Monday, 29 April 2013

W is for Wintonotitan

Unfortunately, there are no dinosaurs that start with 'W' from Alberta, so we're going to talk about a dinosaur from Australia this week. You may have noticed that I haven't talked about any sauropods (long-necked dinosaurs) at all during this series. That is because no sauropod fossils have ever been found in Alberta, so I'm going to take advantage of that and talk about a sauropod from Australia in 'W is for Wintonotitan'.

Wintonotitan fossils were first found in 1974, but were named to the genus Austrosaurus, the only Cretaceous sauropod from Australia known at that time. In 2009, the partial skeleton originally found consisting of a scapula (shoulder blade), partial left and right arms, and fragmentary vertebrae, ribs, hips and more were named as the type specimen of Wintonotitan wattsi [1]. Some caudal (tail) vertebrae found later were also referred to this species. It lived during the mid Cretaceous (approximately 100 million years ago) of Australia, found near a town in the northwest (Queensland) called Winton, hence the name. It is a basal titanosauriform, which includes well known dinosaurs like Saltasaurus and Argentinosaurus, and like other sauropods, it was a large herbivore that walked on all four legs. The fossils of Wintonotitan were found in a sandstone, along with fish fragments, a theropod tooth, and several plant fossils. It lived alongside pterosaurs, other dinosaurs like Australovenator and Diamantinasaurus, insects, bivalves, and more. It lived among many plants like ferns, ginkgoes, flowering plants, and more.
Wintonotitan by T. Tishler from Hocknull et al. [1]
And that's it for Wintonotitan! Next week, we'll talk about our final Albertan dinosaur in the alphabet, with 'X'. Also, don't forget, we are now open to the public for the season! Why not plan to visit us this weekend? The forecast looks great!

1. Hocknull, S.A. et al. 2009. New mid-Cretaceous (latest Albian) dinosaurs from Winton, Queensland, Australia. PLoS ONE 4: e6190. doi:10.1371/journal.pone.0006190

Monday, 22 April 2013

V is for Vagaceratops

This week on the Albertan dinosaur alphabet we have yet another ceratopsian in 'V is for Vagaceratops', the only 'V' dinosaur from Alberta. In 2001, a new species of Chasmosaurus was named, "Chasmosaurus irvinensis". It was distinguished on the basis of a broad snout, absence of orbital horns (the position instead occupied by pits and rugose bosses), a square-shaped frill, and other highly technical characters [1]. It also had 10 forward-facing 'hornlets' (epiparietals) on the back of the frill. It is known from southern Alberta, the Dinosaur Park Formation to be exact, from the Late Cretaceous (about 75 million years ago). The type specimen was a fragmented, but nearly complete skull, while two other skulls were also referred to this species. 
Vagaceratops by Nobu Tamura

As is often the case in palaeontology, further analysis years later suggested that this species was, in fact, not a Chasmosaurus. While describing two other ceratopsians (Kosmoceratops and Utahceratops) from Utah, an analysis suggested that it was more closely related to Kosmoceratops [2]. They erected the name Vagaceratops meaning 'wandering-horned-face', in reference to the fact that the group made of Kosmoceratops+Vagaceratops has been found in Alberta and Utah. While other studies have also found this relationship, not all researchers agree. 

Vagaceratops is yet another example of the many species of horned dinosaur present in Alberta during the Late Cretaceous. They showed a very wide diversity, and there are constantly more species being found. 

Next week, we will be talking about a dinosaur not from Alberta, as there are no Albertan dinosaurs that start with 'W'. And remember, Jurassic Forest will soon be opening to the public for the season! Stay tuned for more details!

1. Holmes, R.B. et al. 2001. A new species of Chasmosaurus (Dinosauria: Ceratopsia) from the Dinosaur Park Formation of southern Alberta. Canadian Journal of Earth Sciences 38: 1423-1438.
2. Sampson, S. D. et al. 2010. New horned dinosaurs from Utah provide evidence for intracontinental dinosaur endemism. PLoS ONE 5: 12292. 10.1371/journal.pone.0012292

Monday, 15 April 2013

U is for Unescoceratops

Last week we talked about the theropod Troodon, and this week, we bring you 'U is for Unescoceratops', a small horned-dino relative from the Dinosaur Park Formation of Alberta. 

Unescoceratops is a leptoceratopsid that lived during the Late Cretaceous (about 76 million years ago) in southern Alberta. Currently, only one specimen is known, a partial left dentary (lower jaw). It was named in 2012 by Canadian palaeontologist Michael Ryan, and several others, including Philip Currie. It was found in Dinosaur Provincial Park, which is a Unesco World Heritage site, hence the name Unescoceratops [1]. The only species currently known is Unescoceratops koppelhusae, in honour of Eva Koppelhus for the invaluable work she has done in vertebrate palaeontology and palynology (study of fossil pollen). The bone was first found in 1995 and shelved as it was assumed to be too impartial to identify. By comparing the partial jaw to other known leptoceratopsids, they were able to determine that it was a new genus, and in fact is an advanced leptoceratopsid. 
Partial left dentary of Unescoceratops (image from Ryan et al. [1])
As you can see, this is a small portion of bone that was used to identify and name this species. This is very common in palaeontology, and palaeontologists are often stuck with small bone fragments to identify. Based on the relative size and comparison to other better-known species, Unescoceratops was between 1-2 m long, and weighed less than 90 kg. Leptoceratopsids are smaller than their better known horned relatives, the ceratopsids, which include large animals like Triceratops, Styracosaurus, and Pachyrhinosaurus

For an excellent artist's rendition of what Unescoceratops may have looked like, check out Julius Csotonyi's website here (Unescoceratops is the top one). 

This is the only dinosaur that starts with 'U' from Alberta, and we'll continue on with the horned dinosaurs next week with 'V'! Only a few more weeks left of the dinosaur alphabet, then we'll return to our regular weekly posts about palaeontology.

1. Ryan, M.J. et al. 2012. New leptoceratopsids from the Upper Cretaceous from Alberta, Canada. Cretaceous Research 35: 69-80.

Monday, 8 April 2013

T is for Troodon

Last week in our Albertan dinosaurian alphabet we talked about the hadrosaur Saurolophus, and now we're going to talk about a well known theropod in ' T is for Troodon'. 

Troodon is a genus of theropod dinosaur from the Late Cretaceous (about 75 million years ago) of North America, with fossils being found as far north as Alaska and as far south as New Mexico. The name means 'wounding-tooth' in reference to the small, pointed, serrated teeth that are characteristic of this dinosaur. As a carnivore, it may have used these serrations much in the same way that you would use a steak knife to cut through meat. However, these teeth are also similar to herbivorous dinosaurs like Stegoceras and lizards, suggesting it may have been an omnivore. In fact their teeth were so similar to pachycephalosaur teeth that for a long time, the pachycephalosaurs were known as troodontids until Canadian palaeontologist Charles Sternberg noted their differences and named the group Pachycephalosauridae in 1945 [1]. Troodon was a relatively small theropod, reaching 2.5 m in length and stood less than a metre tall. It may have weighed as much as 50 kg. It had a large sickle-shaped claw on each foot that it was able to retract and raise while running, and was likely a fast runner. The eyes of Troodon were quite large compared to other dinosaurs, which may mean it was nocturnal, and they pointed forwards, which likely gave it binocular vision and depth perception. It also had the largest brain to body size ratio of any other dinosaur, suggesting it was a more intelligent dinosaur.
Image of Troodon formosus teeth from The Childrens Museum of Indianapolis
The genus was first named from a single tooth from southern Alberta, which is problematic when trying to determine the rest of the animal, as teeth can sometimes be very similar between genera and species. Again, we can highlight the difficulty in naming species from fossils. The first non-tooth remains were named in 1932, but placed in a separate genus (Stenonychosaurus), and a more complete specimen found in 1969 was as well. However, Philip Currie united Troodon, 'Stenonychosaurus' and 'Pectinodon' under the genus Troodon, suggesting they are all the same genus [2]. Of course, as is the story with many dinosaurs, this has been questioned and reviewed since. A more recent study suggests that what we now think of as Troodon formosus is most likely not a single species, or even a single genus especially since many of these identifications are based on single teeth [3]. They also note that since the holotype is based on a single tooth, the name Troodon may be a nomen dubium, which literally means 'dubious name'. Obviously significant work is required to determine what is going on in the complicated history of Troodon

Egg nests of Troodon formosus have been found in Montana that have revealed many aspects about the reproduction of Troodon. They laid eggs two at a time, over the period of a day or so, and incubated the eggs by covering them with their body or with soil [4]. Eggs are found roughly in pairs, suggesting they had two functioning oviducts, and appear to have a reproductive system that is intermediate between crocodiles and birds, as we would expect. Furthermore, their eggs were also intermediate in size between crocodiles and birds. The nests were dish-shaped, 100 cm in diameter, and had 16-24 eggs. 

That's it for Troodon. You can see a feathered Troodon at Jurassic Forest, and remember that we will be opening in less than 3 weeks! Another interesting fact about Troodon: it is Phil Currie's favourite dinosaur! Next week we'll be talking about the only 'U' dinosaur from Alberta, a ceratopsian. 

Other 'T' dinosaurs from Alberta:

1. Sternberg, C.M. 1945. Pachycephalosauridae proposed for dome-headed dinosaurs, Stegoceras lambei, n. sp., described. Journal of Paleontology 19: 534-538
2. Currie, P.J. 1987. Bird-like characteristics of the jaws and teeth of troodontid theropods (Dinosauria, Saurischia). Journal of Vertebrate Paleontology 7: 72-81.
3. Zanno, L.E. et al. 2011. A new troodontid theropod, Talos sampsoni gen. et sp. nov., from the Upper Cretaceous Western Interior Basin of North America. PLoS ONE 6: e24487. doi:10.1371/journal.pone.0024487
4. Varricchio, D.J.  et al. 1997. Nest and egg clutches of the dinosaur Troodon formosus and the evolution of avian reproductive traits. Nature 385: 247-250.

Monday, 1 April 2013

S is for Saurolophus

For this week's Albertan dinosaurian alphabet post, we took to social media to find out what people wanted to hear about. The question was simple: would you prefer to learn about a hadrosaur (duck-bill) or a carnivorous theropod? Much to my surprise, the responses were remarkably one-sided, with only 2 people voting for a theropod, and everyone else going for the hadrosaur. So, the public has spoken, and this week we give you 'S is for Saurolophus'. 

Saurolophus was a large hadrosaur that lived during the Late Cretaceous (approximately 69 million years ago) in both western North America and Mongolia. It's name means 'lizard-crest' in reference to the small crest found on the back of it's skull. The first fossil was found by Barnum Brown in 1911 along the Red Deer River, and constitutes a nearly complete skeleton now on display at the American Museum of Natural History. This is the type specimen for the species Saurolophus osborni, and was nearly 10 m long and weighed 1900 kg. Currently, one other valid species exists, S. angustirostris, and represents the larger Mongolian specimens at as many as 12 m long. The crest of Saurolophus was long and blade-like, and is found in younger specimens as well as adults. Although the crest was largely solid, it did have some hollow chambers, and several different functions have been proposed including respiration, sexual selection, muscle attachment, and visual signalling. 
Photograph of the original Saurolophus osborni skeleton found by Brown along the Red Deer River
Saurolophus lived alongside many well known dinosaurs from the Horseshoe Canyon Formation of Alberta such as the armoured dinosaurs Euoplocephalus and Edmontonia, other hadrosaurs like Edmontosaurus and Hypacrosaurus, and the tyrannosaurs Albertosaurus and Daspletosaurus. In Asia, it lived with some less well-known animals like the armoured Tarchia, troodontid Saurornithoides and the tyrannosaur Tarbosaurus, a close relative to T. rex. Like other hadrosaurs, it was able to walk on 2 (bipedal) or 4 (quadrupedal) legs, and was a herbivore that used its massive battery of teeth to chew and grind tough plant material. 

In recent years, much of the work on Saurolophus has been done by Phil Bell, former University of Alberta student who is now the palaeontologist at the future Philip J. Currie Dinosaur Museum near Grande Prairie. Some of you may remember his talk at Jurassic Forest last season on skin and scale patterns in hadrosaurs. In his study, he proposed that S. osborni and S. angustirostris could be differentiated by their scale patterns, as significant fossilised skin has been found for both species [1]. He described the Mongolian species (S. angustirostris) as having a row of distinctive square scales that ran along the back and tail, while the Albertan S. osborni lacked this row and had only smooth scales. Furthermore, the Mongolian species had vertical rows of scales on the tail, which likely corresponded to a striped pattern in life, while Albertan ones had a radial scale pattern which may have represented a mottled/spotted colouration. This is quite interesting since dinosaur skin is so rarely fossilised, and even more rarely in this much detail or large amounts, making it difficult to distinguish patterns. This was the first time skin had been used as a possible method to distinguish different species. 
Possible colouration patterns in A. S. osborni and B. S. angustirostris. Image copyright Lida Xing and Y. Liu (Bell [1])
And that's it for Saurolophus! I hope everyone that voted for the hadrosaur is happy, and those of you that didn't have learned something interesting about this dinosaur. Next week we're on to the letter 'T' and we'll talk about a well known carnivore (but no, it's not T. rex!)

Other 'S' dinosaurs from Alberta

1. Bell, P.R. 2012. Standardized terminology and potential taxonomic utility for hadrosaurid skin impressions: a case study for Saurolophus from Canada and Mongolia. PLoS ONE 7: e31295 - Freely accessible here doi:10.1371/journal.pone.0031295