Taking Away Fossils

There was a time when Stokesosaurus had a fairly large number of fossils attributed to it. There was even a second species considered for a short number of years not too long ago. This has since, along with all other fossils, including this braincase that was added to the pile of Stokesosaurus material, been overturned and assigned elsewhere. Juratyrant, the new genus generated from the reassigned second species, was described and reassigned by Roger Benson (with Stephen Brusatte as lead author of the reassignment paper). Brusatte and Benson's 2012 paper not only reassigned the second species as Juratyrant and removed a lot of the attributed material, but also investigated tyrannosaur systematics as a whole and re-envisioned their particular family tree (it was also rebuilt by Loewen et al. 2013 which was referenced here last year). Bickering about placements and materials should really be placed into the pile for later, however, for the casual paleontologist. The first step should always be to go to the source and attempt to understand how and why someone considered a fossil, isolated bone or otherwise, to be a unique species. We can go and read about the novel character interpreted by Brusatte and Benson along iliac surface, but first Madsen's reasoning behind attributing this isolated element to  new genus/species should be reviewed. Thankfully, that paper is available online through JSTOR. The description is very traditional in format: introduction, systematics, measurements, images, description, discussion, and conclusion. However, the description is quite detailed and describes other material originally attributed to the animal that is no longer associated with it, allowing for a comparison of attributed materials between that and the 2012 paper.

Motivated Models

Stokesosaurus and other Proceratosauidae are not well represented in the documentary sphere. However, one man, Shaun Stroud, has at least put some effort into making a model of Stokesosaurus.

His eye placement is a little off, but it looks like a fairly well designed model of the body overall. That model is a great deal closer to accurate than the model used in Zoo Tycoon. It is excellent that Stokesosaurus does appear in the game anyhow. Especially when it is painting:

Stoked for Sunday

Stokesosaurus is a well-known tyrannosaur, as we all know. Once again, however, a dinosaur with some clout to its name has come up somewhat dry in the website category. There are a few places to get information, but of course the more the merrier with checking information and compiling facts. The DinoDictionary has a nice concise list of facts for Stokesosaurus. About.com has a slightly wordier version, which is good for young readers to practice reading with. Putting the information into sentences rather than as phrases or single words is great for young dinosaur enthusiasts, as we have said many times over. There are no dedicated kid's websites and no coloring sheets or anything like that, but I wish I had some to share today.

Being Different

Usually when we think of tyrannosaurs we think of Tyrannosaurus rex and Tarbosaurus bataar and other large headed theropods that used their large teeth and bulk to hunt down, overpower, and subdue their prey. The Proceratosauridae were rather different members of the tyrannosaur family. A global distribution has been identified in the family as it contains English, Chinese, Russian, and American found fossil species. The namesake of the family is Proceratosaurus, a small Jurassic, English, tyrannosaur that was most likely capable of hunting in the dense forests that its larger later cousins may not have been able to penetrate. Along with Proceratosaurus and other small members of the Proceratosauridae, Stokesosaurus was probably a small but quick tyrannosaur that used its speed and hands in attacking prey. The differences between the more basal members of this family and the more advanced and larger tyrannosaurs are centered mainly around the heads and hands. All members of the Proceratosauridae appear to have much more streamlined heads that are more gracile and less muscular. The heads of these animals still possess tyrannosaurid characteristics but are much more primitive in shape and build. The hands are also more primitive. Advanced tyrannosaurs have shortened forelimbs and reduced digits on the hand. Proceratosauridae have slightly longer forearms, respective to body size, and a greater number, though still reduced, of digits in the hand. Exceptions and preservational bias can affect these traits in the family, but overall these generalizations can be applied to the family.

Stokes and Cleveland

Illustrated by Conty

William Lee Stokes and James Madsen are famous for the remains they recovered from the Cleveland-Lloyd Quarry in Utah. Thousands of bones were recovered by the pair including a number of Allosaurus remains. In 1974 Madsen cataloged those remains not then described, numbered, and stored. One of these sets of remains he noted as being entirely new to science. This dinosaur he described and named Stokesosaurus clevelandi in honor of his partner and the small Utah town of Cleveland where the quarry is located. The name has stood for 40 years now (there was a brief window from 1976-1980 when Peter Galton considered these remains to be potentially synonymous with British remains of the genus Iliosuchus) despite the holotype consisting of an isolated juvenile ilium, a paratype consisting of an ilium one and a half times larger, and a referred premaxilla. The premaxilla has somewhat recently been referred to Tanycolagreus, another small theropod considered to be more advanced. Opinions are somewhat divided but some consider Tanycolagreus a junior synonym of Stokesosaurus. In 1991 and 1998 new materials, ischia and caudal vertebrae and a partial braincase respectively, were attributed to Stokesosaurus. Studies of the remains continue to show up now and again and in 2012 novel characters were described from Stokesosaurus that allow it to continue to retain its position as a valid taxon. Things have changed drastically in where Stokesosaurus belongs on the family trees however. Described as a small generic tyrannosaur, Stokesosaurus is presently considered to be, more specifically, a proceratosaurid tyrannosaur. Tomorrow we will attempt to explain what that means exactly through the use of imagery and artistic interpretation.

Toys For All

It has been quite a few weeks since I have been able to share toys on here. We have discussed a number of dinosaurs over the past few weeks, at least, that had no toys. Toys are great for a number of reasons including putting dinosaur names into the hands, literally, of young dinosaur enthusiasts, potentially seeding the next generation with new favorite dinosaurs! The most unfortunate thing about some of those toys though is that they are only very vaguely reminiscent of the dinosaurs that they are said to portray. The group of collected prosauropods and basal sauroodomorphs below, for instance, is labeled with many names including Anchisaurus and Plateosaurus amongst a few others that may not even be recognized names now. At least the bipedal stance of these toys is mostly correct (forgive old toys for being propped up by their tails!). The hands are completely wrong of course, but there is a potential start to toy involvement with Anchisaurus.

©Dinosaur Collector Site A

Antsy Anchisaurus

Anchisaurus is a well read dinosaur. That means that there is a lot of literature out there at varied levels that is available to everyone to read; this is a very fantastic thing I assure you all. Marsh's original descriptions appear to be slightly misplaced, but there is the Marsh work Restorations of Anchisaurus, Ceratosaurus, and Claosaurus available online. It appears that it can only be purchased. This is okay though. We have seen Marsh's restoration. It is typical of Marsh and it looks fairly nice, but it is not anything too fantastic. Also out there, published in Wiley's Palaeontology, is an Adam Yates written revision of Anchisaurus. It is one of those articles that is certainly worth your time if you are willing to root around the internet, pay, or find a copy at a library and are interested in Anchisaurus. Additionally, and possibly more easily read, is a short article about the Connecticut Valley dinosaurs and a portion of the book Thunder Lizards. Portions of that chapter are available online and all of the Connecticut Valley article is online (in two places actually!).

Online Lies

The Smithsonian website lied to me today. I thought there was a short explanation of our dinosaur on it today and when I went to open it for everyone to preview it, it was not there nor was there any hint that it ever had been there. I was a bit perturbed. The only video I did end up finding for today is a 30-second clip that goes over very basic knowledge of Anchisaurus and abruptly ends mid-sentence. This is also annoying. Unfortunately this is not a dinosaur that has factored heavily into any documentaries or Dinosaur George questions or anything like that. Strangely, despite being one of those rare East Coast dinosaurs, it has not been discussed in videos anywhere on the news, through colleges, or anything local like that either. I hate having no outreach to share, but I have none today. For a similar dinosaur model in motion, you may wish to consider looking at an animal like Plateosaurus as featured in the first Walking with Dinosaurs special that ever aired. While not entirely accurate, Plateosaurus was similar in a number of ways. A point of argument may be locomotion similarities and differences however. The Walking with Dinosaurs Plateosaurus is shown as an obligate quadruped where Plateosaurus and Anchisaurus are both portrayed more often as facultative quadrupeds and even obligate bipeds. They are both considered basal sauropods and bipedality may have been characteristic of both animals.

Colorful Days

Anchisaurus exists on a number of kids websites including the NHM of London and a more detailed description KidsDinos. The notoriously bland drawings of Enchanted Learning can be used as coloring pages today, but there was also the line drawing of Josep Zacarias that could be used, with his permission, as a coloring page. I have told him he ought to make a coloring book in the past, and hopefully he can some day, but until then the most respectable thing to do is to ask him if he is okay with you and your family coloring his drawings. That image may no longer be online though meaning one would have to ask for it specifically. The Enchanted Learning image can be colored online, which cuts down on using paper and ink of course. This should provide enough starting material to talk about this East Coast dinosaur.

Old Art Like New Art

©Lancelot Speed 1905

The most recent illustrations of Anchisaurus resemble the 1905 interpretation of Marsh's line drawings alarmingly. Most dinosaurs have changed extensively in the past 100 years or so, but not so much Anchisaurus. The dinosaur has not been portrayed with feathering and the posture has not changed much at all from this illustration. Coloration of dinosaurs is always at the artist's discretion, so we cannot really critique the coloration too much. The hands of this illustration are markedly different from more modern illustrations, but this may also be an artifact of the lacking detail in the chest area of the dinosaur. It appears that the dinosaur is holding some sort of vegetation also, which obscures the hands even more. Probably the most disturbing thing about the old illustration aside from the little that has changed in modern renditions of the dinosaur is the snout on that crocodylomorph-like animal in the lower right-hand corner of the image.

Messy History

O.C. Marsh

Nineteenth century dinosaurs from North America are often confusing and jumbled. There are quite a few good reasons for that and the major reason that pretty much always sums up what caused such confusion hovers around the names Marsh, Cope, and Leidy (Leidy is not often between the others but was close to Cope). This week's dinosaur, however, was only confusing because it was massively confused, not because of infighting between paleontologists. Edward Hitchcock initially described this East Coast sauropodomorph and named it Megadactylus polyzelus in 1865. Twenty years later O.C. Marsh recognized the name as previously occupied and renamed the animal Anchisaurus polyzelus. Fossils recovered separately named Amphisaurus polyzelus Marsh 1882 and Yaleosaurus colurus Huene 1932 were later synonymized with Anchisaurus. The type specimen remains Anchisaurus polyzelus Hitchcock 1865. Anchisaurus is unique for a number of reasons including being an East Coast dinosaur, a sauropodomorph, and being mistaken for human remains at one point. Anchisaurus is a small bipedal dinosaur with an herbivorous diet known from Connecticut and Massachusetts with potential sister taxa discovered in Chinese and South African formations of the Early Jurassic (200 - 188 million years ago).

Gaining Popularity

As was mentioned previously, many times, the popularity of dinosaurs is highly variable. There are times when the dinosaurs in question are immensely popular and there are news stories that catapult dinosaurs into the limelight or reignite their popularity. Acheroraptor flew somewhat quietly under the radar at the end of last year when it was described. No documentaries, toys, or other popular science outlets have picked up on Acheroraptor have surfaced yet. This is a dinosaur that needs more charisma and outreach to become more popular as it is so young, geologically and by means of description. As much of a cop-out as it is, to say that there is nothing to share, there is nothing. Acheroraptor will only start to be featured in books, movies, documentaries, and other media outlets if people that love the dinosaur share it and make it more popular. The ball is in the public court with this dinosaur!

Pictures of the Environment

The Montana Department of Transportation hosts a rather interesting listing of geological roadsigns found in the state that discusses the Hell Creek Formation. It is a good place to start looking at the world around Acheroraptor. A lot is known about the Hell Creek Formation overall. The flora and the fauna are well documented and include some rather famous denizens of the Mesozoic. These include Tyrannosaurus rex, Triceratops horridus and Pachycephalosaurus wyomingensis. These large and well-known dinosaurs make up a good portion of the dinosaur species represented. There are also significant invertebrate, fish, amphibian, mammal, and varied reptiles (pterosaurs, crocodylomorphs, turtles, and squamates) recovered from the Hell Creek rocks. These are generally overlooked members of the representative fauna but each represents an animal that could have been prey of or preyed upon the medium dog sized Acheroraptor. The plants of Hell Creek represent a coastal/near coastal flood plain. Ferns, conifers, and mosses dominated the landscape that was evolving into a flowering plant paradise complete with palm trees, magnolias, beeches, and sycamores. This world has been described many times and the artwork depicting Cretaceous Montana is often very detailed and quite beautiful. Just look at images of Triceratops and  Tyrannosaurus in their environment. All of the images of Acheroraptor we have seen lack background, however, the Csotonyi piece that accompanies the ROM display and most announcements of the description shows a lush jungle-like scene along with a feathered Tyrannosaurus.

Pleasing Post

I am always happy when I can say something like this: the description paper of Acheroraptor is available online. However, today it comes with the caveat that it cannot be obtained unless you have a way to get articles from Naturwissenschaften or are willing to pay Springer's prices. These prices are typical for scholarly articles of course, but the bad news is that they are typical for scholarly articles. The first two pages are free to read. That is always good since there is always an abstract that summarizes things. New dinosaurs deserve the whole paper though so that you can fully understand it and/or ask the right questions to clear up what you do not understand. A little background and the systematics are nice, but even nicer is the fact that the 31 pages of supplementary information is online and free. This is the nitty gritty of the paper and, while it does not tell the story as nicely as the paper, it does present us with some nice images including radiographs, trees, graphs, and matrices. As an aside, it is kind of interesting how many question marks can fit on a page (not that I have not had my share of that in the past). The recommendation for the day is to try to find the descriptive paper. Barring that, at least check out the supplementary information, because that is pretty neat as well. It is highly informative of course and anyone looking to make a career in the field ought to practice reading and interpreting that sort of information at some level.

Non-motion Pictures

Usually when a dinosaur is announced there is a flurry of media coverage. There is probably a statistical study out there somewhere that has looked at certain names and their correlation to news coverage, but either way Currie is a name attached to this description that typically gathers some media references. That said, less than a year later I cannot find any television or internet video news stories of the description of Acheroraptor. This is okay also. Sometimes the best thing for a newly described dinosaur is to be largely ignored by the mass media outlets. This allows the dinosaur to be accurately discussed in the paleontology community without a dearth of misinterpreted facts hitting the street (like when Triceratops "ceased to be"). This also slows the popularity growth of certain dinosaur. Happily, we can educate ourselves by reading papers (we will do that tomorrow) and discussing the dinosaurs with others. There tends to not be much discussion here, overall, but it is certainly encouraged; I have as much to learn as anyone else around here from discussion with others. Therefore, without any kind of documentary or news story to turn to today, The education of the day really falls on everyone else to discuss. Some points that could be brought up about Acheroraptor include: How do we know from such little evidence that it is what we are told it is? How distinctive are the teeth of Acheroraptor? What kind of hands and feet did Acheroraptor have? Did it have feathers and what were they like? Think of how to answer these questions for people that are not very familiar with dinosaurs. Knowing how to explain your interests and hobbies to others is a life skill. You would not be reading this if you were not interested in dinosaurs so everyone here should know how to explain them to people that do not understand them very well!

Making Our Own Kids Site

Acheroraptor is a new enough dinosaur that there are not of links designed for educating children. Even our stalwart companions (e.g. About, KidsDinos, etc.) do not have pages hosted on their sites. If you are close enough to Toronto you can spend a day at the Royal Ontario Museum and learn about Acheroraptor while seeing the holotype and, potentially, meeting Derek Larson. The ROM Discovery Corner has an activity time listed to meet Derek Larson, but I think that this is for some time in the past. Though no longer current, he could be around still the museum and the fossils certainly are. I propose a short reading assignment for young dinosaur enthusiasts. There is a concise article on Sci-News.com that would lend itself well to a short reading and discussing the dinosaur. If the time for that does not present itself today then this should suffice for today (template for today borrowed from KidsDigDinos):

Name Means	"Underworld thief"
Type	Dromaeosaur
Lived When	67 - 65 million years ago
Weight	Estimated at approximately 40 kg
Height	Estimated at approximately 3 m
Teeth	Small recurved teeth designed for cutting meat
Diet	Meat
Habitat	Open woodland

The Details

From Evans, et al. (2013)

The key for the image at left is as follows: (a) Saurornitholestes langstoni; (b) Bambiraptor feinbergi; (c) Atrociraptor marshalli; (d) Velociraptor mongoliensis; (e) Tsaagan mangas; (f) Acheroraptor termertyorum.At first glance all six of the maxillae show here are very similar. They are quite similar to be sure. Their similarities are what led to the conclusion by Evans, et al. that Acheroraptor is a member of the exclusively Asian, to that point, velociraptorinae tribe. Looking at the bone the snout does look very Dromaeosaurid and its adult size, assuming that Evans et al. had evidence that this was an adult and not a juvenile of another species, is most definitely indicative of a smaller tribe of dromaeosaurs. The anterior aspect of the orbit appears to have a wider angle at the rostral end than any of the other orbits pictured here; only two of the compiled images have caudal orbital walls making comparison of that portion of the skull impossible. The overall upward curve and shape of the jaws are all highly similar, as are the teeth. However, the teeth of Acheroraptor are recurved less than those of Atrociraptor and Bambiraptor. They are more recurved than Tsaagan. Basing affinities in the tribe on teeth alone the closest members to Acheroraptor would be Velociraptor and Saurornitholestes. The relationships of these dinosaurs are not based entirely on teeth, however, this comparison of jaws is pretty great as a place to start comparing and analyzing Acheroraptor and its tribe.

Young Raptors

By Emily Willoughby, www.emilywilloughby.com
[CC-BY-3.0 (http://creativecommons.org/licenses/by/3.0)]

Welcome to the world of dinosaurs that will be ignoring the Spinosaurus circus. The only thing I am going to say about it is that we will not be talking about it at all.

The dinosaur in question this week, instead, is the newest, geologically speaking, dromaeosaurid from North America. The small Hell Creek dinosaur was described from maxillary and dentary bones containing teeth as well isolated teeth. The description is recent, it was published late last year, but has been accepted so far by the paleontology community without much of an audible uproar. The name given to the dinosaur is Acheroraptor temertyorum. The reference made to Acheron of Greek mythology means that the generic name loosely means "underworld thief". The specific epithet honors the Temerty family. James Temerty serves as the current chairman of the Royal Ontario Museum and Northland Power (a Canadian energy producer). The story of the dinosaur is more important. This new dromaeosaur is geologically young for a North American dromaeosaur and its anatomy is closely allied with the Velociraptorinae. Members of the tribe are typically small Asian dromaeosaurs. Acheroraptor is the first North American member of the tribe. Given the fragmentary remains it is hard to judge its size in relation to other members of the tribe. However, it is going to be an interesting exploration of this "new" dinosaur this week.

Making Do

How do we get dinosaurs to be more popular? Outreach of course, but how is that done with unpopular dinosaurs? Through a lot of luck and the love of people that know about the animal and already love it. Anserimimus has very little current research going on around it, but that which has been done has been done lovingly and the Barsbolds and Kobayashis have educated a new generation to love this animal. The current way to popularity for dinosaurs is not, thankfully, only through research and researchers. A dinosaur like Anserimimus can become popular through video games like Spore and Zoo Tycoon as well as through books, popular magazines (think National Geographic), and as toys. Unfortunately none of those things help out Anserimimus; there is a user created Dinosaur King style card out on the internet. The only way this dinosaur will become more popular, it seems, is by the word about the dinosaur getting spread. Work to spread the word of Anserimimus people, so we can have more popular dinosaur outlets for Anserimimus!

Where Do I Live?

Barsbold in 1988 assigned Anserimimus to a derived clade of Ornithomimosauria known as Ornithomimidae. Gallimimus has been confirmed a number of times, independently, as the closest relative of Anserimimus. The two genera are middle of the tree family members according to the most recent cladogram of Xu et al (2011). Regardless, as dinosaurs of reasonable size, approximately 14 ft (4.3 m) and up to 500 lbs (226.8 kg), Anserimimus was probably a common meal for large theropods of the Nemegt Formation including Tarbosaurus. As many Jurassic Park fans may remember ornithomimids are figured as skilled runners. The best defense Anserimimus had was most likely numbers in coordination with its speed.