Just posting a few images from my impending talk at SVPCA this Thursday.
I’ve written about the recurrent laryngeal nerve before, in Wedel (2012) and in this post. It’s present in all tetrapods, from frogs and salamanders on up. The frog RLN is shown in ventral view above, and in lateral view below, both from Ecker (1889:plate 1, figures 114 and 115). I’ve highlighted the RLN in red in both. Perhaps not a monument of inefficiency, but still recurrent, and therefore dumb.
And in a giraffe – RLN in blue, nerve path to hindfoot phalanges in red. Hollow circles are nerve cell bodies, solid lines are axons.
And in the elasmosaur Hydrotherosaurus, same color scheme plus the nerve path to the tail in purple, base image from Welles (1943).
That’s all for now!
- Ecker, A. 1889. The Anatomy of the Frog. 478pp. Clarendon Press, Oxford.
- 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.
- Welles, S. P. 1943. Elasmosaurid plesiosaurs with descriptions of new material from California and Colorado. Memoirs of the University of California Museum of Paleontology 13: 125-254.
March 22, 2016
I’ve been lucky enough to acquire another beautiful specimen. It arrived in a box (though not from Amazon, despite what the box itself might suggest):
Can it be? It is!
Now I’ve wanted a tortoise for a long time, because they are (Darren will back me up here) the freakiest of all tetrapods. Their scapulae and coracoids have somehow migrated inside their rib-cages (which bear the shell), and their dorsal vertebrae are fused to the shell all along its upper midline. Just ridiculous. Look, this is what I’m talking about. Compare with the much saner approach that armadillos use to having a shell.
Here’s my baby in left anterodorsolateral view:
And in right posteodorsolateral:
Can anyone tell me what species I have here?
Here he is (or she?) upside down, in left posteroventolateral view.
Come to think of it, can anyone tell me the sex of my specimen?
Here he or she is in anterior view, looking very stern.
The problem is — and I can’t quite believe this never occurred to me until I had a tortoise of my own — how on earth do you deflesh such a creature? I have no idea (and obviously no experience). Any hints?
February 29, 2016
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.
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.
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.
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.
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.
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.
- 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.
June 16, 2015
We stopped off at the Peggy’s Cove lighthouse on the way, and spotted a vertebrate, which I am pleased to present:
It’s a whale skull, but I have no idea what kind. Can anyone help out?
So much for vertebrates — it was really all about the inverts. Here are six of them:
I have a 2lb lobster here; my colleague Jakub went for two 1lb lobsters, as did Jason and Wolfram (not pictured). That’s Wolfram’s lobster closest to the camera, giving a better impression of just what awesome beasts these were.
Peggy’s Cove: recommended. For vertebrates and inverts.
(Thanks to Wolfram Schneider for these photos.)
April 27, 2015
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.
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 Spinosaurus – curiously popular in the Mojave Desert, those spinosaurs.
Ornithischians are represented by two stegosaurs, this big metal one and a smaller concrete one under a tree.
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.
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:
If I had noticed it sooner, I would have maneuvered for a better, more comparable shot.
Guess I’ll just have to go back.
March 22, 2015
We adopted a couple of 6-week-old box turtles today.
They are Three-Toed Box Turtles, Terrapene carolina triunguis, and they are insanely adorable.
This one seemed oddly familiar…had I encountered it before?
UPDATE: The last few images here are an homage to Mike’s Gilmore sequence from slide 96 in our 2012 SVPCA talk on Apatosarus minimus (link). I would have linked to it sooner, but I couldn’t find the right blog post. Because there wasn’t one. Memory!
February 8, 2015
Here, for example, is the basal archosauriform Vancleavea. (Thanks to Mickey Mortimer, whose a comment on an earlier post put us onto this, and various other candidate epipohysis-bearers which we’ll see below.)
Here is a pair of Vancleavea cervical vertebrae:
No ambiguity here: the epipophysis is even labelled.
But we can find epipophyses even outside Archosauriformes. Here, for example, is the the rhynchosaur Mesosuchus:
Check out the rightmost vertebra (C7), clicking through for the full resolution if necessary. There is a definite eminence above the postzyg, separated from it by a distinct groove. Unless the drawing is wildly misleading, that is a definite epipophysis, right there.
But even more basal archosauromorphs have epipophyses. Check out Teraterpeton, described by Hans-Dieter Sues in 2003:
This is another one where the epipophysis is labelled (though not recognised as such — it’s just designated an “accessory process”).
Can we go yet more basal? Yes we can! Here are cervicals 2 and 3 of the trilophosaur Trilophosaurus (in an image that I rearranged and rescaled from the published original for clarity):
The parts of this image to focus on (and you can click through for a much better resolution) are the postzyg at top right of the left-lateral view, which has a distinct groove separating the zygapophyseal facet below from the epipohysis above; and the posterior view, which also shows clear separation on both sides between these two structures.
While we’re playing with trilophosaurs here’s here’s another one (probably), Spinosuchus:
Again, the groove separating postzygapophyseal facet from epipophysis (at top right in the image) is clear.
But there’s more! Even the protorosaurs, pretty much the most basal of all archosauromorphs, have convincing epipophyses. Here are two that I found in Dave Peters’ post from two years ago, which I only discovered recently. [Here I must insert the obligatory disclaimer: while Dave Peters is a fine artist and has put together a really useful website, his ideas about pterosaur origins are, to put it mildly, extremely heterodox, and nothing that he says about phylogeny on that site should be taken as gospel. See Darren’s write-up on Tet Zoo for more details.]
Dave shows some probable, but not super-convincing epipophyses in the protorosaur Macrocnemus (shaded purple here) …
… and some much more convincing epipophyses in the better known and more spectacular protorosaur Tanystropheus:
Frustratingly, Dave doesn’t attribute these images, so I don’t know where they’re originally from (unless they’re his own artwork). Can anyone enlighten me? There’s a nice illustration in figure 57 of Nosotti’s (2007) epic Tanystropheus monograph that is at least highly suggestive of epipophyses:
But it’s not as good as the one Peters used, as that one shows a distinct notch between postzyg and epipophysis, so I’d like to track that down if I can.
With this, I believe I am done on cataloguing and illustrating epipophyses, unless something dramatic turns up. (For example, this commenter thinks that nothosaurs have epipophyses, but I’ve not been able to verify that.) Here’s what we’ve found — noting that we’ve illustrated epipophyses on every taxon on this tree except Crocodylia:
So it seems that epipophyses may well be primitive at least for Archosauromorpha — which implies that they were secondarily lost somewhere on the line to modern crocs.
With this lengthy multi-part digression complete, hopefully, we’ll get back to sauropods next time!
- Dilkes, David W. 1998. The Early Triassic rhynchosaur Mesosuchus browni and the interrelationships of basal archosauromorph reptiles. Philosophical Transactions of the Royal Society of London B 353:501-541.
- Kellner, Alexander W. A., and Yukimitsu Tomida. 2000. Description of a new species of Anhangueridae (Pterodactyloidea) with comments on the pterosaur fauna from the Santana Formation (Aptian-Albian), Northeastern Brazil. National Science Museum monographs, Tokyo, 17. 135 pages.
- Nesbitt, Sterling J., Michelle R. Stocker, Bryan J. Small and Alex Downs. 2009. The osteology and relationships of Vancleavea campi (Reptilia: Archosauriformes). Zoological Journal of the Linnean Society 157:814-864.
- Nosotti, Stefania. 2007. Tanystropheus longobardicus (Reptilia, Protorosauria): re-interpretations of the anatomy based on new specimens from the Middle Triassic of Besano (Lombardy, Northern Italy). Memorie della Societa Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano 35(III). 88pp.
- Spielmann, Justin A., Spencer G. Lucas, Larry F. Rinehart and Andrew B. Heckert. 2008. The Late Triassic Archosauromorph Trilophosaurus. New Mexico Museum of Natural History and Science Bulletin 43.
- Justin A. Spielmann, Spencer G. Lucas, Andrew B. Heckert, Larry F. Rinehart and H. Robin Richards III. 2009. Redescription of Spinosuchus caseanus (Archosauromorpha: Trilophosauridae) from the Upper Triassic of North America. Palaeodiversity 2:283-313.
- Sues, Hans-Dieter. 2003. An unusual new archosauromorph reptile from the Upper Triassic Wolfville Formation of Nova Scotia. Canadian Journal of Earth Science 40:635-649.