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I have an impression that there is a large disparity between how the public views museums and how scientists who use museums view them. Presumably there are survey data on public attitudes, but surely the common impression is that museums mainly exist to exhibit cool stuff and educate/entertain the public. Yet, furthermore, I bet that many members of the public don’t really understand the nature of museum collections (how and why they are curated and studied) or what those collections even look like. As a researcher who tends to do heavily specimen-oriented and often museum-based research, I thought I’d take the opportunity to describe my experience at one museum collection recently. This visit was fairly representative of what it’s like, as a scientist, to visit a museum with the purpose of using its collection for research, rather than mingling with the public to oggle the exhibits — although I did a little of that at the end of the day…

Stomach-Churning Rating: 4/10; mostly bones except a jar of preserved critters, but also some funky bone pathologies! Darwin hurls once, totally blowing chunks, but only in text.

Early camel is sitting down on the job at the NHMLA.

Early camel is sitting down on the job at the NHMLA.

About two weeks ago, I had the pleasure to spend a fast-paced day in the Ornithology collection of the Natural History Museum of Los Angeles County (NHMLA or LACM). I arranged the visit (you have to be a credible researcher to get access; luckily I seemed to be that!) via email, took an Uber car to the museum, and was quickly cut loose in the collection. I was hosted by the Collections Manager Kimball Garrett, who is an avid birder (adept at citizen science, too!) and a longtime LA native.

Amongst museum curators and collections managers (there can be a distinction between the two but here I’ll refer to them all as “curators”), there is a wide array of attitudes toward and practices with museum collections, regarding how the curators balance their varied duties of not only making the museum collection accessible to researchers (via behind-scenes studies) and the public (via exhibits and behind-scenes tours etc.), but also curation (maintaining a record of what they have in their collection, adding to it, and keeping the specimen in good condition), research, admin, teaching and other duties.

Most curators I’ve known, like Kimball, are passionate about all of these things, and very generous with their time to help scientists make the most of the collection during their visit, offering hospitality and cutting through the bureaucracy as much as possible to ensure that the science gets done. There are those few curators that aren’t great hosts because they’ve had a bad day or a bad attitude (e.g. obsession with paperwork and finding obstacles to accessing specimens for research; or just not responding to communication), but they are few and far between in my experience.

Regardless, the curator is the critical human being that keeps the wheels of specimen-based museum research rolling, and I am appreciative of how deeply dedicated and efficient most curators are. Indeed, I enjoy meeting and chatting with them because they tend not only to be fun people but also incredibly knowledgeable about their collection, museum, and area of expertise. Sadly, this trip was so time-constrained that I didn’t get much time at all for socializing. I had about five hours to get work done so I plunged on in!

Images, as always, can be clicked to emu-biggen them. Thanks to the NHMLA for access!

My initial look down the halls of the osteology storage. Rolling cabinets (on the right) are a typical sight.

My initial look down the halls of the osteology storage. Rolling cabinets (on the right) are a typical sight.

Freezers ahoy!

Freezers ahoy! With Batman watching over them.

A jar of bats? Why not? Batman approves.

A jar of bats? Why not? Batman approves.

The curator cleared a space on a table for me to set bones on. Then the anatomizing and photographing began!

The curator cleared a space on a table for me to set bones on. Then the anatomizing and photographing began!

On entering a museum collection, one quickly gets a sense of its “personality” and the culture of the museum itself, which emerges from the curator, the collection’s history, and the museum’s priorities. There are fun human touches like the ones in the photos below, interspersed between the stinking carcasses awaiting skeletonization, the crumbling bone specimens on tables that need repair or new ID tags, or the rows upon rows of coffee cups ready to fuel the staff’s labours.

Yet another reason why Darwin kicks ass.

Yet another reason why Darwin kicks ass. And fine curator-humour!

Ironic bird pic posted on the wall.

Ironic bird pic posted on the wall.

Below a typical wall-hanging of a bovid skull, an atypical display of a clutch of marshmallow peeps. Contest to see whether the mammalian or pseudo-avian specimens last longest?

Below a typical wall-hanging of a bovid skull, an atypical display of a clutch of marshmallow peeps. Contest to see whether the mammalian or pseudo-avian specimens last longest?

The NHMLA’s collection is a world-class one, which I why I chose it as the example for this post. When I entered the collection, I got that staggering sense of awe that I love feeling, to look down the halls of cabinets full of skeletonized specimens of birds and be overwhelmed by the vast scientific resource it represents, and the effort it has taken to create and maintain it. Imagine entering a library in which every book had the librarian’s hand in writing and printing it, and that those books’ contents were largely mysteries to humanity, only some of which you could investigate during your visit. Museum collections exist to fuel generations of scientific inquiry in this way. Their possibilities are endless. And that is why I love visiting them, because every trip is an adventure into the unknown– you do not know what you will find. Like these random encounters I had in the collection’s shelves:

Sectioned moa thigh bones, showing thick walls and spars of trabecular bone criss-crossing the marrow cavities.

Sectioned moa thigh bones, showing thick walls and spars of trabecular bone criss-crossing the marrow cavities.

My gut reaction was that this is a moa wishbone (furcula)- not often seen! It is definitely not a shoulder girdle (scapulocoracoid), which would be larger and more robust, and have a proper shoulder joint. It could, though, be a small odd rib, I suppose.

My gut reaction was that this is a moa wishbone (furcula)- not often seen! It is definitely not a shoulder girdle (scapulocoracoid), which would be larger and more robust, and have a proper shoulder joint. It could, though, be a small odd rib, I suppose. EDIT: Think again, John! See 1st comment below, and follow-ups. I seem to be totally wrong and the ID of scapulocoracoid is right.

A cigar box makes an excellent improvised container for moa toe bones- why not?

A cigar box makes an excellent improvised container for moa toe bones- why not?

Moa feet: all the moa to love!

Moa feet: all the moa to love!

May the skull of the magpie goose (Anseranas semipalmata) haunt your nightmares.

May the skull of the magpie goose (Anseranas semipalmata) haunt your nightmares.

Double-owie: headed shank (tibiotarsus) bone of a magpie goose (Anseranas semipalmata). No mystery why this guy died: vet staff at the zoo tried to fix a major bone fracture, and it had time to heal (frothy bone formation) but presumably succumbed to these injuries/infection.

Healed shank (tibiotarsus) bone of the same magpie goose as above. It had its own nightmares! No mystery why this guy died: vet staff at the zoo tried to fix a major bone fracture (bracing it with tubes and metal spars), and it had time to heal (see the frothy bone formation) but presumably succumbed to these injuries/infection.

Kiwi (Apteryx australis mantelli) hand, showing feather attachments and remnant of finger(s).

Kiwi (Apteryx australis mantelli) hand, showing feather attachments and remnant of finger(s).

Now that I’m in the collection shelves area, it brings me to this trip and my purpose for it! I wanted to look at some “basal birds” for our ongoing patella (kneecap) evolution project, to check which species (or individuals, such as juveniles/adults) have patellae. Every museum visit as a scientist is fundamentally about testing whether what you think you know about nature is correct or not. We’d published on how the patella evolved in birds, but mysteries remain about which species definitely had a patella or how it develops. Museum collections often have the depth and breath of individual variation and taxonomic coverage to be able to address such mysteries, and every museum collection has different strengths that can test those ideas in different, often surprising, ways. So I ventured off to see what the NHMLA would teach me.

Shelves full of boxes, begging to be opened- but unlike Pandora's box, they release joyous science!

Shelves full of boxes, begging to be opened- but unlike Pandora’s box, they release joyous science!

Boxes of kiwis, oh frabjous day! A nice sample size like this for a "rare" (to Northern hemispherites) bird is a pleasure to see.

Boxes of kiwis, oh frabjous day! A nice sample size like this for a “rare” (to Northern hemispherites) bird is a pleasure to see.

Well, in my blitz through this museum collection I didn’t see a single damn patella!

As that kneecap bone is infamously seldom preserved in nice clean museum specimens, this did not surprise me. So I took serendipity by the horns to check some of my ideas about how the limb joints in birds in general develop and evolve. One thing I’ve been educating myself about with my freezer specimens and with museum visits (plus the scientific literature) is how the ends (epiphyses) of the limb bones form in different species of land vertebrates (tetrapods). There are complex patterns linked with evolution, biomechanics and development that still need to be understood.

Left side view of the pelvis of a very mature, HUGE Casuarius casuarius (cassowary). The space between the ilium (upper flat bone) and ischium (elongate bone on middle right side) has begun to be closed by a mineralization of the membrane that spanned those bones in life. A side effect of maturity, most likely. But cool- I've never seen this in a ratite bird before, that I can recall.

Left side view of the pelvis of a very mature, HUGE Casuarius casuarius (cassowary). The space between the ilium (upper flat bone) and ischium (elongate bone on middle right side) has begun to be closed by a mineralization of the membrane that spanned those bones in life. A side effect of maturity, most likely. But cool- I’ve never seen this in a ratite bird before, that I can recall.

Hatchling ostrich thigh bones (femora), showing the un-ossified ends that in life would be occupied by thick cartilage.

Hatchling ostrich thigh bones (femora), showing the pitted, un-ossified ends that in life would be occupied by thick cartilage.

A more adult ostrich's femora, with more ossified ends and thinner cartilages.

A more adult ostrich’s femora, with more ossified ends and thinner cartilages.

Rhea pennata (Darwin's rhea) femora (thigh bones), left (top) one with major pathology on the knee end; overgrown bone. Owie!

Rhea pennata (Darwin’s rhea) femora; right (top) one with a major pathology on the knee end; overgrown bone (osteoarthritis?). Owie!

Also very-unfused knee joints of a Darwin's rhea. Cool Y-shape!

Also very-unfused knee joints of a Darwin’s rhea hatchling. Cool Y-shape!

In birds, most of the bones don’t have anything that truly could be called an epiphysis– the bone ends are capped with thick cartilage that only gradually becomes bone as the birds get older, and even old-ish birds can still have a lot of cartilage (see photos above)– no “secondary centre” (true epiphysis) of bone mineralization ever forms inside that cartilage. However, there are two curious apparent exceptions to this absence of true epiphyses in avian limbs:

(1) in the knee joint, something like an epiphysis forms on the upper end of the tibia (shank bone) and fuses during growth (shown below). Sometimes that unfused epiphysis is confused with a patella, as our recent paper discussed; in any case, where that “epiphysis” came from in avian evolution is unclear. But also:

(2) in the ankle joint, several bones on both sides (shank and foot) of the joint fuse to the long-bones of the limbs, acting like epiphyses. It is well documented by the fossil record of non-avian and avian dinosaurs that these were the tarsals: at least five different bones (astragalus, calcaneum and distal tarsals) were individual bones for millions of years in various dinosaurs, then these all fused to form the “epiphyses” of the shank and foot, eventually completing this gradual fusion within the bird lineage. Modern birds obliterate the boundaries between these five or more bones as they grow.

These are worthwhile questions to pursue because they show us (1) how odd, little-explored features of the avian skeleton came to be; and (2) potentially more generally why limb bones develop the many ways they do in vertebrates, and how they might develop incorrectly — or heal if damaged.

Images below from the NHMLA collections show how this is the case. Fortunately(?) for me, they supported how I thought the “epiphyses” of avian limbs develop/evolved; there were no big surprises. But I still learned neat details about how this happens in individual species or lineages, especially for the knee joint.

Juvenile kiwi's shank (tibiotarsus) bones viewed from the top (proximal) ends, showing the bubbly nubbins of bone (very bottom of each bone image) that are the "cranial tibial epiphyses" often mistaken for patellae.

Juvenile kiwi’s shank (tibiotarsus) bones viewed from the top (proximal) ends, showing the bubbly nubbins of bone (very bottom of each bone image; lighter region) that are the “cranial tibial epiphyses” often mistaken for patellae.

Subadult kiwi's tibiotarsi in same view as above, showing the epiphyses fusing onto the tibiae.

Subadult kiwi’s tibiotarsi in same view as above, showing the smooth triangular epiphyses fusing onto the tibiae.

Adult kiwi's tibiotarsi (sorry, blurry photo) in which all fusion is complete.

Adult kiwi’s tibiotarsi (sorry, blurry photo) in which all fusion is complete.

Looking down at the top/ankle end of the tarsometatarsal (sole) bones in a hatchling ostrich: the three bones are separate and hollow, where "cartilage cones" would have filled them in.

Looking down at the top/ankle end of the tarsometatarsal (sole) bones in a hatchling ostrich: the three bones are separate and hollow, where “cartilage cones” would have filled them in. The left and right bones have different amounts of ossification; not unusual in such a young bird.

Ossified tendons (little spurs of long, thin bone) on the soles of the feet (tarsometatarsal bones) of a brush-turkey (Alectura lathami)- seldom described in this unusual galliform bird or its close relatives, and thus nice to see. These would be parts of the toe-flexor tendons.

Ossified tendons (little spurs of long, thin bone) on the soles of the feet (tarsometatarsal bones) of a brush-turkey (Alectura lathami)- seldom described in this unusual galliform bird or its close relatives, and thus nice to see. These would be parts of the toe-flexor tendons. Another nice thing about these two tarsometatarsus specimens is that their fusion is basically complete- each is one single bone unit, as in normal adult birds, rather than five or more.

My visit to the NHMLA bird bone collection was a lot of fun, because I got to do what I love: opening box after box of bone specimens, with bated breath wondering what would be inside. In this case, familiarity was inside, but my knowledge of avian bone development and evolution still improved. I got to look at a lot of ostriches, rheas, cassowaries and kiwis, more than I’d seen in one museum before, and that broadened my sample of young, juvenile and adult animals that I’d seen for these species. Their knees and ankles all grew in grossly similar ways, supporting this assumption in my prior work and building my confidence in published ideas. It’s always good to check such things. Each box opened takes some careful observation and cross-checking against all the facts and ideas swirling around in your head. You take notes, scale photos, measurements, do comparisons between specimens, and just explore; letting your curiosity run unleashed as you assemble knowledge, Tetris-like, in your mind.

And I had a lot of fun because a museum collection visit is like swimming in anatomy. You’re surrounded by more specimens than you could ever fully comprehend. Sometimes you run across an odd specimen whose anatomy tells you something about its life, like pathologies such as the terrible fractured magpie goose leg shown above. Or you see some curatorial touch that makes you chuckle at an apparent inside joke or mutter respect for their careful organization in tending their charges. That feeling of pulling open a museum drawer or box lid and peering inside is like few others in science — there might be disappointment inside (e.g. “Crap, that specimen sucks!”), boredom (“Oh. Another one of these!?”) or the joy of discovery (“Holy *@$£, I’ve never seen that before!”). My first scientific publication (in 1998) came from rummaging through the UCMP museum collections as a grad student and spotting an obscure pelvic bone that turned out to be highly diagnostic for the equally obscure clade of bird-like dinosaurs called alvarezsaurids. I happened to open that drawer with the alvarezsaurid specimen at the right time, shortly after the first ever specimen of that dinosaur had been described in the literature (~1994). Before then, no one could have identified what that bone was!

There is time for hours of quiet introspection during museum collection studies, immersed in this wealth of anatomical resources and isolated in a silent, climate-controlled tomb-like hall. It is relaxing and overwhelming at the same time. Especially in my case with just five hours to survey numerous species, you have to budget your time and think efficiently. It’s a unique challenge to explore a museum collection as a researcher. If you don’t learn something — especially in a good museum collection — you’re doing it wrong. In this time of tight finances and trends to close museums or stow away precious collections, it is important to vocally celebrate what a vast treasure museum collections are, and how the people that maintain them are vital stewards of those treasures.

I set the cat amongst the pigeons by also visiting the Page Museum at the La Brea Tar Pits in LA, to study fossil cats-- like this American lion (Panthera atrox) code-named "Fluffy", that we CT scanned during my LA visit-- more about that later!

I set the cat amongst the pigeons by also visiting the Page Museum at the La Brea Tar Pits in LA, to study fossil cats– like this American lion (Panthera atrox), code-named “Fluffy”, that we CT scanned during my LA visit– more about that later!

EDIT: I hurried this post off during my free time today, and still feel I didn’t fully capture the deep, complex feelings I have regarding museum collections and the delight I get from studying them. Other freezerinos, please add your thoughts in the Comments below!

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This week was a great week for me and giant dinosaurs in many ways, so I’m sharing that experience via photos and a bit of backstory. I hope you like it.

Stomach-Churning Rating: 1/10. Big birds and bones but no barfing.

First, I attended the filming of a new documentary, “T. rex Autopsy” (due for release on 7 June on NatGeo TV, just in time to steal the thunder of get you excited for Jurassic World), on the edge of London. I’m allowed to post these two photos of it. Expect much, much more information later– and I think you will like that information when it comes! Not quite a 50′ tall bird, but… So. Damn. Cool.

trex-autopsy2

trex-autopsy1

Second, my team and I dissected a big animal I’ve mentioned here before. For various reasons, I won’t/can’t post images or details of it right now, but I hope to soon. It’s not a dinosaur, but it was giant as its kind goes, so I’m wedging it in here.

Third, and this is the main impetus for my post, I finally got to see the giant chicken! No, not this one that I recall from my childhood…

hoboken

But this one! A 50’/13m tall chicken made by teacher Ben Frimet’s team of students and teachers at the City of London Academy!

Shortly after my first encounter.

Shortly after my first encounter. I’m still in a state of awed shock. And shadow.

The megachicken was unveiled at a “Chickenfest” event celebrating the sculpture’s completion. Chickenfest also prominently involved members of the “Chicken Coop” team who have drawn together scientists, humanities scholars, artists and more to investigate “Cultural & Scientific Perceptions of Human-Chicken Interactions” — more details here. Their theme helped unite the event’s various displays and lectures as well as some of the City of London Academy’s teaching topics, which inspired students to look at chickens from many angles. The event was so fun and truly integrative that it had me clucking with joy, but the anatomically accurate giant chicken art piece stole the show (as intended). Enjoy the photo tour below.

Giant Chicken 5

Pelvic/thigh region! (no patella, but hey)

Giant Chicken 6

Great views from up to 3 storeys around it.

Giant Chicken 3 Giant Chicken 4 Giant Chicken 7 Giant Chicken 8 Giant Chicken 9

Little chickens made of fast-food forks and stuff.

Little chickens made of fast-food forks and stuff. Very clever.

Chicken bones

One of our research chickens, a 30-day-old broiler, skeletonized by the Chicken Coop team and brought to the event. Chunky and funky!

Our RVC chicken research team (postdocs/fellows Drs. Heather Paxton, Jeffery Rankin, Diego Pereira-Neves) presented a stall with motion capture and chicken bones, like this fun identification display.

Our RVC chicken research team (postdocs/fellows Drs. Heather Paxton, Jeffery Rankin, Diego Pereira Neves) presented a stall with motion capture demos and chicken bones, like this fun identification display.

What will happen to that giant chicken art piece? This is yet to be determined, and was the question asked of the lecture panel (including me, who gave a lame answer involving King’s Cross’s birdcage). It was unanimous that it must not be destroyed– as long as it does not go on a destructive rampage through London…

One of my favourite films of my teenage years, Beastmaster, lends me a phrase I’ll throw out here like a razor-edged boomerang-thing: “Life is a circle. We will meet again.” And so, at the Chickenfest event, past and present worlds collided. I happened to be there presenting a talk just before Luis Rey. Almost exactly 13 years ago, Luis had done this classic T. rex vs. giant chicken race for my “T. rex was not a fast runner” paper in Nature. He likewise has blogged about the Chickenfest event, so check that out!

T. rex vs. chicken race, by Luis Rey

Coincidentally, there was ANOTHER 50′ tall bird placed not far from that giant chicken in southeast London this week, for a very different reason- a huge Norwegian Blue parrot in celebration of the Monty Python reunion! And I’ve been a Monty Python fan since age ~11, so that rocks my world two times over.

IMAGE: FLICKR USER TAYLOR HERRING

IMAGE: FLICKR USER TAYLOR HERRING

Two giant birds in London in one week. It doesn’t get any better than that– unless there were three such birds– if I missed one, chime in in the Comments!

(Edit: British friends tell me I must refer to an Alan Partridge skit here, so I am doing so. I know when to do as I’m told.)

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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’s World Penguin Day! Watch your back though… these penguins aren’t as nice as they seem. But they need us to be nice to them!

Hahaha?Whether you watch a classic GIF like the one above, or a kid-friendly TV/film documentary, you might get the impression that penguins lead carefree, or at least silly or slapstick, lives– happy feet and all that. It works for Hollywood: a Charlie Chaplin comedy relief role to play.  And that’s the vision of penguins I grew up with: they were living cartoons to me.

But what’s the reality? Plenty of documentaries, most notably to my mind the recent Attenborough’s “Frozen Earth” episodes or “March of the Penguins” film, have dealt with the darker side to these two-toned, tuxedo-toting antipodeans. And anyone who has experienced penguins in the wild has probably seen those not-so-light facets of penguinity firsthand. On realiizing just how compulsively horny young “hooligan cock” male penguins were, Natural History Museum ornithologist Douglas Russell wrote: ““just the frozen head of the penguin, with self-adhesive white O’s for eye rings, propped upright on wire with a large rock for a body, was sufficient stimulus for males to copulate and deposit sperm on the rock.”

Stomach-Churning Rating: 5/10; some tears may be shed over cute baby penguins and you might choke if you’re a rhea trying to swallow one, but the anatomy shown is mostly skeletal or dessicated. No penguin juices. Except those just mentioned above.

I’m quick to admit, I didn’t know much about penguins until recently. I couldn’t name many species or say much about their behaviour, anatomy or evolutionary history. When I was a graduate student at Berkeley, I was enthused by a now-classic, elegantly simple study (published in 2000) that fellow PhD student Tim Griffin and biomechanist Dr. Rodger Kram conducted on penguin waddling. They found that the waddling gait of penguins isn’t mechanically disadvantageous, as it appears, but rather is a way that they conserve energy while walking. It’s the short legs, instead, that make their gait metabolically expensive, because shorter legs mean that more frequent, costly steps need to be taken, incurring high costs due to rapid firing of leg muscles to support the body. My vicarious enjoyment of Griffin’s & Kram’s research began my scientific introduction to penguins. Fast forward to 2014: I get a crash course in penguinology.

Punta Tombo (4)

Mostly-fledged Magellanic penguin

That’s what this post is about, and how it brought me in touch with The Existentialist Penguin— the haggard, storm-tossed, predator-harried, starved and bullied wanderer of wastelands.

My personal introduction to penguins over the past year has been initiated by a collaboration with PhD student James Proffitt and long-time colleague Dr. Julia Clarke, both at the University of Texas in Austin. They kindly invited me to collaborate on applying modern biomechanics to the surprisingly excellent fossil record of penguins (Sphenisciformes), among other extant water birds. Before diving into it all, I happened to go to Argentina.

Punta Tombo (2)

Penguin tries to keep cool in the shade, opening its mouth to shed heat in the autumn sun.

Just before I travelled to Patagonia on unrelated business (to study sauropodomorph dinosaurs!), I did a little googling and came across Punta Tombo reserve, near the city of Trelew that I was visiting (more about that in a future post!). It’s where some 1+ million Magellanic penguins (Spheniscus magellanicus) gather every southern summer to breed and fledge before making a long ~5 month swim up to Brazil. I asked my host, Dr. Alejandro Otero, if we might take a day off to visit this spot, where guanacos, rheas and other wildlife were also said to be common, and he basically said “Hell yes!” as he’d never been there. My Flickr photostream gives a big set of my favourite photos from that trip, but here are some others below, to show some of my experiences. We rented a car and took a lovely 90-minute drive south across the Patagonian plains, observing wildlife like tinamous (yes! So exciting for me) as we went. You could get within 1.5m of the penguins according to park rules, and the penguins were very permissive of that!

This jaunty chap was staying put in his burrow while people walked by. We came closer and he kept rotating his head around, staring at us. I first took it as cute juvenile behaviour, but on later observations of penguins realized it was a threat- "My beak is sharp! Stay back, bro, or I'll glock ya!"

This jaunty chap was staying put in his burrow while people walked by. We came closer and he kept rotating his head around, staring at us. I first took it as cute juvenile behaviour, but on later observations of penguins realized it was a threat- “My beak is sharp! Stay back, bro, or I’ll glock ya!”

The video below shows a penguin encounter that left me with no doubts that these animals don’t mess around. The smaller penguin escaped, losing its cool burrow and some of its tough hide, too. Indeed, penguins can be remarkable assholes to each other.

With battles like this erupting all around us, where the penguins struggled to find shade in the desert-like inland parts of the park, often hundreds of meters away from the cool ocean, it came as no surprise to find casualties. The juveniles (and some remaining adults; most having left by now while the ~1 year-old juveniles fledge) not only battled, but also fasted, and roasted in the heat as they shed their insulatory fluff for waterproofed streamlining. This poor little flat Spheniscus had been trodden a bit past streamlined:Punta Tombo (3)

Near the end of our visit, just after I saw an informative sign about the lesser rhea or “choique” (Pterocnemia/Rhea pennata), we managed to get very close to a rhea and follow it for a while, as penguins stood around in apparent disinterest. I’ll never forget that meeting: two flightless birds, yet adapted to such different lifestyles and habitats. The penguins were in the rhea’s domain; a hot, wind-blown, scree-scoured scrubland on the edge of the fertile ocean.rhea-penguin

The choique soon found a dry old hatchling penguin carcass, no meatier than the surrounding thickets, and tried to swallow it. The loss of teeth by its distant ornithurine ancestors proved to be a bad move, because it struggled to get the jerky-like mass through its beak:

That Punta Tombo visit was an experience I’ll never forget. I returned to the UK, abuzz with excitement about penguins. I “got” them now, I felt, at least in a very unscientific, anthropomorphic way. It took the face-to-beak experience to drive that home, more than any emotive film treatment could. Whether enduring Antarctic wintery blasts or unforgivingly hot and dry, burrow-speckled coastal badlands, penguins are buggers with true grit. Survivors, as their >60 million year fossil record attests to. On my return, I delved through my photos of museum specimens to get a better appreciation for penguin anatomy, preparing to also get familiar with that fossil record; all as part of that ongoing work with Proffitt and Clarke. Here’s some of that anatomy:

My first encounter with a penguin in the wild is probably this specimen washed up on a beach in Uruguay. I'm going with the tentative ID of a juvenile penguin skeleton; probably Magellanic.

My first encounter with a penguin in the wild (but not a live one) is probably this specimen washed up on a beach in Uruguay. I’m going with the tentative ID of a juvenile penguin skeleton (short foot; flat wing bones); probably Magellanic. The bevy of vertebrate morphologists investigating dead penguins on this beach during our conference in 2010 will not soon be forgotten!

Magellanic penguin skeleton, "flying" through the Punta Tombo visitor centre.

Magellanic penguin skeleton, “flying” through the Punta Tombo visitor centre.

University Museum of Zoology Cambridge skeleton of one of the "great penguin" (do not confuse with the great pumpkin!) species; either King (patagonicus) or Emperor (forsteri).

University Museum of Zoology Cambridge skeleton of a “great penguin” (do not confuse with the great pumpkin!) species of Aptenodytes; either King (patagonicus) or Emperor (forsteri). Characteristic features, in addition to the robust, dense skeleton, include the short neck, flattened but robust wings and scapulae, robust furcula (wishbone), stubby legs (with a big blocky patella) and thin but longish tail (supposedly used to balance with while walking/standing).

I’ll visit some more penguin anatomy in coming images- those photos are just teasers. And they set the stage for me to go back to my one-stop-shopping for awesome ornithological specimens, the Natural History Museum at Tring (images below presented with kind permission from the Natural History Museum, London; but I took the photos), to pick up an assortment of 11 frozen penguins from helpful curator Hein van Grouw! Such as this “gagged” King penguin:
NHMUK penguin

And this handsome Emperor penguin, going through the Equine Imaging Centre’s CT scanner as I do my usual routine of (1) get cool critters, (2) barrage them with radiation to peek inside:penguin CT (3)

CT scanner monitors as I scan a penguin; mid-torso x-ray slice shown on the right.

CT scanner monitors as I scan a penguin; mid-torso x-ray slice shown on the right.

Awwwwww... baby Gentoo penguin (Pygoscelis papua). Unhappy feet, I'm afraid.

Awwwwww… baby Gentoo penguin (Pygoscelis papua— EDIT: Probably Aptenodytes; see comments below). Unhappy feet, I’m afraid… Happy CT scanning, however– specimens like this are NOT easy to come by in these northern nether regions!

Because I love the CT scan images of these penguins so much (their skeletons are awesome and bizarre!), I’ll share the pilot scans of the best ones now:

Calling all penguin experts! What's up with this? Is that really how much gastrolith volume a penguin carries, or did a museum curator stick rocks up its bum? Seems very caudal in position. I'm fascinated.

Calling all penguin experts! What’s up with this? Is that really how much gastrolith (stomach stone; near bottom of image) volume a penguin carries (answer after some literature reading: maybe yes!), or did a museum curator stick rocks up its bum? It seems very caudal in position, and this is consistent with other animals I’ve seen (some below). A paper on this phenomenon and potential role in ballast is here. Another here.

Side view.

Side view. Nice view of the head at least.

The fluffy baby shown in the photo above. Nice pose, and lots of anatomy shown. And check it out- gastroliths?!? In such a young animal-- is it even feeding yet?

Young juvenile. Nice pose, and lots of anatomy is shown. And check it out- gastroliths?!? In such a young animal– is it even feeding yet? (presumably straight after hatching) And they are relatively big pebbles, too! If I noticed this 5 years ago, it would have been a nice paper to report- first recognition of gastroliths in penguin chicks seems to have been then. Indeed, that study observed some chicks intentionally swallowing stones.

Another youngun.

Another youngun; the fluffy one from the photo above. More rocks up its wazoo.

Three wee little chicks.

Three wee little chicks, all with stomach stones.

CT reconstruction of adult skeleton. This specimen was gutted and flattened, so the gastroliths are few and scattered. Check out the long tail:

From recent skeletons to fossil ones, penguins have wacky anatomy; they break most of the “rules” of being a proper bird, putting other oddballs like rheas to shame. I can’t ably review the many penguin species we know of, but the ancient Palaeocene penguin Waimanu features prominently in recent scientific discussions of penguin evolution, such as the superb research and blog of Dan Ksepka  as well as many workers in the southern hemisphere. I haven’t had a chance to inspect that creature’s bones, but while in Trelew, Argentina, I was very pleased to run into some excellent specimens of a later animal:

Part of the rather nice skeleton of Palaeospheniscus patagonicus, an Oligocene/Miocene largish penguin; from the MFN collections in Trelew, Argentina and collected nearby.

Part of the nice skeleton of Palaeospheniscus patagonicus, an Oligocene/Miocene largish penguin; from the MEF collections in Trelew, Argentina and collected nearby. The genus has been known since Ameghino’s description in 1891, and is closely related to living penguins, especially Aptenodytes. It was not a large penguin, but at about 5kg body mass was no slouch as birds go (roughly similar in size to a Magellanic penguin). I also got to see  Madrynornis mirandus, a Miocene form.

For me, the diagnostic trait of a penguin skeleton: the very short, tobust tarsometatarsus. From Palaeospheniscus, as above.

For me, the diagnostic trait of a penguin skeleton: the very short, tobust tarsometatarsus. From Palaeospheniscus, as above. The great palaeontologist GG Simpson wrote of it: “Despite the innumerable variations in details, the tarsometatarsi, on which all species but P. robustus are based, are quite stereotyped in general structure and leave little doubt that the forms placed here by Ameghino do all belong to a natural group.” A ratio of length to proximal width of >2 is typical of most penguins.  Synapomorphy FTW!

From beach skeletons, to mass suffering of landbound birds, to 3D imaging and fossil skeletons, I’ve had quite the immersion in penguinness lately. And through that experience, I’ve been drawn closer to penguins in more ways than one. I’ve been impressed by their adaptability and durability. In some ways, penguins’ adaptations to harsh freezing winters in wastelands also aid them to survive harsh baking summers in dry badlands.

Yes, those badlands are still coastal, and penguins can still drink the saltwater and excrete salt via their supraorbital glands, but those penguins in Punta Tombo were not having a keg party. They were clearly enduring some serious discomfort, and not all making it through the ordeal. I watched silently along with other penguins as one penguin lay prone in an awkward pose on a bleached-white stretch of hardpan soil, while one flipper meekly raised, then flopped down. It was not long for this world, and there was a host of large scavengers around ready to make the most of that, while penguin-eating giant petrels (a sister group to penguins) wheeled overhead.

penguin-waddle

Waddlers of the wastes

While penguins still spend most of their lives at sea, they retain a sometimes astonishing array of behaviours they use on land: burrowing, hopping/jumping, costly short-legged (but efficiently waddling) walking, and perhaps more that we haven’t yet discovered! Their unique anatomy reflects a compromise between all these factors, and we’re fortunate to have knowledge of their fossil record that shows a lot of detail on how they evolved it all. While penguins are a highly aquatic species, they show how aquatic and terrestrial adaptations can coexist in harmony; it’s not just a black-or-white issue. But with climate change in progress, the ~18 species of penguins have some rapidly altering challenges to adapt to, or go the way of Waimanu. This is a critical Kierkegaardian moment for The Existentialist Penguin.

I raise a glass in toast to that versatile, resilient, gravel-gizzarded Existentialist Penguin! May it persevere all the troubles our ever-changing world throws at it, as it has done since the Palaeocene. And may we draw inspiration from its tenacity, to face our own troubles, together on this crazy spinning globe!

Cheers!

by animalloz, on deviantart

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And I post my blog and stare
Into x-rays of an ostrich
I’ve always known that radiographs never lie
People always say “that’s cool”
To see x-rays of an ostrich
So keen to know what
Lies behind the skin

(evolved from “Eyes of A Stranger” by Queensrÿche, from the epic masterpiece of Operation: Mindcrime (1988). One of my favourite albums of all time, and a fantastic concept album too. The band was operating at their peak. Tight! Drug addict Nikki gets brainwashed by the evil Dr. X and made to assassinate a nun, Sister Mary, who was a prostitute, and then there’s like a revolution or something, and things get all screwed up and no one ends up happy – or alive. All the while, Geoff Tate is singing his guts out. Anyway, I got to see them play the whole album live in 1990 in Madison, WI, for the filming of Operation: Livecrime, which was like a Mecca moment for me back then. Look for me (pre-bald years) in about the 6th row. )

What does that album have to do with the number 2 (two days left in Freezermas)? Hmm… Track 2 is the instrumental Anarchy-X, and today’s post is about X-rays as well as that funky ostrich (2 legs good! 2 toes good, too!) again, so I’m satisfied, and by this point you’re probably just oggling the mind-blowing images below anyway, so fuck it!

Stomach-Churning Rating: 2/10; just X-rays.

Tech/MRes Kyle Chadwick, Renate Weller and the equine imaging team at the RVC took these x-rays of our birdie for us and for an artist who is doing a big x-ray animal art show (more news on this soon!)– thanks to all of them for some truly awesome images! I could stare at the intricate details in these images for hours– go ahead, do it. Click to emostrichinate them (this post needs to be viewed on nice big screen), and oggle away…

Head and neck.

Head and neck.

Another view of the same.

Another view of the same. The highly flexible esophagus and trachea can be seen going diagonally across the neck; twisting from ventral to dorsal. It’s floppy, so it can do that.

Neck near the head; tapering.

Neck near the head; tapering.

Middle of neck. Check out the rings of the trachea!

Middle of neck. Check out the rings of the trachea!

Base of neck and shoulder

Base of neck and shoulder.

Shoulder and chest. Hard to image; thick and dense (still was frozen).

Shoulder and chest. Hard to image; thick and dense (still was frozen), hence the whiteout toward the left side of the image.

Check out that wing!!

Check out that wing!!

Ankle- note the big calloused pad that ostriches rest on (right side of image).

Ankle- note the big calloused pad that ostriches rest on (right side of image).

That two-toed foot... but did you know that normally the missing 2nd toe is still there as a fibrous remnant on the 3rd toe?

That two-toed foot… but did you know that normally the missing 2nd toe is still there as a fibrous remnant on the 3rd toe?

Tomorrow: the final day of Freezermas. What will it be?

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Freezermas continues! Today we have a treat for you. Lots of detailed anatomy! This post comes from my team’s dissections of an ostrich last week (~3-7 February 2014), which I’ve been tweeting about as part of a larger project called the Open Ostrich.

However, before I go further, it’s as important as ever to note this:

Stomach-Churning Rating: 9/10: bloody pictures of a dissection of a large ostrich follow. Head to toes, it gets messy. Just be glad it wasn’t rotten; I was glad. Not Safe For Lunch!

If the introductory picture below gets the butterflies a-fluttering in your tummy, turn back now! It gets messier. There are tamer pics in my earlier Naked Ostriches post (still, a rating of 6/10 or so for stomach-churning-ness there).

All photo credits  (used with permission) on this post go to palaeoartist Bob Nicholls (please check out his website!), who got to attend and get hands-on experience in extant dinosaur anatomy with my team and Writtle College lecturer Nieky VanVeggel (more from Nieky soon)!

Research Fellow Jeff Rankin, myself and technician/MRes student Kyle Chadwick get to work.

Research Fellow Jeff Rankin, myself and technician/MRes student Kyle Chadwick get to work, removing a wing.

This is a male ostrich, 71.3 kg in body mass, that had gone lame in one foot last summer and, for welfare reasons, we had to put down for a local farmer, then we got the body to study. We took advantage of a bad situation; the animal was better off being humanely put down.

The number for today is 6; six posts left in Freezermas. But I had no idea I’d have a hard time finding a song involving 6, from a concept album. Yet 6 three times over is Slayer’s numerus operandi, and so… The concept album for today is Slayer’s  1986 thematic opus “Reign in Blood” (a pivotal album for speed/death metal). The most appropriate track here is the plodding, pounding, brooding, then savagely furious “Postmortem“, which leads (literally and figuratively, in thunderous fashion) to the madness of the title track, after Tom Araya barks the final verse:

“The waves of blood are rushing near, pounding at the walls of lies

Turning off my sanity, reaching back into my mind

Non-rising body from the grave showing new reality

What I am, what I want, I’m only after death”

I’m not going to try to reword those morbid lyrics into something humorous and fitting the ostrich theme of this post. I’ll stick with a serious tone for now. I like to take these opportunities to provoke thought about the duality of a situation like this. It’s grim stuff; dark and bloody and saturated with our own inner fears of mortality and our disgust at what normally is politely concealed behind the integumentary system’s viscoelastic walls of keratin and collagen.

But it’s also profoundly beautiful stuff– anatomy, even in a gory state like this, has a mesmerizing impact: how intricately the varied parts fit together with each other and with their roles in their environment, or even the richness of hues and multifarous patterns that pervade the dissected form, or the surprising variations within an individual that tell you stories about its life, health or growth. Every dissection is a new journey for an anatomist.

OK I’ve given you enough time to gird yourself; into the Open Ostrich we go! The remainder is a photo-blog exploration of ostrich gross anatomy, from our detailed postmortem.

(more…)

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Here, I give you a long-planned post on the patella (“kneecap bone”) of birds, which was my Royal Society Senior Research Fellowship sabbatical project for 2012-13. This is only a brief introduction to the anatomical issues at hand, err, I mean at knee…

Stomach-Churning Rating: 6/10; mostly skeletons/fossils, but there are a few images of the dissection of a guineafowl, which is fresh and meaty.

Archaeopteryx, the Berlin specimen. Helluva fossil, but nary a patella!

Archaeopteryx, the Berlin specimen. Helluva fossil, but nary a patella!

The question I am exploring, first of all, is simply how the patella evolved, because it seems to be present in almost all living birds. However, it is absent in all non-avian dinosaurs, and indeed most Mesozoic birds, too. There is barely a hint of any precursor structure (a “patelloid”) in other reptiles, but lizards evolved their own patella that is quite different (a flattened lozenge, not a rectangular structure lying tightly confined in a “patellar groove” on the femur as it is in birds). Mammals evolved the knobbly, hemispherical kind of kneecap that we’re familiar with, possibly on several occasions (a different story!). So the patella evolved at least three times in the lizard, mammal and bird lineages– and possibly more than once in each of these groups. And that’s about it for almost 400 million years of tetrapod evolution, except for a few very rare instances in fossils and sort-of-patella-like things in some frogs or other weirdos.

Fossil birds exhibit no clear presence of a patella until we come very close to modern birds on the avian stem of the tree of life (see below). And then, suddenly in modern birds, there is a lot of variation and not much good documentation of what kind of patella exists. This makes it challenging to figure out if the patella is ancient for modern birds or if it evolved multiple times, or how it changed after it first evolved– let alone bigger questions of what the patella was “for” (performance benefits, functional consequences, etc.; and developmental constraints) in the birds that first evolved it.

Considering that the patella is such an obvious bone in some birds, and certainly affects the mechanics of the knee joint (forming a lever for the muscles that cross it; homologous to our quadriceps muscles) and hence locomotion, it is a compelling research topic for me.

What follows is a pictorial guide to the patella of some birds, in sort of an evolutionary/temporal sequence (see my earlier post for a recap of some major groups), with a focus on animals I’ve studied more intensively so far (with >10,000 species, there is a lot that could be done):

Gansus, IVPP V15080
The early Cretaceous bird Gansus (from the IVPP in Beijing), represented by many beautifully preserved specimens, all of which lack a patella. This absence is characteristic of other stunningly preserved fossil Chinese birds, indicating that this is almost certainly an ancestral absence of a patella, until…

The famed Cretaceous diving (flightless) bird Hesperornis, from Wikipedia/Smithsonian.  Note the massive, conical/crested patella in front of the  knee (jutting up and overlapping the ribs/vertebrae close to the pelvis; see also below). That elongate patella is characteristic of many diving birds that use foot-propelled swimming; it has evolved many times in this fashion. Other hesperornithiform birds show some transformational states in their anatomy toward this extreme one.
Hesp-patella

Check this out! More Hesperornis (cast), with the femur on the left and the patella on the right. The bloody patella is almost as long as the femur! That’s nuts. With kind permission from the Natural History Museum, London.

Exhibited ostrich skeleton in left side view showing the patella (white arrow).
Exhibited ostrich (Struthio camelus) skeleton in left side view showing the patella (white arrow), on exhibit atThe Natural History Museum at Tring, Hertfordshire, UK. Ostriches are remarkable in that they have this elongate patella (actually a double patella; there is a smaller, often-overlooked second piece of bone) and yet are rather basal (closer to the root of the modern avian family tree)– however, they obviously are specialized in ways other than this double patella, most notably their very large size, flightlessness, and elongate legs. So the unusual patella is more likely linked to their odd lifestyle than a truly primitive trait, at least to some degree (but stay tuned: what happened with the patella in other members of their lineage, the ratites/palaeognaths, is much less well understood!).
Note that ostriches and Hesperornis together hint that the presence of a patella might have been an ancestral trait for living birds, but their patellae are so different that the ancestral state from which they evolved must have been different, too; perhaps simpler and smaller. Hence we need to look at other birds…
Skinned right leg of guineafowl, Numida meleagris.
Skinned right leg of a Helmeted Guineafowl, Numida meleagris, above. That whitish band of tissue in the middle of the screen, on the front of  the knee, is part of what is concealing the patella. That is an aponeurosis (connective tissue sheet, like a thin tendon) of the muscles corresponding to our “quads” or our tensor fascia latae, detailed more below. Guineafowl are fairly basal and well-studied in terms of their bipedal locomotion, so they are an important reference point for avian form and function.
Right guinefowl leg, with patella semi-exposed.
Right guineafowl leg, with patella exposed. Here I’ve peeled away that white band of tissue  and associated muscles, which have been reflected toward the bottom of the screen (AIL and PIL labels corresponding to the anterior and posterior parts of the Iliotibialis lateralis muscle). The tip of the scalpel is contacting the patella. It’s not much to see, but lies atop the bright yellow fat pad that cushions it against the femur. You should be able to see a groove in the end of the femur just above that fat pad, which is where the patella sits and slides up and down as the knee moves/muscles contract. This is called the patellar groove, or sulcus patellaris.
Left leg of a guineafowl (with right tibiotarsus behind it) showing both patellae in articulation; in medial (inside) view. The  patella is the little rectangular bit of bone in the top middle of the screen, interposed between femur and tibiotarsus.
Left leg of another guineafowl (with right tibiotarsus behind it, on the left) showing the patellae in articulation; in medial (inside) and cranial (front) views, respectively. The patella is the little rectangular bit of bone in the top middle of the screen, interposed between femur (thigh) and tibiotarsus (shank). With kind permission from the Natural History Museum, London.  
Penguin-patella
Right leg of a Cape Penguin (Spheniscus demersus) from the University Museum of Zoology in Cambridge, showing the big lumpy patella in this wing-propelled diver. They still walk long distances on land, so presumably a patella plays some role in their gait, helping to explain its large size, which like the ostrich and Hesperornis seems to be a novel trait. Notice the groove across the patella, made by the tendon of the ambiens (like our sartorius/”tailor’s muscle”), which crosses from the inside to the outside of the leg via this route. This groove is often considered a useful phylogenetic character in modern birds, as its contact with the patella (sometimes via a hole, or foramen) varies a lot among species.
Buceros skeleton UMZC
A hornbill, Buceros sp., from the UMZ Cambridge museum as well. This displays the possibly-more-typical, little rounded patellar nubbin that many birds have. See below for more.

Buceros knee closeupCloseup of the knee/patella of the hornbill, Buceros sp., from above. Not much to squawk about, patella-wise, but it’s there.

And so we complete our quick tour of the avian patella, in its grand variation and humble beginnings.

Why does an ostrich have a patella and a Tyrannosaurus, Edmontosaurus or Triceratops did not? Why were birds the only bipedal lineage to evolve a patella (mammals and lizards gained a patella as small quadrupeds), and why did some bipeds like kangaroos “lose” (reduce to fibrous tissue, apparently) their patella?

These are the kinds of mysteries my group will now be tackling, thanks to a generous Leverhulme Trust grant on sesamoid bone ontogeny, mechanics and evolution.  My group is now Dr. Vivian Allen as the postdoc, Sophie Regnault as the PhD student, and Kyle Chadwick as the technician and MRes student, along with numerous collaborators and spin-off projects. We’re looking forward to sharing more! But for now, I hope that I’ve engendered some appreciation for the avian patella, as the silly title indicates (“fella” used in the general sense of anyone!). This work is all unpublished, but some of this should be out in not too long, in much more lavish detail! Much as the patella is the “forgotten lever “of the avian hindlimb, it is the fulcrum about which a substantial part of my research group’s activity now pivots.

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