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.

Describing Bird Mimics

The original description of Anserimimus it appears to be missing from the collections of the internet as a whole. This rarely seems to happen with papers as new as this (1988) but it does indeed happen. Instead, today there is quite a variety of papers that reference and somewhat describe Anserimimus or its neighbors on the tree. Though not the descriptive paper, the best description of Anserimimus in publication is probably an overview of ornithomimids from the Nemegt of Mongolia. Three species are treated in this paper by Kobayashi and Barsbold: Gallimimus bullatus, Anserimimus planinychus, and Deinocheirus mirificus. The known remains of each are well described and their assignments in the family are also discussed. Though not comprehensive of each species, the descriptions are nicely detailed and are fairly easy to read also. The aper is filled with illustrations and photographs, enhancing the written description by showing in addition to telling. This paper is a good read for all three species, not just Anserimimus. The other two major papers, Bronowicz (2011) and Kobayashi and Lu (2003), describe new material similar to Anserimimus and a new bird mimic (Sinornithomimus) respectively. Each paper describes Anserimimus and how closely related it is to the animal being discussed. Bronowicz's paper uses Anserimimus quite a lot because the new material he describes is very similar but distinct (he argues) from Anserimimus. The material described is not assigned in this paper though, so its placement is still up for debate. Kobayashi and Lu's description of Sinornithomimus relies on all ornithomimids and delves into the behaviors of members of the group. These are slightly speculative, as any paleo-behavior study is, but it is also a pretty interesting and well detailed paper. A slight spoiler, the behavior they suggest is a predation deterrent involving safety in numbers, their paper describes it in more detail of course.

You Won't See My Movies

The documentaries featuring ornithomimids are most often centered around the more popular and best known dinosaurs in the family like Gallimimus and Ornithomimus. Anserimimus does not feature in any shows, but for the most part much of the ornithomimid information presented in documentaries could overlap with Anserimimus. There are always gaps in the information and many times reading multiple sources, watching multiple documentaries, and contacting people that have worked with the fossils are the only ways to really learn about the animals. When faced with a lack of documentaries, or only documentaries that discuss related taxa, we have to rely on the other two sources of information. We can also go to the museum and look at the skeleton and the information in the museum and draw some intelligent conclusions. Barring intelligent conclusions, just enjoy looking at the mounted skeleton, like the one below, but remember, it is only a partial skeleton lacking much of the original animal and composed of many similar bones from similar animals.

Mimicking Other Links

The links for ornithomimids are pretty similar, but even Anserimimus has its own individual links geared toward readers of all levels. Probably because of the very weak popularity of Anserimimus there are only two actual websites that have dedicated sites for Anserimimus. Those sites are the NHM of London with its Dino Directory, and the ever present About dinosaur pages. Thankfully both of those sites are very well maintained and loved or we would not have any links today dedicated to mid-level readers or readers that are intimidated by large scientific paragraphs. The NHM site is minimal, as usual, but its tried and true site design is easy to read and use. About's newer site design is still easy to navigate and has slightly more difficult scientific paragraphs. Choose wisely, or choose both today. There are no alternatives, no coloring pages, and no videos.

Paddle Hands

Photo by Robert Bronowicz

The one anatomical character that separates Anserimimus from the ornithomimids is the manus. The fossils of the hand are fragmentary, just like the remainder of the animal's discovered remains. The known bones of the hand are flattened enough that their shape was significant enough that the shape was the basis of the specific epithet. The problem with an assumption that the bones are flatter than others in the family is that we run into all kinds of "what if" scenarios. The most hopeful situation is one in which there is nothing at all incorrect with the bones and that the flatness of the hand is exactly what it is, a flattened hand. Given the idea of accepting that it is the correct shape of the hand, what would a dinosaur need a flattened hand for? Swimming comes to mind, but there is no note of webbing on the hand or anything that would aid in swimming. A terrestrial animal with a flattened hand could most definitely use that hand for the purpose of digging. Many ornithomimids have been proposed to have enjoyed omnivorous diets. A specialized insectivorous diet, not merely the diet of an omnivore, could use a flattened hand to dig into crevices and tear plants apart and get at all those Mesozoic insects. Other uses are certainly possible. This use is definitely a bit more interesting. It is an adaptation than we do not regularly see in insect eating dinosaurs, but if anyone can think of one, make sure it gets shared!

Mocking Geese

The ornithomimids are general bird mimics, as the name states. Some of the more well known genera include an ostrich mimic (Ornithomimus) and a chicken mimic (Gallimimus). One of the slightly less well known bird mimics is a the goose mimic Anserimimus planinychus. A Soviet/Mongolian found Mongolian dinosaur, Anserimimus was discovered in the 1970's and described by Rinchen Barsbold in 1988. Like many other Mongolian dinosaurs discovered in joint Soviet/Mongolian expeditions, this dinosaur is known from a single set of remains. The body plan, overall, resembles other ornithomimid dinosaurs. The name Anserimimus is more traditional than it is descriptive. The dinosaur does not look anything like a goose. The specific epithet references the strange flat claws of Anserimimus. This anatomical characteristic sets Anserimimus apart from all other ornithomimids, but we will learn about that tomorrow.

Photo by Jordi Paya

The Alectrosaurus in the Room

Alectrosaurus is a rather popular animal. Likenesses of the dinosaur have appeared in Dinosaur King games (as user made cards at least), Spore, and in the Planet Dinosaur documentary that was aired on the BBC. On Monday we saw the short Planet Dinosaur clip that highlight Gigantoraptor and Alectrosaurus. Today we can feast our eyes on the best Spore has to offer. This is not the best Spore dinosaur we have ever seen, but it is rather well done except for the textures of the skin. The toy industry does not exist where Alectrosaurus is concerned, but that appears to be of no consequence to the popularity of this dinosaur. Despite missing many opportunities for gaining more popularity with a younger audience, the almost never seen in popular outlets for children Alectrosaurus is quite popular amongst children. Usually dinosaurs that are popular like that have many toys, models, games, and even books aimed at the younger audience. Apparently Alectrosaurus is popular with dinosaur enthusiasts for the sake of being popular alone!

The Leg Is Different

Alectrosaurus has a leg that has certainly led to some of the debate and confusion surrounding its placement in the tyrannosaur family. The reasons for this are that the leg, foot, and ankle are all of lengths that are atypical for tyrannosaurs. The tibia and femur are of nearly equal lengths. The normal condition in tyrannosaurs are tibia lengths that exceed those of the femur. Additionally, the foot and ankle are typically longer than the tibia length in tyrannosaurs, but again, Alectrosaurus differs from this trend by having a hind foot and ankle that are nearly equal to the tibia length. The implications of this change the movement of the dinosaur overall. Long tibiae have been used to indicate swifter running speeds in ornithomimids and the long tibia of Alectrosaurus may have been a useful tool in running at greater speed than other tyrannosaurs. Swifter running speeds may have allowed Alectrosaurus to out compete Gigantoraptor and other predators in pursuing ornithopods like Bactrosaurus and Gilmoreosaurus. A more complete fossil would enable more in depth studying of the gait, but for now the gait of Alectrosaurus is what it is and it appears to be a fairly swift gait also.

This appears to be partially based on a Ryan Lewis drawing, but has no clear attribution.

Describe and Revise

Mader and Bradley (1989) redescribed Alectrosaurus by revisiting the syntypes of the dinosaur that were unearthed by George Olsen in Mongolia in 1923. Gilmore described the dinosaur as a "Deinodont" (synonymous with "tyrannosaurid") that was similar to Gorgosaurus. Gilmore was very confident in considering this dinosaur a tyrannosaurid, but many more recent phylogenetic and systematics studies have questioned the validity of the assignment based on the fragmentary materials. Mader and Bradley turned the dinosaur upside down, but retained the tyrannosaurid connections. In fact, they considered it close enough to ally it with Tarbosaurus. They added previously unassigned caudal vertebrae (AMNH 21784) while eliminating some of the syntype material (forelimbs labeled AMNH 6368) based on the length of the limbs it portrayed. This places it in the Tyrannosauridae, however, Loewen et al. (2013) places Alectrosaurus in a more basal position outside of the Tyrannosauridae. Part of this study included the information that was compiled in Carr (2005) and is laid out in an easier to read list on Wikipedia. The swaying of assignment for this dinosaur has not been tumultuous at all. The only real swaying that it has done, actually, is in and out of the Tyrannosauridae family. At the moment it is outside of that family and is assigned only into the superfamily Tyrannosauroidea., but it has been considered a true tyrannosaur, an Albertosaur, an ally of Tarbosaurus, and it started out as an unknown theropod. Alectrosaurus has come a long way and, like many other dinosaurs, is still disputed, but is obviously loved by enough people to maintain its popularity.

References:
Carr, 2005. Phylogeny of Tyrannosauroidea (Dinosauria: Coelurosauria) with special reference to North American forms. Unpublished PhD dissertation. University of Toronto. 1170 pp.

Loewen, M.A.; Irmis, R.B.; Sertich, J.J.W.; Currie, P. J.; Sampson, S. D. 2013. "Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans". In Evans, David C. PLoS ONE 8 (11): e79420.

Mader, B.J., and Bradley, R.L. 1989. A redescription and revised diagnosis of the syntypes of the Mongolian tyrannosaur Alectrosaurus olseni. Journal of Vertebrate Paleontology 9(1):41-55.

Tribute Monday

Alectrosaurus tribute videos seem to be in every corner of the internet. Some of the best, as usual, borrow images that are not always the animal that they are supposed to be showcasing. A lot of them are actually 2D shadow puppet type shorts that are not scientific or really appropriate for our purposes. The Alectrosaurus tribute that matches our purposes best is actually a fairly good tribute video, which is rarely something that gets said with tribute videos. The best place to see Alectorsaurus however is episode 6 of Planet Dinosaur. While neither a strict documentary nor the best pseudo-science out there, the Alectrosaurs in the episode are well modeled (despite sharing a model base with Daspletosaurus) and they have some pretty fantastic interactions with the other dinosaurs of the episode. A small part of that interaction can be seen below: