The Christmas Post

I know most of us have much more to do today than read about dinosaurs; however, I want to share a few papers on Dryptosaurus that you can read at your own leisure during this week dedicated to Dryptosaurus.
2011: Brusatte, Benson, and Norell; The Anatomy of Dryptosaurus aquilunguis (Dinosauria: Theropoda) and a Review of Its Tyrannosauroid Affinities
1877: Marsh; Notice of a new and Gigantic Dinosaur (Marsh's renaming of Dryptosaurus)
1866: Academy of Natural Sciences (Philadelphia); Proceedings of the Academy of Natural Sciences of Philadelphia (Initial description as presented by E.D. Cope of a new "gigantic extinct Dinosaur")

The two older sources are hosted by The Theropod Archives site, to which we typically owe the hosting of older documents.

Constant Topic of Discussion

First of all, Happy Holidays from me! Have a look at my holiday dinosaur:

I draw cartoon-esque dinosaurs

Second, allow me to share some Dryptosaurus videos. Dryptosaurus has made it into the animatronic dinosaur parks of the world including the Field Station: Dinosaurs in Seacaucus, NJ, which is tied to a number of sponsors including the New Jersey State Museum. An important note for my East Coast readers; Field Station: Dinosaurs is closed for the season and reopens on April 5 for its second season (which is why some of you in NJ even may not have heard of it before now!). Here is their Dryptosaurus exhibit:

Also, whether you have seen it before or not, I am sure that Tyler Keillor still needs support on his digital Dryptosaurus sculpture, so be sure to at least listen to his project description on Kickstarter. Obviously during the holiday season it is a lot harder to afford something like this, but he has a good aim and he has done quality work so he deserves the support he has gotten so far. There are no other high quality videos that I would recommend today, so, enjoy your Christmas Eve if that is your thing, and if not, have a good Monday!

The Tyrannosaur Kids Don't Know

Dryptosaurus has kind of flown under most radars the past 140-ish years. As such, only a handful of professionals and amateur paleo-enthusiasts really truly know what Dryptosaurus was and can imagine it accurately. This is a problem that needs fixing (no need to tell Gary Vecchiarelli) and it needs to start with the youth of the world; as many solutions must. Ask any kid out there for the name of a tyrannosaur and Tyrannosaurus Rex is probably the first and almost only name you will hear. That is not a problem, however, the teacher in me wants the kids to know that there is a whole wide world out there populated by uncles, aunts, distant cousins, and sisters of T. Rex that are just as interesting. Dryptosaurus is one of those relatives and searching as I do on Sundays for adequate kid related materials I have come up with a rather short list of goodies today. Most importantly, I did find a fact sheet that sums up the dinosaur fairly well on Enchanted Learning, and that is a good place to start. Secondly, I found pretty much zero toys/books with which to educate and play with the youngsters, which I find to be most sad. However, the desperate artist in me is placated today by a couple black and whites by Brett Booth on his blog; which has the wonderful subtitle "The Brett Booth Dinosaur Blog, dealing with pointy teeth on bitey things". As with any images online (and because I did not ask Brett specifically this morning to post the images found in posts from September 2012 and October 2010) remind yourself, and loved ones, that you can print out an image and color it in your home, most artists I know are not upset by that idea, but you cannot put someone else's art online without asking (it is never too early to teach a child about respecting another person's ideas and hard work).

The Amazingly Empty Skeleton

Dryptosaurus, as we can see here, was not exactly a complete skeleton. We have, however, seen fewer bones used to identify a species, and as such we cannot really say "Cope, what were you thinking?" Besides, Cope has had enough embarrassment, the poor fellow. The fact that, throughout the years, Dryptosaurus has stood up on such little leg evidence (puns? Oh yes!) as well as small amounts of fossil evidence from elsewhere in its body shows how little the remains have in common with other dinosaurs; that is to say that the few bones we have of Dryptosaurus retain their distinctive characteristics enough that we have not dropped the name as yet as a synonym of another species. Dryptosaurus has, however, been placed into a number of families over the years, starting out in the Megalosauridae and, through a rather laborious sloshing through Coelurosauria and Tyrannosauroidea (placement here was based on the closely related and more complete Appalachiasaurus- come back in two weeks for more on them) and finally in Dryptosauridae thanks to Kenneth Carpenter. Dryptosauridae is considered a subfamily of the Tyrannosauroidea these days.

©Nobu Tamura

Dryptosaurus, as a tyrannosaurid, is subject to the laws of feathering, as it has been applied to other tyrannosaurs. Nobu Tamura's Dryptosaurus has a nice mohawk of feathers and, very happy as it seems with itself, is brandishing the enormous claws which led to its specific epithet (aquilunguis meaning eagle clawed). Having stated my feeling on scaly dinosaurs a week or two ago, I like Charles Knight's scaly Dryptosarus; however, the feathered dinosaur version of Dryptosaurus looks equally valid and quite fantastic. The feathering on this version is not ostentatious and plays very well into the camouflage of the animal which must have been true, to a point, in order to aid in hunting; that is unless Dryptosaurus did not bother to hide at all and just simply ran down and clawed its prey. Feathering would, of course, keep Dryptosaurus a bit warmer than just being scaly, but was it necessary and did it really exist are two questions we cannot answer assuredly for Dryptosaurus at this time.

©Josep Asensi

Feathering, and coloration, as I stated just a moment ago, have to be considered in coordination with the practicality of their use in every day life for an animal. A peacock does not camouflage itself well and sometimes pays the price, but most of the carnivores that live in our day and age, feathered, furred, or scaly, tend to blend in a bit better with their environment to aid in the success of the hunt. Great Whites mimic the surface from underneath and the deeps from above; tigers blend in to the grasses of India; bears in the woods mix with the shadows of the trees and bushes; hawks tend to have white ventral surfaces which at least vaguely look like clouds to the rodents below. Dryptosaurus, therefore, probably blended into its environment at least a little bit in order to hunt effectively. That said, I think the only thing in this version of Dryptosaurus which may be a little disagreeable would be a bright red face. The unfeathered body certainly blend in with the landscape of the Cretaceous grasses and even the shadows of trees, as would the dark feathers along the back. The white perhaps not so much and the red, unless dinosaurs were uniformly color blind (why bother having colors in that instance when patterns would probably be enough), would not help camouflage the dinosaur while it was stalking prey. That is my opinion, certainly feel free to develop your own!

Laelaps or Megalosaurus, Perhaps Dryptosaurus!

©Charles R. Knight

In 1866 New Jersey was about to have its first dinosaur mounted, in about two years, as the first skeleton to be mounted in the world (in Philadelphia, but still). The world had no idea what other amazing things were about to come out of New Jersey. Westward expansion had not yet shown Americans and the land they were occupying to be of much consequence in the world of paleontology as the East Coast had turned up little evidence of the age of dinosaurs to this point in time. New Jersey's Haddonfield find had set more eyes to being careful when they dug in the ground, however, and a mere 8 years later such careful eyes in a quarry would halt work before destroying what would later be identified as the world's first tyrannosaur. A primitive tyrannosaur, still in possession of a fairly useful arm with a three fingered hand and some nasty claws, Dryptosaurus aquilunguis (literally: to tear lizard eagle-clawed), was the fourth North American dinosaur described and lived in relative obscurity as far as the popular world is concerned for a long time. Initially given the generic name Laelaps (meaning storm wind and the name of a dog that never failed at hunting in Greek mythology) by E.D. Cope in 1866, the name change came about in 1877 courtesy of O.C. Marsh due to the preoccupied status of Laelaps by a mite!, Dryptosaurus actually suffers from a quite poor fossil record. The reason that people have heard the names Laelaps and Dryptosaurus is the painting above by Charles Knight. It's a classic given that it was painted during a time when most researchers were convinced dinosaurs were slow and given to soaking in the sun to get the energy to even lifting their heads. Knight's work is pretty fantastic.

The Everyman's Dinosaur

Hadrosaurus is popular in that everyone knows what a "duck-billed dinosaur" is. It is not so much popular as Hadrosaurus as it is popular for being a Hadrosaur, if you follow my meaning. Whenever anyone thinks of "duck-bill"  they think of an animal that closely resembles what the artistic impression of Hadrosaurus has always been; that lack of a skull not allowing its head to to be diagnostically different from other Hadrosaurs is a real bummer for Hadrosaurus. The Hadrosaurus display that initially made it famous, being the first museum mounted skeleton on the face of the earth, we discussed has been remounted and the exhibit has been entirely rebuilt around it (it was reopened in 2008). Haddonfield, as was noted, is proud of their dinosaur as well. During that 150th anniversary (in 2008) Haddonfield had a pretty big celebration around the town's sculpture along King's Highway. They even had a birthday cake.

As with many other dinosaur Hadrosaurus has also made its mark in the animatronic area of dinosaur display, which is fairly special, given that lacking a skull thing. There are at least three books (this one has a misleading cover) about Hadrosaurus that are aimed at children; one of them is rather rare though so do not expect to go digging that one up at the bargain bin.

Yes There Is A Hadrosaurus

Courtesy of Hidden NJ

Given the internal debate we witnessed with yesterday's articles, it is fairly understandable how some paleontologists think that Hadrosaurus is a viable name and others say that it is not a viable name. Regardless of that argument, the people in Haddonfield, New Jersey are not about to relinquish their town's sculpture of the Hadrosaurus that was found in their backyard. The second article yesterday stating that there are some characters available in that small mixed bag of bones which constitute the type specimen of Hadrosaurus I still have not been able to read, but the fact that a detractor had a second look and changed his opinion means that there must simply be quite a bit of evidence that was overlooked the first time (I highly doubt that the people of Haddonfield were beating down his door to restore the validity of the name of Hadrosaurus). Of course, as I stated before, the only sure way to really save Hadrosaurus from this debate would be to find more skeletal elements that possess the same traits that Prieto-Marquez was going to explain in that newer article as allowing Hadrosaurus to retain its validity as a scientific name. That would require the people of Haddonfield, or some investigative spirit on the East Coast at least, to begin poking and prodding all around New Jersey and other likely states with outcroppings or erosion sites of similar geological age to the marl pit that contained Hadrosaurus' type specimen remains. The characters in the leg, arm, vertebrae, and other associated bits can be used to identify other remains of the animal and then those characters can be used to more fully describe and differentiate Hadrosaurus from other dinosaurs. Our wish for Hadrosaurus then is more fossils!

Hadrosaurus Reevaluated, Twice

©Sergey Krasovskiy

I asked if I could use this image earlier in the week without the background. He sent it to me like this with a background. I thought it would be nice to head up this column today. What I really aimed to present today were papers that have come out recently (within the 6 years) that discuss reevaluation of Hadrosaurus. It seems like just about any mention of a reevaluation these days also has Jack Horner as a footnote if not a second, or in this case third, author. Albert Prieto-Marquez and David Weishampel, along with Horner, reevaluated the position and description of Hadrosaurus in 2006. Their determination, to sum up a longer article very briefly, was that the type specimen of Hadrosaurus has no characters which distinguish it from any other animal and that the name is therefore defunct. They made special mention of the idea that it is not synonymous with any other animal and that phylogenetically it belongs in the Euhadrosauria to an undetermined species.

The second paper I found is a short correspondence (if anyone has the full length correspondence that would be nice to find) authored by Albert Prieto-Marquez alone, dated 2011, in which he somewhat refutes his own previous paper and reevaluates Hadrosaurus yet again. He argues that Hadrosaurus actually is diagnosable "based on a combination of plesiomorphic and derived appendicular characters." I am interested to read the full length of this paper. I still have some of the first paper to read ahead of that anyhow though.

Hadrosaurus In The Afternoon

I have two videos showing Hadrosaurus which we can look at and briefly discuss today. The first is of a remounted version of Hadrosaurus at the Academy of Natural Science in Philadelphia. In the same venue that Hawkins mounted the first bipedal dinosaur skeleton cast of Hadrosaurus there has been an adjustment of the display and a remounting to agree with modern theory. It is not too much of an action pose, but it looks much more life-like and much more of what we would expect than Hawkins' version did.

There is also a video that details the history of the Haddonfield site and describes the general site's current status. I really do not believe it needs much more of an introduction than that.

The final video clip I saved is actually a little humorous without intending to be so. It is a walking model of Hadrosaurus in three dimensions. The reason it appears a little humorous is that the legs look very slender and almost unstable. I will let the model do the talking (or walking).

Hadrosaurus For The Family

Hadrosaurus brings us back to two of our favored children friendly information sites for dinosaurs; KidsDinos and Science for Kids. It is a little humorous that KidsDinos places Hadrosaurus within a group simply titled "duck-billed dinosaurs." I know that typically Enchanted Learning is considered one of the most horrendous places to find dinosaur likenesses (I honestly do not remember where I read that or I would quote it, but see for yourself what I mean), but they do present themselves as good coloring pages and have information besides, so I still like to share their pages, this week they have one for Hadrosaurus, so that the children have something to color. They can color it online or print it out and color it the old fashioned way (which I prefer). There is also this guy to print out and color:

Found at: Scrollabook.com

Cretaceous Cows

Courtesy State of New Jersey

I think it is funny that Hadrosaurus, as are Hadrosaurs in general as a family, is thought of, maybe just by myself and no one else, as Cretaceous Cows. Cattle never roamed the earth in such a way as did animals like Edaphosaurus and Hadrosaurus, as great enormous herds, but were in more manageable numbers even before domestication and selective breeding gave us the cattle we see herded in cowboy movies and, in Kansas, lying around in milo fields (what some call grain sorghum). Hadrosaurus was obviously much larger than a cow, but as far as large herbivorous dinosaurs go, it was as cow-like as any dinosaur could be. The small section of the jaw and teeth that were included in the type fossils were indicative of an intense battery of vegetation grinding teeth, as seen in so many other Hadrosaurs, and are quite similar to the teeth (molars especially) of cattle. Why am I so adamantly comparing cows and Hadrosaurus?

Courtesy of Walters and Kissinger Complete Dinosaur Art Studio

The reason is that, all fleshed out, and with a dental array that is like a cow (except for the front teeth because Hadrosaurus had a keratin rich beak), Hadrosaurus was an animal that, in its ecosystem, held the same niche responsibility as cows do in our ecosystems. Cows are invasive, though we do not think of them as such, in many lands, so maybe a more just comparison is between Hadrosaurus and Bison, which would have held a similar niche as Hadrosaurus during the prime of their day in the Great Plains of North America. The herds of Bison probably rivaled the numbers of the Hadrosaurus herds during the Cretaceous also.  Additionally, for comparison, Hadrosaurus is one of the least ornamented of the Hadrosaur family; this can be partially explained by the fact that not many remains of the skull have been found either, leading to a lack of any evidence of ornamentation. This lack of skull has actually led to many considering a nomen dubium or a name that is no longer valid because it cannot be more clearly classified within the Hadrosaur family.

Permission pending artist approval

I think that all that might be missing from the skull, should we discover a complete skull, is ornamentation that further classifies Hadrosaurus. Personally, I hope that if anyone ever discovers a complete skull that it has absolutely no ornamentation, such as we have seen today in the illustrations. I think Iguanodon is lonely in the Hadrosaurs (for everyone: Iguanodon does belong to the Hadrosauriformes clade within the Ornithischia despite being in its own family) because it has no ornamentation and, other than maybe Parasaurolophus, it is the first dinosaur many people think of when they hear "duck-bill" or "Hadrosaur" in a conversation. Hadrosaurus, plain or later discovered to have some kind of interesting skull adaptation, is for now, one of the greatest and earliest discovered Cows of the Cretaceous.

To Hadrosaur or to Hadrosaurus?

From one family to another. For this family we come back to American soil and we venture to a part of the country that is not generally known as having a wealth of dinosaur bones of note in its soil. Typically dinosaur finds in America are detailed in the western half of the continent, but this dinosaur comes to us from the East Coast. In fact, it comes to us from the woods of New Jersey. In 1868 Hadrosaurus foulkii (sturdy lizard of Foulke) became the first ever mounted dinosaur skeleton. Discovered by John Estaugh Hopkins in 1838 and taken home and displayed, they were rediscovered in Hopkins' home in 1858 by William Parker Foulke who, in his interest, had the remainder of the skeleton dug out from the marl (a lime-rich mudstone) where Hopkins found the original bones. Joseph Leidy helped to dig out the find which consisted of a pelvis, 28 vertebrae, parts of the feet, some teeth, parts of the jaw and nearly complete left limbs. Leidy named the skeleton Hadrosaurus with the specific epithet honoring Foulke (leaving Hopkins in obscurity despite his role in the find). The first mounting was designed with the help of Benjamin Waterhouse Hawkins, the  English sculptor responsible for the Crystal Palace sculptures, and placed within the Philadelphia Academy of Natural Sciences as a bipedal dinosaur; Leidy described Hadrosaurus as bipedal in contrast to the quadrupedal common view of dinosaurs at the time. Hadrosaurus is one of the least adorned of its family (it is competing with Iguanodon for most cow-like of the Cretaceous herbivores) and is the embodiment of the word Hadrosaur in the imaginations of many school aged children. The mount, coincidentally, is still available for school aged children, and adult aged children, to view in Philadelphia, though the mount has changed a little and now shows casts of the bones highlighted in the image below (This image is from Haddonfield, NJ).

Abelisaurus As A Video Game Character

I think this week we have looked at Abelisaurus from a good many angles this week. I saved for today the video game snippets. There are not many popular outlets that we have not touched for Abelisaurus to exploit. As far as dinosaur popularity, though, Abelisaurus has most definitely become one of those dinosaurs that is known but not too well known that we see it everywhere (such as in the way Velociraptor and Triceratops are). Regardless, Abelisaurus has shown up in Spore creations

(notice the not so Abelisaurid-like forearms) and it has also appeared in Dinosaur King games.

 Abelisaurus has become popular enough that it was also modified into Zoo Tycoon. The dinosaurs that have been modded into that game are somewhat few and far between; however, many dinosaurs have been modded into the game so it was not really a unique dinosaur to be in there. It looks fairly generic as well, I have to say, but it is pretty neat that it made it into the modded files of some talented computer modder.

Not A Normal Wednesday

Typically on Wednesday I go over some aspect of the skeleton that sticks out or something special about the people that discovered the fossil (Roberto Abel in this case) or the people that described it (Bonaparte and Novas) but seeing as how information on Abel is few and far between and Bonaparte and Novas have been discussed before I do not really want to rehash that information. The skull has few characteristics that have not been mentioned or previously highlighted also. It is truly too bad that the skull is the only bit that has been unearthed so far in relation to this rather large theropod. One thing that Abelisaurus has not gone through, so far as I am aware, is the feathering process under which almost all theropods now find themselves. I am as much for detailing the soft downy dinosaurs that have been discovered with downy elements as the next progressive person, but a part of my brain agrees with Mark Wildman's comment very much when it comes to feathering. While I certainly acknowledge that some theropods, and even some other dinosaurs outside the theropods, may have had feathering or quills or any other number of soft tissue adaptations which were not preserved, sometimes I simply prefer a scaly dinosaur. In respect to Abelisaurus I prefer this scaly dinosaur model. As I stated above, I have not seen a feathered Abelisaurus as yet, and I do not expect to see one unless there is evidence for it that arises in the future. There is a lot of talk right now about how to portray dinosaurs (feathered or not) and I do not want to get in the middle of that whole mess. I just wanted to mention that Abelisaurus is a scaly dinosaur at the moment and that it is beautifully portrayed as it is. Look at this guy and think about what he would look like feathered (I am using the original work by Jordan Mallon, not the updated versions subsequently placed on Wikipedia):

Translations of Descriptions

Many thanks must go out to Matthew Carrano for translating so many works into English for so many paleontologists worldwide that do not know more than one language or, like myself, know a handful but only in enough detail to hold conversation for a bit. For those of us that do not know enough of other languages to read long scientific papers, his Polyglot Paleontologist site saves us all a lot of troubles. For people like me, who took French, German, Latin, or Japanese but never Spanish, today that site and Carrano's translation allow us to read Bonaparte and Novas' paper naming and describing Abelisaurus from a lone skull discovered in the Allen Formation (Rio Negro Province) of Argentina. As we know from the past papers we have read from Bonaparte, a lot of his work has been done in Argentina and he has become the modern day South American equivalent of a Cope, Marsh, or even a Brown or Sternberg (because he's out there finding things himself sometimes). In the abstract the new family is already proposed based on differences from Tyrannosaurs and "other Cretaceous carnosaur families"; Bonaparte and Novas leave us no empty space to conjecture through by coming straight out and telling us why they propose a new family. Though that is often the case with abstracts, leaving it as the closing sentence is equivalent to leaving us with a cliffhanger because they do not give us the differences or explain why they merit a new family until page 3 where it is again lightly touched upon and then definitively comparing the new skull to previously known skulls on pages 7 through 9.

I have uncovered a second paper of interest today written by Roberto Ebner, a medical doctor, and Leonardo Salgado. In this paper Ebner and Salgado used CT scans to measure the optic canal of Abelisaurus. They note in the paper that the scanning has led them to think that Abelisaurus had only a few hundred grams of brain matter and that, despite poor preservation on one side of the skull, the optic canals were scanned and imaged quite nicely; though it does not say to what purpose beyond scanning them. The scan appears below.

Arch Ophthalmol. 2003;121:294-295

Abelisaurus Movies

Abelisaurus shows up in quite a few "movies". There are some from video games and there is the cartoon I showed yesterday. Today, though, I can share another of those "how to draw" videos that I shared a few weeks ago on a Sunday when I could not find anything for the kids to color

as well as a Dinosaur George answer session (there are numerous episodes with Abelisaurus questions)

and a German voice-over of a Discovery documentary. I think it is Planet Dinosaur, but feel free to correct me on this.  Of course, the actual show may just be say it is an Abelisaurid, but the German voice-over says Abelisaurus for certain, so we shall see which is correct.

The Children's Abelisaurus

Abelisaurus pops up a lot for children's pleasures. There are a few good places to get facts, such as the NHM of London. There are a number of interesting things online from Dinosaur King to video game references and some books. There is a group on YouTube, and probably other places online, called HooplaKidzTV that is educational for children. One of the little episodes features a talking Abelisaurus who introduces and describes himself. Not very accurate looking, but educational nonetheless.

He has a cold and a powerful sneeze also. There are a couple of suitable coloring pages as well. I'll post them just below (except for this one from Josep Zacarias, which you can ask his permission to use). I hate to cut it short today, but I have a Biostatistics final tomorrow, so I need to run along and study! Have fun coloring today folks. I may take a moment out to color a sheet myself later!

Afternoon Terrors

This skull is not an exact replica of the skull originally unearthed and described under the name Abelisaurus. That skull was missing a good amount of the right side of the skull and the palate, the roof of the mouth, was fragmentary at best. Above the orbits where the eyes would be housed and along the nasal bone, however, we can see the rugosities and places where keratinous hornlets may have protruded upward from the skull. The mandibular fenestration visible here would have made the closing actions of the jaws extremely powerful as the muscles running through would have added additional strength to the closing of the mandible. An alternative theory, or perhaps secondary use, for a fenestra that large would be for thick bundles of nerves to be threaded through the hole. Why any animal would need that much nervous tissue in that exact placement in its skull I could not say though. Neither of these observations is published, to my limited knowledge of the moment, but it is quite possible these theories have been put forth by others as well.

Illustration Citation wanted

As mentioned yesterday, the lack of post cranial material makes designing the body of Abelisaurus in illustrations a special kind of difficult. Abelisaurus has been argued to be a middle of the family Abelisaurid and it has been argued to be a basal Abelisaurid; a third argument has potentially made it a closer relation to Carcharodontosaurus, and thus not an Abelisaurid at all, which presents an interesting reordering of the family. We do not want to worry about that sort of thing today though. Instead, let us look at the arms, one of the most characteristic and diagnostic post-cranial features of the Abelisaurids that we know of (including Aucasaurus, Carnotaurus and Majungasaurus). The arms of the known post-cranial skeletons are typically very reduced with the palms facing the ribcage of the animal and the fingers pointing toward the tail. That is not to say that this is the only way in which the hands of Abelisaurids were constructed and, if it is a basal member of the family named after it, Abelisaurus may not have arms like other Abelisaurids.

Illustration Citation wanted

If it did it would probably look a lot more like this version. The arms here are not very reduced, but they could be the start of the family trend of evolution where extreme reduction and a rear facing hand become common. That small arm could have been reduced in many other animals that we have yet to unearth or that we also only have the skulls, or very little post-cranial material for, with which to describe the animal. The legs on this illustration have an interesting ball of muscle at the calf, but a muscular calf is not as important to us in this discussion as the speculation about which way the arms faced and how they were held in relation to the body.

Father of the Family

It is not often that we have a head of the family with a week dedicated to them. This week, however, is different from other weeks. Instead of tackling a species whose name appears only at the generic level we are tackling one that has an entire family, and subfamily, named after it. It appears as follows taxonomically (I simplified it a little):

Family: †Abelisauridae Subfamily: †Abelisaurinae Bonaparte & Novas, 1985 Genus: †Abelisaurus Bonaparte & Novas, 1985 Species: † A. comahuensis
As we can all see the dinosaur in question this week is Abelisaurus. Abelisaurus is, somewhat obviously I think, characteristic of the Abelisaurids in specific areas. These characteristics are mostly found in the skull, as that is the only known material; the skull shares many characteristics, though not diagnostic characters, of the Tyrannosaurs. The skull possesses rugosities which may have once supported keratin hornlets along the nasal and supratemporal horns are probably. The skull itself bears many resemblances to Carnotaurus and indicates that the two were fairly closely related. The lack of post cranial skeleton, however, makes it difficult to ascertain total length, skull estimates of 85cm in length indicate a body length from 7 to 9 meters (25-30 feet) making it a rather large theropod of South America, and the posture of the body. Many Abelisaurids are known to have reduced forelimbs, another trait reminiscent of Tyrannosaurs, which are often held facing posteriorly (that is rearwards in layman terms) with the palms against the ribcage. Abelisaurus, though, not having forelimbs associated with its remains, is a bit of a mystery in the posturing of its forelimbs, and as such it is not known if it conforms to this behavior. Knowing that information could shift the placement of Abelisaurus within its own family, a topic which we will discuss in the coming days.

Digging Into Popular Culture

A contest was held quite some time ago in the Spore forums to recreate an Oryctodromeus, but it does not seem to have happened. Additionally, there is no Dinosaur King episode or card that sports an Oryctodromeus. I think Dinosaur King cards are divided, in much the same way other fantasy games/books/etc. are, into elements and Oryctodromeus would certainly make a good earth related dinosaur what with all the burrowing and such. I am actually quite amazed that this has not yet happened. No cartoons, aside from Dinosaur Train, exist or documentaries with crazy CG dinosaurs running around or anything like that. Toys exist. Dinosaur Train toys were shown earlier in the week. The fact that the first dinosaur to be seen in evidence of burrowing and thus conclusively known to be a burrower is not more popular is quite sad. Perhaps in the near future something will happen that will make Oryctodromeus even more popular. However, popularity is not the only important thing in the world and, in fact, Oryctodromeus is far more than cool enough without being popular, so, therefore, let us just continue to love our burrowing friend without it being popular.

The Basal Euornithopod

Using the extensive practice I have these days with scientific names, my history of translating the Anglicization of Greek in scientific names and my past in which I took Latin classes, I can tell everyone here with great levels of certainty that "Euornithopod" translates very roughly to "New Bird Foot." Cladistic analysis of Oryctodromeus placed the dinosaur in a position which makes it a basal (primitive, for new readers) Euornithopod. In addition to this placement at the bottom of the Euornithipod tree branch, it is also placed in a cozy middle position of the Hypsilophodont family tree. In point of fact, Boyd et al. (2009), placed Oryctodromeus in the cozy middle place and not at the base of a further subfamily at all (though this may be partly due to the range of their study), but rather as a sister taxon to Orodromeus and Zephyrosaurus, two animals which show a great many common adaptations for burrowing that have been noted within the characters diagnostic for Oryctodromeus.

Restoration by Lee Hall

The forelimbs of Oryctodromeus only show moderate modifications in adapting for burrowing behaviors; however, the rear limbs, specifically in the pelvic girdle of the animal. The hips of Oryctodromeus show adaptations for balance as well as for digging with the legs. The beak of Oryctodromeus supposedly shows some adaptation for digging, though I think that if we ever unearth a wonderfully fossilized manus we will be able to diagnose more burrowing adaptations from the lower forelimbs than have been previously described for the snout. Above is the recreation drawn by Lee Hall who drew some of the other illustrations for the describing paper of Varicchio et al.

References
Boyd, Clint A.; Brown, Caleb M.; Scheetz, Rodney D.; and Clarke, Julia A. (2009). "Taxonomic revision of the basal neornithischian taxa Thescelosaurus and Bugenasaura". Journal of Vertebrate Paleontology 29 (3): 758–770.

Early Morning From My Burrow

It is a bit chilly in my house. Kansas wind blows out the pilot light on our heating unit (it has a gas shut off so that is not a worry) on such a regular basis that we do not even really use the heater; whomever built a house in Kansas with a pilot light under the house with an opening that does not shield the wind is no genius anyhow. Instead we have cheap but efficient space heaters and warm blankets. I am okay with this system and it allows me, this morning, to simulate typing in a burrow, or a blanket fortress, whichever you prefer (it's about 50F in the house, we are not freezing ourselves to death or anything). The burrows in question this week, not mine, have been studied fairly extensively, as we would expect with such a rare and amazing find. The initial discovery paper is  online free and everyone should at least skim it. It is available thanks to the Proceedings of the Royal Society and the authors. Additionally, David Varrichio, who was lead author on the original paper, has gone on to work with D. Cary Woodruff to model the creation of the fossilized burrow using PVC and sediment experiments with comparably sized rabbit skeletons to simulate the three Oryctodromeus discovered in the burrow. Their results are not available free via the Geological Society, but KU's Palaios has posted  the abstract online. You really have to love the image that came from this experiment that I found though:

Modeling a dinosaur den: a half-size PVC model of a Oryctodromeus burrow used to tests scenarios for how they became preserved. From Woodruff and Varricchio, 2011.

Now, granted I cannot say that the image is the best one from this modeling experiment, it certainly does a good job of showing how much work must have gone in to designing and conducting the modeling experiment. It also renews the sadness of the fate of the three skeletons trapped in the burrow and fossilized.

Moving Oryctodromeus

As far as illustrated Oryctodromeus we cannot really improve much on the fun illustrations of yesterday. Dinosaur Train really characterized the speed that Oryctodromeus is theorized to have possessed; though they did not show it in a running stance so much as they showed speed as a characteristic of their movement in general. Still, it was entertaining and interesting. Today's videos are much less movement oriented in comparison and are actually much more information driven. One of them, which I have not used as a video source in ages, comes from the emails and letters that George Blasing (Dinosaur George) answers on YouTube. Due to that fact it is important to note that in order to hear the information George has on Oryctodromeus you may have to listen through some other emails. Considering I rather enjoy hearing some of the emails he receives and his interpretations.

I also found a short video from Emory University and, specifically, Anthony Martin, showing bits of Martin's hike through Australia and one of the burrow sites that he and his colleagues discovered in Australia. There is not much to it, but it is something to look at and hear some thoughts from the discoverers. An adapted story from the Emory announcement can be seen on a site called Fossil Science.

Introducing New Words

The folks over at the Dinosaur Train camp put together a rather interesting episode called "The Burrowers" featuring Oryctodromeus. The episode introduces words to the audience, intended of course to be children, like crepuscular, which is pretty fantastic. The assumption that children can learn some interesting and difficult scientific words like that, as well as enjoy a "hole" bunch of puns (it happens so often in the episode I could not resist if you told me to), shows a lot of faith in the intelligence of children. As usual, Scott Sampson's interaction with and explanation to the kids is concise, intelligent, and well suited to the kids watching the show. As with most Dinosaur Train episodes there are toys related to the episode that have been released; in this instance the company creating the toys is Tomy. For some rather confusing reason the description of Oryctodromeus on Tomy's site states that it is a carnivore; disregard that. Other kid friendly info sites exist as well, including PBS itself as well as the NHM in London. I have to say, at this point, we have used the NHM so much in finding information that kids can digest about their favorite dinosaurs quickly and easily, that the folks over there putting those fact sheets together have done a fantastic job and should be rewarded somehow despite the fact sheets not being glamorous or showy in any way. Coloring pages, however, I am sad to report do not really exist as such for this dinosaur. It would be a neat little dinosaur to color, but alas, there are none at this point.

Dinosaur Moles

©James Hays

Oryctodromeus burrows were discovered in 2006 in Montana and since then other burrows have been described from Australia. While Anthony Martin, the man responsible for the descriptions of the burrows in America as well as Australia, attributes the Aussie burrows to both a dependence on the earth to hide as well as warm during the theorized long Aussie Cretaceous winter (see leaellynasaura), the Montana burrows would more than likely not have been dug for winter survival as much as simple survival from predators. What else, then, could they have been used for? Certainly running and hiding is enough reason to have a burrow when a slightly larger raptor or a tyrannosaur is trying to end your life; but was there other evidence in the burrow that made the Oryctodromeus burrow find even more important than simply being a burrow? There certainly is and we have the graphics to help understand it.

Adapted from L. Hall/Montana State University

The Montana burrow contained Oryctodromeus skeletal material in a large hollowed out burrow comprised, millions of years later, of sandstone that had, it is thought, originally lined the burrow for comfort, to make a home (a couple of pillows and a sandy carpet, maybe a skylight!) for the small animals. The entrance of the burrow, denoted in the figure above by the letter "U" was just large enough for an adult Oryctodromeus to squeeze in and then meander, probably crouching quite low for a short ways before reaching the larger inner chamber, down to its wider and more open home environment. Using speed to gain distance and then squeezing into a small hole is a somewhat common defensive measure for extant fauna (rabbits, mice, and  shrews; to name a few mammals that can use this strategy) and would have certainly worked in dinosaur times for a smaller herbivore which used speed as its initial defensive strategy. However, the home chamber, labeled "CH", also had a surprise for Martin and the team when it was examined; babies! Along with an adult Oryctodromeus two smaller skeletons, announced as juveniles, were also discovered in the hollowed out nest area of the burrow. This evidence points not only at a defensive strategy but also at a family unit living in the burrow. Whether that family unit is theorized to be a single parent unit or that of a collector and protector role for each parent I have not seen yet, however, given evidence from numerous stay at home parents in the existing animal kingdom, it would not amaze me, for one, if the parents either took turns collecting foliage and bringing it to the nest or if it was a mom at home dad out earning food situation. This could also explain a heart-breaking story of loss when a burrow collapsed and a family was lost with one parent outside unable to help its family...

Photo and arrows by Anthony Martin

Let us, for now, try to ignore the sadness either parenting scenario leaves us in with this burrow and skeletons and look at something that Anthony Martin personally points out on his blog entry from which this photo is borrowed. The arrows, according to Martin (which can be seen in the image above as well once one knows to look for them), indicate accessory, or extra burrows. These would not have been used by the Oryctodromeus, but rather by other animals smaller than Oryctodromeus which survived by living in communion with Oryctodromeus, or vice versa. Martin points out in his blog that the gopher tortoise exists in a similar symbiotic community where the tortoise, or another denizen of the community, begins and extends its tunnel and other smaller animals, insects, smaller mammals even, extend tunnels for their own living spaces in the comfort of knowing that their neighbors will not come through their walls and eat them. The arrows in Martin's photo (and t1 and t2 above) point to other burrows found extending from the main Oryctodromeus tunnel. Oryctodromeus was not, then, just a burrow digger, but a community planner and neighborhood builder. Nifty role for a fast little dinosaur.