Forgotten Dinosaurs of the Lost Continent Part 2

Hey there every peoples!

Last time I gave a little background info on what I call the “Forgotten Dinosaurs of the ‘Lost Continent’”. This time we’ll look at the dinosaurs themselves.

But first I don’t feel like I was clear enough in my reasoning in the last post. Why have I bestowed these animals with the title of “forgotten”? Well even though the West Coast is a crappy place for dinosaur hunters, a few fossils beyond fragments have been found. I call them the “forgotten dinosaurs” because in discussions of Laramidia and dinosaur provincialism, they are almost never mentioned. So now I present you with the few, the proud: the dinosaurs of western Laramidia!

Aletopelta

Not too much to say here since I have already done a post about it. Nonetheless Aletopelta is unique in that it is the only genus endemic to western Laramidia (at least so far). All the other dinosaurs are known from elsewhere, whereas Aletopelta is a beast all its own.

Lambeosaurus laticaudus

Like most other dinosaurs in this discussion, Lambeosaurus laticaudus is known from the El Gallo formation of Baja California. Also, this dinosaur is a member of a genus known from elsewhere. But this dinosaur really stands out from its kin to the northeast. For one, it’s huge, possibly the largest hadrosaur known; it has been estimated at 50 feet long and over 20 tons in weight. It also had a narrow tail, which the original describers interpreted as an adaptation to swimming. The disassociated remains of several individuals have been found, including juveniles, which suggests Baja may have been a breeding ground. A couple hadrosaur specimens have been found in San Diego County, but they are too fragmented to be assignable to any genus.

A fleshed out model of Lambeosaurus at the San Diego Natural History Museum

While most of the Baja fossils have been referred to Lambeosaurus (indeed its own species of Lambeosaurus), there has been some doubt as to its exact identity. Some have suggested it might be a species of Hypacrosaurus. More recently, some think it may belong to Velafrons, a new hadrosaur known from eastern Mexico. However, without a crest, it may be difficult to determine just who Lambeosaurus laticaudus really was.

Saurolophus

It is well known that Saurolophus has been found from Canada and Asia. What people don’t know is that it has been found on the west coast as well. Way back yonder Chester Stock, one of the giants of California paleontology, discovered two skeletons of Saurolophus in the Panoche Hills of Fresno County. One, while fairly complete, was poorly preserved. The other was nearly complete and in good condition. While both lack the diagnostic crest and can’t be assigned to a specific species, they are the most complete dinosaurs found in either Alta or Baja California (or west of the Rockies for that matter)! The LA Museum plans to have a display about California dinosaurs in their new dinosaur hall. Looking at concept renderings it looks like one of these Saurolophus skeletons will make an appearance as well as what looks like a silhouette of Lambeosaurus laticaudus.

skeleton of Saurolophus, the most complete dinosaur on the West Coast

Albertosaurus

A smaller earlier relative of Tyrannosaurus, Albertosaurus is known definitively from Alberta and Montana. It may also be known from Alaska, Texas, and Baja California. Some teeth thought to belong to albertosaurus have been found in the El Gallo formation. Whether it truly is Albertosaurus or something else all together is unknown. Unlike mammals, dinosaur teeth are not very diagnostic beyond the family level. So while Albertosaurus may have lived in California, we cannot say for sure.

Cast teeth of Albertosaurus from Baja California at the San Diego Natural History Museum

Sauronitholestes

Again inferred from a couple of teeth in the Ell Gallo formation. Sauronitholestes was a dromeosaur about six feet long.

Troodon

Inferred from a tooth and a toe bone from the El Gallo formation, Troodon is famous for its relatively large brain.

Cast toe bone of Troodon at the San Diego Natural History Museum

Other dinosaurs

An ornithomimid is known from the El Gallo as well as well as several indeterminate theropod teeth. Fragments of hadrosaurs are known from many places in California such as Orange and Tehama Counties. So far no ceratopsians are known from either Alta or Baja California. This is very interesting since ceratopsians show a high degree of provincialism in eastern Laramidia Perhaps the environment in western Laramidia wasn’t suitable for ceratopsians. Or maybe we just haven’t found them yet.

I mentioned in my last post that the dinosaurs found in Alta and Baja California might throw a monkey wrench into the idea of dinosaur provincialism. Why? Well the idea stipulates that various dinosaur species are unique to their respective regions. Indeed this seems to hold true for the east of Laramidia. Pentaceratops is known only from New Mexico, Kosmoceratops is only known from Utah, and Chasmosaurus is only known from Alberta. The same goes for many other dinosaurs. But the dinosaurs of western Laramidia all seem to be dinosaurs found in Canada. According to dinosaur provincialism, they ought to be their own assemblage, because dinosaurs of the south haven’t been found in the north. See the problem? However, they may not be alone in this problem. Gryposaurus is known from Alberta but also from Utah. But maybe this isn’t such a problem since they are different species. But this still doesn’t wholly explain the dinosaurs of western Laramidia. How did genera found in the northeast somehow end up in the southwest when most other dinosaurs in the south consist of their own genera? Were they somehow able to circumvent the mountains from the north and settle into the west? Unfortunately, most of these apparently lost dinosaurs (save for Saurolophus) are represented by scrappy material. As noted Albertosaurus is inferred from just teeth! Those teeth could have belonged to an unknown theropod for all we know. While California has yielded few informative specimens, Baja California remains our best bet for finding the dinosaurs of Western Laramidia.

Who knows what we may find in the El Gallo formation. It certainly shows promise. But what I have been able to read has not been encouraging. Apparently the terrain is very uneven and the climate harsh, making it difficult to look for fossils and even harder to extract them. Also, apparently Mexico doesn’t like outsiders snooping around. According to a book on California dinosaurs, the LA Museum was pressured to cough up many of its specimens from the El Gallo and return them to Mexico. Whether this holds true for today is unknown to me but if it does it must only be for dinosaur fossils since the LA museum still has tons of Pleistocene fossils from Mexico, which they continue to find. I’d love to try and search for the dinosaurs that called Baja California (and from extrapolation maybe Alta California as well) but right now it doesn’t look like it’s in the cards. Certainly more fossils would help solve the many questions we have about dinosaur provincialism. However, the threat of stirring political ire is a little too daunting for me.

Till next time!

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Forgotten Dinosaurs of the “Lost Continent” Part 1

Hey there every peoples!

The Great Dinosaur Rush of the late 19th and early 20th century left few Mesozoic rocks unturned. Every now and then a new formation would be explored and new dinosaurs would be published. And just when it appeared that we had found all there was to be found, newly explored exposures in Utah began to capture the imagination with an explosion of new species. One of these exposures, the Kaiparowits formation, has gotten loads of media attention not just for its new species but also for its place in the big picture of dinosaur evolution.

The Kaiparowits formation is about 75 to 72 million years old, which means it was from the time when North America was actually two continents cut in half by a shallow sea (which is why marine fossils are discovered in places like Kansas, Nebraska, and Alberta). The two continents have been dubbed Appalachia for the eastern half and Laramidia for the western half. Not much is known about Appalachia due to a poor fossil record. However Laramidia is much better known thanks to such well known deposits as the Dinosaur Park formation in Alberta and the Two Medicine and Judith River formations in Montana. For a long time this was all we knew of Laramidia, and since both regions harbored very similar dinosaur faunas, it was assumed that this must have been the fauna for the whole of the continent (especially since the same dinosaurs were being found in Alaska). But the last 10 or so years has seen this trend turned on its head.

A map of ancient North America, with Laramidia to the west (image from Wikipedia)

As scientists started probing deposits further south, like the Kaiparowits in Utah, the Kirtland formation in New Mexico, and the Aguja formation in Texas, a different picture emerged. While the north had a fairly uniform dinosaur fauna, different regions of the south had each had their own unique collection of species, with a few of the same species from the north. For example, in the north the tyrannosaurs were comprised of Albertosaurus and Daspletosaurus. But New Mexico had its own tyrannosaur, Bistahieverser, and Utah harbored an as yet unnamed species of tyrannosaur. This phenomenon has been dubbed “Dinosaur Provincialism” and has seen more and more support as more fossils are described. But this has all been going on in the east of Laramidia? What about the western half of the “Lost Continent”? Why have the dinosaurs of the west received so little attention in the discussion of Laramidia and dinosaur provincialism?

The simple answer is: the west coast is a horrible place for dinosaurs. It’s a horrible pace for dinosaurs for the same reason as the Midwest. Like the Midwest, a lot of the west coast was covered by shallow sea, an environment dinosaurs did not inhabit. What is more, this shallow sea lapped at the base of a mountain range. While dinosaurs surely lived in said mountains, mountains are very bad environments for the preservation of fossils. As bones are washed down in mountain streams they get tossed around and destroyed so that by the time they reach a flood plain or the ocean there is almost nothing left to be preserved. But low and behold dinosaur fossils have been found on the west coast! They may be few and fragmentary but they are nonetheless dinosaur fossils! And they almost appear to throw a monkey wrench in the idea of dinosaur provincialism. Stay tuned for part 2 of “Forgotten Dinosaurs of the Lost Continent” where we’ll look at the beasts themselves!

Till next time!

Just a Thought

Hey there every peoples!

Just wanted to chime in on some random thought i have had as i sit here looking up random stuff. As you may or may not know, in the last 20 years there has been an explosion in specimens of Tyrannosaurus rex. One of the most famous of these specimens is Jane. Jane was discovered by the Burpee Museum in the Hellcreek formation of Montana. She helped launch the Burpee Museum to stardom and launch their now blossoming paleontology program ( that such a small museum could have such success has been a big inspiration for me). Jane is important because she is a juvenile. Standing 7.5 feet at the hips, stretching 20 feet long, and weighing 1500 pounds, she would have been quite the bully at the playground. Estimated to be 11 years old, she is an important part in our understanding of T. rex growth.

Cast of Jane's skeleton at the Cleveland Museum of Natural History, Ohio (photo from flickr user statePaige)

But wait a minute. We have all heard this stuff time and time again. You’re probably wondering why I’m babbling about her. Well the answer has to do with another T. rex. His name is Thomas. Like Jane he was discovered in the badlands of Montana but by the Natural History Museum of  Los Angeles County. Thomas is a juvenile like Jane but estimated to be 13 years old. Thomas is set to appear as part of a T. rex growth series in the LA Museum’s new Dinosaur Mysteries hall which opens next year. He was quite hefty for a teenager standing 10 feet at the hips, 30 feet from nose to tail, and weighing in at 8,000 pounds.

Reconstruction of Thomas' skeleton with body outline

That’s all well and good, but what do these two have to do with each other and why are they getting a post? Here’s a hint: look at their sizes. It strikes me as odd that these two members of the same species who are only a couple years have such a huge gap in their size. Now I have often read that T. rex went through a freakish growth spurt when growing up: almost 5 pounds a day! Now if Jane was growing at that rate, she would have weighed 5,150 pounds when she reached Thomas’ age. That’s more than half of Thomas’ weight but almost 1 and a half tons short. Now I’m no expert (in dinosaurs or math) but that sounds like such an incredible disparity in size. Was Thomas eating something that helped him put on weight faster? Was Jane simply a runt? Was T. rex like some modern raptors where the female is larger than the male, making Thomas “Tanya” and Jane “Joe”? Or most provocatively, was one a different species than the other? Only time, more fossils, and more research will tell. Just thought I’d share that with all of you.

Till next time!

Better Know a Museum: Los Angeles Part 3

Hey there every peoples!

Time for part three of my of the first part of my new series Better Know a Musem! This week we look at what might be the most popular exhibit at the museum: The dinosaur hall! Except there is really no hall to speak off. It was closed a couple years ago so that it may be reborn in a new part of the museum.

None too soon I would say. The old dinosaur hall wasn’t that much better than the old Cenozoic hall. There were a few mounts that were in life like poses, but most of them were just sitting there. The halls were mostly dark and not much information was to be found. There were few fossils on display in cases. Really the only thing the hall had going for it was the various skeletons on display, from the small Dimetrodon to the gargantuan Mamenchisaurus. However Mamenchisaurus, the centerpiece of the the old hall, had problems: it had the wrong skull. It’s skull looked much more like that of a diplodocid rather than a euhelopid. While the biggest dipslay of dinosaurs on the west coast, it was in dire need of an overhaul.

So in 2008 the dinosaur hall was closed for good. For the museum’s centenial a new dinosaur hall, consisting of two halls (where the Latin America and Native american halls used to be), was to be built. This new hall would be brightly lit with natural light like the Age of Mammals hall. The hall would look like a museum for the 21st century. It will be called Dinosaur Mysteries and will open summer next year. Such specimens to be included in the hall are the plesiosaur Morenosaurus, a partial Triceratops from Montana, a new Corythosaurus mount, a T. rex growth series, and Mamenchisaurus (but with a new skull). Here is a rendering of what one of the halls may look like:

The dinosaur halls reborn!

But while these epic halls are a year away, the museum has created a couple smaller displays to sate the public’s hunger for dinosaurs. First is a small platform in the upstairs North American Mammal hall containing a skeleton and two skulls. Very basic and generic as far as materials go; they have a T. rex skull and a Triceratops skull accompanied by the skeleton of Carnotaurus (only museum I have been to that features this animal). This small display is actually much better, in my opinion, than the whole of the old halls. The Carntotaurus skeleton seems to change modes depending on the angle you are looking at him. If you are looking at him from the front, it looks like he is either chasing after prey or moving in for the kill. If viewed from behind, he looks like he is stalking his prey. The wood railings and rock floor really add some nice naturalistic feel to the display and the lighting is dramatic and moody. See for yourself:

The temporary display of Mesozoic beasts in the North American mammal hall

The other dinosaur display is a thoroughly modern preparation lab:

The Los Angeles Museum's dino lab

This lab was created in 2008 to prep the museum’s teenage T. rex Thomas. Thomas is going to be one of the specimens in the upcoming T. rex growth series. Thomas was 13 when he died and was already a hefty 8,000 pounds and ten feet tall at the hips. But as time went by and significant progress was made on Thomas, the lab has been used to prep other specimens for the new halls and the museum’s collection. Lots of stuff going on in there. Here are some specimens:

What appears to be a hadrosaur sacrum

A block of red sandstone containing the jumbled remains of Coelophysis

A skeletal sketch of some unkown theropod. If anyone can tell me what it is, you get a gold star!

So while the old dinosaur halls left much to be desired, the new halls look to fulfill the museums wish of becoming a dinosaur hub for the West Coast (even if I can get my museum built, they will be able to keep that title at the rate they are going). The temporary displays knock the socks off the old halls and effectively keep the public’s hunger for dinosaurs in check. When the halls are finally finished next year, expect a report and review from me!

Till next time!

On With Their Heads

Hey there every peoples!

Finals are now out of the way and so my busy period is almost over. After that, I’ll be able to do a couple posts I’ve been meaning to put up for a long time. So this week sees another creature feature about an animal you may have heard of.

That animal’s name is Abydosaurus. You probably know him from a flurry of news reports back in March. Abydosaurus is just another of the new dinosaurs coming out of Utah’s cretaceous rocks, in this case the Cedar Mountain Formation. Interestingly, Abydosaurus was found in an outcrop at Dinosaur National Monument near the old visitor center. With any luck, he’ll show up in the new visitor center!

Reconstruction of the early Cretaceous brachiosaurid Abydosaurus

Why? Because Abydosaurus stands out among sauropods. Not because it’s a new species (those pop up all the time), not because of its size (it’s only 25 feet long, though the individuals recovered are juveniles), and it’s not because of its time or relationships (early cretaceous brachiosaurid. I love brachiosaurids!). What makes Abydosaurus unique is that the quarry where the 4 individuals were found yield a complete skull. What is more, it also produced the remains of 3 additional skulls! This is unheard of in sauropods. Their skulls are so small and delicate that they mostly don’t survive fossilization. Paleontologists are ecstatic when they find a sauropod skull. To find 4 is simply unheard of.

The most complete of the four Abydosaurus skulls

This gives us an unprecedented look into the biology of this animal. Skulls are the part of the body that reveals the most about an animal: what it ate, how strong its senses were, the structure of its brain, balance, and possibly even mating habits. And because skulls carry such a suite of features they are very important in classifying animals. The skulls of Abydosaurus upfront showed that it was a brachiosaurid, a group of sauropods who resembled reptilian giraffes. The skulls showed that this animal had wider teeth than other brachiosaurids. The skull is very similar to Africa’s Giraffatitan even though the Abydosaurus , with its age of 104 mya, lived 45 million years after the famous Jurassic giant (who was once known as Brachiosaurus brancai).

The name of Abydosaurus stems from an uncommon source of animals names: Egyptian mythology. I used to be a nut on Egypt back when we studied it in 6th grade. Abydos is the Greek name of a temple that rests on the Nile. According to Egyptian mythology, Abydos is the resting place of the head and neck of Osiris, the lord of the Egyptian Underworld. Seeing as the holoytpe of Abydosaurus consisted of the head and upper neck, and the site overlooked the Green River, the named seemed to apply. In my opinion, an extinct animal needs to be named (whether it’s a nickname or a scientific name) after a mythological figure with one of the coolest names out there: the Greek hero Belerophon.

Till next time!