The Shark-Like Edestus: An Interview With Wayne Itano

We've heard from Wayne Itano before, when he told us about the Kremmling Cretaceous Ammonite Locality in Colorado. (To read the post, click HERE.) A physicist at NIST (National Institute of Standards and Technology) in Boulder, Colorado, Wayne also has a hobby interest in paleontology, and is a curator adjoint at the Natural History Museum of the University of Colorado. He has also been doing some very interesting work with a shark-like animal called Edestus, and he graciously agreed to answer a few questions for me regarding this creature! So please join me in welcoming Wayne Itano, as he tell us about this fascinating prehistoric creature!

Scissor-tooth model for Edestus.  Credit Ray Troll, www.trollart.com

The Natural World:  You've been doing some work with an ancient shark-like creature called Edestus. What can you tell us about it?

Wayne Itano:  Edestus is my candidate for the strangest shark of all time. In my opinion, it is even stranger than the better-known spiral-toothed Helicoprion, since it is harder to imagine how the teeth might have been used.  (Read more about Helicoprion HERE.)  Almost the only fossil remains of Edestus are its symphyseal (midline) tooth whorls, which consist of triangular, serrated teeth, joined together at the bases (roots).

Edestus had one tooth whorl in the upper jaw and one in the lower jaw. Since the whorls are bilaterally symmetric (same on the left side as on the right side), they must have been located in the middle of the jaws.

This is a photograph of a specimen of a species called Edestus mirus. It was found in Pennsylvanian-aged deposits (about 300 million years old) of Iowa.

Smithsonian Institution Specimen USNM V 7255. Scale in cm.  To see a better resolution of the picture, click HERE.  Photo Credit: http://collections.si.edu/search/results.htm?view=&dsort=&date.slider=&q=Edestus+mirus+holotype&tag.cstype=all

This is a rare specimen, since it shows both the upper and lower tooth whorls.

The curvature of the tooth whorls makes it difficult to understand how they could have been used.

According to the conventional reconstruction, the two tooth whorls were used as scissors, to cut prey between the two whorls, as in this drawing by Ray Troll.

Scissor-tooth model for Edestus.  Credit Ray Troll, www.trollart.com

To me, this model seems unlikely, given the curvature of the tooth whorls. It seems that the outer teeth are nonfunctional, since they can’t come together, so there would be no reason to retain them.

It seems to me that the teeth would be more efficiently used if the entire head was moved up and down, with jaws fixed, to slash large prey. This is a radically new idea. I have submitted an article for publication elaborating on this idea, but I expect that it may be some time before it gets into print.

New vertical-slashing model for Edestus. Drawing by Gary Raham, www.biostration.com, reproduced with permission of Wayne Itano

My new reconstruction of Edestus, showing the pair of symphyseal tooth whorls, in front, used for slashing prey, and flat teeth in the rear for crushing prey. Drawing by Gary Raham, www.biostration.com, reproduced with permission of Wayne Itano.

TNW: I noticed that you referred to Edestus as being a candidate for the "strangest shark of all time." Is Edestus truly a shark? If not, how do you classify it?

WI: I was using "shark" in an informal sense, as the term is not well-defined for many extinct fish. Edestus certainly falls within the class Chondrichthyes, which today comprises 2 subclasses - Elasmobranchii (sharks, including rays) and Holocephali (ratfish). There is some evidence that Edestus (and also Helicoprion) belong to an extinct line that is closer to the Holocephali than to the Elasmobranchii, but this is a matter of debate. It is safe to call Edestus a chondrichthyan, and I try to avoid the word "shark" when I write a technical paper, or maybe keep it in quotes.

TNW:  Tell us a little bit about your research.

WI:  I am interested in many aspects of paleontology, but for the last 22 years I have focused on fossil sharks, particularly ones from the Paleozoic (older than about 250 million years ago). My interest in Paleozoic sharks dates from 1991, when I found a finspine of a Pennsylvanian-aged shark called Ctenacanthus in a roadcut near the town of McCoy, in Eagle County, Colorado. I wrote an article about this find for the newsletter of the Western Interior Paleontological Society (WIPS) in 1992, which you can read by clicking HERE.

Ctenacanthus finspine found near McCoy, Colorado. Scale in cm.  Photo Credit: Wayne Itano

In trying to identify this finspine, I read everything I could find about Paleozoic sharks. Knowing of my interest in the topic, Professor Martin Lockley of the University of Colorado at Denver loaned me a large collection of shark teeth and finspines from McCoy that he and Karen Houck, also of CU Denver, had found in the 1980s. His paleontological interests had by then switched entirely to ichnology (footprints and other fossil traces), and he gave me the opportunity to write up the fossil shark specimens. I published an article on the finspines in 2003 with Houck and Lockley, which you can read HERE, but I haven’t finished with the teeth yet.

My interest in Edestus started when an amateur fossil collector showed me an unusual shark tooth that he had found at McCoy. After a bit of study, I realized that it was a tooth of Edestus, the first known from the entire Rocky Mountain region. This eventually led to my publishing a rather long paper on Edestus in 2012, again with Houck and Lockley, which you can read HERE.

Recently, I have also published three short papers related to Edestus: one on an Edestus tooth from England, one on an Edestus tooth with abnormal serrations, and one on a tooth from China that had mistakenly been identified as Edestus, but which actually belonged to a more “normal” shark called Carcharopsis.

TNW:  Do you have any future expeditions or research papers in the works?

WI:  Lately most of my “field work” has been in museum collections. In the last few years I have been able to view specimens in the collections of the Yale Peabody Museum, the Natural History Museum (London), the British Geological Society, the American Museum of Natural History (New York), and the New Mexico Museum of Natural History and Science. I have several publications in the works, largely based on fossil shark specimens I have seen in those collections.

One area is the taxonomy (classification) of Edestus species. About 15 species of Edestus have been named, but I think that many of these are synonymous. For example, people have named new species based on unusually small or large teeth, but I think they are just teeth of the same species of Edestus but of different ages. There may be as few as 3 valid species of Edestus.

I have another project where I am examining microscopic scratches on Edestus teeth. I am hoping that I can find feeding-related scratches and that their orientation will provide some clues as to whether the scissors-model or the up-down-slashing model is correct.

-Thank you so much, Wayne, for answering some of my questions!  I look forward to hearing more about Edestus in the future!  Thanks again!-

Boulder Submerged: Not So Strange 70 Million Years Ago!

Where I live in Boulder, Colorado, we aren't used to having a whole lot of moisture.  For the last few days, however, we have been experiencing record breaking levels of rain: as a matter of fact, the sheer amount of rain that we are being inundated with has resulted in enormous levels of flooding, complete with evacuations, destroyed homes and roads, and unfortunately several deaths.  I am actually writing this Thursday evening after having my very first flood day, and we have a flood day tomorrow, too!  (And now I am finishing the post on Sunday and we are STILL getting rain!)  Despite the fact that all of this water in Boulder is quite unusual, if you were to travel back 70 to 100 million years ago right here in Boulder, water wouldn't be the exception: it would be the norm!

You see, 70 million years ago, there were no Rocky Mountains.  In fact, Colorado was nowhere near a mile high above sea level: it was about three hundred feet below!  Due to the fact that what would one day be Colorado was still located on continental crust, the Western Interior Seaway couldn't be super deep: nevertheless, three hundred feet deep was deep enough to contain an enormous assortment of fun creatures!  We've already met a large number of these creatures throughout different posts in the blog, but let's take another look at these guys, as well as other fun filled creatures of this ancient seaway!

Let's start on the shore: multiple dinosaur trackways throughout the nation (including two that I've been to, Dinosaur Ridge near Morrison and the Heritage Museum of the Texas Hill Country) show that many different dinosaurs roamed the shore of the Western Interior, including large ornithopods and large theropods.  Some of these dinosaurs actually died and were swept out to shore, such as the ankylosaur Niobrarasaurus!

Pyg chilling inside of a cast of one of the large ornithopod footprints from Dinosaur Ridge at the Morrison Natural History Museum

They weren't the only dinosaurs that lived on the shore, though: meet the flightless, cormorant-like bird Hesperornis!  Originally discovered by famous paleontologist Othniel Charles Marsh, Hesperornis grew to around six feet in length, and looks very similar to the Galápagos flightless cormorant via the process of convergent evolution!

Hesperornis probably ate a wide variety of fish, squid, and an interesting group of extinct marine vertebrates called ammonites.  Some ammonites could grow to simply ENORMOUS proportions, such as the one in the top left of the picture below, one from the Heritage Museum of the Texas Hill Country that I mentioned above.  Found all over the country (and, as a matter of fact, the world), one particular ammonite site looks like it might be a nesting site!  To learn more about this ammonite nesting site, click HERE to check out a guest post by paleontologist and physicist Wayne Itano!

Ammonites were by no means the largest creature in the Western Interior, however, and neither was Hesperornis.  As a matter of fact, neither of them were all that close at all!  Hesperornis was relatively close to the bottom of the food chain, a fact that we know conclusively due to the discovery of one particular specimen of an interesting animal called Tylosaurus in South Dakota.  Tylosaurus was a type of animal called a mosasaur, whose closest living relatives today are the monitor lizards (like the Komodo dragon and the Nile monitor).   Contained within the stomach cavity of this particular Tylosaurus specimen were the remains of a fish, a smaller related species of mosasaur, and a Hesperornis!  Platecarpus remains, one of those smaller mosasaurs, are sometimes found within the belly of the Tylosaurus, the belly of the beast!

Paleontologists are always very excited when they think they've found the fossilized remains of a predator with the remains of its prey still inside.  This can help establish a predator/prey relationship between the two creatures, a relationship that might otherwise have simply been theorized.  Fortunately for us paleontologists, multiple critters in the Western Interior Seaway have been discovered with other little critters within their stomach cavity!  One of these, which I have nicknamed "The Inception Fossil," we actually did a whole post about a few months back!  Entitled "Xiphactinus: The Inception Fossil," this post was all about a fish called Xiphactinus and why I called it "The Inception Fossil."  As you might have already guessed from the context, the nickname stems from the "fish within a fish" idea: Xiphactinus is often found with other fish inside of its stomach!  Below, you can see one of these Inception Fossils, where a Xiphactinus died shortly after swallowing a fish called Gillicus.

Xiphactinus and Gillicus were by no means the only fish in the sea!  The other day, my friend Sam Lippincott and I visited the Denver Gem and Mineral Show.  We both purchased several fossils there, and one of my purchases was a small tooth of another Western Interior Cretaceous Seaway (WIKS) fish called Enchodus.  The name of this fish roughly translates to "spear fish," and from the picture below, you can probably see why: this fish was definitely made to catch some other fish!  Fossils attributed to Enchodus have been found on either side of the K/T boundary, meaning that this fish seems to have survived the extinction that killed off the non avian dinosaurs, and many of the marine creatures as well!

It looks to me like this tooth may be one of the large protruding teeth on the upper part of the jaw.

Pyg checks out her new Enchodus tooth from the Denver Gem and Mineral Show!

I got another tooth from another fish that would have inhabited the Western Interior: this tooth belongs to the shark Squalicorax!  When fully grown, Squalicorax was around the size of the living great white shark, and would have prowled the oceans much like sharks do today.  As a matter of fact, sharks have survived relatively unchanged for hundreds of millions of years!

Pyg checks out the other tooth she purchased at the Denver Gem and Mineral Show, a Squalicorax tooth!

Next, we have a funky looking group of reptiles that look like nothing that we have on Earth today!  These are the plesiosaurs, and some of them could grow pretty large!  Remember before how we mentioned that Hesperornis was discovered by a guy named Marsh?  Well, Marsh had a paleontology rival named Cope.  This rivalry got kind of out of hand, and resulted in something that today we call "The Bone Wars."  (To learn more about the Bone Wars from the ridiculously funny "The Oatmeal," make sure to click the link HERE!)  One of the particularly famous instances in this paleontological skirmish was when Marsh's rival, Edward Drinker Cope, reconstructed one of these plesiosaurs.  Called Elasmosaurus, Cope accidentally placed the head of the animal on the tip of the tail instead of in its proper place at the end of the neck.  As you can imagine, Marsh took the opportunity to mock his rival.  This also sets up the perfect joke for The Oatmeal, but I won't spoil it for you: you have to check it out for yourself!

Although there were other plesiosaurs that swam through the ancient North American seas, my favorite is the funky looking Dolichorhynchops!  This type of short-necked plesiosaur has also been found in the stomach of the enormous Tylosaurus!

Dolichorhynchops is most definitely not a familiar face to your average Joe, but what about Archelon?  This massive sea turtle also inhabited the seaway, and is actually the largest sea turtle known to science!  This guy is about 13 feet long, which is about twice as long as the leatherback sea turtle, who are the largest living sea turtles!  And although Archelon looks similar to sea turtles today, it definitely doesn't look like the turtles we have in Boulder!

Just as the floodwaters are subsiding, so too did the Western Interior Seaway drain from the center of the North American continent.  As the Rocky Mountain started getting pushed up and the elevation got higher and higher, the shallow sea got shallower and shallower, until there was nothing left.  Nothing left, that is, except for the fossils that we find today!  And who knows, maybe the floodwaters from the recent storms have eroded away some overburden, revealing some prehistoric marine fossils beneath!

The Truth Behind the "Truth" Behind Megalodon

Today, the great white shark rules the seas and haunts our imaginations.  After the release of the 1975 movie "Jaws," the great white shark and other sharks were feared and loathed more than they already were, although much of this fear was unbiased.  Ever since Jaws, hundreds of books, movies, television programs, and more have all capitalized on the shark craze, producing everything from the fantastic Steve Irwin Crocodile Hunter specials to the recent TV movie Sharknado.  One of the most popular shark-related features in the media is Discovery Channels "Shark Week," an annual event that features a week of shark-related programs.  Although many of these programs, as is to be expected for television programs nowadays, push the limits of reality, I think that the premiere of this year's Shark Week went too far, and I'm not the only one who thinks that, either.

First off, let's meet the star of this program: megalodon.  Estimates of the size of megalodon have varied widely and wildly, with some older estimates as high as about 100 feet long.  Today, however, most scientists agree that the largest megalodon could grow to around 60 feet long.  Which is still pretty massive, given that most great white sharks don't exceed lengths of around 20 feet, and look at how much people are afraid of them!  megalodon would have easily been able to swallow the average human in one bite: just take a look at those reconstructed jaws, below!  Also, below that picture, make sure to check out the size of just one megalodon tooth.  Suffice it to say, this shark was one massive bruiser.  This shark WAS one massive bruiser.  Notice how I emphasized the "was?"  Well, that's because megalodon went extinct about two million years ago.

Pyg encounters a mid-sized megalodon tooth, graciously donated to my collection of fossils and things that I take to local schools by local paleontologist Wayne Itano

Megalodon sounds pretty awesome, right?  I mean, to be honest, it's one of those extinct animals that just doesn't need to be "sci-fied up," because it's already cool enough as is, on par with other animals such as Tyrannosaurus, Spinosaurus, and Utahraptor.  Well, just because it didn't NEED to be sci-fied up doesn't mean that television networks didn't do it anyways.  And this years Shark Week premiere was the culprit.  Discovery Channel aired a two hour "documentary" showing "biologists" on the hunt for a megalodon.  Today.  In the present.

One of those extinct animals that just doesn't need to be "Hollywoodized!"  Meet Stan, the resident Tyrannosaurus rex at the Morrison Natural History Museum!  You can see Pig seated in the bottom jaw for scale!  Yeah, this guy was huge.

We have no evidence to indicate that megalodon is alive and with us today, and the "evidence" included in the "documentary" was very clearly doctored.  For example, below is a picture of a whale that has supposedly been bitten in half by a megalodon:

And here is a photo "uncovered from Nazi archives" of a giant shark fin surfacing behind a pair of U-Boats:

The first picture just screams CG.  And the second one....really?  Nazi's? Very Indiana Jones-esque.  OK then, Discovery.

The "documentary" starts off with "found footage" of a "boat capsizing off the coast of South Africa and several people being eaten, but whose bodies were never recovered."  Already, this reeks of a typical television plot.  Especially given the fact that a quick Google search of this supposed incident, as well as any of the "biologists" in the "documentary," yields diddly-squat.  Apparently the prospect of a giant shark brutally attacking and destroying a fishing boat just wasn't exciting enough to make it to the news, despite the fact that every news story relating to sharks and shark attacks spreads like wildfire.  Perhaps the South African press was just busy that day?

People refute our naysaying by pointing out that "we know more about the surface of the moon than the ocean," and "the coelacanth (which you can learn more about by clicking HERE) and the giant squid were only discovered recently!"  Yeah, that's true.  But megalodon is very different from a giant cephalopod or a five or six foot long fish.  We are talking about an active, 60 foot long predator that's feeding on much, much bigger prey than the giant squid or coelacanth would.  The giant squid and coelacanth eat a lot of fish, and are considered to be primarily piscivorous.  The giant squid, although very large, is by no means at the top of its food chain, and is fed upon by the largest of the toothed whales, the 60 to 70 foot long sperm whale.  And two million years ago, megalodon would have made up the final link in this food chain, feeding on the 60 to 70 foot long sperm whale.

Am I saying that there is no possibility that more giant animals exist in the deepest depths of the ocean, just waiting to be discovered?  No, I most definitely am not.  I do, however, encourage you to consider the ecological resources that would be needed by such a massive animal.  With no evidence of mutilated whale carcasses that could be attributed to such a massive animal, and an equal amount of evidence from first-hand accounts....I think that the conclusion should speak for itself.

The biggest issue that I have with all of this is not that a television program was made that packages myths, untruths, and exaggerations: it was with the fact that they packaged it as a documentary, no quotations this time.  Discovery tried to balance out the fact that they blatantly made stuff up to appease some of their viewers by pointing out that they included disclaimers in the show.  Yeah, true, there were disclaimers: but click HERE to see how short and hazy these disclaimers really were.  The disclaimers read:

None of the institutions or agencies that appear in the film are affiliated with it in any way, nor have approved its contents. Though certain events and characters in this film have been dramatized, sightings of "Submarine" continue to this day. Megalodon was a real shark. Legends of giant sharks persist all over the world. There is still debate about what they might be.

Notice how they never really say that none of it was true.  When he gave a press release, the executive producer of Shark Week, Michael Sorensen, said that “With a whole week of Shark Week programming ahead of us, we wanted to explore the possibilities of megalodon.  It’s one of the most debated shark discussions of all time, can megalodon exist today? It’s Ultimate Shark Week fantasy. The stories have been out there for years and with 95 percent of the ocean unexplored, who really knows?”  The part that bugs me the very, very most about that statement is the line "It's one of the most debated shark discussions of all time."  It isn't, I promise you.  It really, really isn't.  I have never heard of any paleontologist who seriously believes that megalodon swims the oceans today.  There might be some paleontologists who won't discount the possibility, which is fine.  Science changes all the time.  But with a complete and total lack of evidence, no serious scientist will really debate that sort of thing.

There's many more issues that people have had with this presentation, varying from thousands of people on social media voicing their complaints, all the way to actor Wil Wheaton, who wrote about the megalodon fiasco on his blog, which you can read HERE.  Others, such as popular paleo writer Brian Switek, went to Twitter:

I do hope that this backlash will cause the people at Discovery, as well as at other television stations, to reconsider what they make into a television program, and consider the possibility that, just maybe, there's a significant chunk of people out there who don't want to be fed this garbage.  I do hope that this causes some changes in any future programming, and if we are all really lucky, this event might spawn a South Park episode.  You have to admit, it'd be pretty perfect.  Let's just cross our fingers, shall we?

The Story of the Kremmling Ammonite Site and a Painting by Wayne Itano, Guest Blogger

Today, we have a very exciting post for you: a guest post from paleo-enthusiast Wayne Itano!  Here is a bit of background on Mr. Itano:  

Wayne Itano is a physicist at NIST (National Institute of Standards and Technology) in Boulder, CO.  He has a hobby interest in paleontology and is also a curator adjoint at the Natural History Museum of the University of Colorado.

Today, Mr. Itano is going to tell us about the Kremmling Ammonite Site.  Join me in giving him a warm welcome!  Let's get started!

The Kremmling Cretaceous Ammonite Locality lies on BLM (Bureau of Land Management) land to the north of the little town of Kremmling, in Grand County, Colorado.  It was first noticed for the very high concentration of very large ammonites(ammonites are extinct relatives of the modern chambered nautilus and were probably more closely related to octopi and squids).  It has been protected since the 1980s.  It was written up in the book “Cruisin’ the Fossil Freeway” by the paleontologist Kirk Johnson and the artist Ray Troll.

Dr. Kirk Johnson, formerly of the Denver Museum of Nature and Science, is now head of the Smithsonian Museum of Natural History.

Ray Troll is an artist with a special interest in natural history and ancient life.  Here is his painting “Night of the Ammonites” inspired by a visit to the Kremmling Ammonite Locality.

Artist Ray Troll’s picture of the Kremmling area, about 73 million years ago, during the Cretaceous Period, when most of Colorado was beneath the sea.  Picture Credit: Ray Troll

The large disk-shelled creatures are ammonites called Placenticeras.  The ones with narrow, straight, tapered shells are another kind of ammonite, called Baculites. The sharp-toothed swimming reptiles are called mosasaurs.  We have evidence from bite marks on ammonite shells that mosasaurs preyed on Placenticeras.  Over on the left are some strangely shaped small ammonites called Anaklinoceras.

The Kremmling site was featured by Earth Magazine, in a kind of online quiz called “Where on Earth.”  The page with the question and answer is HERE.

If you want to visit the Kremmling site, first pay a visit to the BLM office at 2103 E. Park Avenue, Kremmling.  They can advise you on road conditions.  At times it can be inaccessible, even for 4-wheel drive vehicles. Here is a sign at the site:

Warning sign at the Kremmling Ammonite protected area.  Photo Credit: Wayne Itano

Here is an informational sign.  Collecting is prohibited within the site, but there are nearby areas where collecting is allowed.  Inquire at the BLM office.

Explanatory sign at the Kremmling site.  Photo Credit: Wayne Itano

The area is littered with boulders containing the impressions of giant Placenticeras ammonites.  The fossils themselves have been collected, many to museums.  Intact boulders containing ammonites lie under the surface and could be studied in the future.

Boulders with impressions of Placentideras ammonites.  Photo Credit: Wayne Itano

Baculites (straight ammonites) are also rather common. 

A Placenticeras ammonite impression with a Baculites fossil (cylindrical object) on the same boulder.  Photo Credit: Wayne Itano

Large clams called Inoceramus are rather common.  Here are some examples.

A large Inoceramus clam fossil.  Photo Credit: Wayne Itano

A boulder with impressions of Inoceramus clams.  Photo Credit: Wayne Itano

Emmett Evanoff, a professor at the University of Northern Colorado in Greeley, has been studying the paleontology of this area.  One odd thing is that the great majority of the Placenticeras fossils are of females.  (The males are distinguished by being much smaller and having coarse ribs on their shells.) He thinks this might have been a nesting site.  The males would have fertilized the eggs and then left, leaving the females to guard the eggs.  Katie DeBell was a student of Emmett’s who mapped out the ammonites on the surface and seems to know them all by number.  She lives in Kremmling and often gives tours, especially to school groups.  Here she is, pointing out some features of one of the ammonites.

Katie DeBell explaining some features of an ammonite in 2011.  Photo Credit: Wayne Itano

I have a vacation house in the mountains not far from Kremmling.  I happen to know a painter who is also a fossil enthusiast, named Terry McKee.  I commissioned him to do a painting of the Kremmling site when it was an ammonite nesting ground.  I also asked Dr. Evanoff for advice, and the three of us met to plan the painting.  Here it is, and the original is now hanging in my mountain house.

Painting of the Kremmling Ammonite nesting site.  The large ammonites are guarding their eggs.  Baculites and various smaller ammonites, swim above.  The small round ammonite on the left, facing left, between two of the straight baculites, is a male Placenticeras.  A mosasaur lurks in the background.  Picture Credit: Terry McKee

- Wayne Itano

Thank you very much, Mr. Itano, for the post!  The post was really interesting, and I know I learned a lot!  I found the part about the nesting site particularly interesting!  I have no doubt that my readers, as well as myself, would love to hear from you in the future!  Thanks again! - Zack Neher

Bronze Tree on Dwellable