Mesozoic Miscellany 53

Darren Naish of Tetrapod Zoology fame wrote a rebuttal to the piece published in April in Laboratory News by Brian J. Ford which claimed that dinosaurs would have been obligated to a life in the water because of their size. Tough but fair.

Along the same lines... Against his better judgment, Brian Switek watched the whole Ancient Aliens episode which featured a bunch of dickweeds spinning sub-L. Ron Hubbard sci-fi stories of aliens exterminating dinosaurs as fact. If I seem a bit prickly over this kind of BS, it's because I spent a fair number of years when I was younger buying the nonsense peddled by Richard Hoagland and Graham Hancock, and I can never have that time or mental energy back.

Continuing coverage of his visit to the Field Museum of Natural History, Matt Wedel of SV-POW shared images of the Rapetosaurus skeleton on display there. The only titanosaur mounted in the US, which was a real surprise to me.


Rapetosaurus at the FMNH, photo by me.

Heinrich Mallison also visited a museum lately, the Natural History Museum in London. He found the lower level of the dinosaur hall to be... lacking, shall we say? His very entertaining rant at Dinosaurpalaeo.

Dave Hone reviewed a terrific kid's book from NatGeo, When Dinosaurs Dawned, Mammals Munched, and Pterosaurs took Flight, illustrated by the great Hannah Bonner.

The newest gallery of paleoart has been posted at ART Evolved, and it's a special one, as it honors the recently departed Dan Varner, beloved for his gorgeous illustrations of Mesozoic Sea Life for Mike Everhart's Oceans of Kansas project. Be sure to stop by and check out some terrific work.

Trish Arnold offers her own take on a title Marc wrote about last November Check out what Trish has to say about a book that "creates its fair share of mood whiplash."

The Houston Museum of Natural Sciences blog features a post about "Wyrex," one of the tyrannosaurs starring in their new exhibit space opening this year. "It is a fun fantasy. Think of it: a young mated couple of rexes relaxing after a meal of duck-bill meat, stroking each other’s necks and muzzles, then petting their newly hatched chicks."

At Aero Evo, Michael Habib briefly commented on the importance of pigments to feather strength, and why it's a good idea to study feathers at all.

What role did forest fires play in the Late Cretaceous world of dinosaurs? Mark Wildman writes about recent research in this area at Saurian.

The Dinosaur Toy Blog recently reviewed a stunning model of Torvosaurus by Shane Foulkes.

Brontofarts, Brachioburps, and Titanotoots

No, the other kind of dinosaur gas. Photo by Jason Clor, via Flickr.

If you're reading this blog, you've surely heard about the correspondence published in Current Biology this month which proposed that the titanic sauropods could have produced methane in such large amounts that they could have been a significant factor in the warming of the climate. No surprise, it's been absolutely manhandled by the popular press, which has once again shown its ability to go far beyond the scope of a scientific paper to draw conclusions the authors never intended. Fox News was the worst offender, stating outright that "Dinosaurs 'gassed' themselves to extinction."

I know a story is making a splash when I'm fielding questions from people I know, and my initial reaction was "eh, maybe?" I'm no expert, I've repeatedly stated, and some of the methods used by David Wilkinson, Euan Nesbit, and Graeme Ruxton were well beyond my current understanding. But it was clear to me that their work was presented as a proof of concept and a launching point for further work, not a definitive statement. It's full of assumptions which are built on assumptions, and would require a mountain of research to be demonstrated as plausible. Jon Tennant at Green Tea and Velociraptors is less diplomatic about it. "The less-than-two-page report, however, is pretty devoid of actual science, and is the kind of analysis that I’d expect from an undergraduate. A bad undergraduate." Brian Switek also wrote about the strengths and weaknesses of the work, as well as calling attention to the media's fumbling of it, at Dinosaur Tracking.

My main reason for posting about this paper is that Dr. Thomas Holtz, one of the most visible American paleontologists, summed it up in the most succint, powerful way I've yet read in response to a question on Facebook. It's a great final word on a subject that may or may not receive follow up research in the future, and it's worth quoting here in its entirety.

On the one...er... hand, they are probably correct that sauropods were major methane producers. But in the paper itself they don't deal with any other sources, sinks, or fluxes of greenhouse gases, so it is impossible to say whether these actually contributed to warming.

Nailed it. Wouldn't you know it, Dave Hone has an interview with Dr. Holtz up at Archosaur Musings today, so do head over to Dave's place and read it.

Vintage Dinosaur Art: The evolution and ecology of the Dinosaurs: Part 2

There's far too much 1970s goodness in The evolution and ecology of the Dinosaurs to be contained in a single post. May I now present yet more classic Caselli illustrations and occasional Bev Halstead strangeness. Hooray!

Among other eccentricities, Halstead seems to have a real love for the classic, chimeric "Brontosaurus" a la Marsh. In other books, Halstead referred to apatosaurs as 'brontosaurs' even after acknowledging their correct name; here, he perpetuates the myth that Apatosaurus "used to be called Brontosaurus" (the name Apatosaurus came first - it's a generic name ferchrissake!). Accordingly, Caselli illustrates Apatosaurus semingly based on Marsh's 1880s "Brontosaurus" skeletal, complete with mismatched macronarian head. When it comes to sauropod habits, Halstead is most definitely of the old, swamp-dwelling school, and he points to various features of the sauropod skeleton that are (according to him) adaptations to an aquatic lifestyle, including a long, heavy tail that served as a sort of anchor/propulsion device. Of course, nobody in their right mind would suggest that these days.

Still, I digress - this is supposed to be about vintage art, not giggling at how silly people were in the 1970s (and that they most certainly were). To illustrate Halstead's description of a trackway made by sauropods on a lakebed, Caselli provides a rather strange image of some 'brontosaurs' doing just that. Of course, being all dopey and small-brained, the poor dears have got their tails in a tangle. Looking at this lumpen mess of tails and blobby bodies and protruding limbs is a little...confusing.

Ankylosaurs never get a good deal in these old books. Here, Caselli reverts to a rather lazy "let's all copy Neave Parker!" mode, and produces some truly bizarre beasts (check out the weird taxonomy too!). There's always one with adorable little ears, in this case Palaeoscincus, a dubious genus based on teeth. "Scolosaurus" is, as usual, a sprawling grump with spikes on its club, and Polacanthus is...a terrifying pinhead from your worst nightmare (it'll TEAR YOUR SOUL APART!). Speaking of which...

Unfortunately, it's a tiny image, but here we see what might well be the genesis of an art meme that saw Quetzalcoatlus depicted as an "evil, pin-headed, toothy nightmare monster that wants to eat your soul" (warning: hellish images of bloodthirsty demon-pterosaurs not for the faint hearted). Caselli's Pteranodon aren't bad by comparison, although the individual hanging like a bat on the right hand side is unfortunate (and another art meme - one that's still not quite dead).

Halstead has some very peculiar ideas about ceratopsians and especially Protoceratops, which he claims weighed 1.5 tonnes, in spite of the fact that "it was only 75cm high at the hip". That's one seriously lardy animal. Furthermore, Halstead describes (and Caselli correspondingly illustrates) the neck muscles of this creature attaching to its frill in such a way that it essentially merged into the animal's back. Darren Naish (him again!) has had a look at the absurdly overmuscled ceratopsian head phenomenon, and it's well worth a read.

More Neave Parker copying, in the form of the classic skulking Megalosaurus (with tiny, four-fingered hands), naturally living in, er, the Early Cretaceous. It's a legacy of a time when the name Megalosaurus was applied to every extinct theropod under the sun, of course, but this strange error probably goes all the way back to their depiction alongside Iguanodon in Victorian art (when geology was in its infancy). Note the very Parker-esque Polacanthus and Hypsilophodon with scutes in the background. Regardless of its scientific obsolesence, the scene is still beautifully painted, with a herd of Iguanodon lurking just out of scanner range to the right.

Allosaurus now, clearly based on the AMNH mount/Chaz Knight's restoration of same. A trend I don't understand in old palaeoart is the tendency to ignore the ornamentation on theropod's heads - why does Caselli illustrate an Allosaurus skull with prominent horns on the page opposite this, but not stick them on his life restoration? Got to love the jolly, fat old Ceratosaurus in the background though. Actually, the real animal was rather robust, but probably not so jolly. Its giant fangs have been blunted in art for far too long...

Oh dear. I absolutely love the colours, and the feathers are beautifully rendered, but...why? WHY? You've drawn a skeleton RIGHT THERE! Look at it! Look at an extant bird's skeleton! I need a lie down.

And finally...it's the image you've all been waiting for! Maybe. This illustration of two fighting Pachycephalosaurus is probably my favourite from the entire book. There's a fantastic sense of movement and inertia here, and that impact looks painful - just look at the one on the right, sailing through the air. There's even a brilliant Handy Diagram to show you in which direction the heads would have travelled, just in case you couldn't figure it out for yourself. Just wonderful stuff.

Fruitadens: The Little Ornithischian that Could

Another swell piece of research published recently in PLoS One - the official favoritest journal of Love in the Time of Chasmosaurs - is a detailed description of the anatomy and phylogeny of Fruitadens haagororum, the little heterodontosaurid from the Morrison Formation of Colorado, a formation dating to 150 million years ago. It debuted with a brief paper during the infancy of this blog in 2009, but now it's been properly studied, so what's the scoop?

Lead author Richard Butler describes this paper as "the result of a nearly 30 year long project," building on a substantial body of work by coauthor Peter Galton. Heterodontosaurids were bipedal ornithischians, notable for their varied dentition. Many have pronounced fangs, or caniniforms, in addition to leaf-shaped teeth which would have been good for munching vegetation. And one of them, Tianyulong, was preserved well enough to reveal that it bore long, hollow quill-like filaments along its back.

Fruitadens restored by Nobu Tamura, featuring quills like those of Tianyulong.

Understanding the evolutionary trends of these primitive ornithischians is important for what it can reveal about the common ancestor of all dinosaurs. Unfortunately, there are few windows into heterodontosaurid evolution, with the most productive strata dating to the early Jurassic of South Africa, when Heterodontosaurus, Abrictosaurus, and Lycorhinus lived. The Middle Jurassic of Europe has offered a plethora of teeth which hint at substantial populations of heterodontosaurids, but so far has not coughed up any significant remains to help fill in the details of the heterodontosaurid story. But what we have is enough to build a rough sketch of how the clade evolved over the 55 million year stretch that it existed.

Fruitadens was likely an omnivore, eating what plants, insects, and other invertebrates it could find. Like closely related Tianyulong, it was smaller and less specialized for herbivory than the earlier Heterodontosaurus, which was made to process tough plant material. Butler notes that "it appears that Late Jurassic-Early Cretaceous heterodontosaurids were smaller than most Early Jurassic members of the clade, and displayed less sophisticated skull and dental morphologies." They were becoming generalists. As the clade spread across Pangaea, which was fragmenting by the Late Jurassic, evolutionary pressures - perhaps competition from the sauropodomorphs - were pushing the heterodontosaurids into a more opportunistic lifestyle. Sort of a dinosaurian version of a raccoon, scratching out a living any way they could.

More:
Andy Farke's take on PLoS Blogs
A note from lead author Richard Butler
Brian Switek at Dinosaur Tracking

Sixteen Bit Saurians

I am not a gamer. I've got a bunch of Nintendo systems, some games I like, and not nearly enough time to justify turning any of them on. But I spent many a wayward teenage hour immersed in video games, and one of my favorites of all time was the Super Nintendo version of Jurassic Park. I don't know what made me remember it recently, but I started googling, and you know how that goes.


Photo by Filthfiller, via Flickr.

That's how it goes. It was a huge kick to find the score shared on YouTube, and listening to the music brought all of those memories flooding back in. Running around as Alan Grant, grunting and jumping and firing bolas into packs of compys. Stuffing my virtual pockets full of dinosaur eggs to save the world from John Hammond's nightmare. Getting messages from heavily pixelated likenesses of the JP cast. Wandering into T. rex territory and shooting wildly at it, only to end up its dinner. The game was split between a top-down, freely navigable exterior world and frequently dark and claustrophobic interiors where you were liable to get jumped by a raptor or hit by a Dilophosaurus loogie.

The only other JP game I've played was the one in which Minnie Driver's arms don't work, and I've always assumed I was the only person who actually liked the SNES version. So I was surprised to find that it's gained a cult following. Mostly though, I'm writing this because of the music. It shreds.

For instance, "Triceratops Trot."


"Raptor Rap."


Or this one, from the Visitor's Center.


Ah, memories. Now, where's that SNES...

More: Flying Omelette, Nintendo3DS Community, an unenthusiastic review from Alex Kidman. Download the score, too!

Thursday: Live chat about Late Cretaceous dinosaur diversity

The American Museum of Natural History in New York will be hosting a live chat with paleontologists Mark Norell and Steve Brusatte this Thursday, May 10 at 1pm Eastern Standard Time. The topic will be recent research testing the idea of whether the dinosaurs were experiencing a long-term decline before the mass-extinction event that ended the Mesozoic era. From AMNH:

The team's research shows that hadrosaurs and ceratopsids, two groups of large-bodied, bulk-feeding herbivores, animals that did not feed selectively, may have experienced a decline in biodiversity in the 12 million years before the dinosaurs ultimately went extinct. In contrast, small herbivores, carnivorous dinosaurs, and the enormous sauropods remained relatively stable or even slightly increased in biodiversity.

As Brian Switek recently wrote at Dinosaur Tracking, this is a very complicated matter, and the oversimplification that casts a shadow over much popular thinking needs to be jettisoned. The dinosaurs were not marching in lockstep towards oblivion, and local trends can serve to distort what was happening globally because of selection bias. It should be a fun chat, and a great chance to get young minds to think more critically about nature (hint hint, teachers).

The AMNH also produced a summary video of the research, embedded below.



Questions can be submitted by email or via the Twitter hashtag #AMNHlive, and the chat will be hosted on the museum's site. Visit the AMNH website for more information.

Mesozoic Miscellany 52

It's been over two months since the last of these roundups, for which I apologize. My semester is now wrapped up - I have three paleontology design projects to share when I get some good photos taken - and I'll be back more frequently now. Heck, I've even written two posts about new research in the last week or so, and that feels good. A lot of great stuff has been happening in the dinosaur blogosphere.

First up, Mark Witton's enchanting two-part post for Pterosaur.net, Our Lives with Pterosaurs. It's posts like these that make me sit back and reflact on how unbelievably lucky we are to live in a time when this kind of contact with scientists is possible. Part one, part two.

Darren Naish reviewed Thor Hanson's book Feathers: The Evolution of a Natural Miracle. He's right! It's great! You should read it!

Scott Hartman produced one of the most evocative pieces of paleoart in recent memory with his portrayal of Unenlagia fishing at dawn. "Less is more" isn't just a hollow aphorism, and this is a perfect illustration of it. Breathtaking.

An essential part of any self-respecting human being's visit to the Field Museum is the amazing Mold-A-Rama machine. SV-POW tells it like it is: "The Mold-A-Rama is the king of novelty souvenirs."


The Mold-a-rama T. rex, photographed by Bret Arnett, via Flickr.

Fellow paleo-loving designer Sharon-Wegner Larson has updated the design of her blog Omegafauna, but also stop by to check out her review of the "Dino-Roars" exhibit which recently set up shop at the zoo where she works.

Canada now has legal tender with a glow in the dark Pachyrhinosaurus on it! Check it out at ART Evolved.

Michael Habib wrote a takedown of the silly "aquatic dinosaurs" story that oddly enough gained traction in the press at H2VP. Also be sure to add his new Aero Evo blog to your feed reader, where he discusses the evolution of flight in the various lineages of organisms that have figured out how to cheat gravity.

Dave Hone was an editor of the recent volume New Insights into Asian Dinosaurs. He gives us the skinny at Archosaur Musings.

A Greg Broadmore illustration twists time around, imagining a Styracosaurus happening upon the remains of an ancient race of warlike hominids.

Brett Booth offers his own take on the new Asian spinosaur Ichthyovenator.

At Dinosaurpalaeo, Heinrich Mallison shares a nice selection of photos showcasing the architecture of the Natural History Museum in London.

Delving into the "opposite birds" of the Mesozoic, Matt Martyniuk writes about the cryptic species Enantiornis at DinoGoss.

At JPTaphonomy, Joseph Peterson wrote about the work being done by one of his grad students, Carol Bigalke, to explore further is the true cause of lesions on pachycephalosaur domes.

Stu Pond did some fancy 3D visualization of Confuciousornis, and it's nifty! Check it out at Paleo Illustrata.

At Paleoexhibit in February, Nobu did another fun series, this time on the theropods of the British Isles.Start here.

How does beak shape relate to the shape of the underlying bone? Jaime Headden explores this in extant animals and dinosaurs at the Bite Stuff.

Mark Wildman laments that "there has been a casualty in this race to the truth and that is the humble dinosaur with traditional reptilian scales." More at Saurian.

Brian Switek broke down the amazing glut of dinosaur material we'll be seeing hit the silver screen in the near future, many of which I hadn't even heard of. Speaking of which, Pete Von Sholly shares the trailer for the remixed Dinosaur Revolution movie, Dinotasia. He's pretty excited for folks to see it... TotalFilm on the other hand is a little less enthusiastic, calling it a "dreary, terribly animated mock-doc, in which crudely composited reptiles stalk flat live-action landscapes in search of dinner." If you've seen it, be sure to share your opinion!

Vintage Dinosaur Art: Rourke's Ankylosaurus

Yes, it's time once again to wander into the Mesozoic as rendered by Rourke Publishing. This will be the sixth go-around in Rourkeland for LITC, and it's always a treat. These books, which tell stories about prehistoric animals set in environments built on the latest paleontological understanding, generally provide an excellent snapshot of pop-paleontology in the eighties. More often than not, they feature excellent illustrations as well. Bernard Long's work in the Ankylosaurus title is another good example of the quality titles Rourke released.



One thing which dates the title, as is usual, are the bunny-handed theropods, devoid of the fuzzy and feathery coverings which have become de rigeur these days. The book opens with the titular character waking up to see a Troodon - here called Stenonchysaurus - trotting by with something furry for breakfast. The Troodon is clearly based on the Ron Seguin sculpture (the one almost always seen with the dinosauroid), which I will admit is always going to be the first thing that pops into my head when I hear or read the name. It was the most striking image in my old Doring-Kindersley visual dictionary; something about those big lantern-eyes and smooth, slick skin captured my imagination. It's nice to see my obsolete pal make an appearance here.



A pachycephalosaur makes a cameo as well, in the form of Gravitholus, and the text refers to the well-accepted idea of courtship battles between the "boneheads," which made an appearance here last week.



Our protagonist also meets some hadrosaurs, in the form of Parasaurolophus. I particularly enjoy the look of the one in the foreground. She looks like she's asking to bum a smoke off of Ankylosaurus, though the text says that she's "uttering fierce noises." The reason, of course, is that Ankylosaurus has wandered too closely to the Parasaurolophus nesting grounds, clearly a reference to the then-recent revelations into nesting provided by Jack Horner and his work on Maiasaura.



The next encounters with other dinosaurs is a bit more eventful. The ankylosaur runs across a couple of roughneck Tyrannosaurus rex, immediately going into "stop, drop, and swing" posture. This doesn't stop one of the tyrannosaurs from performing the indignity of jumping up and down on her back, which seems like as good of a method of taking down an ankylosaur as any.



Luckily for Ankylosaurus, an Alamosaurus distracts the giant theropods and they run off for another chance at lunch. Last week's post by Marc also featured T. rex and Alamosaurus, and Hadiaz mentioned in the comments that the Rourke Tyrannosaurus title also features this pairing. I'll be posting about that one soon. It's a bit of a fudge to include Alamosaurus here, as it doesn't occur in the Hell Creek or the Lance formations with Ankylosaurus, coming instead from the Southwest US, either from the Kirtland or Ojo Alamo Formation.



After this long, eventful day, our hero finds some supper and settles in for a well-deserved slumber. but not before watching a slightly anachronistic hunt in which Saurornitholestes slaughters the ornithopod Parksosaurus. The day ends as it began. Nothing like a little dinner theater.



As usual, this Rourke book ends with a great section giving the scientific background so the story we've just read, and this one features a little illustration of the all-but-abandoned Palaeoscincus, a grumpy little guy.



As I said, this is another good example of what a fine job Rourke did with their line of dinosaur storybooks. Ankylosaurus herself is pretty respectable for an 80's reconstruction; Bernard Long avoids the old neckless sluggard look of mid-century depictions as Palaeoscincus above demonstrates, imagining the famous "tank-dinosaur" as a dynamic animal. The plates are a bit armadillo-ish, but on the bright side, Long doesn't slavishly repeat mid-century tropes and the osteoderms and spikes are not too far off of the newer ideas of what Ankylosaurus looked like - see Kenneth Carpenter's recent redescription, for example (PDF). Well done, Mr. Long.

Previous Rourke books featured here:
Brontosaurus (Colin Newman)
Iguanodon (Bernard Long)
Triceratops (John Francis)
Pteranodon (Doreen Edwards)
Allosaurus (Doreen Edwards)

Dinosaurs with ouchies on their noggins

A pair of Pachycephalosaurus put their heads together at Drayton Manor Theme Park. Photo by Matthew Wells, via Flickr.

Since I was a kid, one image has been stuck in my head when I think of the pachycephalosaurs, those rugged ornithischians with the outrageously thick frontoparietal bone: two males ramming into each other headlong like the two dudes in the photo above. I'm pretty sure I'm not alone in this. Even when I read a piece expressing skepticism about the behavior, I think to myself, "okay, but we're going to stick with the rule of coolness here." It's the same attitude that annoys me when people choose to not believe that many theropods wore feathery integument of some fashion. Again, I remind myself that science isn't about accepting things because they seem to make sense or they're pleasant to believe. So it's good that he head-butting hypothesis has recently had a spate of research devoted to it. The latest is a new paper in PLoS ONE, Cranial Pathologies in a Specimen of Pachycephalosaurus.

The rock has offered us scant remains to work from, which is probably a good reason why the pachycephalosaurs - who Tom Holtz refers to lovingly as "buttheads" in his Dinosaurs encyclopedia- have long been the subject of debate. Why were those heads so thickened? How many taxa might simply represent different growth stages of one species? Could they sustain direct head-to-head impacts or was it more likely that they smacked each other sidelong? Because of the patchiness of their fossil record, it's been difficult to put many of these ideas to the test.

In this new study, University of Wisconsin paleontologist Joseph Peterson, with the help of Christopher Vittore from the Department of Radiology at Rockford Memorial Hospital in Rockford, IL employ CT scanning of a Pachycephalosaurus frontoparietal dome at the Burpee Museum of Natural History and compare its apparent signs of injury to lesions in modern animals. Are these spots best interpreted as sites of bone resorption, as the rigors of decay, fossilization, and erosion, or are they evidence of traumatic impact?

Peterson's study concludes that it ain't the first two. Bone resorption, studied extensively in chasmosaurine fossils, leaves a smooth surface, as opposed to the roughness of the lesions in the studied Pachycephalosaurus dome. Signs of likely taphonomic suspects - such as scavenging, insect traces, and water wear - are also absent. But the lesions do match the marks left on the the crania of modern birds which have sustained impact and lived to tell the tale. Moreover, Peterson writes that the marks "are clustered over the thickest region of the dome; this distribution corresponds well to the location of expected traumatic pathologies resulting from agonistic behavior proposed for pachycephalosaurids." That would be head-butting, though they could have been smacking into boulders instead, I suppose. It's less absurd than some recent dinosaur stories in the popular press.

This follows another recent study by Eric Snively and Jessica Theodor, who compared the skull of Stegoceras to modern "buttheads" and found that "some pachycephalosaurs were as competent at head-to-head impacts as extant analogs displaying such combat," including musk oxen and duikers. (check out Eric's guest post at Archosaur Musings for more on this). On Facebook, Andy Farke joked that the "P" in PLoS ONE may as well stand for "pachycephalosaur." That wouldn't be so bad, would it?

Also be sure to follow Dr. Peterson on Twitter and at his blog (which has been dutifully added to the LITC blogroll).

Aquatic Dinosaurs in Saskatchewan

It was always one of the cardinal rules when I was younger: when shown a mosasaur or plesiosaur labeled as a dinosaur, one could quickly refute it by saying that dinosaurs were not aquatic. It missed the point, perhaps, but it was one pithy characteristic to keep at the ready.

Of course, that story is much more complicated now that the dinosaurian origin of birds is recognized, and the line between "dinosaur" and "bird" gets so fuzzy as to be absurd. As Craig Dylke pointed out recently, there certainly were marine dinosaurs, with Hesperornis as a good example.

Continuing its 2012 lecture series, the Royal Tyrrell Museum's YouTube channel recently shared a lecture from Joe Sanchez covering the hesperornithiforme fossil record in Saskatchewan. "Diving Birds in the Prairies: Late Cretaceous Hesperornithiformes" covers a general overview of the family as well as highlighting the bonebeds in Canada which have given us the oldest North American hesperornithiforme fossils, dating to about 95 million years ago. These fossils represent the genus Pasquiaornis, a basal member of the clade, and Sanchez demonstrates the way that its anatomy is transitional between wing-propelled divers and foot propelled divers like the famous Hesperornis. Enjoy!