Liem et al 2001 PPTs - intro slide

Functional Anatomy of the Vertebrates: An Evolutionary Perspective, by Liem et al. (2001), is by some distance my favorite comparative vertebrate anatomy text. When I was a n00b at Berkeley, Marvalee Wake assigned it to me as preparatory reading for my qualifying exams.

This scared me to death back then. Now I love it.

This scared me to death back then. Now I love it – sharkitecture!

The best textbooks, like Knut Schmidt-Nielsen’s Animal Physiology (which deserves a post or even series of its own sometime), have a clarity of writing and illustration that makes the fundamentals of life seem not only comprehensible, but almost inevitable – without losing sight of the fact that nature is complex and we don’t know everything yet. FAotV has both qualities, in spades.

Where vertebrae come from.

Where vertebrae come from. Liem et al. (2001: fig. 8.4).

I’m writing about this now because Willy Bemis, second author on FAotV, has just made ALL of the book’s illustrations available for free on his website, in a series of 22 PowerPoint files that correspond to the 22 chapters of the book. All told they add up to about 155 Mb, which is trivial – even the $5 jump drives in the checkout lanes at department stores have five to ten times as much space.

Aiiiieeee - a theropod! Aim for its head!

Aiiiieeee – a theropod! Aim for its head! Liem et al. (2001: fig. 8.17).

Of course, to get the full benefit you should also pick up a copy of the book. I see used copies going for under $40 in a lot of places online. Mine will have pride of place on my bookshelf until I enter the taphonomic lottery. And I’ll be raiding these PPTs for images from now until then, too.

Countercurrent gas exchange in fish gills - a very cool system.

Countercurrent gas exchange in fish gills – a very cool system. Liem et al. (2001: fig. 18.6).

So do the right thing, and go download this stuff, and use it. Be sure to credit Liem et al. (2001) for the images, and thank Willy Bemis for making them all available. It’s a huge gift to the field. Here’s that link again.

Liem et al 2001 PPTs - shark jaw and forelimb musculature

Dangit, if only there was a free online source for illustrations of shark anatomy… Liem et al (2001: fig. 10.12).

But wait – that’s not all! Starting on June 28, Dr. Bemis will be one of six faculty members from Cornell and the University of Queensland teaching a 4-week massively open online course (MOOC) on sharks. Freakin’ sharks, man!

“What did you do this summer? Hang out and play Nintendo?”

“Yep. Oh, and I also took a course on freakin’ sharks from some awesome shark experts. You?”

As the “massively open” part implies, the course is free, although you have the option of spending $49 to get a certificate of completion (assuming you finish satisfactorily). Go here to register or get more info.

Reference

  • Liem, K.F., Bemis, W.E., Walker, W.F., and Grande, L. 2001. Functional Anatomy of the Vertebrates. (3rd ed.). Thomson/Brooks Cole, Belmont, CA.

Clash of the Titans from above

Here’s the “Clash of the Titans” exhibit at the Sam Noble Oklahoma Museum of Natural History, featuring the reconstructed skeletons of the giant Oklahoma Apatosaurus – which I guess should now be called the giant Oklahoma apatosaurine until someone sorts out its phylogenetic position – and the darn-near-T. rex-sized Saurophaganax maximus, which may be Allosaurus maximus depending on who you’re reading.

Now, I love this exhibit in both concept and execution. But one thing that is more obvious in this view from the upper level balcony is that despite its impressive weaponry, a lone 3-to-5 ton Saurophaganax had an Arctic ice cap’s chance in the Anthropocene of taking down a healthy 30-meter, 40-50 ton apatosaur (which is to say, none). I like to imagine that in the photo above, the apatosaur is laughing at the pathetically tiny theropod and its delusions of grandeur.

Clash of the Titans from behind

In this shot from behind, you get a better look at the baby apatosaur standing under the big one, and it hints at a far more likely target for Saurophaganax and other large Morrison theropods: sauropods that were not fully-grown, which was almost all of them. I am hip to the fact that golden eagles kill deer, and some lions will attack elephants – as Cookie Monster says, “Sometime food, not anytime food” – but not only were smaller sauropods easier prey, they were far more numerous given the inevitable population structure of animals that started reproducing at a young age and made more eggs the bigger they got (as essentially all egg-laying animals do).

In fact, as discussed in our recent paper on dinosaur ontogeny (Hone et al. 2016), there may have been times when the number of fully-grown sauropods in a given population was zero, and the species was maintained by reproducing juveniles. The giant Oklahoma apatosaurine is a unique specimen today – by far the largest apatosaurine we have fossils of – but it may also have been an anomaly in its own time, the rare individual that made it through the survivorship gauntlet to something approaching full size.

Amazingly enough, there is evidence that even it was not fully mature, but that’s a discussion for another day. Parting shot:

Oklahoma Apatosaurus neck and head

Reference

What’s in Mike’s freezer?

February 26, 2016

What’s that in Mike’s freezer? Let’s take it out and have a look.

2016-02-25 15.50.45

Onto the table out in the garden …

2016-02-25 15.51.20

Unwrap another layer …

2016-02-25 15.51.30

Hang on! That looks like … It can’t be, can it?

2016-02-25 15.51.45

It is! It’s a buzzard!

2016-02-25 15.52.10

A buzzard with extremely serious claws!

2016-02-25 15.52.21

And a serious beak as well!

2016-02-25 15.52.33

Further bulletins down the line, when I get a chance to play with it properly.

(Title stolen shamelessly from John Hutchinson’s blog.)

ostrich peeing

cormorant peeing

alligator peeing

Stand by . . . grumpy old man routine compiling . . . 

So, someone at Sony decided that an Angry Birds movie would be a good idea, about three years after the Angry Birds “having a moment” moment was over. There’s a trailer for it now, and at the end of the trailer, a bird pees for like 17 seconds (which is about 1/7 of my personal record, but whatever).

And now I see these Poindexters all over the internet pushing their glasses up their noses and typing, “But everyone knows that birds don’t pee! They make uric acid instead! That’s the white stuff in ‘bird poop’. Dur-hur-hur-hurrr!” I am reasonably sure these are the same people who harped on the “inaccuracy” of the peeing Postosuchus in Walking With Dinosaurs two decades ago. (Honestly, how I didn’t get this written and posted in our first year of blogging is quite beyond my capacity.)

Congratulations, IFLScientists, on knowing One Fact about nature. Tragically for you, nature knows countless facts, and among them are that birds and crocodilians can pee. And since extant dinosaurs can and do pee, extinct ones probably could as well.

So, you know . . . try to show a little respect.

So, you know . . . try to show a little respect.

Now, it is true that crocs (mostly) and birds (always?) release more of their nitrogenous waste as uric acid than as urea. But their bodies produce both compounds. So does yours. We mammals are just shifted waaaay more heavily toward urea than uric acid, and extant archosaurs – and many (but not all) other reptiles to boot – are shifted waaaay more heavily toward uric acid than urea. Alligators also make a crapload of ammonia, but that’s a story for another time.

BUT, crucially, birds and crocs almost always release some clear, watery, urea-containing fluid when they dump the whitish uric acid, as shown in this helpful diagram that I stole from International Cockatiel Resource:

International Cockatiel Resource bird pee guide

If you’ve never seen this, you’re just not getting to the bird poop fast enough – the urine is drying up before you notice it. Pick up the pace!

Sometimes birds and crocs save up a large quantity of fluid, and then flush everything out of their cloacas and lower intestines in one shot, as shown in the photos dribbled through this post. Which has led to some erroneous reports that ostriches have urinary bladders. They don’t, they just back up lots of urine into their colons. Many birds recapture some water and minerals that way, and thereby concentrate their wastes and save water – basically using the colon as a sort of second-stage kidney (Skadhauge 1976).

Rhea peeing by Markus Buhler

Many thanks to Markus Bühler for permission to post his well-timed u-rhea photo.

[UPDATE the next day: To be perfectly clear, all that’s going on here is that the birds and crocs keep their cloacal sphincters closed. The kidneys keep on producing urine and uric acid, and with no way out (closed sphincter) and nowhere else to go (no bladder – although urinary bladders have evolved repeatedly in lizards), the pee backs up into the colon. So if you’re wondering if extinct dinosaurs needed some kind of special adaptation to be able to pee, the answer is no. Peeing is an inherent possibility, and in fact the default setting, for any reptile that can keep its cloaca shut.]

Aaaanyway, all those white urate solids tend to make bird pee more whitish than yellow, as shown in the photos. I have seen a photo of an ostrich making a good solid stream from cloaca to ground that was yellow, but that was years ago and frustratingly I haven’t been able to relocate it. Crocodilians seem to have no problem making a clear, yellowish pee-stream, as you can see in many hilarious YouTube videos of gators peeing on herpetologists and reporters, which I am putting at the bottom of this post so as not to break up the flow of the rant.

ostrich excreting

You can explore this “secret history” of archosaur pee by entering the appropriate search terms into Google Scholar, where you’ll find papers with titles like:

  • “Technique for the collection of clear urine from the Nile crocodile (Crocodylus niloticus)” (Myburgh et al. 2012)
  • “Movement of urine in the lower colon and cloaca of ostriches” (Duke et al. 1995)
  • “Plasma homeostasis and cloacal urine composition in Crocodylus porosus caught along a salinity gradient” (Grigg 1981)
  • “Cloacal absorption of urine in birds” (Skadhauge 1976)
  • “The cloacal storage of urine in the rooster” (Skadhauge 1968)

I’ve helpfully highlighted the operative term, to reinforce the main point of the post. Many of these papers are freely available – get the links from the References section below. A few are paywalled – really, Elsevier? $31.50 for a half-century-old paper on chicken pee? – but I’m saving them up, and I’ll be happy to lend a hand to other scholars who want to follow this stream of inquiry. If you’re really into the physiology of birds pooling pee in their poopers, the work of Erik Skadhauge will be a gold mine.

Now, to be fair, I seriously doubt that any bird has ever peed for 17 seconds. But the misinformation abroad on the net seems to be more about whether birds and other archosaurs can pee at all, rather than whether a normal amount of bird pee was exaggerated for comedic effect in the Angry Birds trailer.

ostrich excreting 3

In conclusion, birds and crocs can pee. Go tell the world.

And now, those gator peeing videos I promised:

UPDATE

Jan. 30, 2016: I just became aware that I had missed one of the best previous discussions of this topic, with one of the best videos, and the most relevant citations! The post is this one, by Brian Switek, which went up almost two years ago, the video is this excellent shot of an ostrich urinating and then defecating immediately after:

…and the citations are McCarville and Bishop (2002) – an SVP poster about a possible sauropod pee-scour, which is knew about but didn’t mention yet because I was saving it for a post of its own – and Fernandes et al. (2004) on some very convincing trace fossils of dinosaurs peeing on sand, from the Lower Cretaceous of Brazil. In addition to being cogent and well-illustrated, the Fernandes et al. paper has the lovely attribute of being freely available, here.

So, sorry, Brian, that I’d missed your post!

And for everyone else, stand by for another dinosaur pee post soon. And here’s one more video of an ostrich urinating (not pooping as the video title implies). The main event starts about 45 seconds in.

References

What is my mystery baby bird?

September 23, 2015

Here’s my newest specimen: a tiny baby bird, maybe 5 or 6 cm from wingtip to foot. This one came from my next-door neighbours: apparently it had been sitting on their car for several weeks before they thought to lift it off and give it to me.

IMG_2012-right-side

As you can see, the specimen is extraordinarily well preserved — more or less mummified, I suppose by wind-drying. Like a Chinese duck, though less appetising.

Here is the slightly flattened left side:

IMG_2014-left-side

So I have two questions:

  • What is this? Beyond the level of “a bird of some kind”.
  • How can I prep it down to just a tiny skeleton? The only idea I have, really, is to slightly moisten it, and leave it in a tub with a hole in the top for inverts to get in. Can I do better?

Help me!

AMNH 460 skeleton model 2

In a recent post I showed some photos of the mounted apatosaurine at the American Museum of Natural History in New York, AMNH 460, which Tschopp et al. (2015) regarded as an indeterminate apatosaurine pending further study.

A lot of museums whose collections and exhibits go back to the late 19th and early 20th centuries have scale model skeletons and sculptures that were used to guide exhibit design. I have always been fascinated by these models, partly because they’re windows into another era of scientific research and science communication, and partly because they’re just cool – basically the world’s best dinosaur toys – and I covet them. In my experience, it is very, very common to find these treasures of history buried in collections, stuck up on top of specimen cabinets, or otherwise relegated to some out-of-the-way corner where they won’t be in the way. I know that exhibit space is always limited, and these old models often reflect ideas about anatomy, posture, or behavior that we now know to be mistaken. But I am always secretly thrilled when I see these old models still on exhibit.

AMNH T rex skeleton model

The AMNH has a bunch of these things, because Henry Fairfield Osborn was crazy about ’em. He not only used 2D skeletal reconstructions and 3D model skeletons to guide exhibit design, he published on them – see for example his 1898 paper on models of extinct vertebrates, his 1913 paper on skeleton reconstructions of Tyrannosaurus, and his 1919 paper with Charles Mook on reconstructing Camarasaurus. That genre of scientific paper seems to have disappeared. I wonder if the time is right for a resurgence.

So in a glass case at the feet of AMNH 460 is a model – I’d guess about 1/12 or 1/15 scale – of that very skeleton. You can tell that it’s a model of that particular skeleton and not just some average apatosaur by looking carefully at the vertebrae. Apatosaurines weren’t all stamped from quite the same mold and the individual peculiarities of AMNH 460 are captured in the model. It’s an amazing piece of work.

AMNH 460 skeleton model

The only bad thing about it is that – like almost everything behind glass at the AMNH – it’s very difficult to photograph without getting a recursive hell of reflections. But at least it’s out where people can see and marvel at it.

Oh, and those are the cervical vertebrae of Barosaurus behind it – Mike and I spent more time trying to look and shoot past this model than we did looking at it. But that’s not the model’s fault, those Barosaurus cervicals are just ridiculously inaccessible.

So, memo to museums: at least some of us out here are nuts about your old dinosaur models, and where there’s room to put them on exhibit, they make us happy. They also give us views of the skeletons that we can’t get otherwise, so they serve a useful education and scientific purpose. More, please.

References

Osborn, H. F. (1898). Models of extinct vertebrates. Science, New Series, 7(192): 841-845.

Osborn, H.F. (1913). Tyrannosaurus, restoration and model of the skeleton. Bulletin of the American Museum of Natural History, 32: 91-92, plates 4-6.

Osborn, H. F., & Mook, C. C. (1919). Characters and restoration of the sauropod genus Camarasaurus Cope. From type material in the Cope Collection in the American Museum of Natural History. Proceedings of the American Philosophical Society, 58(6): 386-396.

Peggy Sue's Diner-saurs - London with sauropod

A couple of weekends ago, London and I went camping and stargazing at Afton Canyon, a nice dark spot about 40 miles east of Barstow. On the way home, we took the exit off I-15 at Ghost Town Road, initially because we wanted to visit the old Calico Ghost Town. But then we saw big metal dinosaurs south of the highway, and that’s how we came to Peggy Sue’s Diner and in particular the Diner-saur Park.

Peggy Sue's Diner-saurs - spinosaur

The Diner-saur Park is out behind the diner and admission is free. There are pools with red-eared sliders, paved walkways, grass, trees, a small gift shop, and dinosaurs. Here’s a Spinosauruscuriously popular in the Mojave Desert, those spinosaurs.

Peggy Sue's Diner-saurs - stegosaur

Ornithischians are represented by two stegosaurs, this big metal one and a smaller concrete one under a tree.

Peggy Sue's Diner-saurs - turtles

The turtles are entertaining. They paddle around placidly and crawl out to bask on the banks of the pools, and on little islands in the centers.

Peggy Sue's Diner-saurs - sign

The gift shop is tiny and the selection of paleo paraphernalia is not going to blow away any hard-core dinophiles. But it is not without its charm. And, hey, when you find a dinosaur gift shop in the middle of nowhere, you don’t quibble about size. London got some little plastic turtles and I got some cheap and horribly inaccurate plastic dinosaur skeletons to make a NecroDinoMechaLaser Squad for our Dinosaur Island D&D campaign.

Now, about that sauropod. The identification sign on the side of the gift shop notwithstanding, this is not a Brachiosaurus. With the short forelimbs and big back end, this is clearly a diplodocid. The neck is too skinny for Apatosaurus or the newly-resurrected Brontosaurus, and too long for Diplodocus. I lean toward Barosaurus, although I noticed in going back through these photos that with the mostly-straight, roughly-45-degree-angle neck, it is doing a good impression of the Supersaurus from my 2012 dinosaur nerve paper. Compare this:

Peggy Sue's Diner-saurs - sauropod 1

to this:

Wedel RLN fig1 - revised

If I had noticed it sooner, I would have maneuvered for a better, more comparable shot.

Guess I’ll just have to go back.

Reference

Wedel, M.J. 2012. A monument of inefficiency: the presumed course of the recurrent laryngeal nerve in sauropod dinosaurs. Acta Palaeontologica Polonica 57(2):251-256.