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First Step Backwards

December 6, 2013, 2:39 pm
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©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!

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Climbing and Slashing

December 7, 2013, 1:34 pm
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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.

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Dromaeosaurs for Kids

December 8, 2013, 11:15 am
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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.
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Movie Star Here

December 9, 2013, 8:13 am
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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:
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Writing About the Terror

December 10, 2013, 7:43 am
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©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.
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Something We Often Missed

December 11, 2013, 2:35 pm
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©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.
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What Has Not Been Mentioned

December 12, 2013, 11:21 am
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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
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Next Oldest Post

December 13, 2013, 11:35 am
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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!
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Furred Polar Brrrrs

December 14, 2013, 2:16 pm
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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.
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Snow Covered Forest for Kids

December 15, 2013, 1:08 pm
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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.


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The Dinosaur of the Week Walks

December 16, 2013, 2:39 pm
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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.
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Written Leaellynasaura

December 17, 2013, 2:08 pm
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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.
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What Large Eyes

December 18, 2013, 4:53 pm
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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.
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Popular Because It's Popular

December 19, 2013, 11:57 am
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Admittedly, almost no one would have heard of Leaellynasaura if not for its role in Walking with Dinosaurs. Since that time any bland appearing ornithopod has been in danger of being labeled Leaellynasaura. Somehow, despite all of this attention, our small dinosaur does not appear across genres very often. Its depiction in books is limited to a few books about Australia and polar dinosaurs with very few exceptions; notably Lita Judge's How Big Were Dinosaurs? shows Leaellynasaura playing with penguins in a well written children's context. A modified model appears in Zoo Tycoon clearly based on illustrations by Matt Martyniuk.


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Double the Crests

December 20, 2013, 6:13 pm
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©Heather Kyoht Luterman
Meaning "Two Crested Lizard"Dilophosaurus was discovered in 1954 in Arizona's Kayenta Formation. One species is recognized, Dilophosaurus wetherilli, and it is a highly recognizable species. The most characteristic identifiers of Dilophosaurus are in the skull. Two crests run along the roof of the skull from the nares to the temporal fenestrae. The premaxilla and maxilla abutment is also characteristic of Dilophosaurus and many basal theropods in general. The "kink" where the two meet is also found in later Spinosaurids as well as some crocodiles and represents a weakened connection between the two jaw elements. Despite the popular image of a dinosaur with a transparent hood, like that seen in Jurassic Park, there is no evidence that indicates such a hood existed. There is also no evidence for the venomous nature of the silver screen Dilophosaurus; Michael Crichton took complete ownership of the invention of the two ideas. Dilophosaurus was, however, a rather interesting basal theropod, and a fairly hefty one at 23 feet (7 meters) and up to 2,200 pounds (1,000 kilograms).
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Feathers or No Feathers

December 21, 2013, 4:18 pm
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Geological Museum of the Polish Geological Institute in Warsaw
As has been mentioned in the not so distant past, the origin of feathering has not yet been pinpointed. Assuming that the feather origin occurred very early in the history of the Dinosauria we can begin to see models, and illustrations, of even the earliest theropods with feathering. A feathered Dilophosaurus is actually quite appealing, to toss out an opinion. As opposed to some newer models and illustrations of feathered dinosaurs (opinions coming here) this Dilophosaurus reconstruction looks very appropriate as a feathered dinosaur. The feathers of this model, thankfully, are not ostentatious; their "drab" nature and subdued coloration in this reconstruction are quite fitting for a theropod that would want to blend in with its surroundings while hunting.

Pink Palace Museum, Memphis, TN.
The non-feathered version of Dilophosaurus that is still somewhat popular is usually a drab color as well. The tiger striping of black and brown is a common color scheme for theropods of the past and the present though. Ignoring that, there are a few other issues with this particular model that can be found in other tight skinned and non-feathered theropods. The most characteristic mark in the reconstructions with tightly pulled reptilian skins on the skull is the formation of the notched junction of the premaxilla-maxilla. In comparison with the other reconstruction, the eye is portrayed as much smaller as well. Additionally, the crests of this reconstruction are larger and more brightly colored. The crest is also divided by ridges and depressions not apparent in the previous reconstruction. The taut skin of the more reptilian reconstruction is a bit of a call back to an older age; it is a bit of a vintage reconstruction to say the least.
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He Means His Jurassic

December 22, 2013, 7:35 am
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A good day for letting your children read or watch a video. There are not any dedicated books that are singularly exceptional about Dilophosaurus, in fact, the majority that are about this dinosaur alone are from the 1980's or 1990's and their covers appear extremely out of date. There are some fairly good online fact pages like KidsDigDinos and Enchanted Learning; though these are not usually our favored pages. Enchanted Learning has a somewhat acceptable coloring page, but the one below is quite a bit better; it is quite cartoony however. I had drawn one at some point that I think would be good for coloring, but every time I find it I am happy I found it then I promptly forget to scan it and forget where it is.

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Jurassic Dilophosaurus

December 23, 2013, 4:39 pm
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Jurassic Park, home to many dinosaurs of the Cretaceous, was also home to Dilophosaurus. Remember the parts of this wonderful scene that were added by Crichton, retained by Spielberg, and have no known basis from the fossil record and enjoy the scene regardless. Probably my favorite of all the Jurassic Park scenes floating around the internet (also, listen closely near the beginning for the funny and overused slide whistle):


Now, for comparison, view these much more fossil based reconstructions of Dilophosaurus from When Dinosaurs Roamed America and note the differences between the two clips (there will be a Christmas Eve test):


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Chinese Dilophosaurus?

December 24, 2013, 3:07 pm
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There are papers about Dilophosaurus that are of interest today; providing you do not have family events for Christmas Eve planned. There are some great papers on a supposed Chinese Dilophosaurus, Dilophosaurus sinensis, that describe the species and the discovery of the remains. There are two different papers from 1993 describing these remains. As of this writing, however, only Dilophosaurus wetherilli is recognized as a valid species. Robert Gay, last noted to be teaching in a public school in Arizona, has written two interesting papers that he hosts on his own web page related to Dilophosaurus; one is on sexual dimorphismin Dilophosaurus (abstract available in two places) and the other on a new specimen from the Kayenta Formation. There are, of course, also book excerpts that mention the world renown Dilophosaurus like Kenneth Carpenter's The Carnivorous Dinosaurs. I think one of my favorite short papers for the day, however, is from Andrew Milner and James Kirkland and explores the possibility that many dinosaurs, including Dilophosaurus, from St. George Discovery Site at Johnson Farm (a site in Utah) might be fish eating in part at least. Dilophosaurus jaws do, recall, slightly foreshadow the piscivorous Spinosaurid jaw morphology; and may have had a diet that integrated fish in addition to terrestrial prey.
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Merry Christmas Post

December 25, 2013, 12:49 pm
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My intentions for today were to write a very short post with my old Dilophosaurus drawing in a bit of a festive getup, but I still cannot find that drawing. For those not celebrating Christmas, today is a normal day and we respect that here. Since it is a fairly major holiday for a wide bit of the audience, I will still keep it short. I want everyone to know there is still a rather festive Dilophosaurus available on the internet from illustrator Frank-Joseph Frelier. Instead, have a basal Christmas Ornithopod! We will have a nice long post tomorrow to make up for today.

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