Heroes in a half shell

In my continued quest to betray my dinosaurian research roots, I went to the American Museum of Natural History in New York to look at turtles! And what turtles they were - this is the skull of Ninjemys (the ninja turtle!), a giant meiolaniid turtle from Australia. Meiolaniids are the best turtles you've never heard of and it's a crying shame that they don't feature more prominently in prehistoric popular media.

Meiolaniids are basically ankylosaur-convergent turtles, all of which are very large for turtles and some, like Ninjemys, which would have been legitimately huge. They are only found in the southern hemisphere (and really mostly in Australia and nearby), and they all have elaborate cranial ornamentation. On the left in this picture is that same Ninjemys skull cast, and on the right we have Niolamia from Argentina - smaller, but arguably even weirder with those huge nuchal crests flaring off the back of the skull.

I'm interested in meiolaniids at the moment because they are one of the other groups of tetrapods that evolved a club-like tail weapon. Here's Meiolania platyceps, an island dwarf (!) meiolaniid, with some kind of boring mammal for scale.

And here's the business end of Meiolania. Stay tuned for more exciting discussion of animal business ends in the future!

Since we're looking at animal butts today, apparently, here are some Edmontosaurus rears...

...and a Triceratops derriere, for good measure.

Elsewhere in the fossil halls, I enjoyed meeting the disembodied floating head of this indricothere, which makes for a nice counterpoint to the fleshed-out model currently on exhibit at the North Carolina Museum of Natural Science's feature exhibit Extreme Mammals.

And here's a lovely trio of cingulates! The big fellow is the derived glyptodont Panochthus, the medium-sized fellow is the early glyptodont Propalaeohoplophorus, and off towards the back the little guy is the extant six-banded armadillo, Euphractus sexcinctus. The tail club on the Panochthus is mounted really weirdly, with it sticking straight out from the back of the shell rather than having any of the mobile rings from the base of the tail present, so I'm not sure what's quite up with that.

I post woefully few fish fossils on this blog, so here's a pretty great semionotid!

Science and anatomy and zoology are all around us if you keep your eyes open! I loved this chameleon logo on the side of a restaurant we came across one evening.

5 Questions for Stephanie Blais

I'm hoping to feature some more University of Alberta-related research over the next few weeks, and first up is an interview with Stephanie Blais, a UALVP grad student studying ischnacanthid acanthodians. Stephanie recently published a paper in the Journal of Vertebrate Paleontology with new information on the origin of vertebrate teeth. So without further ado, here are five questions for Stephanie Blais:

1. What inspired you to conduct this study?

This particular study is really just part of a general interest in the origins of teeth. I don't know if anything really "inspired" it per se, but I've always been interested in teeth as indicators of ecological role, and never really thought about how they originated, and then I learned that nobody actually really knows how they evolved. Which is weird, because they're so widely studied and they're probably the most numerous vertebrate fossils out there! So I decided to look at fossils of some of the oldest animals with 'true' teeth, and noticed some of the specimens from the MOTH locality (NWT) have weird tooth-like scales, which is where this study came in.

The next step is to figure out what function these may have had, and also to look at the other kinds of early gnathostome (jawed vertebrate) teeth and see how they are related.

2. What are the inside-out and outside-in hypotheses all about?

These are the two main hypotheses about the origin of the vertebrate dentition. They're hard to sum up without getting into a lot of evo-devo, and they touch on quite a few points, but I'll try. It's also difficult to explain both without bias, but I'll give it a go. Bear with me.

Basically, the 'inside-out' hypothesis suggests that the developmental machinery that produces teeth originally evolved in the pharynx of jawless vertebrates and eventually became transferred to the oral cavity. This would mean that teeth evolved before jaws. Proponents of this hypothesis have also suggested that conodonts (which lacked odontodes or any form of external denticles or armor) had the first vertebrate teeth, and this would mean that pharyngeal denticles and external denticles have completely different evolutionary histories.

The opposing 'outside-in' hypothesis is that teeth are essentially modified head scales that became specialized along the margins of the mouth in early jawed vertebrates (so teeth evolved after jaws). According to this hypothesis, internal and external denticles share a common evolutionary origin. A modified version of this hypothesis suggests the pharyngeal denticles in some thelodonts developed due to migration of cells or tissue with odontode-producing potential from the outside of the body to the pharynx through the branchial openings.

3. What are ischnacanthid acathodians, and what do they tell us about the evolution of teeth?

 

Ischnacanthids are members of a larger group of small, spiny fishes called acanthodians, which are related to both sharks and bony fishes. They are interesting because they have many kinds of dentition, although they're unique in having special dermal tooth-bearing bones in their jaws. They're also interesting because there are articulated Ischnacanthids from the Silurian, with well-developed teeth. Although other groups had teeth, we mostly find disarticulated specimens or, more often, isolated teeth and scales. The development of their dentition is more difficult to puzzle out, and that's what I'm interested in. Study of ischnacanthids, other primitive acanthodians, and shark-like fishes from the Silurian and Early Devonian can hopefully help us to understand how the first teeth developed, and how different kinds of early teeth are related to each other.

4. What is so special about the MOTH locality?

The MOTH locality is one of the best sources of Early Devonian fish fossils in the world. Hundreds of specimens, from over 70 different species, have been collected from this one site in the Mackenzie Mountains. What really makes MOTH outstanding, though, is that a large proportion (I don't know if it's been figured out for the whole assemblage, but it's probably around 40-50% for acanthodians) of the specimens are of articulated, complete or nearly complete fishes. That is probably partly due to sampling bias, but that's still hundreds of articulated specimens. And a lot of those are perfectly preserved down to the nodes on the ridges on their (microscopic) scales!

As far as ischnacanthids are concerned, articulated specimens of this quality are pretty much unheard of anywhere else. Usually you only find their isolated jaw bones, maybe with a bit of jaw cartilage attached if you're lucky. There have been articulated ischnacanthids described from other localities, but none are as well-preserved as those from MOTH.

5. And finally, because it is a law that all palaeontological news stories must eventually come back to T. rex...what does this study tell us about the teeth of T. rex?

You know, surprisingly, the journalists I have spoken to (all two of them) didn't ask about T. rex. They did ask how these tooth-like scales relate to our teeth though - maybe there are two options to the law - T. rex and/or humans?

Regarding T. rex, I guess my answer will depend on what, if anything, I find out about tooth homology among early gnathostomes. If ischnacanthid teeth are homologous to bony fish teeth, then they could be regarded as the "tooth ancestors" of T. rex teeth, without which T. rex wouldn't have been able to Rule The Dinosaurs! ... And which of course would then make them valid for paleontological study. I rather think they might be.

Thanks Stephanie!

Blais SA, MacKenzie LA, Wilson MVH. 2011. Tooth-like scales in Early Devonian eugnathostomes and the ‘outside-in’ hypothesis for the origins of teeth in vertebrates. Journal of Vertebrate Paleontology 31:1189-1199.

A marvelous thing happened today.

A shark flew!

(Today was the University of Alberta's Open House, and I spent a while in the afternoon talking to prospective students about majoring in science. The shark was clearly getting a bit pooped by the time I took this video at take-down, but it is lovely nonetheless. I fear I may need to purchase one, because this is certainly the sort of practical thing every grad student needs...)

It seems I've been doing a lot of outreach-type activities the last few weeks - today's open house, a "Discover Science" day to celebrate the opening of the new Centennial Centre for Interdisciplinary Studies, and a talk for the local Girl Geek chapter's monthly dinner. I like doing these sorts of things for a variety of reasons. I feel it's important to show people that scientists are just regular folks, that science can be very accessible, and to make science a bit more transparent to the public. I like encouraging people to get involved in science. I also feel that since I have benefitted from government scholarships, and thus I have been paid by taxpayer money, that it is important for me to be 'giving something back', as it were. Finally, I also find science outreach fun, and so I do it for me, too.

Here's a couple of shots from the Discover Science day, featuring a palaeo-themed Biological Sciences booth manned by myself and Currie Lab postdoc Angelica!

Angelica shows off a mammoth tooth. Pro tip: these are really popular with non-palaeontologists because they look so unlike teeth.

 Yours truly with a selection of friends. Many of these casts are also used in our PALEO419 labs, although we also had a few sturdy real fossils to show off.

Beaty Biodiversity Museum

The Canadian Paleontology Conference I attended over the weekend was held at the University of British Columbia campus in Vancouver, and the public lecture, talks, posters, and banquet were all held in the Beaty Biodiversity Museum.

The museum is actually mostly underground, but the ground-level glass atrium is definitely eye-catching! Inside is a suspended skeleton of a 150-foot blue whale, Balaenoptera musculus. It's particularly striking at night.

Once inside, you can view the skeleton from pretty much every angle except dorsally; a ramp runs on the right lateral side down to the galleries. At the end of the talks, we dined on salmon at tables under the whale!

UBC is doing some really innovative things with regards to museums and collections. The Museum of Anthropology, which I visited last year, was the first to renovate its gallery space to include the entire collection. The Biodiversity Museum has followed suit, and the exhibits sit within the collections! It's a pretty good way to kill two birds with one stone, and is a space-efficient (and I'm assuming cost-efficient) way to display specimens. Every few feet one of the storage cabinets has been converted into a display case, and there are a few strategically-placed gaps in the rows to allow for some different display cases. The cases in the middle of this photo had displays about how specimens are collected, and you could pull out the drawers to see more specimens. There were also a couple of interactive kiosks, my favourite being the display about algae. The table had two shopping baskets and a variety of packaged food products; the goal was to separate out the food that had algae in it and the food that didn't (spoiler alert: all but one product had some sort of algae in it!). It was a cool way to teach people about these unappreciated organisms!

What's also great about the museum is that it features all kinds of interesting organisms. The displays include mammals, birds, fish, reptiles, lots of different invertebrates, plants, fungi, and fossils. I really liked the way fossils were incorporated into the exhibits - in the appropriate region of the collection, glass floor panels showed the fossils 'in the ground', like this school of fish from the Green River Formation.

I'm cheating here because this photo is not from the biodiversity museum, but from the Pacific Museum of the Earth (in the Department of Earth & Ocean Sciences) across the street. I had to put it in, because it reminds me how Alberta dinosaurs wind up everywhere. This Lambeosaurus was collected from Dinosaur Provincial Park by the Sternbergs in the 1920s, and is on permanent loan from the Canadian Museum of Nature (and yes, it's real, not a cast).

Raven Wing

Thanks to Dave Hone for hosting a guest post about my recent paper over on his blog Archosaur Musings. I talked a bit about how I came to work on this specimen there, but here I’d like to talk about the specimen itself and what it means for pterosaur palaeontology.

Gwawinapterus is neat for a bunch of reasons. In Canada, we’ve got pterosaur material from Dinosaur Provincial Park that probably belongs to Quetzalcoatlus (including an amazing wing bone with embedded velociraptorine tooth!), but Gwawinapterus is the first pterosaur that is only known from Canada. It’s also, as far as I know, the first cranial material of a pterosaur from Canada (which may not be saying a lot, but there you go).

Victoria, you always pick the prettiest specimens to work on.

Gwawinapterus is also an istiodactylid pterosaur, which is interesting by its own right simply because there aren’t a lot of istiodactylids known in the fossil record, period. Howse, Milner, and Martill showed in 2001 that “Ornithodesmus” latidens from the Isle of Wight actually represented a distinct genus of pterosaur, Istiodactylus, and thus the Istiodactylidae was born. Since then, there have been some more istiodactylid teeth identified in Europe, but most other species of istiodactylids come from China. These include Istiodactylus sinensis, Nurhachius, and a host of others. All istiodactylids have been named in just the last ten years.

Prior to finding Gwawinapterus, there was no indication that istiodactylids were found in North America...with a pretty big and potentially interesting exception. Bakker (1998) noted the presence of some pterosaur teeth in the Morrison Formation that bear a striking resemblance to istiodactylid teeth. Is it possible that istiodactylid pterosaurs were present in North America since the Jurassic? Only more discoveries will help us to sort out the biogeography of the group.

And finally, all other istiodactylids are found in much older rocks from the Early Cretaceous, whereas Gwawinapterus is of Late Cretaceous age. No other pterosaurs of this age have teeth! Why do we find a toothed pterosaur so late in the game? What were the functional advantages to retaining or losing teeth in pterosaurs? Many folks in the media have asked me what kind of things Gwawinapterus was eating. It’s a fair question, although I can’t really give a very satisfactory answer – I suspect it would have been just fine at taking down small prey, and may also have been a good scavenger. The small, tightly packed teeth are somewhat reminiscent of piranha teeth, although I am leery that by saying this people will picture swarms of Gwawinapterus surrounding some big dinosaur and nibbling it to bits within minutes. Even though that would be awesome. (Incidentally, this behaviour is probably not natural for piranhas, either.)

Grr! (Thanks, Wikipedia.)

With its long snout and sharp little teeth, maybe Gwawinapterus was good at sticking its nose into carcasses and nipping bits of meat off the bones. This is not an original idea – Howse et al. proposed it back in 2001 for Istiodactylus latidens. Whatever it was doing, Gwawinapterus was probably doing it differently from other pterosaurs at the time, and I think that’s interesting.


Literature!

Andres B, Ji Q. 2006. A new species of Istiodactylus (Pterosauria, Pterodactyloidea) from the Lower Cretaceous of Liaoning, China. Journal of Vertebrate Paleontology 26:70–78.

Arbour VM, Currie PJ. 2011. An istiodactylid pterosaur from the Upper Cretaceous Nanaimo Group, Hornby Island, British Columbia, Canada. Canadian Journal of Earth Sciences 48:63-69.

Bakker RT. 1998. Dinosaur mid-life crisis: the Jurassic–Cretaceous transition in Wyoming and Colorado. New Mexico Museum of Natural History and Science Bulletin 14: 67–77.

Currie PJ, Jacobsen AR. 1995. An azhdarchid pterosaur eaten by a velociraptorine theropod. Canadian Journal of Earth Sciences 32:922-925.

Howse SCB, Milner AR, Martill DM. 2001. Pterosaurs. In: Martill DM, Naish D (eds.) Dinosaurs of the Isle of Wight. The Palaeontological Association, London, UK., pp. 324–335.

Sazima I, Machado FA. 1990. Underwater observations of piranhas in western Brazil. Environmental Biology of Fishes 28:17-31.

Wang X, Kellner AWA, Zhou Z, Campos DA. 2005. Pterosaur diversity and faunal turnover in Cretaceous terrestrial ecosystems in China. Nature 437: 875–879. 

Chinese Food Adventures

My food adventures did not end when I left Korea – I have had many opportunities to try new things while in Beijing in Liaoning province, and have added several new meats to my ‘animals consumed' list, including donkey, pigeon, and crocodile. Here are a few of the more memorable dishes that Scott and I tried.

Thousand year egg is an egg that is buried in clay and lime and left to sit for several weeks. The yolk turns a dark greenish-brown, and the white becomes a brown jelly. It looks awful, but it mostly just tastes like egg, surprisingly.


All the guidebooks say you have to try Peking duck while in Beijing, so we did. It’s really tasty! Slices of crispy duck are brought out on a little duck platter (and sometimes the head is thrown in, just for fun as well), and you wrap up duck, leeks, cucumber and sauce in a little flatbread. Quite nice!


At a little street market off of Wangfujing Street, we saw lots of interesting things for sale, including skewered scorpions and starfish. The scorpions on these skewers were still alive and wiggling away...

We were not brave enough to try these.

Another real treat was this delicious spiced garfish!

Name that specimen, IVPP edition.

The IVPP’s public galleries are quite a lot of fun, and Scott and I spent a lunchtime wandering around. We saw many famous fossils! Can you guess the identity of the following close-ups? Answers at the bottom!




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1. This scaly appendage is the lobe-fin of a preserved Latimeria.
2. A delicious meal of Psittacosaurus can be found inside Repenomanus.
3. This friendly fangly smile is that of the pterosaur Haopterus.
4. The delicate toes and feathers of Microraptor.
5. The perfectly placed plastron of Odontochelys.
6. A Pachyrhinosaurus wannabe, the nose of the rhino Coelodonta.

A birthday!

Happy birthday smaller sibling!