After the sheep skull ten days ago, here is Logan the wallaby in all his glory:


As always, click through for the full-sized version (6833 × 5082).


Remember I picked up those three sheep skulls (and some other bones, including a complete neck) from a shallow pit in a field near where we live? Here is first of the skulls, cleaned up and photographed in orthogonal views.


It’s interesting to compare it to the pig skull from way back:


Sheep and pigs are both perfectly well-behaved artiodactyls, but their skulls are dramatically different. The pig is extraordinarily more robust, and has absolutely massive jaw-muscle fossae.

The sheep would have been difficult to prepare by the usual simmer-and-slice method — too easy to damage, especially inside the nasal cavity, where the respiratory turbinates are very fragile. The pig is a much easier proposition. I was able to clean out its nasal cavity just by running water through it at fairly high pressure, without doing any damage.

For anyone who wants to get into skull preparation, I definitely recommend starting with a pig.

Just a quick photo-post today. A couple of months ago, walking around the fields near our house, I found a broad shallow pit with a lot of a sheep skeletal elements in it. I took my youngest son out on an expedition, and we rescued the good material. I’ve cleaned up the first two (of three) skulls. Here is the smaller of the two — which is also more complete, and the big one has lost its nasals.


Click through for glorious high-resolution (4000 x 3000, and not a pixel wasted).

I took a nice set of orthogonal-view photos of this skull. When I have time, I will clean them up and composite them as I did with my pig-skull, which I’m sure you all remember:


(Well … I call it my pig skull, but it’s not mine any longer. I donated it as the prize for winning the TetZooCon quiz, and it is now the proud possession of Kelvin Britton. But I have another one, so that’s all right.)

[Update: Here’s that sheep-skull multiview you ordered]

When Fiona checked her email this morning, she found this note from our next-door neighbour Jenny:

I seem to remember Mike wanting a mole – I do hope so because I’ve left you a body on your patio in a cereal box!

Cheers Jen x

What a delightful surprise! And here it is:

The SV-POW! mole, intact

The SV-POW! mole, intact

And a close-up of that awesome digging hand:

The SV-POW! mole, right manus

The SV-POW! mole, right manus

I don’t have time to deal with it properly right now, so it’s gone into a plastic box with some small holes in the lid, where I will trust invertebrates to do my work for me — as they did to great effect with the juvenile baby rabbit whose skeleton I must show you some time.

The end-game here is of course to obtain a complete skeleton; but if not that, then at least the upper-arm bones. I’m on record as saying that next to sauropod vertebrae, mole humeri are the bones that move me most; and elsewhere I nominated mole humeri in response to John Hutchinson’s question, “what are the strangest animal bones (in form & function etc) that have ever been discovered?”

Here’s why:

Left: rat humerus (for comparison), Right: mole humerus. The rat humerus is unfused on top, which is why there is a visible gap between the two parts.

Left: rat humerus (for comparison), Right: mole humerus. The rat humerus is unfused on top, which is why there is a visible gap between the two parts.

I stole this picture from an Ossamenta post, The strangest animal bone?. Get yourself over there for more wacky rat-vs.-mole comparisons!

Yesterday I asked whether anyone could identify this specimen:


There was an interesting range of suggestions, but I suppose no-one will be surprised to hear that Darren Naish was the first to make real progress, saying “Hey, that’s a loooong pelvis… I smell macropod.” From there it was a short leap to William Miller asking “Could it be that wallaby from way back in Things to Make & Do part 3?”

Yes it could, William — you win ten shiny new SV-POW! dollars.

It is indeed Logan the wallaby from waaay back in late 2009. Here’s how I butchered him, and some detail on his feet, and how his skull  turned out. Back then I prepped out a forelimb and a hindlimb, the skull and first few cervicals, and the tail (which I don’t think we’ve ever featured here — I should fix that.) When I ran out of time to work on the rest of the specimen, I just dumped it in a plastic tub, added water, and left it for nature to do the work for me. The plan was to fish out the goodies a few months later, but it seems that while my back was turned, three and a half years have passed. I should get on that — if the bones haven’t softened to the point where they’re useless now.

BTW., AnJaCo wins a bonus prize of five SV-POW! dollar for guessing that the specimen was “Sub-adult or juvenile. From the aforementioned disarticulated innominate, and from the dissociated epiphyses of the centra”. Logan was eighteen months old at death, which makes him a sub-adult as Bennett’s wallabies mature at 20-24 months.

Matt and I have been sniggering at the Lousy Book Covers tumblr (slogan: “Just because you CAN design your own book cover doesn’t mean you SHOULD”). A couple of evenings ago, he wondered whether we could do better. And whether we could do it in half an hour.

In no time at all, a competition was born. Here are the rules:

  1. You have 30 minutes total to create the cover from scratch.
  2. When the time starts, generate a batch of six random titles at the Random Book Title Generator.
  3. Choose the one you like most, and make a cover for it.
  4. Use your own name as the author.
  5. You may only use copyright-free or CC BY materials, and be prepared to demonstrate that you have done so.
  6. The cover must be in the correct aspect ratio for a “B Format” paperback (129 x 198 mm) and in a decent resolution — at least one megapixel.

There are probably better random title generators out there, but we just used the first one we found. It gave Matt these six titles: Silken Magic, The Missing Bridges, Theft of Abyss, The Sorceror’s Slaves, The Year of the Beginning and Cloud in the Petals. And it gave me these: Rough Eyes, The Trembling Spirits, Snow of Eye, The Wind’s Flames, The Names of the Name, and Mists in the Servants. Obviously some of these are completely unusable (“The Mists in the Servants” — I mean to say, what?) but you’re pretty much always going to get at least one that works.

Anyway, here’s what Matt came up with, interpreting his chosen title as non-fiction and sneakily inserting a subtitle:

Year of the Beginning

Pretty sweet work, I think — although Matt was unhappy with the vertical spacing, feeling that the author name was too close to the bottom. The baby-turtle image is by John Winkelman, from flickr, and it’s CC BY. (Matt cut the hand and turtle out so that he could drop the contrast a bit on the background, which accounts for the obvious ‘shoppage around the fingers visible at full res.)

I interpreted mine as a Fantasy novel, and I guess I sort of added a subtitle too, in a way. Here it is:


The background image is cropped and modified from Desert sky scene at dusk by Steve Hillebrand of the U.S. Fish and Wildlife Service, which is public domain. The parts that work well, I think, are the different capitalisation, size and colour of the “the”s and “NAME”s; and the translucent star underneath the title. If I could do it again, I would swap the two dark reds, but there you go.

I ran out of time to do the author name nicely, so it’s pretty blunt. If I’d had more time, I would also have put a small but clear single artifact in the middle of the cover — perhaps a sword or lantern, or maybe something a bit more left-field like a scroll or a leather water bottle. But since I ran out of time, this is how it stays.

(One important lesson I learned is that I need to figure out how the get GIMP on my Mac to recognise more fonts — it has a tiny selection, and all the sans-serif ones look like they’re straight out of a PowerPoint presentation.)

So now we challenge you: what can you come up with thirty minutes total? If you have a go at this challenge, upload your images and post a link in a comment. (You can upload easily at sites like if you don’t have an account on flickr or similar.)

I’ve measured a few necks in my time, including the neck of a baby giraffe. I can tell you from experience that necks are awkward things to measure, even if they have been conveniently divested of their heads and torsos. They have a tendency to curl up, which impedes attempts to find the straight-line length. Even when you manage to hold them straight, you want them maximally compressed end-to-end rather than stretched out, which is hard to achieve without buckling them out of the straight line. And then you need to measure between perpendiculars in a straight line.


Tonight, I needed to measure the mass and length of seven turkey necks. (Never mind why, all will become clear in time.) And I found a way to do it that works much better than anything I’ve done before.

Here’s the equipment:


You will need:

  • Kitchen scales (for weighing the necks)
  • Small numbered labels (for the sandwich bags that the necks will go into for the freezer once they’ve been measured)
  • Pen and paper to take down the measurements
  • Translucent ruler
  • Saucepan full of turkey necks
  • Slightly less than one half of a birthday cake decorated like a map of Middle-earth [optional]
  • A Duplo baseboard (double-sized Lego) and about fifteen 4×2 bricks

Use the bricks to build an L-shaped bracket on the board — about half way back, so that can rest your hand in front of it.


Now you can push the neck into the angle of the bracket. By keeping it pressed firmly against the back wall (yellow in my construction), you can keep it straight. I find the best way to get the neck exactly abutting the left (red) wall is to start with the neck in its natural position, with the anterior and posterior ends curving towards you, then sort of unroll it against the back wall, and finally push the posterior end into place with your little finger (see below). There is a satisfying moment– almost a click — as the back end pops into place and the neck slides along a little to right as necessary to accommodate the added length.


Now use another brick (blue in this photo) as a bracket: slide it along the back wall from right to left until it’s solidly abutting the anteriormost vertebra. If you do this right, there is very little travel: the entire series of vertebrae is lined up and solidly abutted, with bone pushing against the left wall and your new brick. I find there’s less than half a millimeter of variation between the length under gentle-but-firm pressure (which is what I measured) and under the very strongest force you can exert without buckling the neck.


Once you have found the blue brick’s correct position, you need to hold it firmly in place and measure its position relative the the left wall. (It doesn’t matter if you let the neck re-curl at this point, so long as the blue brick doesn’t shift.)

You need a translucent ruler so that you can lay it across the neck and see where blue brick falls under the scale. (My ruler’s zero is, rather annoyingly, 5 mm from the end; so I needed to subtract 5 mm from the lengths I measured.)


Finally, I bagged up each neck in its own sandwich bag, ready for the freezer. Each neck is labelled with a number so that when I take it out for dissection, I will be able to relate the measurements and observations that I make back to these initial measurements.

For the record, here are the measurements:

  • Neck 1: 154 g, 179.5 mm.
  • Neck 2: 122 g, 151 mm.
  • Neck 3: 154 g, 199.5 mm.
  • Neck 4: 133 g, 162.5 mm.
  • Neck 5: 142 g, 169 mm.
  • Neck 6: 80 g, 167 mm.
  • Neck 7: 70 g, 169 mm.

As expected, there is some correlation between neck mass and length; but not as much as you might expect. Naively (i.e. assuming isometric similarity) mass should be proportional to length cubed, but there is a lot of scatter about that line. I don’t know whether that is due to individual variation, or merely because the various necks — all of them incomplete — are different sections of the full neck. Hopefully I will be able to confirm or rule out that possibility when I’ve dissected down to naked vertebrae.

Back in early Februrary, Darren and I got an email out of the blue from biomechanics wizard and all all-round good guy John Hutchinson, saying that he’d obtained the neck of a baby giraffe — two weeks old at the time of death — and that if we wanted it, it was ours.

Of course, the timing wasn’t great for me — Brontomerus day was coming up fast, and the final publicity arrangements were buzzing around like crazy, so it wasn’t possible to go and fetch the neck right then.  But John had an even better proposition: that he could keep the neck frozen, and we could come to the Royal Veterinary College and dissect it on site.  As soon as I’d established with Darren that I’d get to be the one to keep the bones when the dissection was done, we enthusiastically agreed, and booked a date with John.  [The photo here shows a baby giraffe, not the one that we had — note that the neck is proportionally much shorter than in an adult.]

And so it was that on Wednesday 9th March, I drove up from Ruardean to Potter’s Bar and picked up Darren and pterosaur-jockey John Conway from the railway station.  From there, we found our way to the RVC campus easily enough, with only the statutory minimum number of times getting lost (once).

The bad news was that the neck had already been skinned before it made its way to the RVC.  We don’t know why, by whom, or when, and more importantly we don’t know how much of the other soft tissue was removed in the process — for example, the trachea and oesophagus were gone — along with, we assume, the recurrent laryngeal nerve that Matt had asked us to look out for — and we wonder whether our nuchal ligament was complete.  (That is the long ligament that runs along the top of the neck and helps to prevent it from sagging.)

But anyway, here is our baby, in left lateral view, as it came out of its plastic sack, measuring a healthy 51 cm in length.

Like so many specimens, at this point it really looks like an undifferentiated blob of gloop.  There are a couple of things to look for, though.

On the left of the picture, you’ll see that the terminal 10% or so is well separated from the rest, ahead of of portion of exposed bone.  That bone is the anterior margin of the axis (i.e. the second cervical vertebra).  The atlas (first cervical) is still encased in soft tissue at this point, but could be moved around fairly freely, including twisting.

On the right, and you’ll probably need to click through to see this, is a strange metal pin, stuck right into the back of C7.  This was firmly embedded and we never figured out what it was, or what it was doing there.  As you’ll see in the photos below, I’ve allowed it to stay in place, even in the final prepared vertebrae.  If anyone knows what it is, do tell!

I took a bunch of photos and measurements before we ploughed in, but I am ashamed to say that I failed to get many, many of the images and numbers that I should have.  Even allowing for the fact that the specimen was not intact when we got it, we and particularly I fumbled the ball badly.  So much so that I will shortly publish a tutorial on How To Dissect A Neck which will be based primarily on what we failed to do.

I suppose it’s true that we only ever learn from mistakes.  The trick is to learn from other people’s, rather than going through the frustrating and expensive process of making your own.  Oh well.  Next time, for sure.

Here we have John (left) and Darren (right) hard at work teasing away the long epaxial muscles from their fascia.

It was only after that process was complete that we thought to do one of the things we should have done up front — test the range of motion.  We put the necks into poses of maximal extension, flexion and lateral deflection.  Contrary to what I would have expected, the last of these was significantly more impressive than the other two, and is shown here.  You can easily make out the separate extents of vertebrae 2, 3, 4 and 5, and from those see where 1, 6 and 7 are.

(Those are the long epaxial muscles in the background.)

We continued removing muscle and fascia until we had the vertebrae as close to naked as we could manage without risking damage to them, while retaining the integrity of the intervetebral joints — both intercentral and zygapophyseal articulations.  One of the big surprises to us was how very flexible and fragile the latter were compared with the former.  The membrane that contains the zygapophyseal joint is very thin and would contribute almost no mechanical strength of its own.  By contrast, the adjacent centra were bonded very firmly together by extremely tough tissue.  There was no trace of a separate cartilage disc between any pair of centra, just this very dense but flexible material which had to be slowly cut away with scalpels before the vertebrae could be be separated.

The exception to this was the atlas-axis joint, which surprised all three of us in how completely different it was to all the others.  There was no connective tissue at all between the front of the axis and the back of the atlas — the two bones (or rather their cartilaginous surfaces) were free to move against each other without let or hindrance, as shown here (right anterolateral view with anterior towards the bottom of the picture):

And yet the axis was very firmly attached to the axis: although we couldn’t see any attachment, it wouldn’t come away — not even when a great deal of force was applied.  The connection turned out to be between the ventral face of the odontoid process and the dorsal surface of the ventral portion of the atlas.  (If you’re not familiar with anterior cervicals, this should become clearer later on when I show you the individual bones.)  Suffice it for now to say that the atlas is basically ring-shaped, and that the odontoid process is a chunk of the axis that sticks out the front of that bone and sits within the O of the atlas.

Before we separated the vertebrae, though, we prepared the nuchal ligament out from its surrounding muscle.  Here it is, with John and Darren holding its posterior portion up above the vertebrae: you can see that it’s in the form of a sheet rather than, as often envisaged, a cylinder.  (It does extend further anteriorly than shown here, but its much less extensive over C2 than it is more posteriorly.)

We did the best we could at detaching this ligament intact so that we could measure how compliant it is.  It was difficult to remove without damaging, and much more irregular in shape than we’d expected, so that the anteriormost portion had almost no strength and broke as soon as we exerted any force on it.

We were initially able to remove a portion that measured 45 cm at rest (from a total neck length of 51 cm, remember), but once the thin anterior end had broken off, we were left with 32 cm.  We were able, by application of a significant force courtesy of Darren, to extend this to 42 cm but no further.  That’s a strain of (42-32)/32 = 0.3125, which is a lot less than I’d been expecting.  Alexander (1989:64-65) wrote (in the passage that was my first ever encounter with nuchal ligaments):

I am going to suggest that these necks [i.e. those of sauropods] were supported in the same way as the necks of horses, cattle, and their relatives.  These animals have a thick ligament called the ligamentum nuchae running along the backs of their necks (figure 5.5).  Unlike most other ligaments it consists mainly of the protein elastin, which has properties very like rubber.  It can be stretched to double its initial length without breaking […]  In experiments with deer carcasses, my colleagues and I found that the ligament was 1.4 times its slack length when the head was raised to the position of figure 5.5 [i.e. a typical alert posture], and almost twice its slack length when it was lowered to the position of figure 5.5b [grazing posture].  Notice that the ligament was stretched even when the head was high: I doubt whether a deer can get into a position that allows the ligament to shorten to the point of going slack.  If you cut the ligament in a dissection the cut ends spring apart, as if you had cut a stretched rubber band.

So the least stretched life position of the ligament, according to Alexander, is significantly more extended than the most stretching we could achieve.  What does this mean?  I see four possibilities:

  • Alexander was talking a pile of poo.  I don’t believe this for a moment, and mention it only for completeness.
  • I am talking a pile of poo.  I can see why you’d think so, but I know it ain’t so (and Darren and John can verify it).
  • The composition of the nuchal ligament changes through ontogeny, becoming more elastic as the animal gets older: we had a baby, and Alexander had adults.  I don’t think this is very likely either — I can’t see any reason why juveniles would need less elastic ligaments than adults.
  • The composition of the giraffe nuchal ligament is different from that of the deer.

Since I already eliminated the first three options, it won’t come as a great surprise to find that I favour the last one.  And this has some interesting implications if it’s true.  (Darn, darn, we should have saved a chunk of the ligament and found a way to get it analysed for composition.)  If that nuchal ligament of giraffes is largely collagen rather than elastin, then it suggests the possibility of something similar for sauropods, and that would be interesting because the tensile strength of collagen is much greater than that of elastin.

Does anyone know if anyone’s done any work on this?

Well, anyway.

I drew the long straw, and got to bring the remains of the neck home to prepare out as bones.  I simmered gently, then removed the cooked flesh, and was astonished to find how much there was, removed from vertebrae that we thought we’d cleaned pretty well at dissection time:

The disappointing part of this is that such large parts of the vertebrae turned out to be cartilage (partially ossified, I guess) and so came away during the simmering: huge chunks at the front and back of each centrum, like a full centimeter at each end, and all of the zygapophyseal articular surfaces.  I wish I could have kept them intact … and of course a different preparation method probably would have done.  More stupid still, I neglected to get photos of the individual vertebrae before simmering, which would at least have enabled me to show you before-and-after comparisons.  Sorry.

Anyway, having peeled off the soft-tissue including cartilage, I re-simmered, re-picked, then bathed in dilute hydrogen peroxide for two days, and dried out the vertebrae in the sun.  This is the result — C1-C7 in order, in left lateral view:

Note that the odontoid process of the axis is a separate bone from the rest of the axis — you can see it on the left, between atlas and axis.  There was a big chunk of sculpted cartilage joining it to the rest of the atlas, and that’s all gone now, so I am not sure how I am going to join it up — maybe layer on layer of PVA representing the cartilage?

Oh, and notice that the metal pin is still in C7.

In the picture about, I have laid the vertebrae out in such a way that the total neck length (front of C1 to C7) is 51 cm, the same as it was in life.  Notice how this leaves huge gaps between the central: for example, as here between C5 and C6:

Needless to say, anyone trying to reconstruct the living animal from the bones alone — from fossils, say — would get a hopelessly wrong neck if they didn’t take the missing cartilage into effect.  As we’ve noted before, the same is true of sauropod necks.

But just how informative is a juvenile neck?  No doubt, the cartilaginous portions of these vertebrae were proportionally much larger than they would be in an adult, so we do need to be careful about casually extrapolating the huge gaps between ossified centra in the images above into our interpretation of sauropods.  For sure, I now need to go through this process with the neck of an adult giraffe — and if anyone happens to acquire one, I would love the opportunity to dissect it, please contact me if this comes up!

But maybe it’s not quite so misleading as it looks — for two reasons.  First, nearly all the sauropod specimens we have are from subadults, as shown by lack of fusion between scapula and coracoid in, for example, the Giraffatitan paralectotype HMN SII.  So it may be that their vertebrae were also not fully ossified.  And second, sauropods are more closely related to birds than to mammals, and in my limited experience bird necks seem to have a larger cartilaginous component than those of mammals.

Well.  Draw your own conclusions.  But keep ’em qualitative for now.

Next time, I’ll be presenting a tutorial on how to dissect a neck.  But it will be based on what we should have done rather than what we actually did.

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.