The First Giant

In 1818 Georges Cuvier settled a conundrum of William Buckland's when he investigated the large bones of a lizard like animal. The bones had been in Buckland's possession for years, but the Napoleonic Wars had caused a situation in which international visits like the one Cuvier would eventually pay to Buckland to be on a fairly permanent hold until the cessation of the hostilities. This delay did nothing but slow down the description of one of the very first documented dinosaurs in the history of human kind. The descriptions that Buckland and Cuvier worked out together were published in 1824 and the new lizard like animal, "dinosaur" was not coined until 1842 by Richard Owen, was given the binomial name Megalosaurus bucklandii. Megalosaurus was originally restored as a bulldog like quadruped but we now know for certain that Megalosaurus was a Middle Jurassic European Theropod and is found in not only England but also in France and Portugal. No complete skeleton has been discovered to this point, but with multiple points of discovery and a wealth of material, a fairly complete knowledge of the skeleton does exist. This week is all about that original dinosaur, Megalosaurus.

©Sergey Krasovskiy

Not The Least Famous

Wannanosaurus is far from the least favorite of dinosaurs, but it does suffer from being such a small dinosaur and from having so little known about it. The best bet for a dinosaur with few remains to become popular in the world is to have some radical adaptation or ornamentation or to grow to an enormous size. Being a basal pachycephalosaur, Wannanosaurus does indeed have a rather strange ornamentation evident in the skull, but it is not as high developed as it is in later pachycephalosaurs and so only appears to really be a flattened, strengthened roof of the skull. This is important in understanding how the skulls of pachycephalosaurs evolved over time, but does not make for a hugely impressive dinosaur adaptation or ornamentation. Wannanosaurus probably looked more like a lightly helmeted Hypsilophodon than it did a dome headed pachycephalosaur. That of course does not necessarily mean it would be less famous than its cousins, but it does not help either. Hopefully more skeletons of Wannanosaurus will come to light in the future both to make it a more recognizable dinosaur, and to further the study of pachycephalosaur evolution.

A Little History of Wannanosaurus

Hou Lian-hai has gone on since Wannanosaurus to become a fairly prominent Chinese paleontologist studying and writing books about mainly bird fossils. Everyone starts somewhere though, even if he does like paleo-birds more these days, and his contribution to dinosaur paleontology is quite important. The specimen found and presented to him for study was discovered in Wannan (South Anhui), hence the name, in the central portion of the eastern half of China. The Yangtze River travels directly through the area and it is fairly close to the Pacific Ocean, though not bordering it. Wannanosaurus comes from Campanian era rock of the Upper, or Later, Cretaceous period. This means it shared the globe with animals such as Ankylosaurs, other Marginocephalians of course (Ceratopsians and some other Pachycephalosaurs), birds, Hadrosaurs, and even the first flowering plants. Its nearest neighbors were animals like its cousin Homalocephale, Protoceratops, Citipati, and Velociraptor. These animals were not exactly one hundred percent in existence at exactly the same time, there is some overlap here and there, but it gives a picture of what the environment most probably looked like. Regardless, it appears, if Hou was correct in stating that the remains of Wannanosaurus come from adult individuals, that this was a very small Pachycephalosaur. Greg Paul and others have stated that the remains come from a sub-adult juvenile of the species; it is nice that they do not argue against the validity of the species but rather the maturity of the individual since there are distinguishing traits of the skull mentioned earlier which set it apart. Hopefully more complete skeletons of Wannanosaurus will be unearthed in the future to put all of these cross claims aside and give us a more complete picture of the animal because, as a basal animal, it has a  lot to tell about how the Pachycephalosaurs and Ceratopsians evolved away from their common ancestor and what made each group what it became.

Hou 1977 and Describing Very Little

Given that Hou's 1977 description of Wannanosaurus is based on approximately half a skull, a femur, a cervical vertebra, a humerus, a tibia, and part of the pelvic girdle of the type individual, it is quite amazing that there was enough evidence in those few bones to accurately assign Wannanosaurus to a family let alone create a new genus and a new species. The description also takes into account nearby remains which are also partial, but which support the description given by Hou. These remains included a few more vertebrae, two femurs, the left tibia and fibula, part of the pelvic girdle and a foot and claws. Hou used the skull roof, mandible, and teeth mainly in his diagnosis description of Wannanosaurus as a pachycephalosaurid. The description is quite detailed and backs up his diagnosis based on cranial features only found in other members of pachycephalosaur family. As such, that explains how his diagnosis, on very little skeletal remains, has withstood the past thirty plus years of scientific scrutiny. Give it a good read at the link above, it is well worth it.

References
Hou, Lianhai, "A primitive pachycephalosaurid from the Cretaceous of Anhui, China, Wannanosaurus yansiensis gen. et sp. nov," Vertebrata PalAsiatica, Volume 15, Number 3, July, 1977 198-202

Wannannannosaurus!

There are not any "professional" videos of Wannanosaurus to share today, but this short report by some short UK students is enough for me today. In fact, I am going to let them do all the talking today!

Wannanosaurus Report from Mr Miller on Vimeo.

Interesting Children's Information

There are multiple sources of information which, for most school aged children, would be fairly easy to read. Scientific descriptions and writings are difficult for anyone to read, that's why "fairly easy" is about as close to easy as I would dare say any source would ever be for a child to read. There is a strange issue with these pages, though, which does not often come up when searching for information that can be used or read to the youths in our lives. Typically I image Sundays could go something like this: Your young nephew or niece, son or daughter, pulls up a chair or sits on your knee while you read along with them or to them the little dinosaur facts and they can look at the picture of the dinosaur to physically see it; then you print out something to color and everyone has milk and cookies while watching the dinosaur specific Dinosaur Train episode and a happy time ensues. You can still print out something to color today, but there is no picture for them to look at while you read to them on Enchanted Learning, DinoDictionary.com, or DinoChecker. In fact, the second and third resources show pictures of random dinosaurs with a question mark over them instead. It is just very strange. However, if they need to envision Wannanosaurus to enjoy their dinosaur this week, you can print this pachycephalosaur and color while you read. It's an approximation, but probably a fairly good one.

A Slight Conundrum

For the most part the remains of Wannanosaurus have been fairly well recognized as those of a basal pachycephalosaur. This turns up pictures we expect to see of typical dome headed dinosaurs wandering a Cretaceous landscape most of the time. Additionally, it occasionally shows us results like the page from a book over here (anyone that can identify that book gets the satisfaction of being helpful) which looks a lot less like a pachycephalosaur and more like a hypsilphodontid, though early pachcephalosaurs were more than likely fairly bland like this on account of the fact that the skull adaptations were not quite as ostentatious as they would be later in the familial lines. Regardless, these are what we expect to see when we here pachycephalosaur or basal pachycephalosaur.

©Hou 1977

The material on which Wannanosaurus is based, in part, is a non-articulated mandible. The evidence in the mandible, the teeth, which was used to aid in the classification of Wannanosaurus as a pachycephalosaur indicate what could possibly be an omnivorous diet, as many members of the family are thought to have also been. Wannanosaurus had a number of leaf shaped teeth, some of which overlapped, and a few which may very well have been chipped canines. This evidence was very important in Hou's initial description and assigning of Wannanosaurus to the pachycephalosauridae with the addition of the upper cranial elements (part of the skull roof) also discovered. There is a slight problem with this evidence however, in that it is so little in number that it can also be assigned elsewhere in the dinosauria if not carefully examined. The skull roof, however, is quite clearly that of a pachycephalosaur when compared to other members of the extended family.

Regardless of careless indexing, see above, Wannanosaurus is widely agreed to be an adult pachycephalosaur of a small basal species. Very few sources, Gregory Paul's Princeton Field Guide as an example, consider this an immature animal. Paul, though, despite being on the minority side of this consensus as to the maturity of the individual does not, at least, assign it to another genus or species; he recognizes Wannanosaurus as a separate and distinct species despite considering it an immature specimen. The edition of The Dinosauria (Weishampel, Dodson, Osmolska 1990) that I have is very old, but in its pachycephalosauria section (Maryanska 1990) it mentions that "it probably represents an adult individual" based on the roof of the skull.

References
Hou, Lianhai, "A primitive pachycephalosaurid from the Cretaceous of Anhui, China, Wannanosaurus yansiensis gen. et sp. nov," Vertebrata PalAsiatica, Volume 15, Number 3, July, 1977 198-202

Maryanska, T., "Pachycephalosauria," The Dinosauria, Ed. Weishampel, D.B, Dodson, P., Osmolska, H, Los Angeles: University of California Press, 1990

Paul, G.S., The Princeton Field Guide to Dinosaurs, Princeton, NJ.: Princeton University Press, 2010

Chinese Boneheaded Dinosaurs

Wannanosaurus yansiensis. Chinese pachycephalosaur. A very early or basal version of the later pachycephalosaurs, this dinosaur is known from very little physical evidence. The type specimen is actually not much more than a head, a partial leg, and one piece of backbone. The head is fragmented as well, but does tell us quite a bit about the animal. The general consensus is of course that this is certainly a pachycephalosaur, just a very early basal one. Additionally, it is a very small animal by all indications and both robust and thin femurs have been associated with the animal. Most of its teeth, it is thought, have been identified and related to other members of the family. However, when all is said and done there is very little evidence of this dinosaur that has been recovered and accordingly there is a good amount of speculation that has gone into designing the image of the living animal. It is assumed that they engaged in some uniquely pachycephalosaurian behaviors such as headbutting or at the very least feats of strength, shoving matches, with their heads.

That Popular Skorpiovenator

Skorpiovenator, as we have seen this week, is actually a fairly popular dinosaur given that only one incomplete, though rather complete and articulate as far as holotype skeletons and dinosaur skeletons in general are concerned, has been found. The description of Skorpiovenator helped to identify Abelisaurids more solidly as a group and has helped to define the new clade Brachyrostra under the subfamily of Carnotaurines. Skorpiovenator has been featured on Planet Dinosaur on the BBC and has been mentioned in numerous papers and even a few books. It is lacking in the toy department, but that is okay because eventually it will be modeled in plastics or as a plush because it has far too interesting sounding a name to not gain popularity. However, there's also no Dinosaur King yet, and that's usually one of the first outlets to pick up newer dinosaurs these days, along with Dinosaur Train, so keep an eye on both of those. Until then, Skorpiovenator can be filed under "fantastic name, waiting to get popular."

©Tuomas Koivurinne
My favorite young paleoartist from Finland

Skorpiovenator's Fast Legs

There have been studies recently, such as Persons and Currie 2011, which have analyzed abelisaur speed characteristics. The specific animal they studied was Carnotaurus and they looked specifically at muscle attachment sites along the beginning of the tail (caudal vertebrae) and the related attachment sites along the femur. What they found in Carnotaurus indicated a large predatory dinosaur that was capable of short fast sprints, a powerful land-striding gait, and an inability, due to the rigidity of the caudal vertebrae anchoring muscles, to make tight turns at speed. Why is this important for Skorpiovenator, a cousin of Carnotaurus? As a South American ableisaur Skorpiovenator shares more with Carnotaurus than do Indian and African abelisaurs. It is well documented that the South American abelisaurs evolved traits, as a whole, that did not develop on the other continents after the Gondwanan split into more recognizable continents that we have today (see page 5 of Canale et al's original paper linked yesterday). It is not, therefore, too odd to find that the caudal ribs of Skorpiovenator are similar to those of Carnotaurus, indicating that Skorpiovenator too was a fairly quick predator. It may have had different bumps and horns on its skull, but it was a good short distance runner as well. Persons and Currie make no statement to the effect that Skorpiovenator would have had trouble turning, but given that its ribs and muscle attachments are similar to Carnotaurus, it may very well be the case that it as well did not make very good tight turns at speed. Considering that both animals likely hunted large sauropods in numbers, along with smaller animals when they had to including young sauropods, a high rate of turn would not likely have been a factor (I have no paper to cite sauropod turning radii at the present, though I am sorting through some papers by Carrano, Christensen and Bonnan on sauropod locomotion).

Skorpiovenator is Found!

When Skorpiovenator was found, named, and described it was an interesting occurrence in paleontology. It is not because Skorpiovenator is the most popular dinosaur or the most intriguing, but because Skorpiovenator was nearly an entire skeleton and added its story to an already interesting and perplexing family of dinosaurs. Abelisaurs from Asia and Africa have different skulls and arms than those from South America and Skorpiovenator further solidified that divide. Additionally, the interesting differences and characteristics of Skorpiovenator that both set it apart from and identify it as an abelisaur lead to a more complete understanding of the family. The original paper of Canale et al. is available online and explains these ideas further and in greater detail than I provide here. It is short and an interesting read about a new dinosaur.

BBC Doesn't Share With Me

Being in America any time I try to watch something on the BBC's website it tells me I cannot view in my country. The BBC does not love our copyright laws I guess; there is always a blurb about copyright protection in there as well. I just miss a lot of clips from the BBC is all, and not having any kind of television subscription I cannot watch BBC America or anything like that, which means I missed all of Planet Dinosaur in its entirety on television. This is unfortunate this week as the picture used on Friday was a still from Planet Dinosaur and there is at least one clip that goes along with it. Episode 5, I have come to find out, of Planet Dinosaur was all about the abelisaurs of the south including our friend this week, Skorpiovenator. The website for the BBC sort of makes up for not showing clips in America (and no, I do not have time to go through setting up proxies and getting around such things on school days) by having a good page on abelisaurs and providing a synopsis of the episode as well. There are clips on the internet from that episode, however, such as this Argentinosaurus herd eating.

Skorpiovenator Despises Babysitting

Skorpiovenator is not going to be good at teaching your children today, or keeping them occupied. The only thing we have today like a fact sheet for Skorpiovenator is a dinosaur encyclopedia page taken from Wikipedia and reformatted slightly. New dinosaurs often suffer from a lack of child friendly internet material, and that is what has happened today, but never fear! I have a couple links to art, which I did not get the artist's permission to reprint here, which, while not intended as coloring pages, could certainly be used as coloring pages for Skorpiovenator; its got a bit more of a T. Rex head, that's the only bad issue I have with it. There is also this design and the artist states it is going into a comic book, which is pretty neat.

Some Awesome Skorpiovenators for Saturday.

©Mark Turner

There is a fairly well known skeleton of Skorpiovenator that has been found. So far, unless a second skeleton has been very recently discovered, it is still only one skeleton that we as a species have to study for Skorpiovenator. There is nothing wrong with this of course, except that it is sad that there is so little material available to study still. Thankfully, however, that very little material is a nearly complete skeleton in addition to being the only skeleton available. As rare as Skorpiovenator is, though, a complete skeleton, even though Skorpiovenator is missing some of its arms and tail, is one of the rarest thing in paleontology. Given that we have such a large amount of the skeleton and it has been thoroughly described, we know that Skorpiovenator was an abelisaurid, and that gives us a general appearance that we are sure of for those missing parts.

©Dinoraul

The general body shape that Skorpiovenator, and other abelisaurids, follow is a very typical theropod body shape. However, Skorpiovenator does have unique properties, as does every dinosaur, that separates it from its closest cousins. Skorpiovenator, for one, was larger than some of the other carnivores it shared its woodlands with such as Ilokelesia, a medium sized abelisaur, and it was smaller than some of its neighbors as well such as Mapusaurus, a carcharodontosaur. This medium size, though being on the largest end of abelisaurids, would have meant that to pull down the sauropods mentioned yesterday Skorpiovenator either hunted in small groups, picked off the juveniles more than the adults, or had some sort of amazing adaptation, like those thought to exist in Acrocanthosaurus (covered in the December 2010 Facebook page) which allowed it to hunt adult sauropods. The face of Skorpiovenator, however, was actually a lot shorter than that portrayed in this illustration. Long legs, not long jaws, were probably one of its most important weapons in conjunction with a toughened skull which appeared built for impact and high stresses.

©Mark Turner (link above)

Possessing long leg that more than likely powered a somewhat agile, for an almost two tonne animal, and quick predator with a reinforced skull which may have been used in part to wrestle prey to the ground, Skorpiovenator had little use for large arms. Given that much of the forelimb is missing in the skeleton that has been found it is difficult to position the forelimbs completely, but given the knowledge of abelisaurids that we have, and using other existing forelimbs from other abelisaurids as a model, the small stunted looking downward or backward facing hand of Carnotaurus or Abelisaurus itself is probably a very good fit for Skorpiovenator. Alternatively, the skinny abelisaurid arm of Indosuchus is an understandable model as well. Given, though, the geographic location of Skorpiovenator it is most likely that the stunted folded in Carnotaurus style arm would have been present in Skorpiovenator or at the very least beginning to show as an intermediary design between early abelisaurids and Carnotaurus and Abelisaurus, which came later. The exact use of the jaws as killing instruments has probably been surmised in the describing paper of 2009, and if I get my hands on it I will share the conclusion to that end, though I feel it will be much like the killing apparatus found in Carnotaurus as their skulls seem to have been the equivalent of version 1.0 of what would later evolve to be the skull of Carnotaurus.

Scorpion Hunting

The Cretaceous of Argentina was a dangerous place filled with large carnivores and large herbivores. There were also small animals of course, but unlike in the northern half of the world, there were still giant sauropods here that required giant predators to take them down. That's not to say that a T. Rex couldn't take down a titanosaur, they just did not have to where they lived. Regardless, the largest predators in the southern half of the globe were big mean animals from a family called the Abelisaurs. One of them that lived 95 million years ago in the Late Cretaceous of Patagonia was called Skorpiovenator bustingorryi. Skorpiovenator means "scorpion hunter" and was so named because of the large amount of scorpions found in its modern day land. The specific name, bustingorryi, is in honor of the farmer who owned the scorpion infested land, Manuel Bustingorry. The holotype skeleton, the only skeleton thus far found of Skorpiovenator is a rare find actually. The entire skeleton minus some of the bones in the arms and in the tail was found on the Bustingorry farm. Skorpiovenator is a "new" dinosaur, having been first described in 2009 by Canale et al. According to the newest publication by Gregory Paul this places the habitat of Skorpiovenator in the manner of being forest with abundant water and short dry seasons and the main prey item would have been a 40 foot (12meter) long sauropod called Cathartesaura. A lot remains to be discovered about Skorpiovenator, but there is a good amount to discuss already this week and it will be a fun week learning about a newly discovered dinosaur.

Skorpiovenator on Planet Dinosaur

Riojasaurus in Pop Culture

Riojasaurus isn't the most popular dinosaur in the world, we can readily admit that, however, it does have a certain level of notoriety within the general public, which is pretty awesome. Riojasaurus has shown up in a lot of children's links, if you look back to Sunday and a tribute video has been made. They have shown up in Jurassic Park games and books quite regularly. Granted they have not been the main animal discussed for an entire book, but they have been mentioned over and over in many different books. Dinosaur King is lacking, for once, in Riojasaurus materials. There are not very many toys either. It's one of those dinosaurs that has shown up a few places, but doesn't really seem to show up in the places we would expect in order for it to gain popularity. Now that a skull has been found and described and the Galton and Sereno theory has been laid out about sauropod and prosauropod evolution perhaps they will become better known in the near future.

Riddling Riojasaurus

The constituent parts of Riojasaurus are interesting. As a prosauropod, if we agree that prosauropods were a building block in sauropod evolution and not a convergently evolving group of animals, it makes sense that the body of Riojasaurus, being a later Triassic prosauropod, would be bulking up as it evolved traits more often found in its later descendants the sauropods. These of course included the traits easily visible from afar such as a long neck and a long tail. They also include rather thick strong bones in the legs as well as other parts of the body such as the ribs which made the living animal a massive, heavily built, and strong dinosaur. Another trait found in both Riojasaurus and later sauropods is that their vertebrae were pocked by hollow cavities which lightened the bones. This makes sense for a number of reasons.

One reason of course would be to lighten the neck and tail as well as the back itself so that the weight of the animal was not too much for the legs to handle; the heavily built legs more than likely could have withstood the additional weight of solid bones regardless. The second reason that this makes sense is that had it been able to rear up, current speculations say that this was not possible on account of an extra sacral (pelvic) vertebrae and the near identical length of fore and hind limbs as well as the solidity of their makeup, this would have lightened the pressure on the hips and balancing tail, should that have ever met the ground in the process. There is also the possibility, of course, that nerves and blood vessels inhabited the cavities and helped relay messages and nutrients along the length of the body in a more protected manner, given that they were in the bone for some of their journey.

The skull shows serrated leaf shaped teeth with 5 aligned in the front and 24 behind them in a short mouth that ends under the eyes. Additionally, the eyes possessed sclerotic rings, the small bones that are found around the actual eye ball in a lot of animals, mammals and crocodiles being notable exceptions. The sclerotic rings of Riojasaurus show evidence that this dinosaur was rather sloth-like in its daily activities, taking long breaks from activity and being active at short intervals in daylight.

Papers All Over

Riojasaurus and her cousin Plateosaurus
from 2010 South Korean stamps

There are mentions of Riojasaurus in papers all over the internet. Bonaparte's 1969 paper describing and naming Riojasaurus is not among the treasure trove that we find online, but looking back through the archive of this blog you would find very few initial descriptions and new species or genus announcements are to be found online. It is not a problem or a difficulty really, it is just the hard fact that so many of our dinosaurs, and other fossilized animals, that have been discussed were named and described even before the majority of houses had electricity, let alone the internet. Regardless, the citations of papers and the mentions of Riojasaurus in sauropodomorph discussions alone are enormous in quantity. PLoSONE, though relatively new to the internet, hosts four articles that mention Riojasaurus in studies of new dinosaurs or the evolution of sauropodomorphs. A Bonaparte and Pumares paper from 1995 does show up online courtesy of the Ameghiniana journal; a journal put out by the Paleontology Association of Argentina. The paper describes the first complete skull of Riojasaurus, quite a few years after the initial describing and naming of the species. The most unfortunate thing for me is that I never took Spanish and therefore I could not read Bonaparte's papers in their original state regardless of whether or not I found them online. The Ameghiniana paper I cannot read, for instance, and the original naming paper I am sure I would not be able to read. I guess that means it's time I learned Spanish.

Movie-less Mondays

Given that Riojasaurus is from Argentina and that it is a Triassic animal it comes as little surprise that there is not any kind of documentary about it. Triassic animals are seldom fully understood and southern dinosaurs are still being heavily studied and discovered; they have yet to reach the stage of study in which all the long established theories are sometimes tossed out like we have seen recently in some northern dinosaurs. However, scientific upheaval is a good thing sometimes because it invigorates the scientists involved to approve new theories, disprove new theories, or re-investigate animals that have long been considered overly researched. However, I digress, a lot. Riojasaurus is still relatively new to the paleontology community and that means that anything that is published about it right now is likely to be a new idea, but there just are not that many new ideas yet about the animal that constitute an entire documentary being needed. Someday perhaps a giant prosauropod to sauropod evolution video series may be made and Riojasaurus will be a star for an episode, but without that existing for now we will just have to make do with tribute videos and the like. I cannot be sure that Linkin Park is exactly the music for Riojasaurus, but it is today if you watch this, so enjoy.

A Good Day to Be A Kid

It is wonderful when a dinosaur reaches a point where enough of the world knows about it that the world tries to educate children about it. There are quite a few sites that have kid oriented education messages teaching the children of the world something about Riojasaurus. There is one of our favorites to mention on this blog, Kids Dinos, as well as the popular but never possessing a scientifically accurate dinosaur drawing, Enchanted Learning. Enchanted Learning does have the bonus of having a coloring sheet built into their page so that your children and other loved ones can color online if you are low on ink or paper or just do not like to print coloring sheets. Additionally, there are more coloring sheets, one found on Flickr that you should ask permission from the holder if you want to post your art work online after you color it; always try to get permission, it will save you and your parents a lot of hassles in the future kids! Also, this image below comes from Arthur's Dinosaur Clipart, where Arthur got it I cannot say. One last thing before I go today. A while back I mentioned a wonderful little up and coming site called Dinosaur Days that is geared more toward the younger ladies in our families but can be enjoyed by the boys as well. If you or someone you know has a subscription (which is only $5 for the online and $7.25 for online and a cd which is not bad at all as far as education websites go) to Dinosaur Days there is information on it as well about Riojasaurus.