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.

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:

Small Tyrannosaurs for Small Humans

As a well known member of the dinosaur community, Alectrosaurus has become a popular internet dinosaur as well. That in turn leads to more websites hosting appropriate reading materials for all ages. Since goal number 1 around here is to make dinosaurs and the science around them more accessible to all ages and all backgrounds, having more links dedicated to different reading abilities and interest levels always makes us happier people! We have today some of the typical websites that are definitely geared toward quick and easy access of facts for any reading ability like the NHM of London's Dino Directory, which happens to sport an outdated but absolutely awesome illustration of Alectrosaurus, and an updated and spiffy looking new About page complete with an updated and energetic looking Alectrosaurus pair from Sergey Krasovskiy. Lesser used pages also include pages on Alectrosaurus such as this one at Dinosaur Jungle and the wiki space for the pseudo-documentary Planet Dinosaur. What is lacking for such a well known dinosaur, actually, are coloring pages specifically dedicated to the small tyrannosaur. That is actually quite surprising!

Alectrosaurus is Short

In looking at illustrations and discussions the past 24 hours or so I have noticed that there has been a lot of debate around where in the family tree Alectrosaurus belongs. Some say it is an albertosaur, some say it is not. Some say it is not even a tyrannosaur. Most of that is either because of the low number of remains attributed to Alectrosaurus or because the remains point to an extremely short species of tyrannosaur. Regardless, the hypothesized extrapolation of the length and height of Alectrosaurus does indeed appear to indicate that this dinosaur was quite short. Relatively speaking, of course. However, compared to other tyrannosaurs that are well known (e.g. Tyrannosaurus, Tarbosaurus, Nanotyrannus), Alectrosaurus is a very short taxon. The height hypothesized is approximately 2 meters and length is approximately 5 meters. To put that in perspective, Nanotyrannus is approximately 2 meters tall and 5.2 meters long while Tyrannosaurus rex is approximately 4 meters tall and 13 meters long. The overall body design is usually typically tyrannosauroid, but little beyond the feet, tibia, femur, and referred skulls and hindlimbs are known. The referred material has not been assigned without doubt to Alectrosaurus, but that only means that any illustrations of the head and hands, like this one, are somewhat hypothetical, depending on how much assurance there truly is in the referred materials. Regardless, Alectrosaurus is still a rather sleek and dangerous looking tyrannosaur.

Trudging Through Mongolia

In the 19th Century England, Germany, then North America were centers of paleontological discovery. North America still is, but much of the world has joined the fossil hunt and there have been other centers of discovery as time has gone on.  Different parts of Africa were huge fossil hunting magnets over the past few decades. South America has really come into its own over the past few decades as well. For a time, multiple times actually, China and Mongolia have been big. One of those times was during the roaring 20's, pun certainly intended. In 1923 Walter Granger led the importantly titled Third Asiatic Expedition of the American Museum of Natural History. A young man named George Olsen spent the weeks around April 25 - May 4 of that trip digging in a small area and recovered the bones of what is now known as Alectrosaurus olseni. A couple of years later, during the same expedition, Olsen would find a dozen dinosaur eggs with his colleague, the slightly better known, Roy Chapman Andrews. However, the discovery of Alectrosaurus is much more interesting as it is one of the first Asian tyrannosaurs described. At times Alectrosaurus has been hypothesized to be an Asian albertosaur, but a rather long list of autapomorphies compiled by Charles Gilmore in 1933 and subsequent researchers concerned with tyrannosaurs seems to have cemented Alectrosaurus' place in the tyrannosaur family tree.

From now on Fridays will also include some taxonomy (better late than never?):

Kingdom:                                           Animalia

Phylum:                                              Chordata

Clade:                                               Dinosauria

Suborder:                                          Theropoda

Superfamily:                          Tyrannosauroidea

 Genus:                 Alectrosaurus (Gilmore 1933)

 Specific Epithet:                                        olseni

Alectrosaurus from Planet Dinosaur

Never A Cast

Aralosaurus has not, as yet, been singled out in dinosaur toy assemblies. It has been written about in scholarly papers, as we know, and Aralosaurus has been mentioned in much of the larger scale technical tomes as well such as The Dinosauria. It has not, though, been the subject of other popular outlets such as made for kids books, popular encyclopedias (think National Geographic rather than the more technical type), or magazine articles. Movies and documentaries are completely lacking Aralosaurus. Kids shows, even Dinosaur King and Dinosaur Train, have ignored the dinosaur. How or what has made its name popular then? The sole reason that I think we have been able to come up with this week is that this dinosaur is from Kazakhstan and very few dinosaurs have been discovered and described from Kazakhstan. Hopefully that number will swell in the future and more examples of this dinosaur will be discovered and described. Until that time, however, hopefully what has been discussed this week will cause Aralosaurus to become better known in the near future; that is kind of the goal of an educational blog like this after all!

Elephantine Chewing

Aralosaurus has been reported as elephant-sized based on extrapolations from the skull. The most recently updated (2011) appendix for Dr. Holtz's Dinosaurs encyclopedia lists Aralosaurus as rhino-sized. To differentiate the two, using this appendix's weight ranges, rhino-sized is between 1 and 4 tons while elephant-sized is between 4 and 8 tons. The discrepancy, on Rozhdestvensky's part, is most likely due to simple size extrapolation without regard to the actual weight of an elephant. It is quite possible that an Aralosaurus could have been nearly elephant size but in the same weight range as a rhinoceros. Of course, that could be a difficult thing to have happen: squeezing the weight of a rhino into an elephant sized package and not having extra unused space. 

The nasal protuberance, meanwhile, is not an indication of weight, as far as anyone can tell. The wideness and extension of the protuberance has led to speculation that it may have been useful in intraspecific combat and other mating or display rituals. How the protuberance was formed exactly determines how correct the hypothesis of intraspecific combat could potentially be. If the protuberance is more of a horn than a wide, flat, stable surface for butting, than butting could be lethal. If the protuberance is actually a fractional element of a hollow resonating chamber neither hypothesis above would be correct as the structure would be too fragile for any kind of combat. As a resonating chamber it would definitely be significantly useful in display though. My official opinion is that more evidence would be ideal but the evidence present is very inconclusive.

"Aralosaurus skull" by I. Reid (User:Reid,iain james) - Own work. Licensed under Public domain via Wikimedia Commons

Paper Days

Rozhdestvensky's original papers were written in Russian. Cyrilic is hard to read for non-Cyrilic readers typically. Thankfully, then, we have polyglot paleontologists that are willing to translate and post articles that have been translated! The Hadrosaurs of Kazakhstan is hosted on a site called DinoChecker and describes not only Aralosaurus but all of the other hadrosaurs that Rozhdestvensky discovered or described from Kazakhstan. Since that time, I vaguely mentioned before, many authors have revisited Aralosaurus for one reason or another. Godefroit and Alifanov (2004) revisited Aralosaurus for the sole purpose of describing the dinosaur again. Their redscription declared that Aralosaurus remains a valid taxon and discusses the distribution of the dinosaur during their existence. Averianov (2007) mentions Aralosaurus briefly in a discussion on theropods of Kazakhstan, but as they are not the focus of the paper they are only briefly treated. Two papers are particularly interesting from a cranial anatomy standpoint. Maryanska and Osmolska (1979) and Hopson (1975) both discuss hadrosaur cranial morphology with different emphases, but they also both mention Aralosaurus and discuss the known cranial anatomy of the dinosaur. Maryanska and Osmolska are overall more focused on certain aspects of the cranium and focus most of their descriptions and discussions on Saurolophus, but they do discuss characteristics of Aralosaurus in reference to hadrosaurs in general as well as Saurolophus in particular. Hopson, however, discussed the evolutionary trends of hadrosaur display structures of the cranium. While the majority of Aralosaurus' cranial displays are not known for certain, some inferences are made by Hopson of the Lambeosaurine group in general that could possibly be applied to Aralosaurus. There is a lot of good reading material here if one can access it. The Hadrosaurs of Kazakhstan is available for everyone and should definitely be on the reading list of anyone interested in Aralosaurus.

Aralosaurus Stagnant

Aralosaurus does not have any movies or even tribute videos. That is okay though. Instead, let us look at Aralosaurus geography today. Aralosaurus is one of very few known and described Kazakhstani dinosaurs. Present day Kazakhstan is a mountainous steppe country that lies in both Europe and Asia; the Ural mountains that separate Asia and Europe pass through the western portion of the country. This, in part, explains why the range of Aralosaurus, though found only in Kazakhstan, is described as existing in both Europe and Asia. Kazakhstan during the Cretaceous, the time of Aralosaurus was quite a bit different from what it is like today. Fossil seeds that have been discovered in Kazakhstan include members of the Magnolia family, particularly Liriodendroid (tulip tree) seeds. These types of trees typically inhabit temperate and tropical areas of Asia, suggesting that Kazakhstan was probably home to either a temperate or tropical climate during the Cretaceous. Overall, Kazakhstan's sites are not as heavily studied as many dinosaur fossil sites in other areas of the globe and this leaves a rather large gap in the known and hypothesized biology of Aralosaurus. However, with the knowledge that flowering trees existed in the general area of Aralosaurus it is not too much of a jump to hypothesize that the primitive lambeosaur may have been eating flowers!

Children's Kazakhstani Hadrosaurs

Aralosaurus has an absolute plethora of links for the interested children of the world. There are links for all levels of reading ability from the youngest with very brief and easy to read facts to much more involved and longer winded fact pages with more advanced readers in mind. Middle of the ability tree skill levels are also represented in a number of quality pages. Depending on how much your little readers want to read today there are longer paragraphs or there are shorter paragraphs available. Regardless, the interested younger reader is definitely well supplied today by websites catering to different reading abilities.

Hunted by Fragments

©Nobu Tamura

This illustration depicts what appears to be a tyrannosaurid attacking Aralosaurus tuberiferus. As two of the very few recovered remains of dinosaurs from Kazakhstan, this tyrannosaurid and Aralosaurus probably had significant contact during their species' time spans. Here the body of Aralosaurus has been detailed as very typically Lambeosaurine, which it should be, by all rights, if the assigned phylogenetic positioning proscribed to the fossils are correct. The most interesting aspect of this illustration is the interpretation of the wide protuberance of the nasal area. Many of the illustrations I have seen of this fossil animal "fleshed out", and even the fossil "blueprints" that included hypothetical extensions of bony and fleshy boundaries, show this as a part of a ridge that caudally slopes downward into the neurocranium rather than depicting it as a spiky protuberance, as seen here. These usual illustrations follow the illustrations of Rozhdetvensky's 1968 Hadrosaurs of Kazakhstan. Tamura's illustration is one of the few that strays from this in a way that is subtle and flowing rather than depicting it as a spike on the nose.The tyrannosaurid depicted in the attack is also based on fragmentary evidence, but was probably related to Tarbosaurus in some fashion; the closest discussion I have found in Rozhdestvensky's papers thus far are a few mentions of Tarbosaurus from Asia, but not Kazakhstan specifically. Eventually, as I hopefully mentioned yesterday, these dinosaurs will excite more investigation and these dinosaurs from Kazakhstan will become better known. For now, these are some of the best interpretations of the known remains.

Punishment Via Hadrosaur

Fragmentary hadrosaurs are recovered all over the globe. Therefore, deciding to discuss a fragmentary hadrosaur is a difficult and rather peculiar choice a lot of the time. However, it is always possible that the next dinosaur we discuss here may become the favorite of some young paleontologist who will devote their life to finding more and and may potentially make some earth shattering discovery. I am optimistic about the future today. There really is not any specific reason, given that Aralosaurus tuberiferus ("Aral Sea lizard") is one of those fragmentary hadrosaurs. As a primitive Lambeosaurine hadrosaur Aralosaurus was actually quite advanced compared to more primitive hadrosaurs and the known skull bears this out with approximately 30 rows of teeth numbering near a total of 1,000; the total number is not known as only the singular skull has been unearthed to this point in time. Discovered in 1968 and described by Anatoly Konstantinovich Rozhdestvensky, the skull is composed of a portion of the neurocranium, the maxilla, and a limited amount of the nasals and other components of the snout. Not much is known about the dinosaur, but it has been "revisited" a number of times, possibly due to both its primitive characteristics and its wide and prominent nasal protuberance. We will look at these bones in greater detail tomorrow.

©Brian Franczak

Sometimes Popularity Escapes the Popular

Aside from being much talked about, many times illustrated, and even vaguely represented in a single movie/documentary (it is a loose documentary), Unenlagia and Neuquenraptor do not seem to be very popular potential synonyms. No books are devoted to either, though portions of a healthy number of different books are devoted to either one or the other with very little overlap of the two being mentioned in any single given volume. Strangely, and perhaps it is because it is an IMAX movie, there is not a lot of tie-in material to the vague mention of the "raptors" in the loosely based documentary either. No plush toys or anything! Obviously Unenlagia has made it around the museum circuit, as skeletal displays and reconstructions that have been shared this week show. However, models do not appear to have made it around that are labeled as Neuquenraptor. This may simply be an artifact of the more popular name just being popular. Regardless, Neuquenraptor and Unenlagia are widely known dinosaurs, potential synonyms, and the first South American dromaeosaurs; all important positions for the dinosaurs to occupy in the world of dinosaurs.

First Not Worst

The first dromaeosaur discovered in South America was Neuquenraptor. The key dromaeosaur characteristic that was evident with the unearthing of Neuquenraptor was its dromaeosaur foot claw, though the other bones that were discovered also possess dromaeosaur characters. Unenlagia possesses many of the characters of other bones, including the pelvis, that are indicative of the familial relationship between Unenlagiinae and other dromaeosaurids. More important than the anatomical connections between these South American "raptors" and North American and Eurasian genera/species is the geographical implications that were made more apparent by the discovery of Neuquenraptor and cemented by subsequent discoveries like Unenlagia. While the geological implications do not, as yet, appear to be concretely established, the presence of dromaeosaurs in South America points to a land connection between the two Americas after Pangaea split apart. North America at the time would have been part of Laurasia and South America would have been part of Gondwanaland. Prior to the presence of dromaeosaurs on both Gondwanaland and Laurasia there has been no evidence, to my knowledge of hypothesized bridges between northern and southern continents during the Mesozoic post-Pangaea (this is something I definitely want to be kept aware of or corrected on if need be!). Alternatively, however, convergent evolution could be proposed for the occurrence of two groups of animals very much alike on vastly separated continents, though I do not know that anyone has proposed such a hypothesis in regards to dromaeosaurs of South America and North America and Eurasia.

Edit: To look at the map in a larger view, right click and choose view image. It works better than just clicking on the map.

Map of fossil sites of Dromaeosauridae taxa reported on the Paleontology Database

All Kinds of Papers

Mackovicky et al. (2005) described Buitreraptor and proposed that Neuquenraptor and Unenlagia were potentially synonyms with the older Unenlagia holding preference. We know, from previous discussions, that Novas and Pol (2005) disagreed by naming Neuquenraptor when they described it, since it was described a full 8 years after Unenlagia. If Neuquenraptor had been described shortly after it was unearthed rather than a decade later its name would have preference over Unenlagia. The original tentative name may have been used instead, however, so we might be having this debate between Araucanoraptor and Unenlagia instead. Novas and Angolin (2010) retained the individual genera, which I think makes it quite apparent that Novas does not agree with either the Mackovicky or Gianechini and Apesteguía (2011) interpretation of synonymy. It probably helps cement his viewpoint that he coauthored the paper describing and naming Unenlagia as well in 1997. Thankfully for anyone interested in entering in on the debate, though, we have this wealth of papers available online.

Tributes And Nothing Else?

Unenlagia has a couple of tribute videos to its name, but none of them are wonderfully accurate or informational. Again, I am not responsible for any of the images used in the tribute, found here, or the choice of music that is associated with the video. Either Unenlagia or Neuquenraptor appears in the 3D IMAX movie Dinosaurs: Giants of Patagonia, however, they are usually referred to as "raptors". The attribution as either one or the other depends on the review that is read, but Unenlagia is credited more than Neuquenraptor as the source dinosaur. This may be due to the fact that Unenlagia is slightly more well known, as the creators of the movie do not cite precisely what dinosaur the "raptors" are modeled off of for the film in any interviews or sources that I have been able to find. The entire movie is hosted on Youtube (including a version in Spanish, I believe) on a couple of channels, including this one, but are probably not endorsed by the studio or IMAX. Donald Sutherland has a pretty good narrating voice though, regardless of which dinosaur the model is supposed to be. Hopefully more of the fossils attributed to both species will be discovered and increased interest and knowledge will cause there to be more good scientific documentaries developed on these animals. However, we can make do, even if unhappy about the popular documentary format, with Giants of Patagonia for the moment at least.

Double Day

There are fact sheets for both taxa this week, yet another testament to the fact that the hypothesized synonymous nature of the two has not been cleared up quite yet. The About pages recognize both taxa equally hosting pages and well organized fact records for both Neuquenraptor and Unenlagia. There is not a single website other than this that hosts facts of both taxa, but the other sites that do have facts about the respective dinosaurs have pretty thorough facts listed on their pages. The majority of them address Unenlagia instead of Neuquenraptor. The most generous sites, typically, are among those that discuss only Unenlagia and ignore or omit Neuquenraptor. These include the NHM of London and Enchanted Learning.

Feet, Hands, Maybe Some Ribs

Fernando Novas and Neuquenraptor foot

Gianechini and Apesteguía (2011) further discussed the synonymy of Neuquenraptor and Unenlagia. Their paper discussed the skeletal remains and the amount and quality of that material. The phalanges are compared but the authors determined that the proposed synonymy is not possible to ensure based on the comparison of phalanges alone and there we have the main reason that Neuquenraptor and Unenlagia are still both considered valid taxa. The remains of Neuquenraptor also include the tarsals and metatarsals of the left foot, ribs, a radius, and a few cervical vertebrae. Gianechini and Apesteguía (2011) do not compare all of these elements in their discussion of the two genera in part because the remains of Unenlagia, both species, actually lack many of these elements. I considered posting the image from the above paper that best exemplifies the remains of Unenlagia on here, but I think that posting a link to another discussion of these taxa rather than just posting a second image is more beneficial to everyone. In fact, Jaime Headden's article treats not only the two taxa in question, but the entire tribe of South American dromaeosaurs. The remains available do not fit together in a peg and socket fashion, but the missing elements from each species do seem to coincide with present elements of the other species, which may or may not be a sign of the relatedness of the three species we are considering. Presently, however, the synonymy remains in question at this time despite the fragmentary nature of the animals.

References
Gianechini, F. A. and Apesteguía, S. (2011). Unenlagiinae revisted: Dromaeosaurid theropods from South America. Anais da Academia Brasileira de Ciências 83(1):163-195.

A Little Something Crazy

Unenlagia comahuensis ©Nobu Tamura

I want to do something crazy this week. I am going to discuss 2 (3 if we include a tentative name) dinosaurs that may or may not be the same dinosaur. "Like that hasn't happened before" some of you are probably thinking. In the search for a dinosaur for the week during my granola bar feast at lunch, I found a dinosaur name that led to a completely different dinosaur that has been mentioned as a potential junior synonym of a longer known dinosaur. All 3 dinosaurs have been questioned, placed in a subfamily known as Unenlagiinae, and have been described or redescribed a few times. Incidentally, or coincidentally as the case may be, all 3 are small theropods consisting of fragmentary skeletal evidence. Technically the first name, Araucanoraptor argentinus, was only a tentative name attached to the remains that were later named Neuquenraptor argentinus (Thief of Neuquen, Argentina) officially by Fernando Novas (Bernardino Rivadavia Natural Sciences Museum) and Diego Pol (Ohio State University) in 2005. The remains had been unearthed in 1995, the tentative name applied in 1997, and a familial relationship with the Troodontidae considered in 1999. In 2005, shortly after the remains were described and named as holotype of the species, a paper announcing the earliest dromaeosaur, Buitreraptor, from South America was published that suggested the two taxa Neuquenraptor and Unenlagia were similar in time and geography and may represent the same species but are too fragmentary to certainly tell apart. Oddly enough, La Buitrera, where Buitreraptor's remains were unearthed, is in Neuquen province. This matter appears to have not been definitively resolved as yet.

What about Unenlagia? Unenlagia comahuensis (Half-bird of Comahue) and U. paynemili (Half-bird of Maximilo Paynemil) were named in 1997 an 2004 respectively. The animals are both very similar to Neuquenraptor in that they appear to represent very fragmentary dromaeosaurid theropods. Initially Unenlagia was considered by Novas et al. (1997) to be a sister of extant birds, but Norell and Mackovicky (1999) disputed this claim and placed Unenlagia into the Dromaeosauridae where it rests today. I hope to dig up more on these two dinosaurs during this coming week, including some comparisons of the photographed material and maybe, if we are lucky, some commentary from some of the paleontologists involved.

References

Makovicky, P.J., Apesteguıa, S., and Agnolın, F.A. (2005). The earliest dromaeosaurid theropod from South America. Nature 437: 13.

 

Norell, M.A.; Makovicky, P.J. (1999). Important features of the dromaeosaur skeleton II: information from newly collected specimens of Velociraptor mongoliensis. American Museum Novitates 3282: 1–45.

Novas, F.E., Cladera, G. & Puerta, P. (1997) New theropods from the Late Cretaceous of Patagonia. Journal of Vertebrate Paleontology 16, 56A

 

Novas, F.E.; Pol, D. (2005). New Evidence on Deinonychosaurian Dinosaurs from the Late Cretaceous of Patagonia. Nature 433 (7028): 858−861

That Popular Canadian

Leptoceratops has appeared in many interesting and popular culture items and websites. reader information has even pointed us to pretty awesome information that I had missed. One avenue I have not mentioned this week is the popular literature. Academic literature we know has treated Leptoceratops well, but the popular books have somewhat ignored Leptoceratops. Technical volumes, not papers or journals, like The Dinosauria have at least mentioned the dinosaur, but that is not the type of book we usually look for on Thursdays.

Toys have appeared claiming to be Leptoceratops, but as usual they are more than likely based on Protoceratops. That does not take away from the fact that toy companies are trying to make Leptoceratops known to their markets and, consequently known to the next generation. Sadly none of the toys possess the cheek-less quality. That would probably either scare kids or change the face (literally) of the way that kids and the general public view dinosaurs.

Generalist Body Shape

Leptoceratops, along with many other dinosaurs, has a body shape that appears very general overall. This kind of body shape can be fitted to nearly any dinosaur from its family, like when someone draws a rather non-descript sauropod and it is subsequently labeled with any one of 50 different names. The small horns, for example, that contribute to the name Leptoceratops are actually present at different levels in almost all other protoceratopsians. The post-squamosal body of Leptoceratops is also quite general; a ceratopsian family "trait" could be said to be the lack of post-cranial skeleton resulting in exceedingly similar post-cranial bodies throughout the clade. This body is based on partial remains of numerous ceratopsians but might be said to be equal parts fact and fiction. Additionally, the "cheeks" are in question, as they are and have been throughout the history of descriptions of many animals within Ornithischia. There are some of us out there that grew up with dinosaurs with cheeks and that did not and there are some that have drawn conclusions based on evidence either for or against. My stance is that I take no stance because I have not actually thought it out independently for myself, though I have heard arguments against cheeks that make a lot of sense, so I may be slanting in that direction now despite having grown up with dinosaurs with enormous hamster-like cheeks around me. Leptoceratops without a cheek may have looked like the Yale Peabody Museum's cheek-less Triceratops (which was brought to my attention only very recently; no I have not been to the Peabody Museum, shame on me...). Regardless of the cheek situation, the post cranial body suffers from what I call "ceratopsian body disorder" that leaves it so that if you covered the head there would be almost no possibility of guessing the right dinosaur on the first try without firsthand knowledge of the small traits of its recovered skeletal remains. This can allow me to say, regardless of what dinosaur it was actually based on (Protoceratops, as usual), that the little dinosaur sidekick Pepperoni in Turtles in Time #1 is a Leptoceratops like dinosaur without being too far off. If you have yet to see Pepperoni, feast your eyes on this:

Available on many sites, but property of IDW Publishing and the talent of Ross Campbell

The Written Works of Leptoceratops

Paleontology has looked kindly upon Leptoceratops in the past. I sure that there are at least two parts to that phenomenon: 1) Leptoceratops is a ceratopsian and they always seem to capture interest and 2) Leptoceratops is a protoceratopsian-like creature but is in a very advanced position within that branch of ceratopsians. Regardless, a lot of papers have been written about Leptoceratops or its familial affiliations. Some of the best ones involve skeletal reconstruction and a fairly in depth discussion of the dinosaur by John Ostrom. Ostrom's description of Leptoceratops is not anywhere near as in depth as his description of Deinonychus, however, it is still well written and nicely detailed. There is also a paper, more widely encompassing Ceratopsia, that discusses Leptoceratops and the ceratopsian syncervical and how understanding its structure helps to understand the structures of the anterior cervical region of basal amniotes. This paper is a little closer to a "read it or you'll never understand it" than is usually presented here. However, as I usually state on Tuesdays, the most entertaining, but not always the most informative, papers are the original naming and describing papers that were published. Sometimes that is because of the antiquated language used and sometimes it is because of the imagination displayed by the author(s). This week, Barnum Brown's description of Leptoceratops is available to read. It includes many illustrations of the bones (see left) in addition to his detailed description of the remains.

Animated, Just Not on Film

As seen yesterday, Leptoceratops can be a very animated and is actually a fairly well known dinosaur. Unfortunately (trust me when I say I HATE starting sentences with that word) there are no documentaries available online that expressly mention Leptoceratops. There have been dinosaurs that appeared in documentaries I remember from when I was younger that appeared to resemble Leptoceratops and were "Canadian dinosaurs" but they were never referred to as Leptoceratops with a doubt. That sort of vague terminology haunted many dinosaur shows of the 1980's and 1990's; thankfully there were also more informative documentaries at the same time to make up for this. However, that leaves us in the peculiar place of having a well known dinosaur that does not appear in documentaries. We have been here before. In lieu of good animations of Leptoceratops images of Protoceratops could stand in but the habitat would have to be imagined a little differently. Leptoceratops may have also spent more time on two legs than Protoceratops, a characteristic that is a little harder to picture when viewing the linked video, but an interesting prospect that can be seen in Saturday's post featuring the work of Tuomas Koivurinne.

Destructive Leptoceratops

The Leptoceratops in the I'm A Dinosaur video is destructive and likes to show off her muscles. That is quite okay, because it is probably fairly accurate to state that Leptoceratops was a strong ceratopsian.

 That strength of the animal is not expressly mentioned in either the Enchanted Learning or KidsDinos fact pages. It is also not exemplified in either the accurate or inaccurate scientific illustrations that could be used for coloring or as visual guides for drawing your own Leptoceratops to color. Remember, if you use these to color ask permission before you try to post your artwork online!

Quills and Ceratopsians

The news of the potential pushing back of the origin of quills and feathers in recent mass media outlets is not really news to most paleontologists. While the evidence was not there until recently, the quills and potential feather shafts of ceratopsians have pointed paleontologists in that hypothetical direction for quite some time. Leptoceratops has, as a matter of familial traits if for not other reason, been portrayed with tail quills in the most recent illustrated versions of the dinosaur. Those quills have been popularized on Asian ceratopsians like Pentaceratops and Psittacosaurus. However, it makes perfect sense that the North American Leptoceratops, just a little further down the family tree, might have them also. Leptoceratops does look rather dashing with a tail full of quill knobs we have to admit. Evidence for them for this particular dinosaur does not exist to my knowledge, but with remains discovered from Alberta to Wyoming, there are probably many more remains out there to be uncovered and the evidence may simply be laying just under the surface of the stones.

©Tuomas Koivurinne

Forgotten Ceratopsians

©Nobu Tamura

Possessing a name that means small, insignificant, and meager all in one word is kind of sad. However, when the second part of your name means horned face, the small, insignificant, and meager horns seem a little less awful. When that name is in Greek it sounds even better: Leptoceratops. In Alberta's Red Deer Valley in 1910 Barnum Brown and his team unearthed what would be the first smaller ceratopsian dinosaur named and described. The small horns on the face aside, this dinosaur was already well established on the family tree, we just did not know it quite yet. Beak, teeth, and hypothesized cheek as well as a clearly defined head shelf (the meaning of "marginocephalia") were only a few characteristics of Leptoceratops that would be improved upon by later members of the family as they had been up to the time of Leptoceratops' roaming around in Alberta. That time, the Late Cretaceous, was certainly the heyday of the ceratopsians. The fact that these "advanced" but middle-of-the-family-tree characters were still displayed could mean a couple of things, one being that these smaller members of the family tree were beginning to splinter off in a new direction and another being that the cranial anatomy was well suited to dinosaurs of all sizes in the family. Small ceratopsians were, in fact, still doing well in the evolutionary scheme of things and Leptoceratops was the most advanced member of that branch of the family tree. Specializing in getting close to the ground to eat, these smaller ceratopsians could probably have foraged in denser forests than their larger cousins, eating all of the bushes, ferns, and flowering plants growing between the trees. Shearing teeth and a parrot-like beak with a powerful bite most likely meant that Leptoceratops was nearly as fearsome a defender of the dense forest as Triceratops was in more open areas, but with far fewer horns on its head.

New Dinosaur Smell

Eodromaeus is famous for being new. So many dinosaurs are more famous for being new than they are famous because of a great story or because it intrigued many generations of museum goers or paleontologists. It is such a new dinosaur, in fact, that toys and documentaries and the other venues of dinosaur fame have not really had enough time to take hold in the popular psyche. The videos shown on Monday detailed the news impact and the number of hosted copies of the naming paper also attest to the popularity of the animal right now. More importantly than any other outlet or popular culture characteristics is the idea that Eodromaeus helps us understand the origins of dinosaurs just a little bit more. Brian Switek's article for the Smithsonian covers this topic very well and deserves to be read. It would be a shame to rehash his arguments when his own words are available online, so I will not today. Eodromaeus is an early branch on the family tree, but a very important branch.

Shortening and Reducing

The forelimbs of Eodromaeus are shorter than the forelimbs. We expect as much when we are told that an animal is bipedal. We also expect it in theropods, regardless of how basal they might be. As we know and have seen over the past few years here, reduction of digits and shortening of the forelimb in theropods are common evidences in the evolutionary history of theropods. Eodromaeus, despite its rather basal placement on the theropod family tree, was no exception. Digits IV and V on the hands of Eodromaeus were noticeably shorter than the other digits and the forelimbs themselves were noticeably shorter than the hindlimbs. The center of gravity of the animal was shifted backwards toward the hips even further with the long balancing tail extending behind Eodromaeus. All of these characteristics, in addition to a "runner's leg" point toward an animal that may have been rather quick on its feet. Estimates of that speed, however, have not been made at this point through functional studies. Conservative estimates, though, have assumed that a speed of approximately 30 kph (19 mph) is acceptable. This is pretty impressive given its size of approximately 5 kg (11lbs) and 1.2m (3.9 ft) in length and that it was only about as tall as a Border Collie.

Separating News and Science

There are a lot of news stories that come up under Eodromaeus even on scholarly search engines. The paper of interest, and at this point in time there really is only one paper of interest, also comes up in those searches. It also has 18 internet sources, a rather high number for any scholarly paper to be honest. The number of, probably illegal, pdfs available is extremely high also. We as a group probably would not complain about that, however. Today I am inclined to allow the reader to choose their own version of the pdf to read by presenting the list of search results. Regardless of which pdf is chosen, the paper remains the same. It is a paper that presents a short 6 page description of the skeleton of Eodromaeus and compares it to other basal theropods (Herrerasaurus, Eoraptor) and Heterodontosaurus to determine its correct placement in the dinosaur tree. Figure 2 of the paper is my favorite. It shows an illustrated skeleton and the placement of the described bones in that skeleton. I would copy it here, but I think it would make a better surprise image. We know the outcome of the research, but it is an interesting read to see how Martinez, et al. got to that point.

The Experts

Today there are a couple of videos that I want to let do the talking. I think these days are typically very nice because it means we have interviews or quality news stories that address our paleo-fauna (if I ever address paleo-flora I would be amazed to find the plethora of videos we have found). Two good news videos exist that we can watch today. The two together may take up about 6 minutes of your time. The first is an interview with Paul Sereno posted by the University of Chicago's News Office.

The second is National Geographic's announcement of the naming of Eodromaeus. National Geographic does not have an embedding option on their video, but it does include the pretty awesome time lapse sculpting video within its video despite using some of Chicago's interview as highlights. I think these two videos are almost enough dinosaur for a day (is there ever enough paleontology in a day really?).

A Childish Post

Eodromaeus is a dinosaur that will eventually become a favorite. Having been named in 2011 it is still a little young to be capturing the imaginations of most of the younger generation of dinosaur enthusiasts and potential paleontologists. That does not mean it is not know about, only that the resources we have for younger readers are fewer than normal. The Dino Directory of the NHM in London, for example, has Eodromaeus listed, but does not have an actual entry for the small dinosaur. There is, as usual, an About fact page, but in all fairness to the rest of the internet they do have a staff writer assigned to dinosaurs, so they probably should have a page on every dinosaur (and we are very happy that so far there has not been one dinosaur/prehistoric beast where we could not have used About as a resource). Unfortunately, the lightweight dinosaur is a lightweight on the internet as well and has not made much of an impact past that page, in terms of short and easy to read facts that are kid friendly.

Running At Dawn

©Nobu Tamura

Eodromaeus has a typical looking dinosaur body plan. It diverges from what would become the body plan of theropods in a number of small ways including the number of digits present on both hands and feet. The primitive trait of 4 to 5 digits on hands and feet is exemplified in this primitive dinosaur, one of those traits that clearly allies this animal with the base of the theropod tree. This is not an animal at the base of the dinosaur tree, there are animals on lower brnches that are even more primitive including Herrerasaurus and other basal saurischians as well as the basal-most ornithischians. Like its cousins, the family Coelophysidae, and other theropods as well, Eodromaeus possessed a long counterbalancing tail that allowed it to maintain its balance while running on two legs. We know that most basal members of dinosaur clades started their evolutionary paths as bipedal animals, and theropods were no exception as their earliest forms, such as Eodromaeus prove. Theropods were fairly unique, of course, in that they as a group remained bipedal throughout their evolutionary line (arguments have been made to the contrary before).

How Was I Missed?

Somehow I managed to miss a rather interesting South American theropod dinosaur. The small theropod lived in the Late Triassic approximately 232 million years ago and is considered a basal dinosaur, some have even gone so far as to call it the "Eve" of dinosaurs. The skeleton was discovered in 1996 in Argentina by Ricardo Martinez and Jim Murphy in the Valle de la Luna Member of the Ischigualasto Formation. Initially the remains were thought to belong to a new species of Eoprator, previously discussed on this blog, but Paul Sereno, Martinez, and others that have looked at the remains determined that the animal was not a species of Eoraptor but a new species belonging to a new genus was named as Eodromaeus murphi. Like the "Dawn Thief" the "Dawn Runner" was an early dinosaur but unlike its near cousin, it is still considered a theropod; subsequent papers have named Eoraptor as an early sauropodomorph though this is still questioned.