STL Science Center

STL Science Center

28 May 2017

Podcast Win

Despite the well-known nature of Citipati it is probably important to note that the dinosaur is still relatively new in terms of dinosaurs and their presence on the internet. There are news stories floating around and a number of other assorted websites that specifically mention Citipati. These include sites like Prehistoric Wildlife, the Natural History Museum in London, and the I Know Dino website. However, to get right at the crux of the Sunday theme, we can turn to the I Know Dino Podcast, rather than just using their website as a source, to summarize the majority of websites.

27 May 2017

Another Missed Dinosaur

I truly love finding that I have somehow overlooked a dinosaur that I am and have been aware of for quite some time. This week that dinosaur that I suddenly remembered existed is Citipati osmolskae. Citipati is one of the better known oviraptorids and one of the most iconic members of its family. Possessing a crest on its forehead and a beak characteristic of other oviraptorids. Probably covered completely in feathers, Citipati was a large dinosaur at approximately 3m (10ft) long and were the largest members of their family known between 2001 and 2007. Clark, Norell, and Barsbold named Citipati (Hindi for funeral pyre) after the highly successful paleontologist Halszka Osmólska of Poland. Osmólska was a prolific discoverer and describer of oviraptorids and theropods of Mongolia where Citipati was also discovered.
Display from "Dinosaurs. Treasures of Gobi Desert" in CosmoCaixa, Barcelona.
Photo by Eduard Solà

26 May 2017

Polacanthus Presents Itself

©Rodrigo Vega
There are a number of different interpretations of Polacanthus in a number of different views. There are also a number of different actions being undertaken by these interpretations of Polacanthus ranging from sleeping to evading and actively engaging predatory dinosaurs or intraspecific rivals. The type of action in which the Polacanthus in any given interpretation does not necessarily relate how intriguing or impressive the individual piece is; a sleeping Polacanthus has exactly as much potential as a running animal. I would actually go so far as to say that the sleeping Polacanthus image shared here today is almost more dynamic than the second image.Rodrigo Vega's sleeping Polacanthus is the centerpiece of a rather dark image. Two small Hypsilophodon occupy the cliff protecting the large sleeping ankylosaur from above. The Polacanthus itself is quiet and almost appears to be somewhat contemplative. Though I have described it as asleep, it almost appears awake but with its eyes closed which is a very real possibility of course. This, like many ankylosaur illustrations, is a solitary animal living a lonely life. The Hypsiolophodons above the animal may have acted as a portion of a surrogate herd, as animals like Polacanthus are hypothesized to have lived solitary lives except at points where they needed to be around their own kind (i.e. during mating seasons). There is the possibility that this kind of behavior would be related to poor eyesight  on the part of the ankylosaur; essentially it would have used its non-conspecific herd members as its eyes to be aware of predatory dinosaurs.

©Will Brennan
This could be the exact circumstance of the second illustration of a much more awake Polacanthus. This Will Brennan image might be portraying a similar herding behavior in which Polacanthus has adopted a group of Iguanadon as surrogate herd members in the place of other Polacanthus (and smaller animals like Hypsilophodon). The Polacanthus in this image is actually a part of the foreground and is a secondary character of the image. The illustration itself draws the eye to the center with the light in the distant forest and the central Iguanodon braying or calling the herd together. Assuming that the herd is being called together and Polacanthus is a member of the herd that understands this call, that would mean that are smaller ankylosaur was willing to separate itself from the herd in deeper woods, allowing the safety of numbers to be minimized in this situation.

All of these interpretations are, of course, my personal speculation based on the speculation of artist interpretation of events that may or may not have occurred and may or may not have some kind of scientific evidence underlying them. The most important thing to do with these illustrations is to enjoy them, appreciate them, and create your own ideas about what is happening in them.

24 May 2017

Pelvic Polacanthus

Tuesday there was a paper describing the pelvic armors of different ankylosaurs and Polacanthus was one of the ankylosaurs that was specifically mentioned because it possessed very unique pelvic dermal armors. Most ankylosaurs have somewhat uniform sheets, scutes, or patches of dermal bone that protect their dorsal surfaces. Polacanthus also has dermal armor along its back; however, the dermal armor along the pelvic region is uniquely constructed and protective of the dinosaur's pelvis and hips. Assuming that, as many ankylosaurs are thought to have defended themselves, Polacanthus made itself small when threats loomed, making it difficult to get at its soft underbelly, the expansive pelvic armor was capable of protecting the hips of the animal quite well as it would have served as an armored roof to that area. In many illustrations it appears as though the hips are still exposed (such as that below); however, in the skeletal reconstructions of Polacanthus we can see fairly well that the actual hip socket lies medial and ventral to the armored shelf of bone resting on the pelvis. In some line illustrations this has been exaggerated slightly, such as in the Nopsca drawing which pulls the shelf more laterally than some others, but these small errors in representation do not change the fact that the armored shelf protected the hips of Polacanthus very well and probably kept the dinosaur safe from most direct bites, slashes, and kicks to the hindlimb which, as we saw with Edmontonia, was most likely used to pivot the front shoulder spikes of Polacanthus in threatening displays or actual offensive strikes at rivals and predators.
©SADistikKnight (Robert)

23 May 2017

Polacanthus the Printed

Not surprisingly, there are a lot of papers on the armor of Polacanthus and its configuration. Of course, we should start with the original descriptions of Polacanthus fossils but there is only one of those available online. The first few description papers are short and largely unimportant; however, Hulke's 1881 description, featuring a number of quality line drawings of the known fossils to that time, is online and is worth reading. This was followed up approximately 20 years later by a review of English dinosaurs by Franz Nopsca with a dedicated chapter and new descriptions of Polacanthus. This trend of description has continued off and on through a number of different publications, researchers, and specific foci of research in general. The latest descriptive paper of Polacanthus actually describes a number of ankylosaurs and, specifically, focuses on the pelvic armor and its variations across all ankylosaurs.

22 May 2017

Park Darling

Polacanthus has appeared in a number of documentaries (including two episodes of Walking with Dinosaurs) as a major figure. However, the bulk of non-amateur created videos of Polacanthus are documented interactions of visitors to animatronic dinosaur parks with the statues at the parks. Not all of these moving statues are accurately built, meaning there are a lot of versions of this dinosaur at parks and "fossil zoos" that do not accurately portray the animal. The best model is the one shown below, though this clearly has some interesting individuality sculpted into it.

21 May 2017

Learn Your Polacanthus

Polacanthus is a bit more popular than a large number of other ankylosaurs and, by being one of those more famous and known dinosaurs, has a lot more pages and videos dedicated to it online than others. These include sites like KidsDinos and Age of Dinosaurs. As we know, most websites contain similarities and work with the same set of information to build their fact files and paragraphs of information. The same can be said for most videos. The prime example of this is the WizScience video series that relates the same information over a series of images of the fossil animal in question. Strangely, there is no cartoon for Polacanthus like the I'm A Dinosaur series; given its popularity this is a little strange.