Another picture from the recent ostrich dissection (click for full-size, unlabeled version). Last time we were in the middle of the neck, looking from anterior to posterior. This shot is from closer to the base of the neck, looking from posterior to anterior. A lot of the stuff is the same: the ragged cut from the saw at the meat processing plant where the ostrich was cut up; the spinal cord with the supramedullary airways above it in the neural canal; and the large interspinous ligament with diverticula on either side. We’ll have reason to refer back to some of those things in the not-too-distant future, but right now I want to draw your attention to something else: the tendons of the paired longus colli dorsalis muscles toward the top of the photo.

Here’s a modified version of Wedel and Sander (2002: fig. 2) with the course of the longus colli dorsalis highlighted in red (anterior is to the left). It is a curious aspect of bird necks that the large dorsal muscles do not insert on the neural spines but on the epipophyses (or dorsal tori or dorsal tubercles) above the postzygs. A naive approach based on beam theory would suggest that inserting on the neural spines would give those muscles more leverage, but necks are tricky and often defy such a priori predictions.

Instead of inserting on the neural spines, the longus colli dorsalis muscles originate from them, especially in the posterior part of the neck, and that’s what the photo at the top shows. From the reader’s point of view, the big interspinous ligament runs forward to attach to the posterior side of the neural spine (not visible because it’s buried in gloop, but it’s about a third of the way down from the top). The longus colli dorsalis tendons are running forward from the anterior side of the neural spine.

Fig. 20. An MRI of the mid-cervical series of an ostrich (Struthio camelus). In sagittal section, the interspinous ligaments are lighter than the surrounding muscle because of their high fat content. The neural canal is occupied by the spinal cord and supramedullary pneumatic airways. Also apparent in this image are the tendons of the longus colli dorsalis muscle originating from the neural spine. Scale bar is 4 cm.

Here’s the same thing again, also in an ostrich, but in an MRI this time (and with anterior to the right; Wedel et al. 2000: fig. 20). The dark streaks running forward from the neural spines are those longus colli dorsalis tendons. The interspinous ligament also shows up nicely as a series of white bands connecting adjacent neural spines.

References

Those ostrich necks I went to Oro Grande to get last Thursday? Vanessa and I started dissecting them last Friday. The necks came to us pre-cut into segments with two to three vertebrae per segment. The transverse cuts were made without regard for joints so we got a bunch of cross sections at varying points through the vertebrae. This was fortuitous; we got to see a bunch of cool stuff at the cut faces, and those cut faces gave us convenient avenues for picking up structures and dissecting them out further.

In particular, the pneumatic diverticula in the neck of this ostrich were really prominent and not hard at all to see and to follow. The photo above shows most of the external diverticula; click through for the full-resolution, unlabeled version. The only ones that aren’t shown or labeled are the diverticula around the esophagus and trachea (which had already been stripped off the neck segments, so those diverticula were simply gone), those around carotid arteries, which are probably buried in the gloop toward the bottom of the photo, and the intermuscular diverticula, of which we found a few in parting out the dorsal and lateral neck muscles.

There is one final group of diverticula that are shown in the photo but not labeled: the interosseous diverticula that fill the air spaces inside the bone.

We have tons of cool photos from this dissection, so expect more posts on this stuff in the future.

For previous posts showing diverticula in bird neck dissections, see:

Things to Make and Do, part 7: fun with rhea necks

Things to Make and Do, part 7b: more fun with rhea necks (admittedly, not the most creative title ever)

It came from my desk

March 8, 2012

I was putting a new card in my camera and needed some test photos, so I shot what was on my desk: some random doodles from discussions with various folks, and an ostrich cervical.

I love my job.

Bonus SV-POW!bucks to the first person to decipher the diagram on the lower left.

Today was one of the most interesting days of my life.

Vanessa and I needed ostrich parts for dissection, so I had gotten in touch with Doug Osborne of OK Corral Ostrich Farms in Oro Grande. That was on the recommendation of Andy Farke, who got a bag of ostrich heads from Doug a couple of years ago (those heads are in the other Dr. Wedel’s research freezer, waiting for an ostrich head boiling party). I made plans with Doug to meet him at the farm at 9:00 this morning (Thursday). He warned me that it would have to be a quick visit because he was having a big load of hay delivered at 9:30 and he’d have to go supervise the unloading.

Oro Grande is 60 miles from Claremont and Pomona, in the high desert on the north side of the San Gabriels. I left here at 8:00 and rolled up to the marked parking area right at 9:00.

And immediately I could tell that things had not gone as planned. There were two hay trucks in the big ostrich paddock (post-Jurassic Park, any large outdoor enclosure for theropods must be referred to as a paddock), so the hay had clearly come early.

More worryingly, the gate at the corner of the paddock was open and the ostriches were starting to get out.

This is not the ranch, this is just the building where the empty eggs are stored.

I should stop here and mention a couple things. First, when I heard about OK Corral Ostrich Farms I assumed it was like almost every other ostrich farm in the United States: a side-business on a small farm involving a few dozen birds at most. It is emphatically not. Doug has 2500 ostriches, 2000 at Oro Grande and another 500 at a ranch in Elsinore; his operation is the largest ostrich ranch outside of Africa. The ostriches at Oro Grande are not all in the main paddock, but several hundred of them are, and these were starting to trickle out of the open gate when I rolled up.

Second, the open gate wasn’t the fault of the guys in the hay trucks. Doug later determined that the padlock had clicked but failed to engage when one of the ranch hands shut the gate behind the trucks. Stuff happens. He told me it was his first break-out in seven years.

Anyway, when I hopped out of the car there was one ostrich out, but more were moving that way. Fortunately Doug and I had been corresponding by phone so I had his number in my cell. I called him and told him what was up, and he told me to get back in my car (for reasons that will become apparent later on). A few minutes later he rolled up in his pickup, and by that time about a dozen birds were out, including a couple of males.

I jumped out to say hi. I hadn’t been real wild about waiting in the car in the first place. It was clear that getting the ostriches back in the paddock was going to be at least a two-person job, because one person would have to keep each batch of returning birds from running off while the other opened and shut the gate. I told Doug that I had grown up in the country and had to herd cattle before so he’d know I wasn’t as useless as I probably looked. (I hadn’t checked the weather, the temperature was in the 40s F, with a west wind gusting around 40 mph, and I was wearing my ODP t-shirt and no jacket.) He sized me up for about two seconds and said, “Okay, I’m going to start giving you orders.”

And for the next 30 or 40 minutes, that’s what he did. Singly and in groups of two and three, we got all the stray ostriches rounded up and back in the paddock. I’m sure for Doug it was a pain in the arse, having a dozen large, fast, expensive birds on the wrong side of the fence.

For me, it was 100% awesome. I love ostriches. I’ve dissected them, CTed them, measured their bones and sawed them open, looked at their intervertebral joints, eaten their meat, and watched them for ages in zoos, but this was my first experience on the ground with no fence between me and them.

Ostriches are freakin’ huge. I had only dissected babies, or adults piecemeal. It’s one thing to read about how big they are or watch one in a zoo, and quite another to have an 8-foot-tall, 350-lb male ostrich standing 4 feet away, clearly thinking about how freedom is on the other side of this slow, puny, annoying mammal. Doug coached me through flapping my arms and shouting “Ho! Ho! Ho!” and sometimes just getting up in their space and slapping them on the ass. He was keeping a weather eye on them for any aggressive behavior, and I was vacillating between bio-geek squee and healthy fear.

After the ostriches were all back in the paddock, the hay trucks were safely out, and the ranch hands had gotten a stern word about double- and triple-checking the padlock, Doug invited me in for a cup of coffee and we had a nice long chat.

Doug’s an interesting guy. He used to be a Wall Street millionaire, in the executive stratosphere of Merrill Lynch. One year he bought his mother four ostriches as a present. Those ostriches started breeding, his mom started selling them, and Doug realized that there was a living to be made farming ostriches and decided that was more appealing than working on Wall Street. He’s been doing this for 20 years.

As a farmer he has a refreshingly unromantic view of his birds. He loves ostriches, obviously, otherwise he wouldn’t have made a career out of them, but his love for them is grounded in practical matters like cutting the strings off the hay bales so the birds can’t accidentally strangle themselves. To him the birds are interesting but not exotic, and for me it was fascinating to talk with someone who raises them from the egg and works with them every day.

Speaking of eggs, after coffee it was time to go gather them from the paddock. It’s still too early in the season for the females to be laying many, but there were a few. By this time Doug was treating me like one of the team. He gave me an OK Corral trucker hat as a thank-you for my help with the ostrich-wrangling, and I got to ride along on the egg-collecting expedition. There was one small and probably communal nest of half a dozen eggs, and as we drove around the paddock we spotted a couple of isolated “rogue” eggs. The ranch hands gathered most of the eggs, but after they’d gone off to secure the hay I got to get out and pick up the last rogue egg. It was surprisingly heavy, like a shot put, and Doug gave me the same directions I give to students carrying human skulls: “Hold it securely in two hands, all the way to the box.”

I got to see some interesting behavior. The big males would come right up to the pickup, make dominance displays, and snap at us. The truck was dented from having been kicked by ostriches who didn’t want to share their considerable space (the paddock is probably between an eighth and a quarter of a mile on its long axis). Last year Doug was moving birds around and a big male kicked him hard enough to puncture his abdomen and lacerate his liver; he spent two weeks in the hospital. That’s why he wanted me to stay in the car when I first rolled up, and why he didn’t ask for help herding birds until he knew that I had some prior experience moving big animals  around.

Oh, way back at OU I had read about ostriches having sizable penises, and I can now attest to that as an eyewitness. One of the males flopped his out in front of the truck and it was about the same dimensions as my arm below the elbow. Elsewhere in the paddock I saw a male and a female working together to make zygotes*.

*That’s biologist-talk for “gettin’ their gangly theropod freak on”.

Back at the ranch house the eggs went into the incubator, Doug went into the walk-in freezer to get the ostrich necks I was there to buy, and I got a few minutes to just wander around and gawk. In addition to the ostriches Doug has about 50 emus in a separate pen, and roaming loose in the big fenced and gated area around the ranch buildings are turkeys, chickens, peacocks, and geese. Three tom turkeys–Los Hermanos Mariachis, Doug calls them–followed me around, puffing up and showing off. I could see some signs of interspecific socialization: the geese hung out with the turkeys by the ranch house, while the peacocks and chickens claimed the area around the little red building where the empty, blown-out eggs are stored. Doug talked about how the “Goose-waffe” would fly down the driveway in formation and use the open truck-shed as a hangar.

My last encounter of the day was also my favorite. Abigail is a tame female ostrich who wanders around the yard with the smaller birds. She broke her ankle when she was a baby, and rather than put her down Doug nursed her back to health (I told you he loves ostriches). She’s quite even-tempered and he said she would tolerate being hugged and petted. So while Doug finished up a last bit of farm business before he could escort me out to the gate, I hugged and petted Abigail. She is my height and my weight, but because her neck and legs are so long and skinny almost all of that weight is concentrated in her torso, which is very bulky and solid. Abigail pecked at my watch a few times and then ignored me; with all the petting and hugging she probably assumed I was an oversized and somewhat slow-witted child. That’s her on the right in this pathetically undersized photo.

I have two regrets from the day. First, the only camera I had along is the crappy one in my POS (positively old school) cell phone, which is why these pictures are few and mostly sucky. More sucky still is that Vanessa missed the ostrich wrangling. She had master’s program responsibilities today and I thought (and Doug thought) this would be a quick stop of just a few minutes to get some necks, not a three-hour ostravaganza. Doug invited us back for a proper tour sometime, and we will definitely go, but unless something goes terribly wrong there won’t be any more ostrich-herding opportunities. I feel like I got in on all the fun.

Previous SV-POW! posts on ratites, from our Things to Make and Do series:

Elsewhere on the web, Darren has blogged extensively about ratites at Tet Zoo. Dissecting Ozbert the ostrich is a good place to start, and that post has links to several others.

Finally, all of my pre-SV-POW! ratite stuff is linked from the ratite clearing house post on my old blog.

 

What’s that?  You want proof, you say?  Well, I find your lack of faith disturbing; but since you asked, you got it!

What we have here is the part-way assembled skull of our old friend Veronica, in dorsal view, with anterior to the left.  The long pointed bones down there are the nasals: you don’t see their anterior ends in complete skulls because they’re covered by the fused premaxillae.  Posterolateral to those are the lacrimals, forming those posterolaterally directed spurs.  Between the nasals towards their posterior end is the top of the mesethmoid.  Behind the nasals and mesethmoid are the frontals, the largest bones on view here; and behind those are the parietals.  Ventral to those superficial bones are the palatines (sticking forward and showing on either side of the nasals), plus the pterygoids, the squamosals, and of course the braincase including the parasphenoid rostrum and fused vomers, but those are all hidden in this dorsal view.

Here’s the whole hill of beans in ventral view: this time you can see the parasphenoid rostrum going down the midline, with the vomers fused onto its anterior end; and the pterygoids attached near the base of this process, and the palatines extending anteriorly from them.  In this view, the squamosals are the lateralmost projecting bones.  Zoom through to the full-sized images to see the cool pneumatic openings up inside the squamosals and the parts of the braincase that they articulate with.

Still waiting to be attached to the cranium: the quadrates (which go on the lateralmost points of the skull); then the quadratojugal, jugals and maxillae, forming a straight line directed anteromedially from the point of the quadrate; and finally the fused premaxillae which go on the end of the snout and join the nasals medially and the maxillae laterally.  Those bones will of course obscure some of what we can see at the current stage of assembly, so I thought it would be useful to show you this intermediate stage.

Since I’m here, I may as well show you how the partially reassembled cranium looks in left lateral view, too:

From here, you can really appreciate the weird shape of the lacrimals, with their ventrally directed processes that I think are going to contact the maxillae once I’ve got them attached.

Finally, those of you who have been wise enough to get hold of some red-cyan anaglyph glasses will be able to appreciate this spectacular 3D view of the skull in ventral view.  The rest of you: come on, sort it out: they cost maybe a couple of bucks, and they’ll revolutionise your perception of, well, anaglyphs.

Work continues apace with Veronica, my tame ostrich.  (See previous parts one, two, three and four).  I’ve been photographing the individual bones of the skull — a skill that’s taken me some time to get good at, and one that I might do a tutorial on some time, to follow up the one on photographing big bones.

Here is a preview of the result of this photography-fest: a multi-view figure of the ethmoid ossification.

The top row shows it in dorsal view; the middle row in left lateral, posterior, right lateral and anterior views; the bottom row in ventral view.

This is a midline bone, or rather complex of bones, that lives between and slightly ahead of the eyeballs, as shown in the photographs of part 6c.  The top part is the mesethmoid, which contributes to the roof of the skull between the nasals and ahead of the frontals.  Below that is — well, I’m not sure what it’s called.  Jaime said in a comment that it’s “a portion of the ossified interorbital septum”, but it’s not like a septum: it’s a hollow capsule with very, very thin walls.  Anyone know its proper name?

By the way, I strongly encourage you to click through the image above and see it in its full high-resolution (5943 x 3384) glory.  As a taster, here’s a small segment — the rear portion of the dorsal view — in half resolution:

As you can see, that’s some very well textured bone — much more so than is apparent to the naked eye.

Cleaning and bleaching is complete!  Here are all the bones of Veronica’s skull [see earlier part one, part two and part three], laid out as they were in life (though of course much more widely separated), all in dorsal view:

On the left, we have the bones of the lower jaw, palate and braincase, with the first three and a half vertebrae at the bottom.  At the top is the mandible, which is intact on the left side but has separate articular, angular and surangular on the right; between the mandibles are the hyoid bones, of which one of the cartilaginous extensions has survived.  Behind those on the midline are the fused vomers, parasphenoid rostrum and braincase, all fused together.  Alongside this element are the palatines and pterygoids, and to the right of those are the midline supporting cartilage and mesethesmoid ossification.  Behind the braincase are the first three and half vertebrae of the neck.

On the right, we have the superficial bones.  Reading down from top to bottom of the midline, we have the premaxilla, nasals, lacrimals, frontals, parietals, and (out towards the sides) squamosals; from top to bottom down the sides we have the premaxilla (again), maxillae (the left one broken in two), the jugals and quadratojugals (which are still fused together on the right) and finally the quadrates.

That’s everything!  My next tasks are:

  • Repair the three broken bones: left maxilla, left posterolateral process of the premaxilla, and left lacrymal.
  • Photograph every individual bone from all six cardinal directions and maybe some interesting oblique angles.
  • Put the skull back together.
  • Photograph the entire skull, including 3d anaglyphs.

Then I think I’ll be done.

Special bonus encouragement

A few articles back, Zach Miller commented:

You lucky bastard! First a monitor lizard, now this? I’ve really GOT to get some kind of deal going with my local zoo. :-)

Lucky?  Nothing to do with it!  One of the points I keep meaning to make in the Things To Make And Do series is how very much this is something anyone can do.  Well, OK, I admit I was super-lucky to score the monitor lizard; but I got the pig’s head by walking into a butcher’s shop and saying “One of your finest pig’s heads, please, my stout yeoman!”.  I got Veronica by googling for “ostrich farm” and emailing the ones in the UK asking whether any of them had any heads to spare. I urge you, and anyone else who loves anatomy, to do the same.

Anyone can do this!  You don’t need qualifications, or even experience; this is how you get experience.  Seriously, I’ve learned ten times more about dinosaur skulls in the last week from playing with Veronica than I did in the last five years of feeling guilty that I never read any head-related papers.

For reasons that seemed good to me at the time, I took my best shot at photographing the right cervical rib from cervical vertebra 3 of my ostrich, Veronica [see earlier Part A, Part B and Part C for context].  I thought you might like to see the result, so here it is:

Third right cervical rib of subadult female ostrich (Struthio camelus), total length 23 mm. (Total length of the rib, I mean, not total length of the ostrich.) Left column: anterior view; middle column, top to bottom: dorsal, medial, ventral and (inverted) lateral views; right column: posterior view.

For some reason, cervical ribs don’t seem to get a lot of love in the literature: the only paper I know that figures them in half-decent detail is Osborn and Mook’s classic (1921) monograph on Camarasaurus, and even there, the job is done in rather a half-hearted fashion.  I’m planning to buck this trend by properly figuring the cervical ribs of the Archbishop when I finally get around to finishing that paper, and I included a sneak preview of the rib that I’ve arbitrarily designated X1 a while back.  It’s instructive to compare that illustration with this one.  In fact, here it is again:

Brachiosauridae incertae sedis NHM R5937, "The Archbishop", cervical rib X1. Preserved portion is 32 cm long. Top row: anterior view (dorsal to left); middle row, left to right: lateral, dorsal, medial and ventral views (all with anterior to top); bottom row: posterior (dorsal to left)

Enjoy!

Update (the next day)

It occurs to me that I should have composed the ostrich-cervical-rib illustration in the same orientation and order as the Archbishop one, for easier comparison.  So that’s what I’ve done below.  Since the Archbishop rib X1 is from the left side, I’ve also flipped the right-sided ostrich rib to match.  Here it is:

Third right cervical rib of subadult female ostrich (Struthio camelus), reversed, total length 23 mm. Top row: anterior view (dorsal to left); middle row, left to right: lateral, dorsal, medial and ventral views (all with anterior to top); bottom row: posterior (dorsal to left)

After the third simmering, Veronica the Ostrich Head started to come apart beautifully — more so than she should have done in one or two places, as it became apparent that her skull, as well as being incompletely fused due to presumed subadult age at time of death, was slightly damaged.  Still, I’ve been able to tease the bones apart nicely, remove pretty much all the remaining soft tissue, and figure out where most bits go, well enough that I think I’ll be able to put her back together once everything’s been cleaned.

[Anyone who’s not yet read parts one and two of this ostrich-head series should probably do so before going on to this one — apart from anything else, the pictures will make more sense that way.]

Here’s my girl as she emerged from the pot (cranium only — the mandible was separate by this point).  What may not be apparent here is just how fragile she was by this stage: I had to hold her snout as well as the main part of the skull to prevent it from falling off.  You can see that it’s skewed a little sideways, rotating clockwise with respect to the rest of the skull so that the posterodorsally oriented midline “tongue” of bone is off to the left (our right), and lies alongside the central bulging bone rather than overlying it as in earlier stages.

The squamosals are still in place at the sides of the back of the skull, but they came away very easily, and cleaned up nicely.

I carefully removed the snout, and was astounded to see how very thin the bones that connect it to the rest of the skull laterally are:

The midline bone here apparently is the fused ascending processes of the premaxillae, despite my having said last time that it probably wasn’t — thanks to Nick Gardner for putting me straight.  but what are the posterolaterally directed spines?  Can they also be processes of the premaxillae?  Or are they the maxillae?  I think the former: read on.

It’s hard to tell in part, of course, because of the horny beak which obscures whatever sutures might be up there at the front of the skull.  I don’t want to remove that, partly for fear of causing damage to the bones but mostly just because it’s nice to keep.  What I’d not appreciated until I started this exercise is that there’s no hard demarcation between beak and soft-tissue, but they grade into each other so that the posteriormost preserved parts of the beak are not horny at all, but rubbery — even stretchy.  It’s hard to know how much of this to remove.  If there’s a Standard Operating Procedure, I don’t know it — anyone?  Maybe I’ll leave the snout in a bug-box and let the dermestids decide.  (Let the Dermestids Decide would be a good title for a debut novel, and its Oscar-winning movie adaptation.)

(Of course this continuous gradation between tissue types is familiar to all of us who’ve ever tried to remove the cartilage from a skeleton: in some cases, like the cartilage caps on long bones, there’s clear bone and clear cartilage, but in other cases it’s not so well-defined.  Think, for example, of the partially ossified but partially cartilaginous breastbone of a chicken — take a look the next time you have a Sunday roast.  This is a real problem in cleaning skeletons.)

Once I’d removed the snout, here’s what remained:

On the midline, half way along the remaining skull (i.e. anteromedial of the orbits) is a very fragile self-contained bony capsule which seems to be full of some kind of soft tissue — maybe fat.  It’s not easy to make out its boundaries in this photo, so here is another that I took of the skull after lifting the capsule out — you can see it in the background.  Does anyone know what the capsule is?  My feeble bird-skull literature isn’t telling me anything about this.

With this capsule gone, it was with me the work of a moment to lift out the two big, spongy, soft-tissue masses from in front of the orbits, which you’ll remember I decided not to attempt last time.  A very good decision that proved.  Having removed them, I found a neat cartilaginous midline structure which I’d like to preserve for the final reconstruction of the skull, but which is already changing shape dramatically as it dries up so I fear I’m going to have to let it go.  Anyway, the bony structure of the remainder of the skull is now much more apparent:

I am guessing that the anteriormost lateral bones are the maxillae, which are a super-weird shape.  As you can see, the left bone is broken: its anterior portion is missing.  Happily, I have this bit, and it’s a perfect fit for the posterior part, so a bit of superglue should fix this problem — but it does emphasise just how insanely delicate many of the skull bones are.

I think the “wing” bones projecting laterally from near the back of the skull must be quadrates: if so, then the bones that project anteriorly from them are quadratojugals, which shade into straight, elongate jugals (you can see the junction in the near side of the photo above) and then connect with the maxillae.

The midline bone, which is surprisingly robust, seems to be made up of fused vomers or somethingat the front, and the parasphenoid rostrum to the rear [thanks to Nick Gardner for this and other corrections].  They’re hard to see in this photo, but there’s also a pair of oddly shaped more-or-less horizontal plates ventrolateral to this midline bone (I think they must be the palatinespterygoids) and two longer, narrower bones anterior to these (which might be the vomers, in which case the fused midline bones are something else? are the palatines).

Once I’d removed all these, I was left with a solid braincase fused together with that midline bone that might be vomersmade up of the parasphenoid rostrum and vomers.  And that, with surprising suddenness, was that.

So here is the complete set of skull bones, laid out in something resembling their order in life: top of the skull at the top of the picture, facing left, with vertebrae to their right; bottom half of the skull (mandible first, then palate) at the bottom of the picture, also facing left.  (Sorry that the contrast is not great: the sun was almost down by the time I took this photo):

When I looked at this, I was reminded of a passage in one of Dave Barry’s old columns, ‘Mister Mediocre’ Restaurants, in which he proposed some surefire business ideas, including a place where you could have your non-functional gadgets permanently destroyed:

The idea there was that consumers would bring their broken electronic devices, such as television sets and VCR’s, to the destruction centers, where trained personnel would whack them (the devices) with sledgehammers. With their devices thus permanently destroyed, consumers would then be free to go out and buy new devices, rather than have to fritter away years of their lives trying to have the old ones repaired at so-called factory service centers, which in fact consist of two men named Lester poking at the insides of broken electronic devices with cheap cigars and going, Lookit all them WIRES in there!

Similarly, I found myself thinking: lookit all them BONES in there!

Happily, help was on the way: Nick Gardner sent me a copy of Maxwell 2009, which has a few useful figures, and from these I was able to take pretty good guesses on the identities of more of the bones.  (That’s why I’ve included more guesswork above than in previous articles in this series.)  So I leave you with an annotated version of the photo above, with my best guess at identifying the bones.  PLEASE MAKE CORRECTIONS IN THE COMMENTS — I will make up a revised version of this annotated photo once they’re all in.  For for now, here it is Here is the initial version, which Nick critiqued in the comments:

And here is the corrected version, so far at least:

Now let’s get those corrections going!

References

  • Maxwell, Erin E.  2009.  Comparative ossification and development of the skull in palaeognathous birds (Aves: Palaeognathae).  Zoological Journal of the Linnean Society 156:184-200.

Yesterday, I followed up Veronica‘s second simmering by taking more flesh off the bones, and in doing this I stared to take apart the bones that constitute the skull.  I assume you’re all keen to see pictures, so here she is upside down and in right posteroventrolateral view:

The interesting thing here is that I have removed all the cartilaginous hyoid apparatus, as I suspected last time that I’d end up doing, only to find that part of that apparatus was bony after all: the pair of slender anteromedially oriented bones that you see at the top of the photo.  Here they seem to be directly somewhat ventrally from back to front (i.e. upwards in the photo, since the head is upside down), but comparing with the earlier lateral-view photos of the intact and skinned head, I think that this is post-mortem displacement caused by cooking, and that in life they were more or less in the horizontal plane.

When I removed these bones, I found that their proximal ends were not articulated with other bones, but that they were extended by cartilage rods that continued posteriorly and seem to have been anchored only in soft tissue.  Is that weird?  Or should I have expected it?  It frightens me sometimes how little I know about heads.

You’ll also notice from this photo that I’ve now removed the anterior part of the neck that was attached to the head: as a result, I have a nice bonus set of atlas/axis complex, C3 and the front half of C4 (all pictured below).

Anyway, it was easy to tease away the soft tissue enclosing the mandibular joint and then to remove the bony mandible completely.  This they now do.  The mandible itself is amazingly lighlty built — see the photo at the end of this post, and more to the point the ones in the next post which I’ve not written yet.  Here’s the cranium in ventral view once the mandible was gone and I’d removed some of the skin from the roof of the mouth:

I’m not even going to expose myself to ridicule by attempting to identify any of the bones of the palate — that’s an area that I don’t know at all beyond the fact that there are things called “vomers”, which would make a good name for a race of bad guys in Buffy.  Clearly I need to get hold of a general bird-skull osteology.  Can anyone recommend anything?  Better still, can anyone offer a PDF?

Instead, let’s flip Veronica over and take a look at her top.  After the second simmering, the bones of her skull were very easy to disarticulate, so that’s what I’ve started to do here:

Those two main bones forming the crown of the skull are the frontals.  I assume those are elongate nasals in front of them, reaching down to the lateral edges of the snout (with the maxillae not visible in this view), but I don’t know what that tongue of bone on the midline is, between them: surely it’s too far back to be fused premaxillae?  Someone help me out here.

Anyway, the frontals lifted away cleanly and easily (the right frontal bringing its ?nasal with it, being still slightly attached).  This reveals how huge the eyeballs are (the big, black globes) and how relatively feeble the brain is (the pale brownish yellow lump between them):

It was easy enough to remove and discard the eyeballs and brain, and some surrounding gloop.  The parietal bones that form the back of the skull also came away easily.  At this stage I could have continued to tear the skull down but there are some very delicate bones along the midline and I thought it wiser to simmer again before tackling those.  So here is Veronica, as she was just before going into the pot for the third time, in right dorsolateral view:

It’s easy to make out the three cavities where the eyeballs and brain were.  There’s still a big mass of soft tissue in the middle of the skull, ahead of the eyes and behind the beak, but there’s no safe way to get at it until I’ve removed more of the bones — and those of the snout are very, very delicate.

Finally, here are the bones that I’ve removed from the main cranium (i.e. to get it into the state seen in the previous picture):

Top left (and facing left) is the mandible in dorsal view, and inside it the pair of hyoid bones, oriented as in life.  To the right of those are the ?nasals, then the frontals, then the parietals; outside the frontals are the ?lacrimals that I noted in the first post were coming away from their position in front of the orbit.

The bottom row is of course the vertebrae: atlas in posterior view, and axis, C3 and partial C4 in dorsal view, all facing to the left.

That’s all for now.  More to come.