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!-

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?

Xiphactinus: The Inception Fossil

If you were to travel back 100 million years from where I live in Colorado, the face of a very, very different planet would emerge.  I suppose emerge isn't necessarily the best word in this context: submerged is more of an adequate description!  You see, unlike the mountains you would see in Colorado today, Late Cretaceous Colorado was even flatter than present-day Kansas....and a whole lot closer to sea level!  Between about 100 and 70 million years ago (MYA), an enormous seaway stretched northwards from the Gulf of Mexico, and southwards from the Arctic.  Within these waters, hundreds, perhaps thousands of animals flourished, many of which we have nothing like today.  Massive sea turtles like Archelon slowly swam through the waters, while the long-necked plesiosaurs cruised around, snapping up fish before they even knew they were there.  While sharks and mosasaurs were probably the most impressive denizens of the seaway, these massive carnivores fed on fish as well.  And the subject of today's post is one of those fish: a 17-foot long beastie called Xiphactinus.

Due to the numerous pictures uploaded to Pinterest by the Best Western Denver Southwest hotel (read more about it HERE), I'm going to be using a lot of pictures from this site!  Make sure you check it out by clicking HERE!  Unless otherwise noted, photo credit for all of the pictures in this post goes to that Pinterest page!

Why did I call Xiphactinus (pronounced zye-FACT-un-us) "The Inception Fossil?"  Well, that's a description that I came up with (don't ever let anyone tell you otherwise!) that has to do with one of the most interesting things about Xiphactinus: numerous specimens of the fish have been found with the remains of other fish in its stomach!  Just as the premise behind Inception is "a dream within a dream," so too are specimens of Xiphactinus sometimes "fish within a fish!"  The specimen below is a thirteen foot Xiphactinus that died with a fish known as Gillicus arcuatus in its stomach!

Unlike sharks, Xiphactinus would have been unable to bite off chunks of flesh from its prey, and instead would have had to swallow its prey whole, which is what makes the Inception Fossils so spectacular!  Some paleontologists propose that this lack of chewing may have been what killed some of these Xiphactinus specimens, and that they actually choked to death on their last meal!  I suppose it's possible, but I don't actually know enough about these specimens to be a very good authority on them!

The next three pictures below are pictures that I took of a specimen that I saw a week or so ago.  Long story short, my friends Isabel and Sam Lippincott and I had gone to a presentation given by paleontologist Dr. Ian Miller about the Snowmastodon Project a few months back, and he was impressed with Sam's paleo drawings when we showed him after the lecture.  He invited us to come on down to the Denver Museum of Nature and Science so that he could show us around behind the scenes, which he very kindly did a few weeks ago!  These are pictures I took of the 80 MY old Mancos Shale specimen of Xiphactinus, which was discovered in 1966 by some kids who had been hunting with their dad near Snowmass in Colorado.  They had stumbled across the rib cage of the animal, and had notified the Denver Museum.  The next summer, the museum excavated the remarkably complete, 13-foot specimen, taking it back to the museum, where it has been stored to this day!

Here are some more cool pictures from the Pinterest page!  This is a diorama of paleontologist Charles Sternberg caught in the act of discovering one of his "Inception fossils!"

And here are another pair of reconstructions of Xiphactinus!

Make sure to check out the Pinterest page of the Best Western Denver Southwest by clicking HERE!

Aquarium Spotlight: Georgia Aquarium

In 2006, my family and I visited what would soon become my most favorite aquarium I have ever been to: the Georgia Aquarium!  It was fantastic, and they had a ton of really cool animals that I had never seen before!  So join us for this Aquarium Spotlight on the Georgia Aquarium, with a bunch of pictures that my mother took while we were there!  Let's start off with the penguins.  The Georgia Aquarium has a colony of adorable African penguins there, sure to be a favorite on your trip!

Another animal that is sure to be a favorite is the whale shark.  The largest shark and, for that matter, largest fish, still alive today, the whale shark behaves more like a whale than a shark, being a filter-feeder, consuming copious quantities of krill.  (Like that alliteration back there?)

Now, the photo below I originally thought was a whale shark, but it looks like its tail might move up and down like that of a whale, dolphin, or porpoise as opposed to side-to-side like that of a whale shark, so I'm not really sure what the heck that is!

The four whale sharks are all in an enormous tank with a ton of other animals, such as large schools of fish, stingrays, and guitarfish, amongst others.  Something that seems to be pretty standard in aquariums these days is the circular walkway thing (pictured below), but, in my opinion, that never gets old!

 

 A stingray

A guitarfish (left) and a stingray (right)

Another fast-favorite will undoubtedly be the beluga, one of my favorite animals of all time!

 

Another smaller and more unassuming creature that is just as interesting as the African penguin, whale shark, or beluga is the leafy sea dragon, THE SUBJECT OF A PREVIOUS ANIMAL SPOTLIGHT. 

 

Another really cool animal was the giant Japanese spider crab!  Inhabiting the seafloor of the Pacific Ocean near Japan between 150 and 1000 feet below the surface of the ocean, the giant Japanese spider crab has evolved to be able to cope with the extreme cold and lack of light experienced so far down in the ocean.

A sea turtle swimming around.

 

 

Greatly interactive, the Georgia Aquarium also has a number of touch tanks for a hands-on experience!

 

Finally, some jellyfish!

Jasper on Dwellable

The Denver Gem and Mineral Show Part 2: The Piscivores (Excepting Penguins)

As we started talking about a few weeks ago, my friend Masaki Kleinkopf and I were able to visit the Denver Gem and Mineral Show at the Denver Merchandise Mart.  Last time, we talked about the giant ammonites, the baby eryops that Dr. Robert Bakker was working on, the gliding Indonesian lizards of the genus Draco and the pterosaurs that evolved from creatures purportedly much like this millions of years ago.  Today, we are going to talk about all of the piscivorous animals that we saw there, except for the fossil penguin that I saw there.  Knowing me, that would easily take up one whole post of its own there.  Keep in mind throughout this post that I'm not certain for all of these animals that they actually eat fish, I just know that the large groups that they belong to often eat fish.  Today, we are going to be looking at the mosasaurs, crocodilians, pterosaurs, sea lions, other fish, sharks, and the dreaded piscivorous dinosaur Spinosaurus.  

MESSAGE FROM ZACK FROM THE FUTURE:  Hello, everyone.  This is Zack Neher.  I have travelled to this post from the future.  I wanted to give you a link to the Homebase for these posts.  I am like Rose Tyler, leaving clues in the form of Bad Wolf.  Except this is not quite like that at all really.  Anyways.  The Homebase for the series is HERE.

Myself next to a gigantic mosasaur skull

I am pretty sure that this is the skull of a mosasaur , anyway.....it looks more like a mosasaur skull than the skull of a crocodilian, if you ask me

A mosasaur jaw, from Morocco by the looks of it

A mosasaur skull (Platecarpus, if memory serves, but it is entirely possible that I am wildly off) in front of a fossil ray

Another huge mosasaur skull

We also got to see the teeth of a piscivorous pterosaur.  The teeth of a piscivore are usually different from those of other carnivorous animals due to their conical shape.  The teeth of the fish eaters, like those of crocodilians and dolphins, are usually conical in shape, to prevent prey from struggling out of their grasp.

The teeth of a piscivorous pterosaurs

Below are the skulls of various crocodilians.

 

 

The skulls of these dudes seem like they should be out of a cartoon or something, they are so weird and comic looking!

Here are a pair of photos of fossilized sea lion teeth, both from the extinct sea lion Imagotaria sp., from the Miocene to Pliocene in the Atacama region of Chile.

Imagotaria sp., from the Miocene to Pliocene in the Atacama region of Chile

Imagotaria sp., from the Miocene to Pliocene in the Atacama region of Chile

Next, a picture of a pair of fossil jellyfish!

Fossil jellyfish!

Next are the teeth of the gigantic, fifty to sixty foot long carnivorous (or actually, piscivorous) dinosaur: Spinosaurus.  Also in the picture are the teeth of another enormous carnivorous dinosaur that lived in the same area of Northern Africa as Spinosaurus at this time of the Cretaceous Period: Carcharodontosaurus, who was not a piscivore, at least not primarily a piscivore, like a penguin, or as Spinosaurus is purported to
be.  (Did you see that alliteration?  My language arts teacher would be most impressed).  I discuss both Spinosaurus and Carcharodontosaurus in two previous posts, which you can look at HERE FOR SPINOSAURUS and HERE FOR SPINOSAURUS AND CARCHARODONTOSAURUS.

The teeth of Spinosaurus.  Actually in this shot, it looks as if most or all of these teeth belong to Spinosaurus.

And now for some pictures of the teeth of Megalodon, the largest shark that is ever known to have lived!  I have talked about Megalodon in the past, click HERE to learn more.

 

Now for some random ones.

It's a fish eat fish world out there

A pair of shark jaws.  I am not certain as I don't remember at all and they are unlabeled, but I believe them to be jaws of sand tiger sharks.  Again, I could be totally off on this!