he’d have appreciated my freezers. Not so sure about this blog…

Find the "patella"! From Professor Owen C.B., F.R.S., F.Z.S., &c. (1883), On Dinornis (Part XXIV.): containing a Description of the Head and Feet, with their dried Integuments, of an Individual of the species Dinornis didinus, Owen. The Transactions of the Zoological Society of London, 11: 257–261. http://onlinelibrary.wiley.com/doi/10.1111/j.1096-3642.1883.tb00360.x/abstract FREE!

Find the “patella”!
From Professor Owen C.B., F.R.S., F.Z.S., &c. (1883), On Dinornis (Part XXIV.): containing a Description of the Head and Feet, with their dried Integuments, of an Individual of the species Dinornis didinus, Owen. The Transactions of the Zoological Society of London, 11: 257–261.
http://onlinelibrary.wiley.com/doi/10.1111/j.1096-3642.1883.tb00360.x/abstract FREE!

So that’s my ode to Owen, which lightly touches on highlights of his storied career. Opinions vary on how fun he would have been to quaff pints of ale with (what do you think?), but as fabled (if flawed) heroes of science go, he deserves the label, and morphologists should continue to imbibe and savour his scholarly works, seeking draughts of inspiration within their contents as gourmands of Owen-ia. With some 600 papers published by Owen, there’s surely more for us all to discover.

Morphologists and friends, what’s your favourite Owen paper and why? Speak up!

[If you remain silent, at least do that while reading some Owen today!]

And happy Darwin Day!

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Stomach-Churning Rating: 1/10 for ambiguous sacks.

I mainly post here about my team’s research and interests, but today I felt like sharing something special and concrete: the contents of our freezers. They are not just John’s and there’s more than one freezer; thus there is room to share, within reason. So if you’re a researcher, especially in the UK/EU, needing unusual research specimens/tissue, you might want to contact me to use them. This blog’s posts summarize most of what I have available, and for security/other reasons I don’t want to get into deep detail here, but we sport a respectable collection of limbs/bodies of animals like:

Birds: ostriches, emus, broiler chickens, guineafowl, assortment of others.

Crocodiles: Nile, Osteolaemus, Morelet’s and some others (1 Melanosuchus, 1 normal Caiman).

Squamates: a monitor lizard or two and some other random lizards.

Amphibians: a few fire salamanders and such.

Mammals: of course, plenty of elephant bits (no ivory!), rhinos too (no horns!), giraffes, a dwarf forest buffalo, alpacas, deer, pieces of camels and zebras (feet etc.), wild cat species (no penises!) and a few other things. And then the usual assortment of veterinary species like cows and horses. A heavy focus on limb material– very few if any heads, torsos, etc.

This is in addition to a nice little comparative skeletal collection, focused on cleaned members of the above groups and a smattering of others. Nothing on the scale of RVC’s marvellous Anatomy Museum, but we’re young.

And two African land snail shells (inhabited) I was reminded of during a recent inventory… Here are some of my helpful helpers in that inventory extravaganza!

inventory

Especially if you’re searching for CT scan data (sooner or later these data will appear online; I want it to happen!), tissue samples for genetics or cell biology (if frozen is OK!), comparative anatomical specimens to inspect, or other uses of frozen anatomy (photography? other art? We’ve helped artists before!), the freezers might be able to help you! The less destructive, the better, but even some destructive analysis might be OK. We regularly accommodate visitors, either independent ones or collaborators, and I aim to provide good hospitality when I can accommodate them!

Get in touch with me if the above description is you. It’s not an open invitation to everyone, but for valid research purposes I can and should try to help. But I don’t run a museum-style collection (yet), I’m limited by time and other human factors, so I can’t do everything and help everyone. The primary purpose of all the hard work we’ve done accumulating these specimens remains to support our research, but there’s room to help others too, and we want to maximize the impact of our research collection, including potentially on teaching and public engagement with science where feasible. So I’ve put it out there, and that ends this post.

Is there something in the "Non-Elephant Freezer" for you?

Is there something in the “Non-Elephant Freezer” for you?

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In the Name of Morphology

Stomach-Churning Rating: 8/10 don’t look at the gooooaaaaaaaaaaaat!!!! Too late.

Goat morphology is cool! (from work with local artist)

Goat morphology is cool! (from work with local artist)

Morphology in biology, to me, is about the science of the relationship of anatomical form to function (including biomechanics), evolution, development and other areas of organismal biology. It thus encompasses the more descriptive, form-focused area of anatomy. But in common parlance I use the two terms interchangeably, because many scientists and the general public do know what anatomy is but get confused by the word “morphology”. Not wishing to wage a semantic skirmish or get into what linguistic or other morphology is, I shall move on. But as the title betrays, this post is about morphology and how we should be proud of it as scientists who study it. This is a companion post to my earlier post on Anatomy, which was aimed at a more general audience than at my colleagues. Yet general audience, stick around. You might find this interesting.

I’m a morphologist at heart. What interests me most about organisms is how their form is not only beautiful and amazing itself but tells us profound things about other aspects of biology, as I stated in the first sentence above. I tend to call myself an evolutionary biomechanist, but morphology is in there too, at the heart of what I do, and biomechanical evolutionary morphologist — while more accurate — just does not roll off the lingual apparatus. I’ll dodge that semantic minefield of branding issues now. I’ll instead move on to my more important point that many (but not all) morphologists go through a phase in their career in which they have some strong feelings of being looked down on by other biologists/scientists as doing outmoded or inferior science. I explained in my Anatomy post that this “inferiority” is not the case today, moreso than ever; that the field is in a dynamic renaissance; so if you want some talking points go there. Regardless, these feelings of being almost stigmatized can exacerbate Imposter Syndrome, especially early in a scientific career.

Lizard morphology is cool! And museums exist to house morphological specimens like these.

Lizard morphology is cool! And museums exist to house morphological specimens like these.

I can think of one such case of bad feelings in my not-too-distant memory: at a conference dinner, one colleague sitting to my right said to my colleague to my left “What do you think about anatomy? Should students even do any research on it?” and went on with a bit of diatribe about the why-bother-ness of anatomy relative to other areas such as biomechanics. They both knew of my interests in this area, I’m quite sure, so it was as if I was not there sitting in between them. I was so appalled I was stunned into silence, but seething, and the colleague to my left didn’t defend the field either, even though they did a fair amount of research in it. It took a long time for me to cool down, and I still feel a bit offended and shocked that my colleague would say something so awkward and obliquely confrontational. Similar situations occurred during my PhD work at Berkeley, where biomechanics was having a heyday and anatomy was just beginning to rise from the ashes. It’s odd to me when biomechanists devalue morphology, because so much of mechanics depends on and relates to it, but to each their own. In many biological fields there are reductionist schisms that think they can divorce organisms from other aspects of their biology without losing something, so I’m not surprised, but maybe I am falling into my own trap of condescension here…

Anyway, I had those feelings of being on the receiving end of collegial condescension for a long time myself, and maybe that’s part of why I settled on calling my speciality something other than morphology. Shame on me, and double shame for getting back to that branding issue. But maybe not– maybe it IS important to talk about branding. I’ve been thinking a lot about my career and morphology in recent years, and keep returning to the thought that I need to embrace morphology in an even tighter love-hug. This blog has long been intended as a step in that direction (my Pinterest “Mucho Morphology” page is another step), but I could do more. Speaking of morphologists generally, perhaps we all could. Morphology still has some PR issues, most of us would probably agree, despite its arguable renaissance.

Fetal whale morphology is cool! (at Queen Mary UofL)

Fetal whale morphology is cool! (at Queen Mary UofL)

Thus my point of this post is simple: let’s try using the words morphology or anatomy more often in our scientific communications. Put those words out there and say them with pride. Let’s keep name-dropping morphology everywhere we can, within reason, and defending its value if challenged. To do this, we’ll need to know how we individually feel about morphology, and ensure we’re well informed to defend it. So think about those things, too, if you join this cause. By waging a PR battle against the forces of anti-morphology condescension, be they waxing or waning, we can get others to give our field its due credit. Fly that flayed banner of morphology high.

See a cool picture of an animal and want to post it on social media? Emphasize that it doesn’t just look cool but has amazing anatomy. Publish a cool new paper showing how a novel adaptation evolved? Remind readers of the morphological (or at least phenotypic) basis of that adaptation and how it interacts with the environment. Summarizing your research interests and discipline to a colleague or on a website/CV? Put morphology in there. Stand up straight when you do, too. Morphology, morphology, morphology. Learn to love that word and it will serve us all well. Branding and PR are only part of the struggle that needs to happen, but much as they may be to our distaste they can help. Doing great morphology-based science is the most important thing, but as social human beings the PR issue cannot be ignored.

Cat shoulder morphology is cool! (RVC teaching collection)

Cat shoulder morphology is cool! (RVC teaching collection)

This was a shortish post for me but it’s something I feel strongly about. My feelings have been magnified by taking on the role of Chair-Elect of the Division of Vertebrate Morphology at SICB, assisting the awesome current Chair Dr. Callum Ross and wise past-Chair Alice Gibb in addition the the rest of the committee and division, and as an Executive Committee member in the International Society of Vertebrate Morphology. I now have some extra responsibility to do something. Complaining about the state of affairs doesn’t help much– doing something can. If you’re a vertebrate morphologist, you should join these professional societies/divisions, attend their superb meetings and join their increasing presence on social media like Facebook (and soon Twitter?). Speak up and join in, please, these societies exist to help you and morphology!

Did you notice I didn’t use the title of the post as a lead-in to altered lyrics from a certain hit U2 song? Well I did. Maybe you’ll appreciate me resisting the temptation here. My Xmas song about our three new morphology papers didn’t exactly evoke angelic choruses.

What do you think, morphologists and non-morphologists? I am sure there are analogous situations in other fields. I’m curious how other morphologists or fields deal with or have struggled with this kind of image problem before. Especially under situations where the science itself is vigorous and rigorous, but the perception may be otherwise.

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I hinted at another post in last round, and here I deliver. (The “amazeballs” in the title is a running joke with our Xmas guests here in England, but it applies to the subject of these images, too… which will be the subject of a future blog post involving a dissection of the subject!)

This will end the 2014 round of Mystery Anatomy. What 2015 will bring, I am not sure, but here we have 15 images for my 15th mystery CT post and 2015 around the corner.

I do have a new, fun regular anatomy post idea planned for 2015 but I’ll explain that later.

Stomach-Churning Rating: 2/10; digital images; the cadaver is gutted but I am chuffed.

Mystery Anatomy 2014same rules as before.

Identify (1) the animal shown in the 15 slices, to species level (max. 5 pts), and then the major features (anatomical regions) evident in as many of the 15 slices as you can; details help (max. 5 pts for thoroughness and accuracy). 

Difficulty: No scale, sort of. Otherwise, pretty easy.

Answers will come on New Year’s Day, to ease your hangovers (or encourage vomiting).

1

1

2

2

3

3

4

4

5

5

6

6

7

7

8

8

9

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10

10

11

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14

14

MysteryCT15(15)

15

Onward!

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Deck the ‘Nets With PeerJ Papers– please sing along!

♬Deck the ‘nets with PeerJ papers,
Fa la la la la, la la la la.
‘Tis the day to show our labours,
Fa la la la la, la la la la.

Downloads free; CC-BY license,
Fa la la, la la la, la la la.
Read the extant ratite science,
Fa la la la la, la la la la.

See the emu legs before you
Fa la la la la, la la la la.
Muscles allometric’ly grew.
Fa la la la la, la la la la.

Follow the evolvin’ kneecaps
Fa la la la la, la la la la.
While we dish out ratite recaps 
Fa la la la la, la la la la.

Soon ostrich patellar printing
Fa la la la la, la la la la.
Hail anat’my, don’t be squinting
Fa la la la la, la la la la.

Dissections done all together
Fa la la la la, la la la la.
Heedless of the flying feathers,
Fa la la la la, la la la la♪

(alternate rockin’ instrumental version)

Stomach-Churning Rating: 5/10: cheesy songs vs. fatty chunks of tissue; there are no better Crimbo treats!

Today is a special day for palaeognath publications, principally pertaining to the plethora of published PeerJ papers (well, three of them anyway) released today, featuring my team’s research! An early Crimbo comes this year in the form of three related studies of hind limb anatomy, development, evolution and biomechanics in those flightless feathered freaks of evolutionary whimsy, the ratites! And since the papers are all published online in PeerJ (gold open access), they are free for anyone with internet access to download and use with due credit. These papers include some stunning images of morphology and histology, evolutionary diagrams, and a special treat to be revealed below. Here I’ll summarize the papers we have written together (with thanks to Leverhulme Trust funding!):

1) Lamas, L., Main, R.P., Hutchinson, J.R. 2014. Ontogenetic scaling patterns and functional anatomy of the pelvic limb musculature in emus (Dromaius novaehollandiae). PeerJ 2:e716 http://dx.doi.org/10.7717/peerj.716 

My final year PhD student and “emu whisperer” Luis Lamas has published his first paper with co-supervisor Russ Main and I. Our paper beautifully illustrates the gross anatomy of the leg muscles of emus, and then uses exhaustive measurements (about 6524 of them, all done manually!) of muscle architecture (masses, lengths, etc.) to show how each of the 34 muscles and their tendons grew across a more than tenfold range of body mass (from 6 weeks to 18 months of age). We learned that these muscles get relatively, not just absolutely, larger as emus grow, and their force-generating ability increases almost as strongly, whereas their tendons tend to grow less quickly. As a result, baby emus have only about 22% of their body mass as leg muscles, vs. about 30% in adults. However, baby emus still are extremely athletic, more so than adults and perhaps even “overbuilt” in some ways.

This pattern of rapidly growing, enlarged leg muscles seems to be a general, ancestral pattern for living bird species, reflecting the precocial (more independent, less nest-bound), cursorial (long-legged, running-adapted) natural history and anatomy, considering other studies of ostriches, rheas, chickens and other species close to the root of the avian family tree. But because emus, like other ratites, invest more of their body mass into leg muscles, they can carry out this precocial growth strategy to a greater extreme than flying birds, trading flight prowess away for enhanced running ability. This paper adds another important dataset to the oft-neglected area of “ontogenetic scaling” of the musculoskeletal system, or how the locomotor apparatus adapts to size-/age-related functional/developmental demands as it grows. Luis did a huge amount of work for this paper, leading arduous dissections and analysis of a complex dataset.

Superficial layer of leg muscles in an emu, in right side view.

Superficial layer of leg muscles in an emu, in right side view. Click any image here to emu-biggen. The ILPO and IC are like human rectus femoris (“quads”); ILFB like our biceps femoris (“hams”); FL, GM and GL much like our fibularis longus and gastrocnemius (calf) muscles, but much much bigger! Or, perhaps FL stands for fa la la la la?

Data for an extra set of emus studied by coauthor Russ Main in the USA, which grew their muscles similarly to our UK group. The exponents (y-axis) show how much more strongly the muscles grown than isometry (maintaining the same relative size), which is the dotted line at 1.0.

Data for an extra set of emus studied by coauthor Russ Main in the USA, which grew their muscles similarly to our UK group. The exponents (y-axis) show how much more strongly the muscles grew than isometry (maintaining the same relative size), which is the dotted line at 1. The numbers above each data point are the # of individuals measured. Muscle names are partly above; the rest are in the paper. If you want to know them, we might have been separated at birth!

2) Regnault, S., Pitsillides, A.A., Hutchinson, J.R. 2014. Structure, ontogeny and evolution of the patellar tendon in emus (Dromaius novaehollandiae) and other palaeognath birds. PeerJ 2:e711 http://dx.doi.org/10.7717/peerj.711

My second year PhD student Sophie Regnault (guest-blogger here before with her rhino feet post) has released her first PhD paper, on the evolution of kneecaps (patellae) in birds, with a focus on the strangeness of the region that should contain the patella in emus. This is a great new collaboration combining her expertise in all aspects of the research with coauthor Prof. Andy Pitsillides‘s on tissue histology and mine on evolution and morphology. This work stems from my own research fellowship on the evolution of the patella in birds, but Sophie has taken it in a bold new direction. First, we realized that emus don’t have a patella– they just keep that region of the knee extensor (~human quadriceps muscle) tendon as a fatty, fibrous tissue throughout growth, showing no signs of forming a bony patella like other birds do. This still blows my mind! Why they do this, we can only speculate meekly about so far. Then, we surveyed other ratites and related birds to see just how unusual the condition in emus was. We discovered, by mapping the form of the patella across an avian family tree, that this fatty tendon seems to be a thing that some ratites (emus, cassowaries and probably the extinct giant moas) do, whereas ostriches go the opposite direction and develop a giant double-boned kneecap in each knee (see below), whereas some other relatives like tinamous and kiwis develop a more “normal”, simple flake-like bit of bone, which is likely the state that the most recent common ancestor of all living birds had.

There’s a lot in this paper for anatomists, biomechanists, palaeontologists, ornithologists, evo-devo folks and more… plenty of food for thought. The paper hearkens back to my 2002 study of the evolution of leg tendons in tetrapods on the lineage that led to birds. In that study I sort of punted on the question of how a patella evolved in birds, because I didn’t quite understand that wonderful little sesamoid bone. And now, 12 years later, we do understand it, at least within the deepest branches of living birds. What happened further up the tree, in later branches, remains a big open subject. It’s clear there were some remarkable changes, such as enormous patellae in diving birds (which the Cretaceous Hesperornis did to an extreme) or losses in other birds (e.g., by some accounts, puffins… I am skeptical)– but curiously, patellae that are not lost in some other birds that you might expect (e.g., the very non-leggy hummingbirds).

Fatty knee extensor tendon of emus, lacking a patella. The fatty tissue is split into superficial (Sup) and deep regions, with a pad corresponding to the fat pad in other birds continuous with it and the knee joint meniscus (cushioning pad). The triceps femoris (knee extensor) muscle group inserts right into the fatty tendon, continuing over it. A is a schematic; B is a dissection.

Fatty knee extensor tendon of an emu, showing the absence of a patella. The fatty tissue is split into superficial (Sup) and deep regions, with a pad corresponding to the fat pad in other birds continuous with it and the knee joint meniscus (cushioning pad). The triceps femoris (knee extensor) muscle group inserts right into the fatty tendon, continuing on over it. A is a schematic; B is a dissection.

Sectioning of a Southern Cassowary's knee extensor tendon, showing: A Similar section  as in the emu image above. revealing similar regions and fibrous tissue (arrow), with no patella, just fat; and B, with collagen fibre bundles (col), fat cells (a), and cartilage-like tissue (open arrows) labelled.

Sectioning of a Southern Cassowary’s knee extensor tendon, showing: A, Similar section as in the emu image above. revealing similar regions and fibrous tissue (arrow), with no patella, just fat; and B, With collagen fibre bundles (col), fat cells (a), and cartilage-like tissue (open arrows) labelled.

Evolution of patellar form in birds. White branches indicate no patella, blue is a small flake of bone for a patella, green is something bigger, yellow is a double-patella in ostriches, and grey is uncertain. Note the uncertainty and convergent evolution of the patella in ratite birds, which is remarkable but fits well with their likely convergent evolution of flightlessness and running adaptations.

Evolution of patellar form in birds. White branches indicate no patella, blue is a small flake of bone for a patella, green is something bigger, yellow is a double-patella in ostriches, black is a gigantic spar of bone in extinct Hesperornis and relatives, and grey is uncertain. Note the uncertainty and convergent evolution of the patella in ratite birds (Struthio down to Apteryx), which is remarkable but fits well with their likely convergent evolution of flightlessness and running adaptations.

3) Chadwick, K.P., Regnault, S., Allen, V., Hutchinson, J.R. 2014. Three-dimensional anatomy of the ostrich (Struthio camelus) knee joint. PeerJ 2:e706 http://dx.doi.org/10.7717/peerj.706

Finally, Kyle Chadwick came from the USA to do a technician post and also part-time Masters degree with me on our sesamoid grant, and proved himself so apt at research that he published a paper just ~3 months into that work! Vivian Allen (now a postdoc on our sesamoid bone grant) joined us in this work, along with Sophie Regnault. We conceived of this paper as fulfilling a need to explain how the major tissues of the knee joint in ostriches, which surround the double-patella noted above, all relate to each other and especially to the patellae. We CT and MRI scanned several ostrich knees and Kyle made a 3D model of a representative subject’s anatomy, which agrees well with the scattered reports of ostrich knee/patellar morphology in the literature but clarifies the complex relationships of all the key organs for the first time.

This ostrich knee model also takes Kyle on an important first step in his Masters research, which is analyzing how this morphology would interact with the potential loads on the patellae. Sesamoid bones like the patella are famously responsive to mechanical loads, so by studying this interaction in ostrich knees, along with other studies of various species with and without patellae, we hope to use to understand why some species evolved patellae (some birds, mammals and lizards; multiple times) and why some never did (most other species, including amphibians, turtles, crocodiles and dinosaurs). And, excitingly for those of you paying attention, this paper includes links to STL format 3D graphics so you can print your own ostrich knees, and a 3D pdf so you can interactively inspect the anatomy yourself!

(A) X-ray of an ostrich knee in side view, and (B) labelled schematic of the same.

Ostrich knee in side view: A, X-ray, and (B) labelled schematic.

3D model of an ostrich knee, showing: A, view looking down onto the top of the tibia (shank), with the major collateral ligaments (CL), and B, view looking straight at the front of the knee joint, with major organs of interest near the patella, sans muscles.

3D model of an ostrich knee, showing: A, View looking down onto the top of the tibia (shank), with the major collateral ligaments (CL), and B, View looking straight at the front of the knee joint, with major organs of interest near the patella, sans muscles.

You can view all the peer review history of the papers if you want, and that prompts me to comment that, as usual at PeerJ (full disclosure: I’m an associate editor but that brings me £0 conflict of interest), the peer review quality was as rigorous at a typical specialist journal, and faster reviewing+editing+production than any other journal I’ve experienced. Publishing there truly is fun!

Merry Christmas and Happy Holidays — and good Ratite-tidings to all!

And stay tuned- the New Year will bring at least three more papers from us on this subject of ratite locomotion and musculoskeletal anatomy!

♬Should auld palaeognathans be forgot, 
And never brought for scans? 
Should publications be soon sought, 
For auld ratite fans!♪

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It has been a long time since we had some Mystery Anatomy fun here, so I am cutting loose with a double-barrelled blast of images– dive for cover!

I’m also giving out a Crimbo present as a bigger post, on a special day coming soon, count on that. This is just an advent snack.

Stomach-Churning Rating: 2/10 and 7/10: digital body and glistening, snotty.

Mystery Anatomy 2014same rules as before; remember that the scoreboard has been reset.

Identify (1) the animal shown in the four-panel top images (CT scan/reconstruction), and (2) the DIFFERENT animal (and/or the main central, pink structure) shown in the big, gooey bottom image (Dissection). No special rules. Potential for double points!

And someone will get these, I am sure. This might be the final round of 2014’s Mystery Anatomy game.

Difficulty: Plenty.

Mystery CT 14

Mystery CT 14

Mystery Anatomy 15

Mystery Anatomy 15

Go forth!

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