A friend’s daughter owned a pet corn snake, and a hamster. About a month ago, the former got into the latter’s cage — and in a reversal of the usual course of such events, sustained some nasty injuries. As snakes often do, it struggled to recover, and the wound seems to have necrotised.

This morning I got an email from the friend saying that the snake had died, and asking whether I would like it. I managed to restrain my enthusiasm for long enough to express condolences to the daughter; and an hour later, the snake was delivered!

IMG_1861-cleaned

Here it is — as with all these images, click through for the full resolution. I’ve learned that it’s difficult to measure the length of a snake — they don’t lay out straight in the way that you’d like, even when they’re dead — but as best I can make out, it’s 120 cm long. It weighs 225 g, but don’t tell Fiona I used the kitchen scales.

The hamster wound is very apparent, just behind the neck, on the left hand side. Here’s the head and neck in close-up:

IMG_1847-cleaned

Ouch — very nasty. It can’t have been pleasant watching a pet linger on with a wound like that.

He (or she? How do you sex a snake?) was a handsome beast, too. Here’s the head. You can easily make out the individual large scales covering it, and make out some of the shape of the skull.

IMG_1852-cleaned

The skulls of snakes are beyond weird. Here is one from an unspecified non-venomous snake at Skulls Unlimited (i.e. probably not a corn snake):

variants_large_3861

Hopefully at some point I’ll be able to show you my own snake’s skull. In the mean time, this guy says he has a corn-snake skull, but the photography’s not very good.

Finally, here is my snake, mouth open, showing the pterygoid teeth on the roof of the mouth:

IMG_1857-cleaned

What next? It seems clear that bugging is the only realistic way to free up the skeleton, and this may be the specimen that persuades me to invest in a proper colony of dermestids rather than just relying on whatever inverts happen to wander past.

It might be worth trying to skin and gut the snake first. Gutting will be easy; skinning might be very difficult. I think that removing the skin from the skull without damaging the very delicate bones might be impossible. Can dermestids cope with snake skin?

I’m taking advice!

 

How bigsmall was Aquilops?

December 12, 2014

Handling Aquilops by Brian Engh

Life restoration of Aquilops by Brian Engh (CC-BY).

If you’ve been reading around about Aquilops, you’ve probably seen it compared in size to a raven, a rabbit, or a cat. Where’d those comparisons come from? You’re about to find out.

Back in April I ran some numbers to get a rough idea of the size of Aquilops, both for my own interest and so we’d have some comparisons handy when the paper came out.

Archaeoceratops skeletal reconstruction by Scott Hartman. Copyright Scott Hartman, 2011, used here by permission.

Archaeoceratops skeletal reconstruction by Scott Hartman. Copyright Scott Hartman, 2011, used here by permission.

I started with the much more completely known Archaeoceratops. The measurements of Scott Hartman’s skeletal recon (shown above and on Scott’s website – thanks, Scott!) match the measurements of the Archaeo holotype given by Dodson and You (2003) almost perfectly. The total length of Archaeoceratops, including tail, is almost exactly one meter. Using graphic double integration, I got a volume of 8.88L total for a 1m Archaeoceratops. That would come down to 8.0L if the lungs occupied 10% of body volume, which is pretty standard for non-birds. So that’s about 17-18 lbs.

Archaeoceratops and Aquilops skulls to scale

Aquilops model by Garrett Stowe, photograph by Tom Luczycki, copyright and courtesy of the Sam Noble Oklahoma Museum of Natural History.

Archaeoceratops has a rostrum-jugal length of 145mm, compared to 84mm in Aquilops. Making the conservative assumption that Aquilops = Archaeoceratops*0.58, I got a body length of 60cm (about two feet), and volumes of 1.73 and 1.56 liters with and without lungs, or about 3.5 lbs in life. The internet informed me that the common raven, Corvus corax, has an adult length of 56-78 cm and a body mass of 0.7-2 kg. So, based on this admittedly tall and teetering tower of assumptions, handwaving, and wild guesses, Aquilops (the holotype individual, anyway) was about the size of a raven, in both length and mass. But ravens, although certainly well-known, are maybe a bit remote from the experience of a lot of people, so we wanted a comparison animal that more people would be familiar with. The estimated length and mass of the holotype individual of Aquilops also nicely overlap the species averages (60 cm, 1.4-2.7 kg) for the black-tailed jackrabbit, Lepus californicus, and they’re pretty close to lots of other rabbits as well, hence the comparison to bunnies.

Of course, ontogeny complicates things. Aquilops has some juvenile characters, like the big round orbit, but it doesn’t look like a hatchling. Our best guess is that it is neither a baby nor fully grown, but probably an older juvenile or young subadult. A full-grown Aquilops might have been somewhat larger, but almost certainly no larger than Archaeoceratops, and probably a meter or less in total length. So, about the size of a big housecat. That’s still pretty darned small for a non-avian dinosaur.

Although Aquilops represents everything I normally stand against – ornithischians, microvertebrates, heads – I confess that I have a sneaking affection for our wee beastie. Somebody’s just gotta make a little plush Aquilops, right? When and if that happens, you know where to find me.

References

As I mentioned in my first post on Aquilops, I drew the skull reconstructions that appear in figure 6 of the paper (Farke et al. 2014). I’m writing this post to explain that process.

We’ve blogged here before about the back-and-forth between paleontologists and artists when it comes to reconstructing and restoring extinct animals (example 1, example 2). Until now, I’ve always been the guy making suggestions about the art, and asking for changes. But for the Aquilops project, the shoe was on the other foot: Andy Farke was my ‘client’, and he had to coach me through drawing a basal ceratopsian skull – a subject that I was definitely not familiar with.

Aquilops skull - Farke et al 2014 figure 3

I started from the specimen, OMNH 34557, which is more complete than you might think at first glance. The skull is folded over about 2/3 of the way up the right orbit, so in lateral view it looks like the top of the orbit and the skull roof are missing. They’re actually present, just bent at such a sharp angle that they’re hard to see at the same time as the lateral side of the skull.

Archaeoceratops lateral

I also used a cast skull of Archaeoceratops as a reference – it’s clear from what we have of Aquilops that the two animals were pretty similar.

Aquilops skull lateral 1 - outline

I started with this pencil outline on a piece of tracing paper.

Aquilops skull lateral 2 - rough stipple

And then I went right ahead and stippled the whole thing, without showing it to Andy until I was done. Yes, that was dumb. Noe the lack of sutures in this version.

Aquilops skull lateral 3 - rough stipple marked up

I added sutures and sent it off to Andy, who sent it back with these suggested changes. At this point I realized my error: I had already spent about a day and a half putting ink on the page, and I’d have to either start all over, or do a lot of editing in GIMP. I picked the latter course, since there were plenty of areas that were salvageable.

Aquilops skull lateral 4 - redrawn bits

Next I did something that I’d never done before, which is to redraw parts of the image and then composite them with the original in GIMP. Here’s are the redrawn bits.

Aquilops skull lateral 5 - penultimate version

With those bits composited in, and a few more tweaks to sutures, we got to this version, which was included in the submitted manuscript.

Aquilops skull lateral 6 - beak curvature issue

Then we brought Brian Engh in to do the life restorations. When Brian takes on a project, he does his homework. If you’ve seen his post on painting Aquilops, you know that all of the ferns in the Cloverly scene are based on actual fossils from the Cloverly Formation. Brian came to Claremont this summer and he and Andy and I spent most of a day at the Alf Museum looking at the specimen and talking about possible layouts for the full-body life restorations. He took a bunch of photos of the specimen while he was there, and a day or two later he sent us this diagram. He’d chopped up his photos of the skull to produce his own undistorted version to guide his painting, and in doing so he’d noticed that I had the line of the upper jaw a bit off.

Aquilops skull lateral 7 - partly revised

That required another round of digital revisions to fix. It ended up being a lot more work than the earlier round of edits in GIMP, because so many features of the skull had to be adjusted. I ended up cutting my own skull recon into about 8 pieces and then stitching them back together one by one. Here’s what the image looked like about halfway through that process. The back of the skull, orbit, and beak are all fixed here, but the snout, cheek, and maxilla don’t yet fit together.

Aquilops skull lateral 8 - final published version

After a little more work, I got the whole thing back together, and this is the final version that appears in the paper. It is not perfect – the area in front of the orbit where the frontal, nasal, maxilla, and premaxilla come together is a bit dodgy, and I’m not totally happy with the postorbital. But eventually you have to stop revising and ship something, and this is what I shipped.

Aquilops dorsal recon lineup for SV-POW

I did the dorsal view after the submitted version of the lateral view was finished. It went a lot faster, for several reasons:

  • Most of the gross proportional issues were already sorted out from doing the lateral view first.
  • The bilateral symmetry didn’t cut down on the number of dots but it did cut the conceptual workload in half.
  • I did all my roughs in pencil and didn’t start inking until after we had almost all of the details hashed out.

I did have to revise the dorsal view after getting feedback from Brian about the lateral view, but that revision was pretty minor by comparison. I stretched the postorbital region and tinkered a bit with the face and the frill, and both of those steps required putting in some new dots, but it was still just one afternoon’s worth of work. Here’s the final dorsal recon:

Aquilops dorsal skull reconstruction - final published version

In addition to the Life Lessons already noted in this post, I learned (or rather relearned) this important principle: if you do a big drawing and then shrink it down to column width, fine errors – a shaky line here, an ugly dot there – get pushed down below the threshold of perception. But there’s a cost, too, which is that uneven stippling becomes more apparent. I was skipping back and forth a lot between 25% image scale to see where the problem areas were, and 200% to revise the lines and dots accordingly.

All in all, it was a fun project. It was my most ambitious technical illustration to date, I learned a ton about ceratopsian skulls, and it was nice to get to make at least one substantial contribution to the paper.

Now, here’s the take-away: this is my reconstruction, and both of those words are important. “Reconstruction” because it has a lot of extrapolation, inference, and sheer guesswork included. “My” because you’re getting just one possible take on this. You can download the 3D files for the cranium and play with them yourselves. I hope that other artists and scientists will use those tools to produce their own reconstructions, and I fully expect that those reconstructions will differ from mine. I look forward to seeing them, and learning from them.

For other posts about my stippled technical illustrations, see:

Reference

Farke, A.A., Maxwell, W.D., Cifelli, R.L., and Wedel, M.J. 2014. A ceratopsian dinosaur from the Lower Cretaceous of Western North America, and the biogeography of Neoceratopsia. PLoS ONE 9(12): e112055. doi:10.1371/journal.pone.0112055

Life restoration of Aquilops by Brian Engh. Farke et al. (2014: fig. 6C). CC-BY.

Life restoration of Aquilops by Brian Engh. Farke et al. (2014: fig. 6C). CC-BY.

Today sees the description of Aquilops americanus (“American eagle face”), a new basal neoceratopsian from the Cloverly Formation of Montana, by Andy Farke, Rich Cifelli, Des Maxwell, and myself, with life restorations by Brian Engh. The paper, which has just been published in PLOS ONE, is open access, so you can download it, read it, share it, repost it, remix it, and in general do any of the vast scope of activities allowed under a CC-BY license, as long as we’re credited. Here’s the link – have fun.

Obviously ceratopsians are much more Andy’s bailiwick than mine, and you should go read his intro post here. In fact, you may well be wondering what the heck a guy who normally works on huge sauropod vertebrae is doing on a paper about a tiny ceratopsian skull. The short, short version is that I’m here because I know people.

OMNH 34557, the holotype of Aquilops

OMNH 34557, the holotype of Aquilops

The slightly longer version is that OMNH 34557, the holotype partial skull of Aquilops, was discovered by Scott Madsen back in 1999, on one of the joint Cloverly expeditions that Rich and Des had going on at the time. That the OMNH had gotten a good ceratopsian skull out of Cloverly has been one of the worst-kept secrets in paleo. But for various complicated reasons, it was still unpublished when I got to Claremont in 2008. Meanwhile, Andy Farke was starting to really rock out on ceratopsians at around that time.

For the record, the light bulb did not immediately go off over my head. In fact, it took a little over a year for me to realize, “Hey, I know two people with a ceratopsian that needs describing, and I also know someone who would really like to head that up. I should put these folks together.” So I proposed it to Rich, Des, and Andy in the spring of 2010, and here we are. My role on the paper was basically social glue and go-fer. And I drew the skull reconstruction – more on that in the next post.

One of the world's smallest ceratopsians meets one of the largest: the reconstructed skull of Aquilops with Rich Cifelli and Pentaceratops for scale.

One of the world’s smallest ceratopsians meets one of the largest: the reconstructed skull of Aquilops with Rich Cifelli and Pentaceratops for scale. Copyright Leah Vanderburg, courtesy of the Sam Noble Oklahoma Museum of Natural History.

Anyway, it’s not my meager contribution that you should care about. I am fairly certain that, just as Brontomerus coasted to global fame on the strength of Paco Gasco’s dynamite life restoration, whatever attention Aquilops gets will be due in large part to Brian Engh’s detailed and thoughtful work in bringing it to life – Brian has a nice post about that here. I am very happy to report that the three pieces Brian did for us – the fleshed-out head that appears at the top of this post and as Figure 6C in the paper, the Cloverly environment scene with the marauding Gobiconodon, and the sketch of the woman holding an Aquilops - are also available to world under the CC-BY license. So have fun with those, too.

Finally, I need to thank a couple of people. Steve Henriksen, our Vice President for Research here at Western University of Health Sciences, provided funds to commission the art from Brian. And Gary Wisser in our scientific visualization center used his sweet optical scanner to generate the hi-res 3D model of the skull. That model is also freely available online, as supplementary information with the paper. So if you have access to a 3D printer, you can print your own Aquilops – for research, for teaching, or just for fun.

Cloverly environment with Aquilops and Gobiconodon, by Brian Engh (CC-BY).

Cloverly environment with Aquilops and Gobiconodon, by Brian Engh (CC-BY).

Next time: Aquilöps gets röck döts.

Reference

Farke, A.A., Maxwell, W.D., Cifelli, R.L., and Wedel, M.J. 2014. A ceratopsian dinosaur from the Lower Cretaceous of Western North America, and the biogeography of Neoceratopsia. PLoS ONE 9(12): e112055. doi:10.1371/journal.pone.0112055

A while back, Ben Miller reminded me that when I posted about the old Yale “Brontosaurus” skull, I promised:

So how did the YPM come to make such a monstrosity? What was it based on? Tune in next time for the surprising details!

I told him at the time that I’d soon get around to writing a post. But before I did, he wrote a post on this himself: Bully for Camarasaurus. And it’s excellent. Go and read it!

I don’t have a lot to add to what Ben has written, except regarding this:

What Marsh had instead [when restoring the skull for his 1891 “Brontosaurus” reconstruction] were a few fragmentary bits of Camarasaurus cranial material, plus a snout and jaw (USNM 5730) now considered to be Brachiosaurus.

Here’s what Marsh came up with:

Marsh1891-plateXVI-Apatosaurus-skull-UNREVERSED

But what of the supposed Brachiosaurus skull that he used as a reference? It was finally described 107 years later by Carpenter and Tidwell (1998), in a paper that helpfully also lays out the history behind it. Here’s how it looks:

CarpenterTidwell1998-fig1

The skull was found by a crew under the supervision of M. P. Felch in the western part of his Quarry 1, Garden Park, Colorado. Felch reported it to O. C. Marsh in a letter of 8 September 1883. It was found by a meter-long cervical vertebra that probably belonged to Brachiosaurus “which was destroyed during attempts to collect it” (McIntosh and Berman 1975:196). [Of course, Felch and Marsh could hardly have been expected to identify this vertebra correctly, as Brachiosaurus would not be discovered and named for another twenty years (Riggs 1903), and the nature of its neck would not become apparent until Janensch (1914) described the related brachiosaurid Giraffatitan (= “Brachiosaurus“) brancai.]

The Felch skull, along with other material from the quarry, was shipped to Marsh at Yale in October of that year, and was initially assigned the specimen number YPM 1986. At that time it was only partially prepared, hence the rather poor resemblance between the restored version above and Marsh’s hypothetical “Brontosaurus” [= Apatosaurus] skull that was based on it.

It’s notable that Holland (1915) was quite certain that this was not a skull of Brontosaurus, and that a Diplodocus-like skull found with the A. louisae holotype belonged to it. It’s worth reading the skull section of his paper to see just how solid his reasoning was. And it’s extraordinary to think that Osborn’s power, all the way over in New York, was so great that he was able to successfully bully Holland, 370 miles away in Pittsburgh, into not putting the evidently correct skull on the Carnegie Museum’s Apatosaurus mount. That mount remained sadly headless until after Holland’s death.

Aaanyway, YPM 1986 was pretty much ignored after Marsh’s abuse of it as a reference for the Brontosaurus reconstruction’s skull. After Marsh’s death in 1899, much of the material collected by Felch was transferred to the Smithsonian (US National Museum of Natural History). The skull was among these specimens, and so was re-catalogued as USNM 5730.

As so often, it was Jack McIntosh who rediscovered this skull and recognised its true affinities. Some time after his tentative identification of the skull as pertaining to Brachiosaurus (presumably on the basis of its resemblance to that of Giraffatitan), Carpenter borrowed the skull, had it more fully prepared, wrote the description, and had a restored model constructed from casts of the preserved elements and models of the missing ones.

Carpenter and Tidwell (1998:fig. 2) also handily showed the restored Felch quarry skull alongside those of other sauropods:

CarpenterTidwell1998-fig2

By re-ordering the top row, we can see what a neat intermediate it is between the skulls of Camarasaurus (left) and Giraffatitan (= “Brachiosaurus” of their usage):

CarpenterTidwell1998-fig2-top-row-reordered

I provisionally accepted USNM 5730 as belonging to Brachiosaurus in my re-evaluation of 2009, and included it in my reconstruction (Taylor 2009:fig. 7):

Taylor (2007: figure 7). Skeletal reconstruction of Brachiosaurus altithorax. White bones represent the elements of the holotype FMNH P 25107. Light grey bones represent material referred to B. altithorax: the Felch Quarry skull USNM 5730, the cervical vertebrae BYU 12866 (C?5) and BYU 12867 (C?10), the "Ultrasauros" scapulocoracoid BYU 9462, the Potter Creek left humerus USNM 21903, left radius and right metacarpal III BYU 4744, and the left metacarpal II OMNH 01138. Dark grey bones modified from Paul's (1988) reconstruction of Giraffatitan brancai. Scale bar equals 2 m.

Taylor (2007: figure 7). Skeletal reconstruction of Brachiosaurus altithorax. White bones represent the elements of the holotype FMNH P 25107. Light grey bones represent material referred to B. altithorax: the Felch Quarry skull USNM 5730, the cervical vertebrae BYU 12866 (C?5) and BYU 12867 (C?10), the “Ultrasauros” scapulocoracoid BYU 9462, the Potter Creek left humerus USNM 21903, left radius and right metacarpal III BYU 4744, and the left metacarpal II OMNH 01138. Dark grey bones modified from Paul’s (1988) reconstruction of Giraffatitan brancai. Scale bar equals 2 m.

But as noted by Carpenter and Tidwell (1998:82), the lack of comparable parts between the Felch skull and the Brachiosaurus holotype (which remains the only definitive Brachiosaurus material) means that the assignment has to remain tentative.

What we really need is a more complete Brachiosaurus specimen: one with both a skull and good postcervical elements that let us refer it definitively to Brachiosaurus altithorax by comparison with the holotype. And heck, while we’re at it, let’s have a specimen with a good neck, too!

The real question remains: how did Marsh, using a brachiosaur skull as his basis, come up with this?

Marsh1891-plateXVI-Apatosaurus-skull-UNREVERSED

 

And stranger still, how someone at the Yale Peabody Museum — we don’t know who — used it, or more likely Marsh’s reconstruction, as a basis for this sculpture:

IMG_0517

 

The Yale mount didn’t go up until 1931 — the last of the Big Four Apatosaurus mounts after the AMNH, Carnegie and Field Museum, which is surprising as it was the first of those specimens to be found. So by the time the skull was sculpted, sauropod skulls were actually reasonably well known. It’s not clear quite how anyone working from a decent reconstruction of, say, a Camarasaurus skull — the one in Osborn and Mook (1921:figure 30), say — could come up with this monster.

The last thing to say is this: it does credit to the YPM that they display this historically important sculpture rather than hiding it away and pretending it never happened. For me, part of the fascination of palaeontology is seeing not just how organisms evolved through prehistory but how ideas evolved through history. It’s great that we can still see important mistakes, alongside their corrections (i.e. the new and lovely skull on the YPM Apatosaurus mount.)

 

References

  • Carpenter, Kenneth, and Virginia Tidwell. 1998. Preliminary description of a Brachiosaurus skull from Felch Quarry 1, Garden Park, Colorado. Modern Geology 23:69-84.
  • Holland, William J. 1915. Heads and tails: a few notes relating to the structure of the sauropod dinosaurs. Annals of the Carnegie Museum 9:273-278.
  • Janensch, Werner. 1914. Ubersicht uber der Wirbeltierfauna der Tendaguru-Schichten nebst einer kurzen Charakterisierung der neu aufgefuhrten Arten von Sauropoden. Archiv fur Biontologie, Berlin III, 1(1):81-110.
  • Marsh, O. C. 1891. Restoration of Triceratops (with plates XV and XVI). American Journal of Science, 3rd series 41(244):339-342.
  • McIntosh, John S., and David, S. Berman. 1975. Description of the palate and lower jaw of the sauropod dinosaur Diplodocus (Reptilia: Saurischia) with remarks on the nature of the skull of Apatosaurus. Journal of Paleontology 49(1):187-199.
  • Osborn, Henry Fairfield, and Charles C. Mook. 1921. Camarasaurus, Amphicoelias and other sauropods of Cope. Memoirs of the American Museum of Natural History, n.s. 3:247-387, and plates LX-LXXXV.
  • Riggs, Elmer S. 1903. Brachiosaurus altithorax, the largest known dinosaur. American Journal of Science 15(4):299-306.
  • Taylor, Michael P. 2009. A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914). Journal of Vertebrate Paleontology 29(3):787-806.

 

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

wallaby-skull-multiview

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 first of the skulls, cleaned up and photographed in orthogonal views.

sheep-skull-composite

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

pig-skull-white

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.

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