What Large Eyes

The eyes of Leaellynasaura are thought to have been quite enormous, given the size of the orbits of the skull. Proportionately the orbits, and therefore the eyes, are quite a bit larger than most other dinosaurs that have been described to this point in time. The point of large eyes is, probably without needing to be said, to see better in lower light conditions. Polar winters, having longer periods of darkness, would have required animals to possess many specialized adaptations like enlarged eyes in order to successfully survive in the darkness. Without adaptations like these the ornithopods like Leaellynasaura, such as Muttaburrrasaurus, would have had to migrate away from the Antarctic Circle. More sensitive eyes, in addition to unknown adaptations of the softer anatomy that have not been preserved, allowed Leaellynasaura to take advantage of the nearly vacant polar stretch of Australia during the winter season. Predators were mainly represented at this time by smaller forest dwelling theropods like the generically named "Dwarf Allosaur"; which to this point is highly speculative and without solid evidence. It is logical, however, that some predatory dinosaur would have been able to withstand the winter conditions with similar adaptations to Leaellynasaura.

Written Leaellynasaura

The accessibility of some papers is better than others. The accessibility of free results for Leaellynasaura is one of those conundrums that ends in disappointment; not that there are not papers out there, it is just that they are nearly all well about the $30 mark. Scientific American, thankfully, bucks this trend a little by making an issue with references to Leaellynasaura and other Antarctic dinosaurs available for only $8. The Journal of African Earth Sciences is another place where we can find the importance of Leaellynasaura in writing. This time the article was pertaining to the significance of Gondwanan polar dinosaurs in the history of dinosaurs as a group. Taylor and Francis, probably not surprisingly today, takes the prize for most expensive articles (they are cheaper in some journals so please do not assume I hate Taylor and Francis). Coming to us at $44, the article reexamines the holotype of Leaellynasaura and addresses doubts and worries concerning the relationship of the skull and body skeleton of the holotype. As with any potentially volatile situation, I would not like to make assumptions on the outcome of any article I have not been able to read in full, but considering that Leaellynasaura is still considered a usable name it is fairly safe to assume that the doubts were confidently negated by the article.

The Dinosaur of the Week Walks

This is one of those days that the movie gets to do the talking for us. Enjoy this episode, if you have not previously, of Walking with Dinosaurs:

Parts 2 and 3 can be found from this part.

Snow Covered Forest for Kids

Leaellynasaura is one of those types of smaller dinosaurs that people, for lack of a better term, consider adorable. Not much needs to be said in addition to showing the links for the day honestly, considering that Walking with Dinosaurs has done a rather good job of describing Leaellynasaura. KidsDinos has a nicely shortened and concise web site for Leaellynasaura. Enchanted Learning has a good site with a fairly nice illustration, thankfully. There are few times we get to mention Enchanted Learning having a quality illustration to color, so I enjoy getting to say that today. There is also the below coloring page that depicts a very angry looking Leaellynasaura.

Furred Polar Brrrrs

Leaellynasaura was a polar dinosaur. The area in which Leaellynasaura lived was well below the Antarctic Circle meaning that during part of the year, at least, the Antarctic winter caused that area of Australia to be darker and colder for a longer portion of the day. To combat this the long tailed and large orbited Leaellynasaura could have certainly been feathered, or at least covered in a fine downy coating of adaptive filoplumes. Though, to my knowledge, no evidence of these filoplumes has been recovered with the remains of Leaellynasaura. Ornithopods with this kind of covering, and we may find the evidence for it, then push the origin of filoplumes into a rather odd direction marking it as either independently evolved in multiple lineages (Theropods, Marginocephalians, and then Ornithopods at least) or being derived from a much more ancient common ancestor than previously assumed. Regardless, a furry Leaellynasaura running through the snow covered darkened forests of Antarctic Australia foraging for what little food is available are pretty fantastical and intriguing. It is quite unique as well, of course; thinking of dinosaurs as snow dwelling dinosaurs. The majority of images of Leaellynasaura portray a scaled ornithopod and a feathered, or down, covered version is quite fantastic.

Next Oldest Post

Nobu Tamura

Continuing in the revamped original 8 posts this week is Leaellynasaura. Another Australian dinosaur from south of the Antarctic Circle (look back to Atlascopcosaurus), Leaellynasaura amicagraphica was named after the daughter of Tom Rich and Patricia Vickers-Rich (Leaellyn Rich); our intrepid Australian dinosaur discoverers of countless specimens. The specific epithet references the Friends of the Museum of Victoria and National Geographic, which have helped finance  Australian paleontology for years. Two nearly complete skeletons and two fragmentary skulls as well as multiple other fragmented skeletons have been recovered. The tails and orbits of Leaellynasaura are defining characteristics of the small ornithopods and represent highly adaptive evolutionary characters of the skeleton suited for the polar ecosystem in which they lived. Small forest dwelling polar ornithopods are the topic of the week here, be prepared!

What Has Not Been Mentioned

This week has been fraught with popular culture references already; it almost seems like too much to devote an entire post to popular culture. However, I have barely scratched the surface of how many times Deinonychus has appeared somewhere on television or in the movies. Accepting that the dromaeosaurids of Jurassic Park are meant to be based on Crichton's description of Deinonychus (as Velociraptor) we can say that Deinonychus has appeared in at least 4 feature films; it is very safe to say that the 4th installment will have some of these fellows floating about. There are also appearances in numerous documentaries, television shows, cartoons (including Dinosaur King and Dinosaur Train), and even video games (both Zoo Tycoon and Spore models have been made). It has also appeared in many books, as many different toys, sometimes as a plush animal, as models, statues... really there is too much to link today, so I have not created links for all of these categories. Deinonychus is a very prominent dinosaur in the dinosaur figure arena. Most of the plush dinosaurs have been fairly inaccurate; this is what I would love to see as a plush version:

©John Conway

Something We Often Missed

©Emily Willoughby

Deinonychus was a tad slower than we have been led to believe. Ostrom (1976) stated that the foot-tibia ratio of .48 indicated that Deinonychus was not much faster than contemporary dinosaurs. Some estimates put its top speed at around 6m/h; still plenty of speed to run down a human being of course. It also ranged a lot further than previously thought according to a hypothesis based on teeth from Maryland. These teeth were described by Lipka (1998) as being near deinonychid if not from Deinonychus itself. Speaking of those teeth, the bite force of Deinonychus was found to be relatively weak; recall papers from yesterday. They were short recurved teeth designed for tearing flesh, but they were weakly rooted and the force of bite was not sufficient to be the main predatory apparatus of Deinonychus, meaning that the feet and hands were most likely responsible for the killing of prey items and that the muzzle most likely acted in coordination with strengthened arm muscles and sometimes weight, while standing on its prey, to aid in the tearing of flesh while dining on its victims; not unlike the feeding Deinonychus in the Emily Willoughby image today.

Lipka, Thomas R. "The affinities of the enigmatic theropods of the Arundel Clay facies (Aptian), Potomac Formation, Atlantic coastal plain of Maryland." Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin 14 (1998): 229-234.

 

Ostrom, J.H. (1976). "On a new specimen of the Lower Cretaceous theropod dinosaur Deinonychus antirrhopus". Breviora 439: 1–21.

Writing About the Terror

©Emily Willoughby

The definitive description of Deinonychus material was penned by John Ostrom in 1969 and was published in that July as a 172 page edition of the Yale Peabody Museum Bulletin. Description of the materials are rigorous and make up nearly 135 pages of the bulletin with only about 20 pages discussing the habits and placement of Deinonychus. A more in detail description of anything would be difficult to find, but our vast knowledge of the skeletal material and composition of Deinonychus comes from this absolute tome. Since that time there have been many other studies of Deinonychus including predator-prey taphonomy studies and studies of pack hunting and gregarious habits amongst members of the species. As noted Saturday studies have been conducted on the use of the noted and infamous claw of Deinonychus (and other Dromaeosaurids) but little mention has been made of studies concerning the forelimbs of these animals. Senter 2006 explored the comparisons of forelimbs of Deinonychus and Bambiraptor and determined a number of interesting outcomes from manually manipulating the forelimbs. One important outcome of the study is the knowledge that Bambiraptor had the ability to grasp things one-handed while Deinonychus did not have the dexterity to do so. Bite force has been calculated for Deinonychus as well, leading to a nearly completed picture of this dinosaur from head to tail and inside out.

The egg mentioned previously is, however, a "new" and important discovery. The egg is actually associated with gastralia from a 1931 dig and, as such, is not actually new, but has not been studied in depth until recently (some may be able to generate the full pdf through EBSCO).  The egg is small and crushed, but shares many characters with known theropod eggs and is confidently placed between oviraptorid and troodontid egg characters, making its likelihood of being representative of Deinonychus, and therefore one of the first recovered Dromaeosaurid, eggs much more likely. Preservation of the shell itself is considered to be phenomenal and the images taken from the egg by various means including high resolution microscopic images, are astounding. The fact that the authors determined it to be associated with the adult skeleton makes the find that much more remarkable and, with certainty, we can now say that we have recovered the first Dromaeosaurid (and Deinonychus) incubating an egg as well as the first egg of its kind. It makes the image at the top of today's entry seem that much more relevant.

Movie Star Here

Slightly larger than they should be, and under the misnomer of Velociraptor, dinosaurs based on Deinonychus but the size of Utahraptor pepper all of the Jurassic Park movies. Understanding the idea of Michael Crichton and being quite happy with the fact that he used a synonymic name that was, by the time of the movie's release, outdated and overturned, I am quite okay saying that Crichton's "raptors" were as accurate as he intended them to be in his book. Bearing that in mind, look at the "raptors" of Jurassic park in the way they were intended to be portrayed:

Also, one of my favorite quotes from the book:
“Hammond whined. ‘But what are you going to do to my animals?
‘That’s not really the question, Mr. Hammond,’ Muldoon said. ‘The question is, what are they going to do to us?’” (p. 303).

Also, for a slightly more updated look, check out how Deinonychus was portrayed in the BBC show Primeval:

Dromaeosaurs for Kids

Deinonychus has many sites that relate information at lower, middle, and higher reading levels; one of the many perks of being a more popular dinosaur I suppose. KidsDinos hits the lowest level readers with concise and pretty accurate facts while the middle level readers in your house can fairly easily read Kids Dig Dinos, though be aware that some of the facts presented are a little incorrect or exaggerated. The highest level kid related page we have today is New Zealand based Science Kids, but it is a short read also. Just to wind up today. There is a Dinosaur Train episode featuring Derek the Deinonychus and there is also a wealth of coloring pages.

Climbing and Slashing

Artist Unknown

For the past few years there has been some discussion here and there concerning the use of the extra large pes claws of Dromaeosaurids, particularly important to us of course, is the use of these claws by Deinonychus. The original idea for the large claw of Deinonychus is that it is used in disemboweling and killing prey items. In this illustration that claw is being used a strike against a hadrosaur's neck. Usually the strike is depicted as being directed toward the belly of the animal, but the neck would be just as vulnerable to attacks. This mode of use has been studied since the debate began not too long ago.

©John Sibbick

As this slightly older illustration of Deinonychus shows, one of the thoughts behind the the use of the claws was that it could be used to aid the gracile hands in grasping and holding prey. None of the animals in this illustration are using their pes claws for anything other than grappling with their prey item. In this manner of hunting they are using their hands and mouths to wear down the Iguanodontid that they are attacking. This manner of attacking is relevant to the second argument for use of the pes claw by Deinonychus.

Photo by Davide Meloni

One of the arguments for use of the claw has stretched the traditional boundaries of thought concerning the oversized foot claw of Deinonychus. In 2006 Manning et al fully explored the concept of Deinonychus claws as large climbing tools rather than as weapons of destruction and death. Climbing and grasping ability as well as the ability to use this claw as a weapon of disembowelment were tested using analyses of morphology and a robotic model by the researchers in question. All of the analysis done determined that climbing and grasping were far more likely uses of the claw than a disemboweling strike. The use of the claw in climbing could have serious implications in the generation and evolution of arboreal-terrestrial gliding flight and eventually powered flight.

First Step Backwards

©Nobu Tamura

As promised a week or two ago, I plan to go back over the oldest list of dinosaurs I covered prior to the inception the blog/Facebook page devoted directly to this pursuit of knowledge and education. The first dinosaur that I covered in that respect was a well known and loved dinosaur: Deinonychus antirrhopus. As the face of Jurassic Park (yes, the raptors are based on Deinonychus, though Michael Crichton referred to them as Velociraptor antirrhopus, a synonym used during the late 1980's by Gregory S. Paul most notably in 1988's Predatory Dinosaurs of the World) and the usual image conjured up by the word "raptor" these days, Deinonychus is a much revered dinosaur and the subject of many fables or half truths as well. Officially named and described by Ostrom in 1969, Deinonychus remains are actually known from long before that, though they were falsely attributed to a larger theropod with a different tentative name (Daptosaurus agilis) by Barnum Brown in 1931 while working on Tenontosaurus. Thankfully the very fragmented remains were not described by Brown and the name did not stick; Ostrom instead decided upon Deinonychus, meaning Terrible Claw (antirrhopus means "counterbalanced" and references the stiffened tail). Since the 1960's many other remains have been recovered including, in 2000, what is thought to be a Deinonychus egg, though the results of the dig and identity of the material are, at the moment, unknown to myself (I will look into this of course). This should be a fun dinosaur to cover that I have hitherto not covered with a wider audience, so I hope this is a good kickoff to my retro list!

Popularity Island

©Cheung Chung Tat

We saw the painting above illustrated in a time lapse video on Monday. We have also seen a lot of news articles about Europasaurus including this short National Geographic blurb about Europasaurus  and bone growth. There are not a lot of video game references or anything else of that nature. There is some pretty fantastic sculpture out there. Notably Hirokazu Tokugawa's piece of art is very remarkable. The face is highly detailed and really quite strange looking; it is very unique in its expression and almost alien.

Shrink Wrapped

©Gerhard Boeggemann (His site is not working lately, so it is not linked)

Hypotheses from Sander et al. (shared Tuesday) state that something like Europasaurus would have become "rapidly dwarfed" after its habitat began to shrink rapidly around it. There is the idea that Europasaurus and other island dwelling dinosaurs immigrated or were washed ashore upon islands after tidal waves or some other sort of calamity. This could have happened and a rapid, occurring in only a very few generations, evolution could have forced animals like Europasaurus to begin to "shrink" rather quickly. Shrink is the wrong word really; selection favoring smaller members of the species is a more appropriate phrasing. Should this "shrinking" selection have occurred over a much longer timeline, however, the results would have been similar if not identical. A longer timeline could be the result of changing habitat limits; rising water levels or increased erosion lowering landmasses, shifting of landmasses, earthquakes, etc. Any number of interactions possibly created the islands on which Europasaurus lived. Paleogeographic and paleoecological studies have begun to explain how these islands came about and more and more miniaturized species are being discovered as time progresses; Balaur, Magyarosaurus, Telmatosaurus, and Europasaurus are only a handful of dwarfed species. The dwarfism of Europasaurus is exceptional though in that Macronarians were some of the largest animals to ever walk the Earth and a dwarfed species of such large animals are quite intriguing.

Reading A Lot About A Little

©Nobu Tamura

Europasaurus, for all of its small stature, is a fairly widely read dinosaur; meaning that people write about it quite often and it is therefore read about globally, not that the dinosaur itself read a lot of literature. An article in Systematic Paleontology discusses the postcranial axial skeleton of Europasaurus in a fair amount of detail, if you can get a copy of it for yourself. Old news articles are usually a welcome source of information as well. This Geotimes article discusses the "newly discovered" Europasaurus and gives the small dinosaur a short but emphatic introduction to the world via a non-peer reviewed entry into the literature of the world without being too sensationalist; as the media has a tendency to do with dinosaur news. I typically dislike posting a search result, it happens from time to time, but there are a few pdf's in the search for Europasaurus that cannot be linked as they open directly from the search. I recommend Sander et al.'s supplementary information (Geology and taphonomy of the Langenberg quarry locality) and at least inspecting the abstract of Bolecsek and Wings here (Europasaurus holgeri–the dwarfed dinosaur from the Late Jurassic of Germany).

Europasaurus Time Lapse

I found two videos that are time lapsed and pretty interesting. The first is of a painting of Europasaurus which is fantastic.

The second video is a time lapse of the preparations of a Europasaurus fossil.

German Resources

We have good English resources today from the London NHM as well as National Geographic making Europasaurus an international star for children. The home state, Germany of course, also gets in on the Europasaurus fun in the Dinosaur Park of Rehburg-Loccum in the Neinburg district of central Germany. The park hosted an art contest for Europasaurus not too long ago. One of the results of this was some art that can be used as a coloring page:

Looking at Europa

©Paulo Marcio

This image has been featured before here. It was featured back in March of 2012 in a discussion about Germanodactylus. This week, of course, we are highlighting the other animal (not the fish or lizard) that are seen here. We can tell, assuming that the Germanodactylus is not enormous, that the sauropods they nearly rival in size are rather small. Europasaurus was a small sauropod resulting from insular dwarfism, the same phenomenon that created the likes of the Sicilian Dwarf Elephant and Balaur bondoc the Romanian Maniraptorid discovered only a few years ago. The small size of these animals results from generations of adaptation that lead to a large dinosaur that was large enough to still be a large dinosaur but small enough to not eat all of the limited vegetation on the small islands. Dinosaurs this small in proportional situations are almost funny looking, but it is important to see them in a relative size to other animals when it is claimed that they are miniatures of their relatives.

©Andrey Atuchin

Other illustrations, however, barely show the relative size of insular dwarf species. If we assume, regardless, that the small pterosaurs to the right and in the background are the same or similar in size to the Germanodactylus shown in the previous illustration then this must be an adult where the previous illustration was showing juveniles. Even at an adult size this is a rather small dinosaur, especially for a sauropod. The close relationship with Brachiosauridae is fairly evident in this interpretation as well especially in the posture of the animal, its neck, and the makeup of the skull of the little sauropod.

Big Nostril Lizard Foot

Picture by Nils Knötschke

Latin and Greek roots make for some rather fun to say dinosaur names and hierarchical categories. The macronarian sauropods of the Late Jurassic and Cretaceous were one such group of funny named animals; macronarian sauropod effectively translates to "Big nostril lizard foot". One member of the group, at the basal end of the family tree, was Europasaurus holgeri (meaning European lizard of Holger Lüdtke, who discovered the first fossil remains). This macronarian taxa is slightly more derived than the North American Camarasaurus but less so than Brachiosaurus and is therefore considered the sister to Brachiosauridae. The chief character marking Europasaurus as more derived than Camarasaurus is the resultant size of the body due to insular dwarfisim. That is correct ladies and gentlemen, we have here a "tiny" sauropod dinosaur. Weighing in at somewhere between 1,000 and 2,000 pounds and ranging between 5.6 and 20.3 feet (1.7 and 6.2 meters) 11 individuals are known from the initial quarry at Langeberg near Goslar, Lower Saxony (that is in central Germany for the geographically stumped). The idea that central Germany was once comprised of many small islands with dwarf sauropods inhabiting those islands is pretty funny, unique, and very interesting.

Turkey Day Tribute

Compsognathus is a good little dinosaur. It has been an interesting dinosaur to discuss and research. I wish to keep things short today as I have a lot of Thanksgiving related things to do and so too does the American audience. However, Compsognathus is so popular in popular culture that I feel it is of great importance that I need to share the above Spore creature, a plush dinosaur from a friendly Finnish artist , and this wonderful image of what a turkey wing could look like if it came off of Compsognathus or another theropod:

Grasping Hands For Grabbing You Up

©Shelley Kornatz (Eykoart)

There are a lot of things that have not yet been discussed in terms of Compsognathus, though the papers yesterday and the discussions about feathers have given us quite a lot to talk about already. Regardless, one thing that has not been mentioned and cannot be ignored is the hand anatomy of a dinosaur like Compsognathus. Early German specimens appeared to possess only two digits, while later French specimens have three digits clearly seen. The third digit, Digit I, was short and incompletely preserved in the German specimens, but the implications of the digit arrangement is that the hand appears to possess the ability to grasp prey. Grasping hands certainly appear in the Maniraptoriformes and in the earliest relatives of birds. The grasping ability of the forebears of the Maniraptoriformes are sometimes used to differentiate theropods as well. Regardless of how the character is used, it is fairly evident in Compsognathus and a lot about the diet can therefore be conjectured at including the ability of the dinosaur to grasp and eat its prey rather than having to relay on jaw muscles and teeth alone.

All the Papers

©Karola (Caimryo)

Almost "turkey day" here in the US (strange how the colloquialism has become solely about a food that was possibly not even present at the historical Thanksgiving feast), and what better way to celebrate than reading papers about the great (x 15 million, give or take a few generations) grandparents of modern turkeys? I like to think of the following list of reading material as following the bouncing Compsognathus literature, hence the use of the image above. Let us not argue about the exact evolution of turkeys and Compsognathus given the previous statement but instead enjoy the original naming and description of Compsognathus, if one can read German; English translations of this are, as far as I can tell, not available. One could also read about the synonymization of C. corallestris with C. longipes in Peyer's 2006 paper. Gishlick and Gauthier in 2007 examined the hand morphology of Compsognathus and restructured our vision of the digit count ad use of the digits in Compsognathus. For those interested in taphonomy, I found a paper by Reisdorf and Wuttke that uses decay in modern domestic chickens (referred to as "Gallus gallus L.", which is a hybridized Sri Lanka Junglefowl) to describe taphonomy in Compsognathus as well as Juravenator. There is plenty to read here today.

Compy Puppets!

I am going to let the videos do the talking today. There is a puppet video as well as the I'm A Dinosaur version for Compsognathus.

Coloring and Learning

©Emily Sheldon

There are a variety of sites that offer some knowledge on Compsognathus in literature that is written for a younger audience; which we always love to see. The sites that get used the most are represented quite well today including KidsDinos and Enchanted Learning. I am far more excited about the coloring today. Share the information with those around you, but share the coloring more today, because there is a lot of it!

Staring Pretty

©NRG (a good fellow from Argentina)

Compsognathus, as a near relative of some of the earliest known feathered dinosaurs, may or may not have had feathering. These could have been fibrous filaments or it could have been downy tufts or even full fledged feathers, depending upon how long ago feathers actually did begin to develop as more highly evolved and adapted keratinous scales. Regardless, older illustrated versions of Compsognathus or those illustrations at least done in older styles, show scaled individuals. Some show them as highly active predators while others show them as simply stereotypical small dinosaurs walking about in ferns and other prehistoric backgrounds. Rarely do they appear illustrated, feathered or scaled, with any sort of anthropomorphic intelligence. In this scene it almost appears that our little Compsognathus friend is surveying the world and taking a relaxing moment. Most of the physical features of the dinosaur are obscured enough that the neck and tail anatomy are about all we can comment on in terms of the physical build of Compsognathus.

©Nobu Tamura

As far as newer versions of illustrations are concerned, the feather fibers of Compsognathus are a little debatable overall. This version highlights an early version of feather evolution with the appearance of downy fibers all along the body. The snout, feet, and hands are lacking in feathers as they would not require nearly as much insulation as the body of Compsognathus would. Physiologically, blood traveling from the body to the feet, hands, and snout would heat the blood returning to the body from veins in/from the feet. This would keep the body warm in the same way that birds keep their bodies warm while allowing their feet and beaks to remain cold. Insulation in this manner would be the practical physiological purpose of filamentous feathers like these, but additionally these feathers would be pigmented and be able to be used for display purposes.

So Small I Missed It All This Time

I've seen this before, but I cannot make out the illustrator's name.

"The compys didn't look dangerous at first sight. They were the size of a hen and walked nervously like a hen. But he (John Hammond) knew that they were venomous. Their bites delivered a slow-acting poison that they used to kill wounded animals." —Jurassic Park (novel)

Granted the above quote is in reference to the novel's Procompsognathus denizens and we are covering their descendant, Compsognathus, it is still a wonderful little quote from the novel about a somewhat understated lineage of dinosaurs. Both Procompsognathus and Compsognathus were small theropod dinosaurs with "elegant jaws" (the meaning of Compsognathus). Compsognathus consists of a single species, C. longipes, though a now synonymous species was once purported to exist as well (C. corallestris). The originally described size was slightly smaller than the full grown adult size of just over a meter or about 3.3ft. The reason for this is that a juvenile specimen was initially described as an adult. Regardless, at approximately a meter long and between 1.8 and 7.7lb (0.83 and 3.5kg) Compsognathus was the smallest non-avian dinosaur known for many years. An obligate biped, Compsognathus was quite gracile and agile, able, more than likely, to chase down many smaller prey items like large insects and small mammals and lizards. Though often depicted (in Jurassic Park related media primarily) as pack hunters, no evidence of this behavior exists that has been documented. Feather coverings, though not depicted often, may have been present on living members of the species, as they are closely related to known feathered dinosaurs such as Sinosauropteryx and Sinocalliopteryx.

Exciting Times!

There is little to discuss in terms of the popular culture impact of our small basal Ornithopoda friend Atlascopcosaurus this week. As such, we will discuss the world in which this dinosaur lived. Atlascopcosaurus was discovered in Dinosaur Cove's Eastern area in 1984. 104 million years ago the Dinosaur Cove area was closely associated, geographically, with the landmass of Antarctica and well below the Antarctic Circle. Current research indicates that the areas within the southernmost area of the globe near the Antarctic Circle potentially occurred dark and light seasons. More famous denizens of this light and dark season land include Muttaburrasaurus (the taxon in which Atlascopcosaurus is sometimes considered a member due to its fragmentary nature), Leaellynasaura‎, and even a carnivore simply referred to most often as Dwarf Allosaurus. It is unfortunate that more of this little dinosaur has not been recovered (and also that it actually be a nomen dubium that belongs to another species). Regardless, the adaptations to light and dark seasons that could potentially be seen in this taxon would be wonderful. Should more ever be discovered it will tell us a lot about the dinosaur and it will definitively answer the question regarding the position of the dinosaur itself.

Once A Hypsilophodont

©Robinson Kunz

Originally diagnosed as a middle of the group Hypsilophodontid, Atlascopcosaurus, has since been reassigned to the honored position of one of the basal-most Ornithopoda. Hypsilophodontidae would still be recognized as the family to which Atlascopcosaurus is assigned had it not been deemed paraphyletic and effectively banished from dinosaurian systematics. Regardless, as a basal member of the Ornithopoda Atlascopcosaurus possesses many characters that define the clade later on. Bipedal herbivores, Ornithipoda like Atlascopcosaurus, possess predentary beaks and occluding grinding teeth in a distinctive cheek region along the maxilla and dentary. They also should, remember that Atlascopcosaurus remains are exceedingly fragmentary postcranially, possess ossified tendons along the caudal vertebrae that stiffen the tail, making structurally very much like a cantilever bridge; it provides stability and support to balance out the center of gravity oriented in the upper thoracic area. The nearly horizontal body position is well exhibited in this illustration, and the feathering or filamentous fibers, are a fairly certain reality as well at this point. Small basal members of Ornithopoda are no longer so bland as they used to be thankfully.

A Book Star

Atlascopcosaurus has not made a significant impact, overall, in the peer reviewed scientific publication world. It has, however, appeared in a number of books as passing information and even as a key character. Some of these books may have been mentioned in prior entries given that they have information contained with that discusses other Australian dinosaurs. These include books like Minmi and Other Dinosaurs of Australia as well as World's Smallest Dinosaurs. Rich and Vickers-Rich published the initial naming and describing paper, as previously stated, but they also co-wrote a 1999 paper which was much more about the Hypsilophidontids of Australia as a whole; the abstract can be found through this link. Chapter 18 of Dinosaur Systematics describes the basal Ornithopoda and here too Atlascopcosaurus is touched upon. The Witmer Lab at Ohio University hosts a PDF version of this chapter, making it available online; Dr. Witmer is a co-author of the chapter.

Australia in Motion

Atlascopcosaurus is not a vividly in motion Australian dinosaur. There are few resources that show Atlascopcosaurus in motion adequately but there is a tribute video, and that is a step in at least a somewhat progressive direction. Beyond that there really is not much in the way of videos. Below is the tribute video that shows Atlascopcosaurus, however briefly it is; it is a video highlighting all Australian dinosaurs afterall.

Atlascopcosaurus and Little Fact Pages

Atlascopcosaurus shows its face rarely if at all in terms of reliable internet sites. This is not much different from the types of things that exist to present on normal Sundays; in a perfect world there would be far more sources for every animal for younger readers. However, today the only quality links, and thankfully they are quality links that happen to exist, come to us from About and the NHM in London. I also took the liberty of clearing out a rather blank image to begin with for coloring purposes.

Blank Faced Ornithopods

©Karkemish (via Deviantart)

Today I have decided that we will only have on illustration. There is a reason to such madness. The fragmentary nature of the discovered cranium makes it difficult to illustrate or even describe what the post cranial skeleton looks like. Therefore, any recreation is little more than an approximation based on a generalized Ornithopod body plan. Some studies have gone as far as to determine that Atlascopcosaurus is a nomen dubium (none cited in the Paleobiology Database though this is where the original claim of nomen dubium originates) while others have claimed that the likelihood of a relationship between Atlascopcosaurus and Muttaburrasaurus requires a redefinition of the Iguanodontia including the designation of the family Muttaburrasauridae. Atlascopcosaurus is a much smaller animal than Muttaburrasaurus but the likelihood of a parallel evolution of body shape within the closely related Australian Ornithopods is more than likely what most illustrators and descriptors are basing their images on.

The Riches

The world owes a fairly big chunk of its knowledge of Australian dinosaurs to Tom and Patricia Rich (more correctly known as Patricia Vickers-Rich). Using the equipment of a company known as the Atlas Copco Company in 1984 (naming and describing taking place during 1988 and 1989) the duo dug out and named a dinosaur after their tool company! Additionally, the specific epithet honors the state manager of Atlas Copco, and an assistant in the dig, William Loads. Therefore, the name Atlascopcosaurus loadsi, was coined in the description of this dinosaur. A small basal Ornithopod dinosaur, Atlascopcosaurus is known from fragmentary cranial skeletal material and not well known at that. Since the postcranial material is missing, not much is known about the overall shape of these dinosaurs other than that they were basal bipedal Ornithopods, and this is hypothesized from the skull. Difficult weeks are a lot of fun around here!

Star Tyrannosaur

The story behind the long narrow snout of Alioramus remains quite unsolved and a little bit conjectural. The purpose of such a snout clearly has an embedded purpose and we have certainly entertained many interesting and educated guesses/hypotheses during this week. Alioramus is something of a star also, having had many mentions in many different areas of popular culture. Brian Switek has written about the horned features, that we never covered, in the skull of Alioramus altai. More importantly, in terms of pop culture, the nearly always represented Dinosaur King and Spore video games once again give us pop culture links for our dinosaur of the week. The Spore model is pretty well done actually, even going so far as to include the ridged nasal bones seen in many of the illustrations:

This one dances, so it may be more inaccurate, but... it dances, so really it is also pretty awesome:

Alioramus is Unique Enough

Whenever an image says only "artist's rendition" I cringe a little for the artist and hope that someone knows someone that did the artwork. That stated, this Alioramus is even more unique than expected of the long snouted and interesting dinosaur that we have come to love (or at least enjoy thinking about how this clearly tyrannosaur-like dinosaur looks so very much like an allosaur). What sort of necessity is there to this interesting camouflage scheme though? Is it artist's fancy or is it well thought out considering the ecosystem of the Nemegt Formation? Floodplains with large river channels and the related soil deposits make up the majority of the Nemegt Formation sediments. Hardened calcium carbonate deposits mark periodic droughts in the Nemegt sediments as well. A variety of prey items lived alongside Alioramus, and Tarbosaurus as well, in this periodically dry floodplain in present day central Mongolia. Camouflage for the smaller tyrannosaur would most likely be a must not only for ambushing prey but for hiding from the larger Tarbosaurus as well. Camouflage, of course, is not the only reason for markings on any animal; species recognition and looking attractive are also quality reasons to have some wonderful and interesting markings. A strangely white background in the environment, such as chalk cliffs, would make sense with this illustration's color scheme.

Looking at Brains and Heads

There are quite a few studies of Alioramus out there to be read. There is a little for everyone in fact. There are studies on osteology of Alioramus specimens out there. The study referenced in this paper even questions the validity of A. altai based on the fact that it appears to represent a younger individual that may in fact only have ontogenetic differences separating it and A. remotus. Additionally, this paper makes note of, and reinforces, the point made here earlier that the jaw, unique amongst Tyrannosaurids, was probably not used in a typical tyrannosaur method of excising large chunks of food for swallowing. An alternative is not mentioned specifically, but instead it is proposed that that mode of feeding may in fact be present in adults of the genus; unfortunately only individuals deemed to be immature have been discovered.

A second paper of interest examines the braincase, via CT scanning, and describes the structure in a highly detailed manner. 21 characters from this structure were used in redefining the tyrannosaur phylogeny recently and all of these characters are addressed and discussed in this paper. It is certainly well worth the read if one has the time. Interest in a somewhat separate area of tyrannosaur phylogeny is represented in this PLOS ONE paper that expounds upon the hypothesis that the rise and fall of  tyrannosaur lines can be used to parallel the rise and fall of the Cretaceous oceans. Much of this paper discusses Larimidia (the western half of North America) and the Western Interior Seaway, but there is also mention of the Asian tyrannosaur families as well. Of these North American tyrannosaurs, those from Utah are most highly discussed and the parallels of the ocean habitats of the Cretaceous are drawn from these animals. Despite not being of particular central interest to this paper, Alioramus is a tyrannosaur and, supposedly at least, the same conclusions ought to be able to be drawn by studying Alioramus in a similar fashion.

Disney Has Fun

A minute into the Dinosaur! ride at Disney's Animal Kingdom an Alioramus rears back and ingests what is supposed to be a Champsosaurus according to the accounts I have read. The only real problem with that is that Champsosaurus is a North American genus that, to my knowledge, has no representative species seen in Asia where Alioramus resided. Regardless, the long snouted Alioramus digging into the ground to pull out the long bodied Champsosaurus kind of meshes well with the statement made Saturday that the long snout allows for extension into cavities, though body cavities not caves and caverns, in search of food. Regardless, digging for food was probably not the primary means of extracting prey items for a dinosaur with a long snout based on its shortened forelimbs. As hypothesized earlier, the snout was probably used as the primary weapon, inflicting quick and sudden bites on prey items during hunting expeditions. The idea that the elongate snout could be used for digging or extracting animals from crevices, while not entirely farcical, would most likely have been a last ditch attempt at procuring food items.

Kids Play with Alioramus

Alioramus shows up in a few kid related areas, which is always nice. Notable sites that I love to reference include, of course, Dinosaurs for Kids and Academic Kids. For the higher level students there is an entry on the Tree of Life site that discuss Tyrannosaurid systematics a bit more in depth. There is also a nice coloring sheet that really accentuates that Allosaurid snout that has been mentioned.

Two Species and Not A Single Skeleton

Constructed by Steveoc86

Alioramus remotus is the more fragmentary skeleton of the two named species. However, it is still distinctive enough to be both Alioramus and a distinct second species of the genus. The skull, obviously lacking in many aspects, does contain the majority of the dentary and maxilla as well as a good portion of the postorbital surface of the skull. The postcranial skeleton is represented entirely be two toes and a portion of the ankle. Fortunately, it appears, that the general size and shape of this dinosaur can be approximated using the few bones we have knowledge of, comparative proportions of other Alioramus specimens, and most likely proportional comparisons to its close relative Tarbosaurus as well.

Constructed by Conty

Alioramus altai, however, consists of quite a bit more skeletal remains, overall at least. Regardless, the dimensions of the dinosaur are quite well known from the collective fossil assemblage of all of the Alioramus specimens. The most distinctive feature of the skull as a whole is the long narrow snout of Alioramus. This type of snout, overall, appears to be appropriate for reaching deep into prey items as well as lunging attacks with quick snaps of the powerful and solid built jaw. Given the apparently agreed upon configuration of the forelimbs as highly tyrannosaurid, a long quick jaw related attack would more than make up for these rather small forelimbs.

A Different Branch of Dinosaur

Tyrannosaurids are always a fun branch of dinosaurs to discuss. After last week's nearly non-existent information on Aeolosaurus I think we ought to cover a nearly equally difficult to fossil carnivore. The love people show to tyrannosaurs ought to somewhat offset the little available fossil material of Alioramus remotus Kurzanov 1976 or Alioramus altai Brusatte 2009. Alioramus is a bit of problem child as fragmentary evidence of the two species has been recovered only from Asia and only as fragments. There is no real problem with being an Asian dinosaur, it is just that the fragments have only been discovered in Asia and that the dinosaur has been noted only as being related to Tarbosaurus bataar which, itself, has debated origins and positioning in the phylogenetic tree. There are some rather interesting similarities between Tarbosaurus and Alioramus that will need to be highlighted to understand where Alioramus belongs on the tyrannosaurid tree, and hopefully we can go over what makes this dinosaur an Asian tyrannosaur during the course of the week!

©Nobu Tamura

What We Know

We know that Aeolosaurus is not a popular dinosaur, unfortunately. That has been borne out over the week. No one has offered any answers to any of the questions that remain without closure, sadly. However, I do have one more image I can share that is attributed to Aeolosaurus. The image has no attribution as far as I can find in terms of illustrator though.

Aeolosaurus and Its Tail

The tail of Aeolosaurus had some rather interesting neural spines on their vertebrae. We mentioned previously that Aeolosaurus has anteriorly deflected neural spines on the caudal vertebrae. What is the precise reason for having a neural spine that is positioned forward rather than the typical convention which faces posteriorly, or backwards? Neural spines are used for muscle attachment, as well as other attachments such as stiffening tail rod ligaments in some species of dinosaur. There are other instances, other than closely related titanosaurs, which have anteriorly directed neural processes. Searching for for some valid reason, other than a different configuration of muscle attachment that serves the same purpose as posteriorly deflected processes, that neural spines would be deflected forward rather than to the rear has been fairly difficult and, honestly, nearly impossible to find in morphological studies. Muscle configurations that serve the same purpose but are aligned differently would not necessarily be farcical; it could simply be that Aeolosaurus was built differently. It could also be that something was put together incorrectly, it has happened before. I hope that someone somewhere is studying the configuration or that someone knows the answer already and I just have not found it or do not see the answer clearly at this moment, but will sometime soon!

Writing Like A Maniac

Aeolosaurus has been written about a lot more than it has starred in documentaries. The mentions of it in scholarly articles are pretty fantastic as well as the number of papers dedicated solely to Aeolosaurus. One of these papers that is of great importance is a 2007 article by Casal, et al. which details the discovery of a new species of Aeolosaurus from Argentina. This species is the second named species, which is why it is an important paper. Additionally, Martinelli, Riff and Lopes wrote a paper discussing when and where fossils of Aeolosaurus have been discovered in South America that makes for a rather fun and interesting read. I encourage everyone to read the first paper if you have to choose between them for any reason!

Motionless Winds

Sadly, for a dinosaur so rooted in winds, by virtue of its name, Aeolosaurus is rather motionless. There are a variety of reasons that this could be, but the sad fact is that there is simply not any documentaries or even wireframe models out there constructed by dinosaur enthusiasts. There are not even modded models in games like Zoo Tycoon. The most important thing about Aeolosaurus that should not be forgotten, despite this lack of wonderful motion and images of a rather unique and interesting sauropod, is that there are many individuals, fragmentary as they are, that are known and therefore the ability to create models in the future becomes greater with every discovery. Since that does not exist, however, please enjoy this wonderful image of Aeolosaurus today:

Kids and Dinosaurs

Aeolosaurus is not well known, we can accept that many of the titanosaurs are not well known I think. Cutting out a lot of the speculative and scientific debate of many other articles online, Academic Kids does a good job of just posting the bare minimum of information to introduce kids to the dinosaur. Unfortunately, the bare minimum for a poorly understood dinosaur is a very little amount of information to begin with. For a little more in depth information, after gathering the bare minimum, the outline version of information presented on Bob Strauss' About pages again offer a good place to direct the children eager to read more and talk about this dinosaur more. Sadly today we have no coloring pages to offer up while children read or are read to, but perhaps the kids out there could draw one of these dinosaurs for themselves.

Pointing Forward

From Garcia and Salgado 2013

One of the most unique features that allies Aeolosaurus with other titanosaurs, specifically Gondwanatitan, is that the neural spines on the caudal vertebrae are angled forward in the direction of the head (anteriorly). That sort of trait is not common in the titanosaurs meaning that Gondwanatitan and Aeolosaurus are closely related. As some of the only material discovered with the type species, these caudal vertebrae were an important piece of the puzzle as to what this animal was exactly. They united Aeolosaurus with other titanosaurs as well because they were elongated medially from front to back and they possessed shallow fossae on the lateral sides of the centra; both are titanosaurid characters of caudal vertebrae. The initial puzzle pieces consisted of these few vertebrae, elements of the forelimbs, and the right hindlimb. These elements also aided in identification of the animal, of course.

Picture ©Marco Aurelio Esparz

The femur of Aeolosaurus was a rather large bone, as we expect from titanosaurs. The size, dimensions of proportion, and general shape of the femur all attributed to the diagnosis of belonging to a titanosaurid dinosaur. The relationships alluded to by the femur are hazy and basically educated guesses at this point as titanosaurid material is both rare and incompletely understood. However, the femur of Aeolosaurus is rather large and quite a nicely preserved bone all in all.

Keeper of the Winds

©Karkemish

Aeolus, keeper of the winds in Greek mythology, would probably be a little more light on his feet than the dinosaur that can claim him as a namesake. Aeolosaurus is a genus consisting of three recognized species; A. rionegrinus Powell, 1987 (type), A. colhuehuapensis Casal et al., 2007, and A. maximus Santucci & De Arruba-Campos, 2011. This South American titanosaur of the Late Cretaceous measured in at approximately 45 ft (14 m), however, weight estimates are not accurate when available due to the loss of much of the skeleton. There are a number of distinguishing characters in the skeletal material that has been recovered and these, of course, will be topics of much consideration and discussion over the course of this week. We will start bright and early tomorrow in this discussion.