Animal of the Day: Coelophysis

Today's Animal of the Day is Coelophysis!  The picture of the cast you see off to the left (taken by me at the Denver Gem and Mineral Show a few months back) is from the AMNH (American Museum of Natural History) in New York.  I actually know a little bit more about this particular specimen of Coelophysis than I believe was labeled there, as I remembered seeing this specimen in my Dinosaur Atlas book from DK Publishers.  One of around 500 or so individual Coelophysis specimens discovered at a place called Ghost Ranch in New Mexico, this particular specimen was once thought to reveal something interesting about the species: Coelophysis was once thought to probably be a cannibal, as the remains of a baby Coelophysis were found in the area of the stomach!

Dinosaur cannibalism is not unheard of, and almost certainly occurred in the Late Cretaceous Abelisaur Majungasaurus from Madagascar.  However, this was disproven in 2002 by Rob Gay, when he showed that the baby Coelophysis were either crushed by the smaller ones, or that they weren't even baby Coelophysis!  Instead, many of them were found to be other, small reptiles, such as the archosaur Hesperosuchus, a member of the same group as the crocodilians, dinosaurs, and pterosaurs, amongst others.  So for now, it looks like Coelophysis was probably not a cannibal, but future discoveries may force us to change our minds once again!

Another picture of Coelophysis that I took, at the DMNS

Coelophysis is one of the oldest known dinosaurs, inhabiting North America around 220 million years ago (MYA), during the Late Triassic Period.  The site at Ghost Ranch is interesting, because there are just so many different specimens all clumped together.  Some paleontologists have suggested that a flash flood drowned a huge herd of these animals, or perhaps that they died while trying to cross a river.  We might never know what, exactly, killed these dinosaurs, or why so many of them died in such close proximity.  

Some Like It Hot....Radioactive Hot

Today was quite an eventful day, for many reasons!  Went to the Zoo Lights at the Denver Zoo with some good friends of ours; learned that Ray Wise is not in X-Men Origins: Wolverine, but is actually in X-Men: First Class; and learned that the building off the highway called "Quaker Steak and Lube" is actually a restaurant, and not a car repair place.  Also, on my way to the Morrison Museum this morning, I saw what I am pretty sure was a peregrine falcon, as well as a number of red-tailed hawks and kestrels, and the great-horned owl that I have seen a few times recently perched on the "speed limit" sign on the highway!  It was pretty awesome!  Oh, and did I mention that one of my fossils might be radioactive?

One of the Zoo Lights was this tiger, but I'm pretty sure he's supposed to go around something a little thicker....

I was talking to Dr. Bob today at the museum, and we were talking about fossil hunting in Texas, chiefly the fossils that I got down there when we went to visit my gramma last Christmas, as well as the fossil dig-site that he has down there.  As we were talking, I thought back to the fossilized wood (top picture, the thing with the penny on it and everything to the right and above that piece) that I had picked up in Santa Rosa, New Mexico, on one of the first nights of our trip.  I had never been able to figure out what formation or what geologic time period it came from, so I asked Dr. Bob.  He said that there are a lot of different aged rocks from throughout the Mesozoic Era (the time of the dinosaurs), from the Triassic to the Cretaceous.  Then, as a sidenote, he mentioned that some of the fossilized wood down there tends to be radioactive, sometimes dangerously so.  Well then!  I am currently sorting this out, but I feel like I don't really have enough to worry about.  Famous last words, right?

Animal Spotlight: Gasparinisaura

Gasparinisaura is just one of those many dinosaurs that are not very famous at all, and not very well known.  In fact, I hadn't even heard of it until this morning, when my episode of Dr. Who made the computer momentarily freeze, so I picked up my Jurassic Park Institue: Dinosaur Field Guide by Dr. Thomas R. Holtz and Dr. Michael Brett-Surman that was sitting next to me on the computer table and turned to page 74.  Learn something new every day!

Gasparinisaura is considered to be a part of the basal, or primitive, ornithopods.  Ornithopods are different from other ornithischian dinosaurs in that they have a premaxilla bone that reaches further than their maxilla bone, and that their jaw joint is further down than in other dinosaurs.  Most of the basal ornithopods were around during the Jurassic Period, such as the Late Jurassic Othnielia rex, who inhabited what would become the rocks of the Morrison Formation of Colorado, Utah, and Wyoming.  Most of the rest of the basal ornithopods didn't survive past the Early Cretaceous Period, but Gasparinisaura has been found in rocks dating from around 80-90 MYA, right smack-dab in the Middle Cretaceous Period of Argentina.  According to the Jurassic Park Institute, "Remains of dinosaurs from this time span are so extremely rare, all the specimens in the world would fit in one small exhibit hall!"

Let's take a brief look at what we know about the evolution and the dispersal of the basal ornithopods, shall we?  According to my massive, 861 page book called The Dinosauria, every member of the clade Ornithopoda (which includes the iguanodonts and the duck-billed hadrosaurs, as well as the basal ornithopods) had a common ancestor that came from Asia.  This is interesting to note, because two other major clades of dinosaurs, the Marginocephalians (which includes the ceratopsians like Triceratops and the Pachycephalosaurs like Pachycephalosaurus and Stygimoloch) and the Thyreophorans (which includes stegosaurs like Stegosaurus and ankylosaurs like Ankylosaurus [yes, I know, that sounded incredibly redundant]) are hypothesized to have originally evolved in Asia, before spreading out to other parts of the world.  Whew, that would have been a mouth-full if I had had to say that out loud.

Anyways, paleontologists believe that this common ancestor would have inhabited Asia during the Early Jurassic Period, or perhaps even before that.  According to the book, prior to the Late Jurassic, a "major dispersal to North America took place."  Following this dispersal to North America, two "subsequent dispersals from North America" followed, one to Europe, and the other to South America.  (Keep in mind that, at this time in Earth's history, the continents were intermittently connected, allowing for the over-land dispersal of animals that would be entirely unable to do the same thing today.)  The European dispersal contained ornithopods of the lineage that would one day lead to the relatively famous dinosaur known as Hypsilophodon.  This dispersal is thought to have occurred before or during the Early Cretaceous.  Meanwhile, the South American dispersal "took place (at the latest) during the early Late Cretaceous," and was composed of members of the lineage that would one day lead to our home-dawg, Gasparinisaura.  Boy, am I the only one who just skimmed those last two paragraphs?

Gasparinisaura, like many of the basal-most members of the ornithopods, was just a little guy, only around two feet long, and probably weighing about as much as a chicken.  Remains of Gasparinisaura are found in the Río Colorado Formation.  With further digging (oh so witty) in The Dinosauria, I have been able to come up with other dinosaurs found in this formation. Here is a list of all of the dinosaurs mentioned in the book. 

Alvarezsaurus, a member of the group of dinosaurs known as the alvarezsaurids, a group of Maniraptoran dinosaurs thought to be fairly closely related to the ornithomimosaurs.  

Patagopteryx, a flightless bird that probably weighed around as much as a turkey.  

Neuquenornis, a small, pigeon-sized bird.  Apparently, paleontologists have not only discovered a partial skeleton of this animal, but also some eggs with embryos!  Pretty neat!  

Velocisaurus, a four or so foot long ceratosaur, not very well known.  A noasaurid, and, as you can see in the pictures below (all four of the pictures are of Velocisaurus), looks a lot like its close relative, Masiakasaurus, whose picture you can see if you click on the word "Masiakasaurus" where it is yellow. 

Aucasaurus, a thirteen or fourteen foot long abelisaur, thought to be a close relative of Carnotaurus.  Known from a skeleton that is quite complete, but not yet fully described.  

Neuquenosaurus and Titanosaurus, a pair of sauropod dinosaurs. 

Top Ten Favorite Dinosaurs by Zack Neher (Part 4)

Part four of my Top Ten Favorite Dinosaurs list.  Enjoy!

2. Struthiosaurus

Just like Masiakasaurus, Struthiosaurus also lived during the Late Cretaceous Period.  Also like Masiakasaurus, Struthiosaurus was small.  But Struthiosaurus was small in a very different way than Masiakasaurus.  Remember when we talked about island/insular dwarfism in the context of the Channel Island fox?  Well, island dwarfism is back, in all of its glory!  A brief refresher, island dwarfism is what sometimes happens to animals that have become trapped on islands.  Over many generations, they shrink in order to match the limited food supply.  If there is a limited supply of food, then the smallest of your species, not the largest, are much more likely to survive.  Another factor that often helps island dwarfs is that predation is typically not as intense on islands as compared to mainlands, but that is not always the case.  Anyways, around 75 MYA, global sea levels were much higher.  In North America, we had the Western Interior Seaway dividing the continent, while Europe was simply reduced to a number of individual islands, one of which is now known as Hațeg Island.  And, if you are any good at guessing how stories end, you can probably see where this is going.  Yes, Struthiosaurus was an island-dwarf!  He is also really cool because he is an ankylosaur, a group of dinosaurs that are incredibly interesting!  Another thing that I absolutely have to mention here pertains to the picture of Struthiosaurus that we have below.  This picture was drawn by an incredibly talented young artist named Sam Lippincott.  Only in eighth grade, he is well on his way to achieving artistic greatness!  Below are some more pictures of his, all of them absolutely fantastic!  He made these pictures for my last lecture and I have the Struthiosaurus and Magyarosaurus pictures framed on my wall, I love them so much!  Let's all give Sam a round of applause! 

Struthiosaurus, an ankylosaur, by Sam Lippincott

Telmatosaurus, a hadrosaur, by Sam Lippincott

Magyarosaurus, a sauropod, by Sam Lippincott

Hatzegopteryx, a pterosaur, by Sam Lippincott

Europasaurus, another dwarf sauropod dinosaur, but from an island other than Hațeg Island

TO BE CONCLUDED IN PART 5

Top 10 Favorite Dinosaurs by Zack Neher (Part 3)

Part three of my Top Ten Favorite Dinosaurs list.  Enjoy!

3. Masiakasaurus

A fairly small dinosaur at only around six feet, Masakisaurus knopfleri, as discussed IN A PREVIOUS POST, was named for the famous musician Mark Knopfler.  The animal, found in Madagascar, was named in 2001 by Matthew Carrano, Catherine A. Forster, and Scott Sampson, the author of Dinosaur Odyssey and the dude from Dinosaur Train.  Living on what was still an island, the little dinosaur lived about 70 MYA during the  Late Cretaceous Period, and was a contemoporary of the abelisaur Majungasaurus, the bird-like Rahonavis, and the sauropod Rapetosaurus.  Although Masiakasaurus sounds pretty unremarkable thus far, a quick glance at the picture below (which many of you have no doubt already done) says otherwise: Masiakasaurus definitely had some funky teeth!  These teeth are clearly not suited tearing into food like the teeth of Allosaurus or Velociraptor would be, and many paleontologists (including myself, even though I am not really a paleontologist.  I guess it would be better to say "many paleontologists, paleontologists-in-training, and myself."  There, much better.) believe that these weird, pointy teeth are an evolutionary adaptation to a piscivorous (fish-based) diet.  A look at various marine reptiles such as the plesiosaurs (like Elasmosaurus) and Liopleurodon show a similar pattern of interlocking teeth that point outside of the mouth.  Excellent when it comes to catching fish, and not so excellent when it comes to most, if not all, other diets, be they meat- or plant-based.  

TO BE CONTINUED IN PART 4

Top 10 Favorite Dinosaurs by Zack Neher (Part 1)

Just a few days ago, we had our first ever guest blog post by David Church.  Mr. Church did his top ten favorite dinosaurs, which got me thinking about what my favorite dinosaurs were, and inspired me to do this post!  So here is my top ten favorite dinosaur list!

10. Argentinosaurus

Inhabiting South America during the Late Cretaceous Period, the enormous sauropod Argentinosaurus is the heaviest known terrestrial animal and, according to BBC, also has the record for being the longest land animal.  It was, of course, discovered in Argentina, and would have been a contemporary of Giganotosaurus.  

A picture of Argentinosaurus (background) under assault from a Giganotosaurus (foreground) with my parents off to the left at the Fernbank Museum in Atlanta, Georgia, United States

Another shot of the Argentinosaurus at Fernbank

9. Allosaurus

Allosaurus was a thirty or so foot long carnivorous dinosaur from the Late Jurassic Period.  Discovered in the Morrison Formation of Colorado, Montana, New Mexico, Oklahoma, South Dakota, Utah, and Wyoming, this dinosaur (or one quite like it) was also likely found in the Tendaguru Beds of Tanzania.  The Cleveland-Lloyd Dinosaur Quarry near Price, Utah holds the remains of more than forty individual Allosaurus bones.

Assorted Allosaurus bones from our visit to the Cleveland-Lloyd Dinosaur Quarry

8. Spinosaurus

Spinosaurus is an enormous carnivorous dinosaur that we have talked about on multiple occasions, both in our "Biggest Carnivorous Dinosaur" trilogy of posts awhile back, but also in Mr. Church's Top Ten list.  Spinosaurus, despite the fact that it is easily the largest known carnivorous dinosaur, with an estimated length of almost sixty feet, did not eat meat like the other enormous dinosaurs: instead, Spinosaurus was a piscivore, or a fish eater.  This giant creature lived in Africa during the Cretaceous Period.

 7. Parasaurolophus

Parasaurolophus is another one of those dinosaurs that overlaps from Mr. Church's list to my own.  Parasaurolophus is certainly an interesting creature!  A member of the hadrosaurs, or duck-billed dinosaurs, Parasaurolophus, as Mr. Church discussed, is the only dinosaur I know of where paleontologists know with a high degree of accuracy what they sounded like.  The large crest on the back of the head of Parasaurolophus is full of hollow tubing, similar in shape and structure to the trombone, as well as similar in sound, too.  Unfortunately, I could not find a sound file or video of the call, so if anyone has access to a scientifically reconstructed call, let me know!

TO BE CONTINUED IN PART 2

Cal Orck'o: Not A Place for the Acrophobic

In 1994, Klaus Schütt discovered an enormous slab of dinosaur tracks.  You're probably thinking enormous like Jabba the Hutt enormous or my cat enormous.  (She's a big kitty).  But no, I mean ENORMOUS enormous.  And by ENORMOUS enormous, I mean a mile wide and 500 feet tall.  Yeah, that big.  Another thing about Cal Orck'o: its on a 70 degree incline.

Real fast, let me include a brief disclaimer: I have looked at probably 25 different books and websites that mention this place, and half of them spell it "Cal Orco," and the other half spell it "Cal Orko," while a few even spell it "Cal Orcko."  The UNESCO website calls it "Cal Orck'o," so that's the one that I went with on the blog.  So yeah, I really don't know which way is which, but nevertheless, this place is quite an interesting fossil site!

It wasn't until 1998 that Christian Meyer, a Swiss paleontologist, lead a team of scientists to investigate the site, which is near a concrete factory in Sucre, Bolivia.  They found that the enormous trackway is from the Late Cretaceous Period, dated at around 68 million years ago (MYA).  They learned that, at the time that the rocks and footprints were formed, the area was a lakeside where animals from all over would come to drink.  They also determined that Cal Orck'o was the "largest site of dinosaur tracks found so far," possessing the largest number of dinosaur footprints of anywhere in the world.

Cal Orck'o has over 5,000 dinosaur tracks made by at least six identified dinosaurs in around 250 trackways, some of which extend for hundreds of feet in a single direction.

Due to the extremely steep face of the fossil site, erosion is a constant threat to the dinosaur footprints.  The Bolivian government combats this by spending a whopping $30 million every year.  Despite this, a large chunk broke off in February of 2010, destroying around 300 footprints.   

Information on Cal Orck'o is extremely spotty, and the website for the site doesn't seem to have an "English" option.  My Spanish skills are pretty rudimentary at best, but I think I was able to come up with a list of the dinosaurs whose tracks are preserved at Cal Orck'o.  Now, keep in mind, very rarely do you definitively know what animal made a fossilized footprint, and most of the time these are simply good guesses.  For the picture below, I used ones taken from the garden area thing at the Cal Orck'o museum.  So if you are going to blame someone for inaccurate data, make sure you blame them and not me!

An abelisaur, a type of carnivorous dinosaur like Abelisaurus or Carnotaurus.

An iguanodont, a type of herbivorous dinosaur like Iguanodon.

A ceratopsian, a type of dinosaur like Triceratops or Protoceratops.

An ankylosaur, a type of dinosaur like Ankylosaurus.

A titanosaur, a type of sauropod dinosaur like Saltasaurus.

A dromaeosaur, a type of carnivorous dinosaur like Velociraptor.

A ceratosaur, a type of carnivorous dinosaur like Ceratosaurus.

A hadrosaur, a type of herbivorous dinosaur like Parasaurolophus.

A tyrannosaur, a type of carnivorous dinosaur like Tyrannosaurus.

Again, keep in mind that I have next to no idea which of these, if any, were found at Cal Orck'o.  I plan on doing a little bit of digging within the next few weeks, so hopefully I will be able to get back to you sometime soon!

Cochabamba 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!

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.  

What REALLY Killed the Dinosaurs?

Today, almost all paleontologists believe in one of two scenarios that brought upon the downfall of the dinosaurs; the Silver Bullet Hypothesis, and the Blitzkrieg Hypothesis.  Proponents of the Silver Bullet Hypothesis consider the asteroid that hit Mexico 65.5 MYA to be the cause of the dinosaurs extinction, while fans of the Blitzkrieg Hypothesis believe that the asteroid worked in concert with other factors, like a number of extraordinarily large volcanic impacts and receding sea levels.  Although both of these hypotheses hold great weight, and stand up well to investigation, I find myself more in the Silver Bullet camp.  (If you are unsure, check out this video: http://www.youtube.com/watch?v=5gqq2rgOmi8 .  It's a bit long, but you can skip parts of it and still get the gist.  I was simply blown away after watching it, and landed smack-dab in the center of the Silver Bullet camp.)

However, this post is not to talk about the merits of the generally accepted dinosaur-death hypotheses; just like the post regarding the oddly named animals (http://thenaturalworld1.blogspot.com/2012/07/masiakasaurus-knopfleri-and-other.html), Scott Sampson's book Dinosaur Odyssey had another especially interesting tale, a tale about the many different hypotheses (over one hundred in all!) about how the dinosaurs died from over the years.  Here are some of the more interesting ones, quoted from Scott Sampson's book:

1.   Disease
2.   Slipped Vertebral Discs:  Because dinosaurs were so big
3.   Loss of Interest in Sex
4.   Poisonous Plants 1:  The consumption of these plants led to a deadly diarrhea amongst the dinosaurs
5.   Poisonous Plants 2:  The consumption of these plants led to a deadly constipation amongst the dinosaurs
6.   Fungal Invasions
7.   Climatic Change 1:  Global Warming
8.   Climatic Change 2:  Global Cooling
9.   Cosmic Radiation From a Supernova
10.  Egg-Eating Mammals
11.  Sunspots
12.  Nasty Aliens
13.  Not Enough Room on Noah's Ark
14.  The Racial Senility Hypothesis:  Dinosaurs, as a group, were young and restless when they first appeared in the Late Triassic Period.  During the Early Jurassic, the dinosaurs experienced "adolescence," as they expanded "in both form and diversity."  When they reached the Late Jurassic and Early Cretaceous, the dinosaurs had "reached their evolutionary peak;" they were middle-aged, and had nowhere to go but down.  Thus, in the Late Cretaceous Period, when the dinosaurs like Triceratops, Parasaurolophus, and Pachycephalosaurus grew interesting crests, frills and the like, these were "the result of hormones gone wild and certainly symbolic of a group on its way out."

Obviously, some of these solutions are more interesting than others, but all of them are, at this point in the study of dinosaurs, outdated.  But who knows: perhaps, someday soon, someone will discover proof that it was aliens, and not an asteroid, that ultimately did-in the dinos.

The Biggest Carnivorous Dinosaur Part 2: Carcharodontosaurus Vs. Spinosaurus

As I promised yesterday, today we are going to take a closer look at Carcharodontosaurus (kar-kar-o-DON-to-SAUR-us).  Carcharodontosaurus was a relative of Colorado's own Allosaurus.  However, Carcharodontosaurus was four times larger, and found in Egypt, Morocco, Algeria, Libya, and Niger.  At around 46 feet long, Carcharodontosaurus was similar in size to yesterday's Giganotosaurus (pronounced jig-a-NOTE-o-saur-us), and longer than Tyrannosaurus, though Tyrannosaurus was undoubtedly much bulkier.  Regardless, Carcharodontosaurus was a monster-sized killer, and almost certainly had a monster-sized appetite to match.  It is almost a certainty that such an animal would have a fairly large territory, and would have needed to eat a great deal to maintain its fast metabolism, similar to your average teenage dude.

Clearly, such a large predator had little competition from other carnivorous dinosaurs.  Or did it?  As a matter of fact, 95 MYA, North Africa was home to not one, but two monster-sized killers, Carcharodontosaurus, and the even longer, 50 foot (15 meter) Spinosaurus.  (Some not so conservative estimates even place the maximum size for Spinosaurus as 60 feet (18 meters) in length, but this does seem extreme.)

Now, in the modern day, predators can inhabit the same area.  Take the plains of Africa, for example; in many places, lions, leopards, cheetahs, wild dogs and hyenas all inhabit the same area.  There is a clear hierarchy amongst the animals, and each seems to get enough to eat.  However, this is partly because each animal exploits a slightly different set of resources, so contact amongst them is less frequent than if all five of the large carnivores all hunted the same animal, say, the Thomson's Gazelle.  This is a phenomenon known as resource partitioning, and it occurs all over the place in nature, arguably one of the most important factors involving ecology and evolution. Scientists believe that a similar sort of partitioning took place between the two mega-carnivores of Mid-Cretaceous North Africa, with Carcharodontosaurus being a terrestrial carnivore, while Spinosaurus took to the water.  We will conclude "The Biggest Carnivorous Dinosaur" trilogy tomorrow with a look at the environment Spinosaurus was able to so successfully exploit.

A fantastic visual representation of resource partitioning amongst large herbivorous mammals in Africa.  The giraffe, the zebra, and the wildebeest will all inhabit the same area and eat plants, but the types of plants can differ.  Photo Credit: Ted and Gail Neher

The Biggest Carnivorous Dinosaur Part 1: Move Over, T-Rex (Kind Of)

Tyrannosaurus rex, the "Tyrant Lizard King," has long been a dinosaurian favorite the world over.  He is quite the interesting animal, and simply massive; the publicity received by him and the giant-sized Velociraptor in Jurassic Park helped a bit, I'm sure!  However, T-rex is no longer thought to be the largest carnivorous dinosaur.  Well, yes he is.  But he isn't.

A picture of the Tyrannosaurus rex specimen Stan at the Morrison Natural History Museum.

Imagine someone who has never heard of the giraffe and elephant asks you which one is biggest.  You might say the elephant, because the elephant is much heavier and has more bulk.  But what if they mean which animal is taller?  Somewhat of a dilemma.  So using words like "biggest" (as I have done here) is not the best way to go.  So Tyrannosaurus still seems to be the heavyweight champion, there are other dinosaurs that, while more slender, were probably longer.  Kind of confusing, I know.

The fact that T-rex has some serious competition has put barely a dent into his popularity, and some of the other larger carnivores are receiving a lot of attention, too. The longest of these carnivores, which we will learn about on Wednesday, was possibly around 20% larger than Tyrannosaurus Rex!  Today, we are going to look at another enormous killer, of South American origin; the massive, the monstrous, Giganotosaurus.

A Giganotosaurus on display at Fernbank Museum, in Atlanta, Georgia

Giganotosaurus is an estimated 46 feet long, comparable in length to the average Tyrannosaurus!  We do have some specimens of Tyrannosaurus that are around the same size as Giganotosaurus, but either way: Giganotosaurus was a massive animal! Of course we don't actually know for sure what the maximum size for any dinosaur is as, unlike for most living animals, we generally have a relatively small sample set, but we can make close estimates based on the finds we have.  And these estimates indicate that Giganotosaurus grew to simply massive proportions.  One of the largest terrestrial animals that we know of is Argentinosaurus (who, like Giganotosaurus, was also found in Argentina), a sauropod dinosaur that lived at the same time as Giganotosaurus.  For Giganotosaurus to prey on even the juveniles of such a large herbivore, it would similarly need to grow to massive proportions.

Giganotosaurus vs. Argentinosaurus at Fernbank Museum, in Atlanta, Georgia

Giganotosaurus vs. Argentinosaurus at Fernbank Museum, in Atlanta, Georgia

This pattern repeats itself all over the world, the pattern of gigantism evolving in sauropods, along with the subsequent evolution of gigantism in the theropods (meat-eating dinosaurs), is a pattern repeated throughout the world, and throughout the Jurassic and Cretaceous Periods of the Mesozoic Era, the two periods in time when the rule of the dinosaurs was absolute.  Here are some more of the predator-prey, giant-sized carnivore/giant-sized herbivore relationships seen throughout the Mesozoic.  The first animal named will be the predator, and the second will be the sauropod.

Asia, 160 MYA: Sinraptor, Mamenchisaurus
Europe, 125 MYA: Neovenator, Ornithopsis
North America, 150 MYA: Allosaurus, Diplodocus
North Africa, 95 MYA: Carcharodontosaurus, Paralititan

In tomorrows post, we will look at the last relationship, and focus on another larger (or longer) than life carnivore, Carcharodontosaurus.