What's In John's Freezer?

Less words, more pictures in this post, and I’ll get the one lame cake joke out of the way early. I’ve nearly finished my research blitz through the postcranial material of the NHM-Tring’s osteological collection and have made some pit-stops for cake skulls now and then when I see one that pleases me. Now I shall present a survey of some of the species I’ve examined. I’ll proceed up from the base of the crown clade of living birds (Neornithes/Aves; the most recent common ancestor of living birds and all its descendants) and first take a tour of Palaeognathae; the ratites and kin; then move another step up into the Neognathae, first featuring the lineage featuring the ground fowl (Galliformes) and then the waterfowl (Anseriformes). If all this taxonomy and phylogeny is a bit much, check out this page for a brush-up on the bushy branches of bird biodiversity.

First, lots of bones of our cast of currasows, chachalacas, cassowaries and other kooky characters. And then, perhaps, a stop to the excessive alliteration. Finally, I will finish with some examples of species oddity (hat tip to Chris Hadfield).

Stomach-Churning Rating: 2/10- some bony pathologies but still just dry bones. Minimal cake jokes, and no filthy swearing this time.

BRING ON THE BONES:

My photographs are shown with kind permission from the Natural History Museum, London.

Exploded skull of an ostrich, Struthio camelus. This kind of careful preparation takes crazy skill, and creates a thing of rare beauty.

Imposing skull of a cassowary, Casuarius casuarius, with a rather worn head casque.

Mummified Owen’s Little Spotted Kiwi, Apteryx owenii. The feathers were still soft and fluffy, but I would not call this specimen cuddly.

Dorsal view of the back/hips of the Great Spotted Kiwi, Apteryx haasti. I like this photo and am not sure why. The symmetry and shading pleases me, I guess.

Front view of the back/hips of the Great Spotted Kiwi, Apteryx haasti, watching over my laptop and watching me while I write this blog on my laptop… so meta(ornithine)!

Wing of a kiwi, showing the fragile bones and feather attachments. “Apteryx” = “no wings”… well not quite. Click to emkiwi(?) so you can identify the individual bones, from the humerus right down to the fingers! I love this specimen.

The titanic left leg (in front view) of the Elephant Bird, Aepyornis maximus, from Madagascar, with a small moa nearby in left side view. There’s so much awesomeness about elephant birds I don’t know where to start, but this is one good place to do so.

The smaller end of the palaeognath scale: a mummified Undulated Tinamou, Crypturellus undulatus. Somehow the head got stuck into the abdominal cavity underneath the sternum, so this tinamou almost had its head up its arse. A tinamou with head in its proper position looks and sounds like this (video).

And now we take a left turn into the Galloanseres, most basal branch of the neognath birds, to see some of the neglected, strange early branches off from the “main line” that led to the modern diversity of ducks, geeses and swans (Anatinae, Anserinae).

Screamers (Anhimidae) are to Anseriformes as megapodes (see below; brush turkeys) are to Galliformes. By that I mean that both screamers and megapodes are very early branches off the main line of their respective lineages’ evolution, and both are quite strange when seen in that context… an unfair one, frankly; over-focused on the most familiar, “modern” or most speciose group. More about this issue further below.

This was my first hands-on experience with screamer anatomy; I was familiar from reading Tetrapod Zoology and other material about them. Check out the sound that gives them their name here! I’m now a big fan- they have so many strange features: oddly chunky but often very light bones, big feet with long toes, and then these switchblade-wrists, which would make Batman jealous:

Crested Screamer, Chauna torquata, showing the wicked spur (and smaller one) on the carpometacarpus.

Horned Screamer, Anhima cornuta; similar carpometacarpal spurs as in Chauna.

Torso of a screamer seen in top view. Nice narrow body, and no uncinate processes (spur-like bony struts that cross the ribs and act as levers for the muscles that move the ribcage during breathing)

The long, gracile, clawed toes of a screamer. Those toes, especially as they belong to an animal called a screamer, are spooky for me. Note also: very little toe-webbing for a “waterfowl.”

Not to be outdone, on the Galliformes side of Galloanserae, we have some funky headgear in the Maleo (a megapode bird/Megapodiidae; a very basal branch of “brush turkeys” and kin) and curassows (part of the Cracidae; odd South American birds whose males make booming sounds, presumably using their head-casques as resonating chambers?):

Skull of a male Maleo, Macrocephalon maleo. AR Wallace famously pursued it, and here is its funky call.

Australian brush-turkeys, Alectura lathami, at the Alma Park Zoo near Brisbane, Australia; they run wild there. Here they are doing what they are best known for: making a mound-like nest. We were doing kangaroo biomechanics experiments and they were everywhere. I was in awe to see such exotic (to me) birds; locals seemed not so enthused (the birds are loud and make a lot of mess).

Skull of Helmeted Curassow, Crax/Pauxi pauxi,  showing that resonating chamber. Along with this boom-boom-room, the male uses a piece of food that he holds to draw in the female; if she takes it, then it’s sexy time.

Foot of a Siberian Black Grouse, Tetrao tetrix (nothing to do with a certain videogame), with and without flesh. Regard the broad, feathered feet, well insulated and with plenty of surface area for prancing around in the snow or moorlands. Tetrao engage in a cool display pattern called lekking, in which the males group together and show off to watching females.

A theme in the section above that is not to be missed is that there is some amazing disparity of anatomical forms in these basal lineages of poultry-relatives. Don’t dismiss the Galloanserae as just boring food-birds! Heaps of not-so-well-studied species exist here, surely with a treasure trove of cool neontological and evolutionary questions waiting for the right person to ask! Darwin’s chickens may get their share of neglect, but that pales in comparison to how little we understand about many basal Galloanserae.

What a lot of people think of as a “ground fowl” or galliform way of life is more of a way of life somewhat typical of the Phasanidae- chickens, pheasants and their familiar kin. Megapodes, curassows, guans, grouse and other Galliformes do not necessarily do things in the “typical” ground fowl way, much as the earlier branches of the Anseriformes don’t always look/act like “proper water fowl” (i.e. Anatidae). The phenomenon at play here is one of the great bugaboos in biology: essentialism— the often implicit misconception that variation away from some abstract ideal is negligible, uninteresting or just not conceivable due to mental blinders. When we say something like “the chicken is a fascinating species” we are sliding down the essentialistic slope. There is no “the chicken.” Not really. Oh dear, speaking of slippery slopes, I’d best stop here before I start talking about species concepts. And no one wants that to happen! Anyway, essentialism still pervades a lot of modern scientific thinking, and has its place as a conceptual crutch sometimes. But in biology, essentialism can be very insidious and misleading. It burrows in deep into the scientific mind and can be hard to root out. Unfortunately, it is entrenched in a lot of science education, as it makes things easier to teach if you sweep aside the exceptions to the essentialist “rules” in biology. I catch myself thinking in static, essentialist ways sometimes. The punishment is no cake for a week; so awful. 🙂

And speaking of “normal” or “typical,” morphology is of course often not that way even within a species, age class or gender. Pathology is a great example; by definition it is abnormal. It is a shattering of the “essence” of animals, brought on by some malady.

Next I’ve highlighted some of the amazing pathologies I’ve seen in the Tring skeletons. There have been so many I’ve been unable to keep track of them– some of these birds had the stuffing beaten out of them, and I’m not talking about Thanksgiving turkeys. Some were captive animals, in which the pathology might be blamed on living an inappropriate environment, but some were wild-caught — given the extreme pathologies, it’s a wonder those even survived to be found, but perhaps less a surprise that they were caught.

BONES GONE BONKERS:

View of left knee of a specimen of the Highland Guan, Penelopina nigra, showing some nasty osteoarthritis around the whole joint. Eew.  A happier Guan sounds like this.

Femora and tibiotarsi of the Blue-throated Piping Guan, Aburria cumanensis. Amazing pathology involving the left femur (broken, rehealed) and tibiotarsus (secondary infection?). Interestingly, the non-fractured limb also showed some pathology, perhaps indicating general infection and/or arthritis in reaction to the severe damage to the other leg, or just increased load-bearing on that leg.

Little Chachalaca, Ortalis motmot, showing a broken and rehealed right femur and the tibiotarsus. As in the guan above, this animal was not walking for many weeks; its femur had snapped in two, but somehow melted back together. The tibiotarsus didn’t look too great, either; lumpy and bendy. In better times, the Chachalaca does the cha-cha like this.

These two specimens blew my mind. On the left is a normal Tetrao tetrix (Black Grouse); on the right is one hybridized with another (unknown) species.

In the picture above, what amazed me first was the very unusual flattened pelvis/synsacrum of Tetrao, which characteristically is light and wide. But in the hybrid this morphology was completely gone; the pelvis had a more standard “galliform” (read: Phasianid)-like shape, deeper and narrower and more solid in build. I am guessing that the hybrid was a cross with a pheasant like Phasianus itself, whose anatomy would be more like this. Somewhere in here there is a fantastic evo-devo/morphometrics project waiting to happen.

That’s my quick specimen-based tour of “basal birds”. Beyond these two clades of Palaeognathae and Galloanseres, there lies the forebidding territory of Neoaves: much of living avian diversity, and extremely contentious in its phylogenetic relationships. I’m tackling them next for my research on the evolution of the patella/kneecap. But first, I’ll be at the NHM-Tring today for a whirlwind tour through the respectably speciose “normal” Galloanseres clades of Phasianidae and Anserinae+Anatidae, so off I go! (It’s my wife’s birthday celebration, so cake may have to wait for later this time)

So what do you think? What’s your favourite neglected “primitive” bird group (more apropos: early branching avian lineage that may still be very specialized, rare and poorly understood), or cool factoid about palaeognaths and basal neognaths?

No quaggas were harmed during the writing of this post. Polly wanna quagga?