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!

A Look Ahead, Fun Fact 8/9/2012

First off, check out today's post about the coati, down below!

Here's this weeks "A Look Ahead:"

Friday:  Simba, Pumbaa, and Other Swahili Names From "The Lion King" - Learn what the names of some of your favorite characters mean!

Saturday:  The Light Rail Coyote - All about the coyote who hitched a ride on a train.

Sunday:  Guards of the Fairy Penguin - Guarding the world's smallest penguins with professional snipers! 

Monday:  Shrinky Dink: The Channel Island Fox and The Island Effect - How getting trapped on an island caused these foxes to shrink!

Tuesday:  Stupid People Stealing Turtles - What sounds better than stealing a bunch of turtles from a museum?

Wednesday:  The Sounds of Star Wars - Chewbacca may look like a bear, but was he voiced by one, too?

Thursday:  The Loch Ness Monster....Fact or Fiction? - Spoiler Alert:  It's Fiction
 

Friday:  Perfume-Loving Lions and Record-Breaking Cheetahs - Lions from the Denver Zoo fawn over the men's perfume "Obsession," while Sarah the cheetah become the world's fastest animal!

FUN FACT:   THE JACKALOPE IS REAL

A "jackalope."  Photo Credit:  Mona Kamath

 "Scoff," most of you are probably saying.  "This guy is pathetic."  Pathetic I may be, but the jackalope is, in fact, real; just not necessarily in the way you might think.  

Although the first picture is a fake (photo credit: Mona Kamath), the one above, as well as down below, are both real.  Clearly these are not antlers, but what are they?  Well, these "antlers" are actually tumors, caused by the Cottontail Rabbit Papilloma Virus (CRPV).  Many rabbits get by just fine with these growths.  In 2003, a man named Grant VanGilder (a cool last name if there ever was one) took this picture in Mankato, Minnesota, an hour or so outside of Annandale, Minnesota.  According the Mr. VanGilder (awesome), “He is still alive and kicking and is the talk of the neighborhood.”  However, if the tumors grow to big, they could effect the animal in its ability to feed or flee, which would eventually lead to its downfall.  The picture above is of a mounted cottontail rabbit, caught near Topeka, Kansas.

When early settlers would see these animals, they would most likely assume that they were a crossbreed between a deer and a rabbit.  Although most people understand this now, at the time, people also thought that the jackalope was so rare because it would only mate during lightning storms with hail, tasted like lobster, and can mimic the voices of drunk people.

So presumably, settlers, cowboys, and the like would discover these cottontails, dead or alive, and talk about them, show them around.  From this, it has been speculated, and seems most likely, that the jackalope arose.  It seems as if rabbits in Germany get this cancer as well, explaining the origin of Germany's "Wolpertinger."

More recently, people such as Ronald Reagan have used the jackalope as a way to mess with people.  The story goes that during press tours of his house in the '80s, he would show the reporters a mounted jackalope head, and tell them he had caught it himself, when, in actuality, it had been a gift from James Abdnor, a senator for South Dakota.

So next time one of your friends says "There's no such thing as a jackalope!" make sure to set the record straight.  Tell them everything that you have just learned, and they will think you are really smart.  Because you ARE smart.

Top Ten: Extinct Sea Monsters (Part 5 of 5)

Our final edition of "Top Ten:  Extinct Sea Monsters!

9.  Tanystropheus - Living during the Middle Triassic Period, Tanystropheus is somewhat of a misfit amongst this group, as he is not really a sea-monster, and was, at most, a semi-aquatic animal (think otters).  Purportedly piscivorous, Tanystropheus fossils are usually found in semi-aquatic sites.  Its neck has been likened to that of the Plesiosaurs, like Elasmosaurus.  They would all use their necks to surprise a group of fish, long before the fish would be able to see the body of the reptile. Remains have been discovered throughout France, Germany, and Italy, amongst other places. 

10.  Tylosaurus - Interestingly enough, the closest living relative of the extinct mosasaurs, of which Tylosaurus is a member, are the monitor lizards, like the Komodo dragon.  Both the monitor lizards and the mosasaurs have a third eye on the top of their heads, although it just looks like a little white dot on the top of the head of the monitor lizard.  It doesn't work in the same fashion as their other eyes, however.  Look towards a light (not the sun, because apparently that can actually be harmful) and close your eyes.  You can still still some light, right?  Now, move your hand back and forth in front of your face, between your eyes and the light.  Can you see how the light changes?  You can't see anything more distinct than the fact that something moved between you and that light.  That is what the third eye of monitor lizards and mosasaurs would have been like.  Tylosaurus also inhabited the Western Interior Seaway during the Late Cretaceous.  Remains, amongst other places, have been discovered in Alabama and Kansas, amongst other places.

So that concludes our "Top Ten:  Extinct Sea Monsters" edition!  Unfortunate that we had to break it up into five parts, to be sure, but hey, that's life!

This post is part of the "Top Ten: Extinct Sea Monsters" series.  For the rest of the posts in this series, click HERE.  

Top Ten: Extinct Sea Monsters (Part 4 of 5)

7.  Archelon - Archelon is the largest sea turtle that has been discovered to date, the closest living relative that Archelon has is the "Critically Endangered" leatherback sea turtle, the largest sea turtle alive today.  Living in the Late Cretaceous Western Interior Seaway between 75-65 MYA, Archelon has been discovered in the states of South Dakota, Wyoming and Kansas. 

8.  Leedsichthys - Often cited as the largest fish known to humankind, the largest Leedsichthys had an estimated length of 72 feet, but some researchers believe that it could have grown to sizes that would rival those seen in the blue whale, the largest known animal ever to live on planet Earth.   Although Leedsichthys swam the seas only during the Jurassic Period, the group that it belonged to survived until the end of the Cretaceous Period.  Remains of this filter feeder have been uncovered in England, France, Germany, and Chile.  


COMING UP NEXT WE HAVE:

9.  Tanystropheus
10. Tylosaurus

This post is part of the "Top Ten: Extinct Sea Monsters" series.  For the rest of the posts in this series, click HERE.  

Top Ten: Extinct Sea Monsters (Part 3 of 5)

 5.  Elasmosaurus - Next up on our trip across time is Elasmosaurus.  One of the largest of the Plesiosaurs ever discovered, Elasmosaurus grew up to 46 feet long, which was about half neck.  Equipped with a fairly small head, Elasmosaurus would have been incapable of going after large prey, so it would have mostly stuck with fish.  Elasmosaurus lived during the Late Cretaceous, a time when much of North America was "Beneath the Waves," under something that we call the "Western Interior Seaway."   Remains of this animal were first uncovered in Kansas, but it almost certainly swam all over the seaway, including in Colorado.

6.  Dunkleosteus - Dunkleosteus, a creature we talked about a few weeks ago in our post about the Coelacanth, is another fascinating animal.  Almost thirty-five feet in length, Dunkleosteus was a member of the Placoderms, a group of armored fish that were only around for about 50 MYA.  A long time, to be sure, but not very long compared to the 400 million year reign of the sharks.  While the Placoderms themselves lived during the Silurian and Devonian Periods, they went extinct during the transition to the Carboniferous Period, at the end of the Devonian.  Dunkleosteus fossils have been discovered in North America, Poland, Belgium, and Morocco.

 COMING UP:

7.  Archelon
8.  Leedsichthys
9.  Tanystropheus
10. Tylosaurus

This post is part of the "Top Ten: Extinct Sea Monsters" series.  For the rest of the posts in this series, click HERE.  

Convergent Evolution: Hesperornis and Penguins

Everyone who is reading this blog, and most people who aren't, have heard of penguins, and know, more or less, what they look like.  However, most people have no idea what a Hesperornis is, which is entirely forgivable.  What is especially interesting about Hesperornis is that it was really the "original penguin," in the loosest sense of the terms.

If not for the captions below each picture, these two animals would most likely be quite difficult to tell apart.  One major difference between the two birds is in the mouth: Hesperornis had teeth, a feature which no modern birds possesses.  Another major, but non-skeletal difference, between the two birds is that Hesperornis died out 78 MYA, during the Late Cretaceous.  Its remains have been found in the United States (Kansas), Canada, and Russia.

The similarities between Hesperornis and modern day penguins is called "Convergent Evolution," a fascinating topic which we will undoubtedly touch upon numerous times.  According to Science Daily, convergent evolution is, "In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches."  In English, when two animals, not necessarily closely related at all, evolve similar features that serve the same purpose.

An (excellent) drawing of the skull of Thylacosmilus

 Another example which we have already talked about is the long, saber-like canines that evolved in both the saber-toothed cats, such as Smilodon, and the South American marsupial carnivore Thylacosmilus.

 This post is part of the "Convergent Evolution" series.  For the rest of the posts in this series, click HERE.