Citipati's Anatomy

The skull of Citipati is among the most iconic skulls of all theropods, if not all dinosaurs. This skull has brought about much interest and description. The original description of the material, of course, is online and is worth reading. The paper includes detailed photographs of the skull Citipati and a second description of another oviraptorid, Khaan mckennai. One of the original descriptions was published less than a year after the description of the original material as a re-description of the cranium by Clark, Norell, and Rowe with comments on another specimen, Oviraptor philoceratops. This paper contains a detailed description of the cranial material and multiple angle, well labeled, photographs of the holotype cranial material, skull and mandible, that are very helpful for understanding the overall anatomy of the skull. The publication also includes CT scans of the material. Beyond the anatomy, Citipati has been used as a basis for parental care in dinosaurs and to explain the origins of avian parental care. Their nesting and parental care has also served as the base for growth studies in nesting dinosaurs. The reason that there are so many studies of Citipati eggs, nesting, and growth is because there have been many finds of Citipati on their nests as well as eggs containing Citipati embryo without the parents found nearby.

Photo by Jordi Payà from Barcelona, Catalonia

Forget Everything but the Short

There are a few mentions of Citipati in different documentaries and news stories, but rather than posting any of those today I think that the only video we need to really watch is a beautiful short showing Citipati. Unfortunately the entire short does not appear online. However, the trailer to the short (and the fact that it won an award) make me really want to find the entire film to share with everyone here. The film shows Citipati in an everyday-life situation that then gets turned upside down and shows Citipati in an environment that really evokes the namesake of the dinosaur; the Buddhist protector deity and "Lord of the Crematorium" Citipati. Please find the trailer, posted by the creator Andreas Feix, below, and take a moment to enjoy the film that you can see. I hope to hear from Andreas to be able to share the full short with everyone soon.
Citipati (2015) - Trailer from Andreas Feix on Vimeo.

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.

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

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.

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)

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.

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.

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.

More Ankylosaurs

During the past week I made mention of different types of ankylosaurs including their namesake group, nodosaurs, and polacanthids. This week to continue painting that picture and better understand what makes each kind of ankylosaur fit into that familial relationship, we will discuss the polacanthid Polacanthus foxii, the namesake of its subfamily. Polacanthus was originally discovered by the Reverend William Fox of the Isle of Wight in 1865; hence the specific epithet. This came about because the reverend, disliking a name given by Lord Alfred Tennyson (Euacanthus Vectianus), the first describer of the fossil, presented the fossil to Richard Owen with the new name in tow; this information is attributed to an anonymous pair of 1865 sources thought to be by Owen, Fox's own 1866 writings naming Owen, Huxley's 1867, and Hulke 1881. Regardless, Polacanthus was an ankylosaur of respectable size, measuring in at approximately 5 m (16 ft) and weight estimates of approximately 2 tonnes. Featuring armor and spikes similar to other ankylosaurs, Polacanthus was not a typical armored dinosaur and possessed unique armors, especially over the pelvis, that separated it from its closest relatives in unique ways.

Model in Sandown, Isle of Wight, Photo ©Henry Burrows

Special Edition - Save the Fossils and Their Land!

peak out for fossils! Executive order 13792 mandates a review of the boundaries of 21 US national monuments, including two whose express purpose includes protecting vertebrate fossils -- Bears Ears and Grand-Staircase Escalante. Both monuments are in southern Utah and both contain rich vertebrate fossil resources.

Please consider commenting that the boundaries of Grand Staircase-Escalante Monument should be maintained and and those of Bears Ears expanded.

Comment submission form: https://www.regulations.gov/document?D=DOI-2017-0002-0001

Deadline for comments on Bears Ears and Grand Staircase-Escalante is May 26.

Famous Dinosaurs

The popularity of Edmontonia is rooted mostly in its representation in the fossil record. Some very popular and well known dinosaurs have not been well represented in the fossil record, so we can certainly say that it is possible to be poorly represented but very well known. Edmontonia is one of those dinosaurs that is both well known and well represented. Due to this popularity it appears in video games, card games, documentaries (announced simply as "an ankylosaur" in the linked video), cartoons, books (too many to list), and almost any other medium one can think about. I like to share, when they are available, these images from information cards on dinosaurs because they re the kind of things that I used to love when I was a kid and really got me into dinosaurs (of course I am a huge nerd though). These summarize some of the things we know about Edmontonia at the same time as making the animal appear dynamic and interesting to people that would consider themselves dinosaur enthusiasts. They serve the purpose of a popular culture outlet in that way exceedingly well, and are therefore an important resource for popularity day here.

Dermal Armor and Spikes

E. rugosidens, specimen AMNH 5665
Photo ©Shriram Rajagopalan from Vancouver, Canada

The armor of nodosaurs is generally similar across taxa with variation changing sizes, shapes, and numbers of plates and spikes depending on not only the genus or species, but also the individual animal. Edmontonia, for the most part as a genus, possesses armor that is constituted of flat, mostly smoothed, dermal plates starting with laid out rounded rectangles in organized rows from the neck into the tail. The skull and head lack dermal plating entirely. Over the pelvic and pectoral girdle the dermal plating is significantly different, making the armor patterns similar over the torso and abdomen and pelvis and tail. The torso and abdomen pattern consists of large oval plates guarding large areas of the rostral back (dorsum) of the animal whereas from the pelvis to the caudal-most plates the shape of the plates is more spherical and the shapes are more populated. This causes the armor to leave smaller gaps, possibly providing greater overall protection from crushing bites and injuries than the more rostral armor. The trade-off is in the sizes of spikes and mobility; not to mention Carpenter's hypotheses of sexual dimorphism and/or age as judged from the sizes of shoulder spikes. Nodosaurs do not have tail clubs like ankylosauridae genera nor do they have vertical spikes or sheets of armor across their pelves like some polacanthinidae genera. Instead, nodosaurs like Edmontonia possess large lateral spikes across their shoulders with smaller spikes trailing down to the pelvis, a trait that has led to many representations of nodosaurs hopping about to thrust their shoulder spikes at attacking predatory dinosaurs. The smaller links of armor around the pelvis would enable such movements as the plates would not take up as much space and could be compressed well as the animal twisted and turned. Additionally, the large plates could be similarly manipulated to manipulate the shoulders, but larger plates need more space between one another to move in a similar fashion, which could account, in part, for the large gaps between plates in the torso area. These large gaps could have also enabled the animal to look upward at a slight degree as the spacing between rows could be compressed as the head and neck pushed the extreme rostral rows of dermal plates back toward the shoulders.

Please remember that these are hypotheses based on looking at fossils, the papers of others, and generally restating shown interpretations of the animal already distributed via film and screen and that we still have many unanswered questions about these very interesting animals. When traits like spikes and armor plating are highlighted everyone automatically (it seems) thinks of two possibilities: defense or mating. The defensive capabilities of nodosaurs like Edmontonia are fairly clear in looking at the skeleton and associate spikes and dermal plates: a large, but squat, animal with hardened scales on its back and large sharp protrusions of bone was probably very good at getting low and defending itself regardless of how it actually managed it. If its shoulder spikes were used as offensive weapons they were probably used mainly to intimidate as they would otherwise need to be picked up, moved with speed, and very accurately aimed. Any movement that elevated and sped up the body of this animal would have left the unprotected underbelly exposed long enough that it could have been tragic. This leaves us with two possibilities, as I see it: Edmontonia was much more turtle-like in its defense of itself or it was a brash and intimidating animal that attempted to scare away predatory dinosaurs rather than actually fight them. Both of these possibilities are intriguing and the behaviors behind both could be fascinating. Please feel free to discuss the likelihood of either or both scenarios. I enjoy these kinds of conversations and thoughts.

Edmontonia the Northern Dinosaur

Whenever we hear and see discoveries from the extreme northern or southern areas of the globe there is a certain amount of amazement not only because of the remoteness of the discoveries, but also because of the idea that dinosaurs lived in colder areas. This, of course, is regardless of the current climate in these areas. There are hypotheses of the climate, seasonal change, and temperatures of places like Antarctica and Alaska. These are discussed in the literature concerning Edmontonia on a fairly regular basis because many examples of the animal have been discovered at higher latitudes in both Canada and Alaska. New species of Edmontonia were hypothesized from Alaska during the 1990's, such as in this Gangloff article from 1993 calling the remains the first ankylosaur remains of their kind from Alaska. A great deal of the Edmontonia articles do not reach as far north but stop with remains from Dinosaur Provincial Park in Alberta, which has held a wealth of Edmontonia remains that have been recovered. This has led to many studies revealing more about cranial anatomy, flexibility in naturally occurring dermal armors, or even the teeth of Edmontonia (or whatever ankylosaur you are personally interested in).

Watching A Drawing

Sometimes my favorite videos are not portions of documentaries or news stories. Some of my absolute favorites are actually sped up art videos. Whereas I have a few not-so-good documentary clips and one fairly nice time-lapse artwork image, I choose to share the artwork today instead of the weak documentaries. There are nodosaurs in documentaries that are based off of Edmontonia more than any other nodosaurs; however, given that these are only based on the dinosaur and do not expressly discuss the animal, the artwork video is still a slightly better choice for sharing today. Enjoy!

Nodosaur Facts

For Sunday's fact entry, I am choosing to link a few videos. The I Know Dino podcast about Edmontonia says anything and everything I could in a nice quick format. I Know Dino is run by a team of dinosaur enthusiasts that has made digging up and presenting information about dinosaurs their number one goal.

The Dinosaur Diversity lecture in University of Alberta's Coursera lecture series also discusses, and shows, Edmontonia and the anatomy of the dinosaur. This lecture can be found here.

Edmonton's Nodosaur

In the news lately there has been a lot of talk about a nodosaur mummy. This week, therefore, I thought it would be prudent to discuss a nodosaur, though honestly a totally different nodosaur than the fossil mummy. This week's nodosaur is known as Edmontonia and the genus contains two species: E. longiceps and E. rugosidens. Nodosaurs like Edmontonia were covered in osteoderms and armor that we will see plenty of this week. Known from materials originally discovered in 1915 from the Edmonton formation of Southwestern Alberta. Specimens have been discovered as recently as 2010 and the taxonomic history of the genus is interesting and complicated. A lot is known about Edmontonia and so we will have a lot to discuss this week, but before we do, appreciate some art based on the original finds.

©E.M. Fulda, 1922; based on the 1915 AMNH specimen

A Busy Day

Yesterday was busy, so here is Friday's artwork on Saturday afternoon (I will get you all a new dinosaur/fossil within the next few hours). The artwork I shared the other day was a brilliant family portrait of a Troodon and three young animals on a beach. I could easily put another well done family illustration as there are plenty of them online; Troodon families are apparently a very popular motif in the paleoart world such as Blair Sampson's woodland family illustration. This extends not only to young animals but also to eggs and groups of adults as well. Groups of Troodon are, simply stated, popular topics for people to draw and paint. As long time readers know, I prefer well thought out or imagined artworks that challenge our preconceptions or show active and energetic animals. Unfortunately, there are a lot of Troodon images online that are one or the other but not very often both active and imaginative. This image comes from BBC's Prehistoric Planet, which shows the dinosaur in many active and imaginative situations. The feathering that was placed on this Troodon is rather extensive, but looks very well thought out, not simply plugged in to make a completely feathered dinosaur.

©BBC, Prehistoric Planet

Seen on Video

Dale Russell and Ron Seguin, 1982 
Canadian Museum of Nature, Ottawa, Canada

Troodon has appeared in so many popular venues from books to video games to movies to toys that it is nearly impossible to focus on any single area of the dinosaur's sphere of influence. Instead, we should look a little closer at Dale Russell's interpretation of Troodon evolution and the hypothesis of its continued and increasing intelligence. This hypothesized animal was dubbed Troodon sapiens by Russell and was given form by sculptor Ron Seguin in 1982. I remember seeing it when I was young and being impressed and a little confused. The idea that other forms of animals could take on humanoid forms in the course of their evolution was very odd but not out of the realm of possibility. An intelligent dinosaur, like Troodon, that had been able to evolve (without a major extinction event limiting them), would have potentially been capable of evolving large heads and changing their posture. Therefore, Russell's hypothetical "Dinosauroid Man" was not, and is not, actually all that bizarre. Though any dinosaurs, intelligent or otherwise, could have potentially evolved into more upright, tail-less, postures over millions of years. The fact that someone put that idea into a solid form and wrote a paper about that idea is bold, but that did not endear Russell to everyone. Though I do not know how controversial the "thought experiment" was or still is, it was apparently controversial enough that many disliked it. One of the chief complaints, and what makes it so eerie, is the extent of the antrhopomorphic characteristics of this evolutionary experiment. As I mentioned on Monday (or Tuesday because I mixed up my days), discuss this sculpture, but do not lose friends over it!

Anatomy of A Stereotypical Dinosaur

Troodon is nothing if plain looking in terms of dinosaur morphology. In modern terms that even includes the inclusion of feathers along both limbs and the majority of its body. The more numerous, and older, portrayals of Troodon are still out and flooding the internet with gracile dinosaurs that look emaciated and a strange oily green-black skin. That skin was typically portrayed as smooth rather than scaly but it is not overly important, considering that the interpretation and knowledge of what Troodon probably looked like has changed and become so much more feathered. Troodon was not, as we tend to see stereotypical gracile dinosaurs thought of, a small animal either. The dinosaur was approximately 2.4 m (7.9 ft) long and tall enough to rival the average human, though at 50 kg (110 lbs) it was the weight of a large dog, which many of us know does not need to be tall to knock down an average sized human being. Exhibiting eyes that face partially forward, indicating depth perception capabilities, that were rather large proportionally, indicating a potentially nocturnal lifestyle, and a brain that was equally proportionally large for its size, Troodon was most likely a very intelligent animal. Intelligence has been debated for a long time in fossils, but Troodon, for many years now, has been generally accepted as an intelligent dinosaur that was capable of manipulating its manual claws, i.e. that it was able to grasp and manipulate objects. This has many implications, including the idea that intelligence and social behavior often go hand-in-hand. That idea specifically has led to many great interpretations of the dinosaur and its capabilities and has told us a great deal about the intelligence of these animals once thought of as slow, stupid, and mostly solitary outside of herds.

©Taena Doman