C is for Chasmosaurus!

The third instalment in our 'A-Z of Dinosaurs in Alberta' brings us to the letter C: C is for Chasmosaurus. Chasmosaurus is a ceratopsian dinosaur from the Late Cretaceous (about 75 million years ago) of North America. It was named by well known Canadian palaeontologist Lawrence Lambe in 1914. Its fossils are found mainly in Alberta, but may also be found in Montana and possibly New Mexico. The name means 'opening lizard', in reference to the large fenestrae or openings in the frill of this dinosaur. 

Image of Chasmosaurus belli showing the large openings in the frill. Image from FunkMonk, Wikimedia Commons.

Chasmosaurus was an average sized ceratopsian dinosaur, at about 5-6 m in length and weighing 3600 kg. It is well known with most of the skeleton having been found. In general, the body of ceratopsians is not very distinct, while the skull is what makes the difference between different genera and species. In the case of Chasmosaurus, it has a small horn on it's nose, and small horns above its eyes, along with the large holes in the frill. In some specimens, show ossifications on the frill called epoccipitals, which are commonly found in ceratopsians. Along with all other ceratopsians, it was a herbivore, using its large battery of teeth to break down tough plant material. Two species are known, Chasmosaurus belli, and Chasmosaurus russelli. One specimen of C. russelli actually showed traces of fossilised skin, which is a remarkable find. Chasmosaurus is a very commonly found dinosaur in southern Alberta, and it was one of the earlier dinosaurs to be named as well. 

Artists impression of Chasmosaurus from ArthurWeasley (Wikimedia Commons)

That's it for Chasmosaurus. Next week, we'll have a large theropod for the letter D!

Other Dinosaurs that start with 'C' from Alberta

Chirostenotes

Corythosaurus

Centrosaurus

Coronosaurus

B is for "Brachyceratops"

To continue with our 'A-Z of Dinosaurs from Alberta', we have B is for "Brachyceratops" this week. You will notice that "Brachyceratops" is surrounded by quotation marks. This indicates that the name is not valid, which will be explained here. 

"Brachyceratops" was named in 1914 from some partial skeletons found in Montana [1]. The name means 'short-horned face', because it has an abbreviated face compared to other ceratopsians. It comes from the Upper Cretaceous, approximately 75 million years ago. It is characterised by its short face, small horns over its eyes (supraorbital horns), and small size. It has also been found in Alberta [2].

"Brachyceratops". Image from Wikimedia Commons (Nobu Tamura)

Unfortunately, the characteristics that were used to differentiate it from other species are also characteristic of juvenile ceratopsians, specifically centrosaurine ceratopsians [3]. It is found in areas where other ceratopsians like Einiosaurus and Achelusaurus are found, and may represent juveniles of these genera, while one specimen has been identified as a juvenile Rubeosaurus [3,4,5]. Because of this, "Brachyceratops" has been classified as a nomen dubium, or 'dubious name', and is not generally considered to be a valid genus of dinosaur, as all specimens are juveniles of other ceratopsian dinosaurs. It can be difficult to determine which dinosaur the juvenile belongs to, but it seems that "Brachyceratops" may represent different ceratopsian juveniles. 

Rubeosaurus from McDonald [5].

Other B dinosaurs from Alberta
There are no other non-avian dinosaurs starting with B from Alberta, but there is one bird called Baptornis.

Stay tuned for next week: C is for Chasmosaurus!

References:

1. Gilmore, CW. 1914. A new ceratopsian dinosaur from the Upper Cretaceous of Montana, with not on Hypacrosaurus. Smithsonian Miscellaneous Collections 63(3): 1-10.

2. Russell, LW. 1934. Fauna of the upper Milk River Beds, southern Alberta. Transactions of the Royal Society of Canada, series 3 4(29): 115-128.

3. Sampson, SD, Ryan, MJ, and Tanke, DH. 1997. Craniofacial ontogeny in centrosaurine dinosaurs (Ornithischia: Ceratopsidae): taxonomic and behavioral implications. 

4. Ryan, MJ, Holmes, R, and Russell, AP. 2007. A revision of the late Campanian centrosaurine ceratopsid genus Styracosaurus from the Western Interior of North America. Journal of Vertebrate Paleontology 27: 944-962. 

5. McDonald, AT. 2011. A subadult specimen of Rubeosaurus ovatus (Dinosauria: Ceratopsidae), with observations on other ceratopsids from the Two Medicine Formation. PLoS ONE 6(8): e22710. 

A-Z of Dinosaurs in Alberta: A is for Albertonykus

Today we are going to start a series called the A-Z of Dinosaurs in Alberta. This series will take 26 weeks, a week for each letter of the alphabet, and will take us all the way to April 2013 when we will open for the 2013 season. The idea for this series came from Brian Switek, a science writer that focuses on palaeontology. He is currently doing his own A-Z of dinosaurs on his Smithsonian blog 'Dinosaur Tracking', and he agreed to let us use his idea. 

Each week, we will introduce a new dinosaur from Alberta that starts with the letter of the alphabet in question. Now there are plenty of dinosaurs from Alberta, but there are a few letters with no dinosaurs found here. For these letters, I will discuss a different dinosaur from around the world. Now, let's get started with 'A'!

A is for Albertonykus

Albertonykus is a small theropod dinosaur found in southern Alberta. Named in 2009 by Nick Longrich (previously of the University of Calgary, now at the Yale Peabody Museum) and Philip Currie (University of Alberta), it's a relatively new dinosaur from Alberta. It's name means 'Alberta-claw', in reference to it's many claws. It is known from a variety of bones from at least two individuals including a a left ulna (lower arm bone), right tibia (lower leg bone), end of left tibia, and several hand and foot bones. Most of the bones are found in a single bone bed in Dry Island Buffalo Jump Provincial Park, which is known as the Albertosaurus bone bed, as the remains are dominated by Albertosaurus. So far, all Albertonykus remains have been found in Alberta.

Artists impression of Albertonykus borealis. Image from Wikimedia Commons user Karkemish

There is one species of Albertonykus known, Albertonykus borealis. It is a small theropod, an alvarezsaur, from the Late Cretaceous, living approximately 70 million years ago. Although it's remains are quite partial, it was likely about 1 m long, with quite small, reduced forelimbs, which is common among alvarezsaurs. Like other alvarezsaurs, it is thought that Albertonykus was an insectivore, feeding primarily on small insects like termites. It could have used it's forelimbs to claw at wood, getting at the termites within the trees. 

Classification

Dinosauria

      Saurischia

           Theropoda

                 Maniraptora

                       Alvarezsauridae

                             Albertonykus

Other A-dinosaurs from Alberta

Albertosaurus, Anchiceratops, Ankylosaurus, Arrhinoceratops, and Atrociraptor

Reference

Longrich, N. R., and Currie, P. J. 2009. Albertonykus borealis, a new alvarezsaur (Dinosauria: Theropoda) from the Early Maastrichtian of Alberta, Canada: implications for the systematics and ecology of the Alvarezsauridae. Cretaceous Research 30: 239-252.

The end of the dinosaurs

For the last two weeks, we've been talking about mass extinctions (part 1 and part 2), and last week we introduced the Cretaceous-Palaeogene (AKA Cretaceous-Tertiary, K-T, or K-Pg) extinction. Of course this is the most famous mass extinction because this is the one that caused the end of the dinosaurs. This week, we'll go into the K-Pg mass extinction in a bit more detail. 

The impact hypothesis

This is the most strongly supported hypothesis for what caused the mass extinction, and is generally supported by the majority of palaeontologists and scientists. At the very least, the occurrence of the impact is supported, although some people still debate whether it caused the extinction. How did this hypothesis come to be? It's actually quite an interesting story. In 1980, a team of scientists including physicists, geologists and chemists suggested that the extinction was caused by an impact from an extra terrestrial object (Alvarez et al. 1980). They found that the sediments at this time contained much larger amounts of an element called iridium than either before or after. Iridium is a very rare find on Earth, but is found in high concentration in meteors and asteroids. This led them to believe that an extra terrestrial impact occurred at the time of the extinction, and therefore caused the extinction. They predicted that object that collided with Earth would have been about 10 km in diameter, and would have caused a crater over 100 km wide. They also predicted that it would have hit the ocean, and caused large amounts of highly pressured sediment to be ejected into the atmosphere. They were able to identify very fine sediment and clay from this time that could be explained by a large amount of sediment being kicked up into the atmosphere and slowly settling. The catch: they did not have the crater. 

At this point, some people thought the idea was a good one, but many people thought they were totally on the wrong track. Iridium can be caused from volcanic eruptions, and after all, they didn't have a crater. Then, in 1991, a crater was identified with a diameter of 180 km that is partially on the Yucutan Peninsula, but mainly in the Gulf of Mexico (Hildebrand et al. 1991). It was identified from studying sediment core samples that had been retrieved in oil exploration. This crater is called the Chicxulub crater, and appears to match the time of the K-Pg extinction. 

Results of a NASA topography study showing the shape of the Chicxulub crater

How does an impact cause a mass extinction?

There are several different stages of an impact that can cause extinction. First of all, any animals living close to the impact would have died instantly either by the impact itself, or by the high amount of pressure and subsequent shockwave. As the impact was partially in water, huge tsunamis would have occurred, wiping out anything living close to the coastline. The biggest problem, however, comes from the dust ejected into the atmosphere. It's hypothesized that such a large amount of sediment was ejected into the atmosphere that it would have blocked out the sunlight. This was further made worse by gas and aerosols going into the atmosphere and absorbing sunlight before it could reach the Earth. This may have occurred for up to 10 years, which means that anything that relies on photosynthesis (plants and small animals like phytoplankton) would die. Of course this causes a chain reaction, since herbivores would then die from starvation, and eventually carnivores would also die. It also may have caused global fires and acid rain. 

Artists impression of some pterosaurs flying by the impact, which eventually would cause their extinction

Volcanism as a cause

The leading alternative hypothesis of the K-Pg extinction stems from a huge volcanic eruption that occurred in what is now India, in what is called the Deccan Traps. There is an extremely large amount of basalt, a type of rock formed by lava, that can be found in this area. It is thought to have been caused by constant volcanic eruptions occurring from about 68 to 65 million years ago. It's thought that this could have caused similar problems to the impact, injecting large amounts of aerosols into the atmosphere. It also may have greatly increased the amount of carbon dioxide into the air, which may have had a greenhouse effect and caused global warming. 

Picture of the Deccan Traps near Mumbai. Image from Wikimedia Commons (user Nichalp)

What really happened?

There is some debate that dinosaurs were already dying out before the end of the Cretaceous, and that the impact just finished them off. Other people suggest that the impact occurred earlier and could not have caused the extinction. Finally, some people think it most likely was caused by a combination of the impact and volcanism. Either way, the Earth was particularly volatile at this point in time and wouldn't have been a great place to live!

References and Links

University of California Berkeley - The Great Mystery

Alvarez, L.W. et al. 1980. Extraterrestrial cause for the Cretaceous-Tertiary extinction. Science 208: 1095-1108.

Hildebrand, A.R. et al. 1991. Chicxulub crater: a possible Cretaceous/Tertiary boundary impact crater on the Yucutan Peninsula, Mexico. Geology 19: 867-871.

Mass Extinctions (part 2)

Last week, we introduced mass extinctions by explaining what they are, some keys to surviving extinction, and then describing the first three mass extinctions in Earth's history: the end-Ordovician, the Late Devonian, and the end-Permian. This week, we will talk about the last 2 major mass extinctions, and some other events that were major, but not considered to be huge mass extinctions. 

The Big Five mass extinctions continued:
4. The Triassic-Jurassic extinction event - This extinction event occurred at the boundary between the Triassic and Jurassic periods, approximately 200 million years ago. It affected both life on land and in the sea, with twenty percent of all marine families being lost, and many on land as well. Animals affected on land include many therapsids, large reptiles (non-dinosaurian archosaurs), and large amphibians. The extinction of these large animals allowed for the dinosaurs to really evolve and take over the landscape, filling the ecological niches left open by the extinct animals. Like most other mass extinction events, the cause is not clear. Possible causes include climate change resulting in sea-level changes or ocean acidification, an asteroid impact, or large volcanic eruptions. Of all of the mass extinctions, the Triassic-Jurassic extinction event is probably ranked fifth in terms of extinction rate. 

Smilosuchus was a phytosaur, a group of reptiles that went extinct in the end-Triassic extinction. Image from Wikimedia Commons user ArthurWeasley.

5. The Cretaceous-Palaeogene mass extinction - Also known as the Cretaceous-Tertiary extinction, or K-T/K-Pg for short, this is the most famous mass extinction to ever occur, although it is not the largest. It marks the end of the Cretaceous period, approximately 65 million years ago. In addition to the extinction of non-avian dinosaurs and pterosaurs, large marine reptiles like mosasaurs and plesiosaurs also went extinct, as well as many plants and invertebrates like ammonites. It affected both animals on land and in the oceans, with a total of 65-70% of all species going extinct, making it the second (or third) largest extinction event in Earth's history. This mass extinction is the only one that the cause is most likely known. It was almost definitely caused by a meteor impact in the Gulf of Mexico, although there is some evidence that it was caused by increased volcanic eruptions in what is now India. To learn more about the Cretaceous-Palaeogene extinction, check out Mesozoic Mondays next week.

Artists rendering of the bolide impact that likely caused the Cretaceous-Palaeogene extinction

Other lesser extinction events have occurred throughout history, during the Precambrian, Cambrian, Silurian, Carboniferous, Permian, Jurassic, Cretaceous, and Neogene. The last extinction event occurred during the Quaternary, and resulted in the extinctions of the large megafauna that existed. Only large animals were affected, so it is not considered to be a true mass extinction, although animals all over the world went extinct. Several events occurred during the Quaternary extinctions, and cause has been attributed to over hunting by humans, climate change, disease, predation, or a swarm of comets. As you can see, it can be very difficult to determine the cause of these mass extinctions. 

Large megafauna like the mammoths went extinct during the Quaternary. Image from Plos Biology credit Mauricio Anton.

Now you have seen a summary of what a mass extinction is, the Big Five extinction events in Earth's history, and some other extinctions. Next week, we will talk about the Cretaceous-Tertiary extinction in detail!

Mass Extinctions (Part 1)

Throughout geological time, several mass extinctions have taken place, significantly changing the makeup of plants and animals over time. This post will be talking about mass extinctions, what they are, what causes them, and some examples, followed by another post next week. 

The first question to ask is 'what exactly is a mass extinction'? A mass extinction (also known as an extinction event) is a time when levels of extinction are much higher than normal background levels for a large number of groups, and is not limited to one group or one environment. Mass extinctions are widespread: the have global affects, and they result in a large decrease in diversity and abundance in microscopic and macroscopic life. 

No organism is immune to extinction, but there are characters that can help one survive a mass extinction. Organisms that are widespread are more likely to survive, as they are often more flexible and able to live in different environments. For example, if an animal is found only in a specific environment and a certain area of the world, and that area has a massive fire, then that animal will most likely die. Another thing that helps is numbers. If there are many of the animal, they are more likely to survive. For more details on what helps an animal survive a mass extinction, check out UK palaeontologist Dave Hone's post "How to survive mass extinction.

In the past, there have been several mass extinctions. In palaeontology, we refer to the "Big Five" mass extinctions. This week, we will talk about the first 3: 

Graph showing number of families of animals over time, indicating the 5 major mass extinctions. Image from UMass.

1. The Ordovocian extinction event - occurred at the end of the Ordovician, about 443 million years ago. It was characterised by 2 peaks of extinctions separated by as much as a million years. As the Ordovician is quite early in the evolution of life on land, most life was still in the ocean, and therefore it was marine life that suffered, including a large number of brachiopods and bryozoans. More than 60% of all marine invertebrates went extinct, and as much as 85% of all life, making it the second (or possibly third) most deadly mass extinction of all time. Although the immediate cause is difficult to determine, it seems to have been caused by a decrease in temperature worldwide, resulting in glaciation and fall of sea level. 

Diorama of typical Ordovician life before the extinction. Image from Wikimedia Commons

2. The Late Devonian mass extinction - This likely occurred as a series of events (2 or more) and the event as a whole was approximately 360 million years ago at the end of the Devonian period. Again, primarily marine life was affected, with shallow seas being particularly deadly. Approximately 75% of all life died, including nearly all the corals, which had previously colonised much of the Earth's sea, producing large reef systems. Again, the cause of this extinction is not clear, with theories including a bolide (extraterrestrial) impact, sea level changes, and lack of oxygen in the oceans. This is the least deadly mass extinction.

Typical Devonian ocean life. Image credit: University of Michigan University of Paleontology

3. The Permian mass extinction - The Permian mass extinction occurred at the end of the Permian and the end of the Paleozoic, approximately 250 million years ago. This event is also known as the Permian-Triassic event, as it separates the Permian from the Triassic, the first period in which dinosaurs occur. This is by far the largest mass extinction event in history. It's estimated that as many as 96% of all marine species and 70% of terrestrial species went extinct at this time. This caused a major faunal turnover, with many new groups appearing in the Triassic to exploit the areas left empty by all of the animals that went extinct. Several causes have been proposed including a large release of methane gas, large fires, huge volcanic eruptions, bolide impacts, and sea level changes, although it is likely a result of several different events. Whatever the cause, this is definitely the most catastrophic event that has happened on Earth. Trilobites, foraminiferans, brachiopods, and ammonites suffered substantially, with trilobites going extinct completely. On land, many mammal-like therapsids as well as other reptiles and amphibians died out. 

Trilobite fossil from the Permian of Russia. Image from the Carnegie Institute for Science

Next week, we will continue talking about mass extinctions, including a description of the final two: the end Triassic extinction, and the end Cretaceous extinction, which is the end of the dinosaurs! 

Links:
For more information, check out the BBC Nature website on mass extinctions!

2012 season in summary

As you all should know, yesterday Jurassic Forest closed its doors for the final time in 2012, capping off the 2012 season. This week on Mesozoic Mondays we wanted to just give a quick summary of the last year and thank everyone who helped make it a success. 

We opened up at the end of April this year, and saw a great two months of school trips. We had many first-timers, and several repeats from last year, which made the school season great. We had all ages from Kindergarten to high school, doing both our 'self guided' basic packages, but mainly taking advantage of our curriculum based All-Inclusive packages. If you're looking for somewhere to bring your school this year, check out our Educational Resource Area of our website. 

As summer rolled in, we welcomed many corporate family events, birthday parties, and special events. Highlights from special events include Dr. Phil Currie and Dr. Eva Koppelhus from the University of Alberta talking about their dinosaur hunting trip to Antarctica, and Dinosaur George who gave one of his always-entertaining talks on dinosaurs. 

Dr. Phil Currie giving a talk on dinosaurs and field work in Alberta

Dinosaur George in front of a very packed crowd for one of his several shows

Of course, this year also featured many talks from local PhD students on pterosaurs and dinosaurs, as well as many visitors from the Royal Alberta Museum, like Peter Heule (the "bug guy"). We also had another visit from the Grande Prairie Regional College, who brought out some real fossils to show off and talk about the finds in the region, plus Dr. Phil Bell from the not-yet-built Philip J. Currie Dinosaur Museum in Grande Prairie. Of course we also had some local reptile, amphibian, bat, fish, and plant experts out. All-in-all, a pretty eventful year for special events! We're already thinking about events for next year, so if anyone has any ideas or suggestions, we'd love to hear them. 

Of course, we can't forget to mention that we welcomed two brand new dinosaurs into the park! Well technically, we welcomed one Troodon, and three Pachyrhinosaurus, but who's counting? We had another great day with some helicopter dino-landings to bring in the Pachyrhinosaurus', and the new dinos were definitely a success. Both dinosaurs are commonly found in Alberta, and Pachyrhinosaurus is especially well known from the Grande Prairie region, and Dinosaur Provincial Park. 

One Pachyrhinosaurus flying through the air!

As summer ended and fall began, we had more school trips to cap off the year. This year was a great year at Jurassic Forest and we already can't wait for next year. Unfortunately, the dinos need to have a break for the winter since they are pretty tired from the long season. 

We may be closed to the public, but we are still pretty busy already planning next year. We have some great new ideas, so watch Twitter, Facebook, and sign up for our newsletter for more details throughout the next few months! Our E-store is also available for any dino-related Christmas (or other) gifts you may want to purchase, and you can always give us a call at 780-470-2446 for more information! Also, Mesozoic Mondays will be continuing, although it may be less often than weekly. Keep checking for more details!

We hope everyone had a great year this year, and can't wait for the 2013 season! See you all in April!