Monday, 20 May 2013

Z is for Zupaysaurus

After 26 long weeks, we are now at the final dinosaur from our dinosaurian alphabet! This week, we bring you 'Z is for Zupaysaurus', a theropod from Argentina.

Zupaysaurus lived during the Late Triassic period, about 215 million years ago in northern Argentina. The name comes from the local Quechua word 'zupay' meaning devil. It was a medium-sized bipedal theropod, between 3 and 4 m in length, and weighed about 200 kg. It is known from one definitive specimen, which includes a nearly complete skull, vertebrae, and incomplete arms and legs [1]. In the original description, it was thought to have two parallel cranial crests, like those seen in Dilophosaurus. However, more recent analysis has suggested that these "crests" were simply bones that had been pushed up during deformation of the skull [2]
Artists impression of Zupaysaurus by FunkMonk
Like most theropods, Zupaysaurus was a carnivore. Most analyses suggest that it was a coelophysoid dinosaur, being closely related to the Antarctic theropod Cryolophosaurus, and was the first coelophysoid to be found in South America. It was found in the Los Colorados Formation of Argentina, which is thought to have been a floodplain. This formation is home to many sauropodomorph dinosaurs, like Riojasaurus, and many other tetrapods such as therapsids, pseudosuchians, and other archosaurs. In fact, it is one of the earliest known animal fossil assemblages that was dominated by dinosaurs!

And that is it for our dinosaurian alphabet! I hope everyone has enjoyed it. I'm looking for ideas of what to do for the blog in the future, so if anyone has anything they'd like to learn about, please let me know!

1. Arcucci, A. B., and Coria, R. A. 2003. A new Triassic carnivorous dinosaur from Argentina. Ameghiniana 40: 217-228. 
2. Ezcurra, M. C., and Novas, F. E. 2007. Phylogenetic relationships of the Triassic theropod Zupaysaurus rougieri from NW Argentina. Historical Biology 19: 35-72.

Monday, 13 May 2013

Y is for Yulong

Last week was our last dinosaur that was actually from Alberta. Now our second last dinosaur of the dinosaurian alphabet is a newly described theropod from China: Yulong

Yulong was described at the beginning of this year by a group of Chinese palaeontologists as well as well-known Canadian palaeontologist Philip Currie from the University of Alberta [1]. It comes from the Luanchuan County of Henan Province. Unfortunately, the exact age of the the formation is unknown, but it is likely from the Late Cretaceous based on the other animals that are found in this formation. The name Yulong is derived from the Chinese "Yu", the abbreviated name for Henan Province, and "long" meaning dragon. Only one species of Yulong is currently known, Yulong mini in reference to the fact that the specimens are very small. 
Photograph of 3 Yulong mini skulls (a-c) in right lateral view and d in right lateral view (from Lu et al. [1]). Note the scale bar showing how small these skulls are! 
Yulong was an oviraptorid dinosaur of approximately chicken size. Most oviraptorids are larger, and can reach sizes up to 8 m in length. Although Yulong is described as being chicken sized, it was likely larger as the fossils that have been found are all juveniles. Several specimens are known, including well preserved skeletons, skulls, and even a well preserved embryo coming from a nest of 26 eggs. A thin section through a rib showed no growth lines, suggesting the animal was not yet a year old when it died. 

That's it for Yulong as it's a fairly newly described species. Tune in next week for our final dinosaur of the alphabet to learn about a neat theropod from Argentina!

1. Lu, J. et al. 2013. Chicken-sized oviraptorid dinosaurs from central China and their ontogenetic implications. Naturwissenschaften 100: 165-175.  

Monday, 6 May 2013

X is for Xenoceratops

Today we introduce the final Albertan dinosaur from our Albertan dinosaurian alphabet with 'X is for Xenoceratops'. This dinosaur is the only one from Alberta that starts with 'X', and was named only last year. 

In 1958, a well-known American palaeontologist named Wann Langston Jr. discovered a partial skull of a ceratopsian in the Foremost Formation (near the town of Foremost) of southern Alberta. These remains were then returned to the Canadian Museum of Nature in Ottawa, and were left undescribed. 50 years later, some palaeontologists became aware of these bones, and wondered about the animal that they belong to. Upon further examination, they concluded that it was a new animal, and named it Xenoceratops foremostensis [1]. The name Xenoceratops means 'foreign/alien horned face', referring to the fact that it is the only known ceratopsian from the Foremost Formation. It lived during the Late Cretaceous, about 78 million years ago, making it the oldest known ceratopsian found in Canada so far. 
Reconstruction of the frill of Xenoceratops foremostensis (centre) from Ryan et al. [1]
Xenoceratops was a centrosaurine ceratopsian, a group of dinosaurs that get their name from another Albertan ceratopsian, Centrosaurus. In the above image, Xenoceratops is surrounded by other centrosaurines including Centrosaurus (B), Styracosaurus (C) and Pachyrhinosaurus (F). As you can see, it has a very different frill from the others: the midline of the frill bore two thick bony knobs,  two pointed spikes (pointing to the rear and top of the animal in life), several small bumps, and a larger bony projection in the most anterior (forward) position. 

Through analysis of the bones, they determined that Xenoceratops was the most primitive centrosaurine found thus far. Unfortunately, the fragmentary nature of the remains makes it difficult to know for sure where it would have sat in the ceratopsian family. An unprepared skull found in the same region in 2010 does have portions of the face including elongated orbital horns, and has been referred to Xenoceratops. It also may have had  low, ridge-like nasal ornamentation, like those seen in Albertaceratops and Medusaceratops

This find was especially exciting for palaeontologists as it was only the second dinosaur fossil found in the Foremost Formation from more than just teeth. Very few outcrops of this formation are present, making it difficult to excavate and less likely to find fossils than the younger Oldman and Dinosaur Park Formations also of southern Alberta. Unsurprisingly, the species found in this formation are from known groups of dinosaurs from this area, but they are consistently more basal in their respective groups. 

Xenoceratops is yet another ceratopsian from Alberta, and is unfortunately the last dinosaur that we will talk about from Alberta, since no 'Y' or 'Z' dinos exist from our province. Stay tuned for next week, with a theropod from China!

1. Ryan, M.J., et al. 2012. A new ceratopsid from the Foremost Formation (middle Campanian) of Alberta. Canadian Journal of Earth Sciences 49: 1251-1262.