Almost Birds... Again

I discuss birds a lot. It is kind of my thing (along with plesiosaurs). This week, traveling to Madagascar, in our minds, we will look at another kind of near bird. Small dromaeosaurids like Rahonavis ostromi are interesting little animals. Animals like this are difficult to diagnose as either birds or dromaeosaurs. Rahonavis does not have a raging battle surrounding it in this regard, but is debated in these terms. Quill knobs on the ulna make it very bird-like. Large sickle shaped claws on the hindlimbs make it more dromaeosaurid-like. Somehow, however, this border straddling dino-bird has escaped many of the arguments of pro evolution and anti evolution debaters. The name is Malagasy based, meaning "Cloud menace bird", and the toothed little dino-bird may be related to Archaeopteryx.

©Nobu Tamura

A Short Wrap Up

Kritosaurus is a small hadrosaur in a sea of its kind. Unfortunately, it lacks all of the defining characteristics of dinosaurs that are popular enough that they have stuffed animals, plastic figurines, models, and video game add-ons. Seeing as how it lacks all of the common popular culture extensions of dinosaurs, could we really say that it is a popular dinosaur? I think that, in its own way, mostly on account of the debate still "raging" around Kritosaurus it would or could be. Sadly, we do not really have more to talk about in that regard though. If anyone wants to discuss the taxonomy feel free to, but I think that is enough for now!

That Roman Nose

Kritosaurus means "Separate lizard" but it is noted that it has been mistranslated as "Noble lizard". This is thought to have been in reference to the bulbous and hooked nose of Kritosaurus. However, if we remember the original Brown recreation based on Edmontosaurus, the nasals were absent from the initially discovered fossil. The nose, unintentionally noted in the name, did not exist for Brown, making the mistranslation a rather horrible error that Brown most definitely did not intend. Strangely, despite the use of Edmontosaurus as a reference for the recreation of the nose, it was not the first genus to be considered as a synonym to Kritosaurus. After the initial discovery, though I may not have said this explicitly before, a great amount of material of Kritosaurus was recovered, but it was most often given the name Gryposaurus when represented in art and literature; Gryposaurus is a close relative of Kritosaurus with a similarly built skull. Placed together with another hadrosaur named Secernosaurus, these three dinosaurs make up a tribe known as the Kritosaurini. Since the creation of this tribe a few other species have been added to the tribe and the group has been placed into the Saurolophinae, which consists of other well known hadrosaurs like Edmontosaurus, Maisaura, and Saurolophus to name a few. This tribe and upper clade nesting makes up a large group of hadrosaurs that span in range from Canada to areas of South America. Kritosaurus is much smaller in its range, but is an important individual and, as we have seen, is morphologically very similar to other hadrosaurs, adding to the taxonomy confusion.

©Nobu Tamura

Writosaurus Kritosaurus

Kritosaurus was written about Barnum Brown in 1910, as if we had not noticed this before when we discussed the naming of the dinosaur. Brown's announcement in the Bulletin of the American Museum of Natural History is a rather detailed and somewhat short account of the fossil that Kritosaurus was described from. The morphology of a skeleton, discovered later, of course, was described very recently by Albert Prieto-Marquez. If one, other than myself, could get their hands on it and read it, it is well worthwhile. Skeletons attributed to Kritosaurus have also been recovered from Canada and Argentina. Whether these are, taxonomically speaking, actual examples of Kritosaurus or not has not been debated or overruled, but there is still contention in the species known and accepted, or not accepted depending on who is asked and when they are asked and the evidence that is being debated or has been analyzed. Reading the papers found here today should shed more light on the different sides of the debates and on the evidence that is presented by either side of the line.

No Roles Available

"Hadrosaur" is one of the easiest roles to fill in a documentary or motion picture; there are just far too many varieties of this wide ranging, globally, group to choose from. There is only one tribute video that even mentions Kritosaurus, that is how many there are out there. That and the fact that Kritosaurus is not exactly the most well known of all of the hadrosaurs. Having so little to share on a movie Monday is sad, but even the tribute video is better than nothing, despite not being comprised of entirely Kritosaurus images and having a few other closely related hadrosaurs thrown in; taxonomic confusion will do that to you I suppose.

Cryptically Child-like

Kritosaurus is summarized by the London Natural History Museum very concisely and the entire taxonomic map is laid out on the page; showing how complicated the history of Kritosaurus is in a linear and easy to read way. Animal Planet goes a little further and includes a short paragraph that summarizes the knowledge that we have about Kritosaurus. There is not much else to do with kid's education and Kritosaurus.

Hadrosaurs of the Southwest

Photo by Elias Garcia-Ortiz

The skeleton of Kritosaurus is not well known. Recreations of the skeleton and fleshed out body are based in part on Barnum Brown's reconstructions using Edmontosaurus and in part on the similarities inherent in all hadrosaurine body plans. The skull, as we know, was the only definitive evidence of the existence of Kritosaurus and it was crushed on the front half of it. Other evidence of Kritosaurus has been fragmentary at best and does not fill in too many of the gaps. The latest published studies have upheld a single species, Kritosaurus horneri, as existing distinguishable from other remains and synonymizing Kritosaurus navajovius with Anasazisaurus, another hadrosaur. The taxonomy is difficult and the relationships are very intertwined at the moment; looking at the skeleton is not going to settle this argument for sure!

Never Enough Hadrosaurs

Kritosaurus consists of two accepted species; one is questionable. This genus has been mislabeled some times as Gryposaurus but is in fact its own genus and is not synonymous. Named by Barnum Brown in 1910, the type species was named Kritosaurus navajovius in honor of the Navajo people of New Mexico, where the skull that is the type specimen was discovered. Brown was forced to reconstruct much of the skull, using Edmontosaurus as a template, due to severe crushing and weathering of the anterior portion; the most affected areas are constituted of the nasals, maxilla, and premaxilla but also affects some of the middle skull bones. The arguments for and against different alignments of Kritosaurus (as valid taxon and as a member of any variety of other taxa) is still being discussed and studied at this time, but for this week we are going to treat it as a valid and unique genus worthy of our attention and view the evidence both for and against incorporation.

Original reconstruction of Barnum Brown, presented in his 1910 paper

Not As Popular As Carnotaurus

©Ezequiel Vera (A pretty awesome guy)

Whether it was the size of the dinosaur or those impressive orbital horns, Carnotaurus beat out Aucasaurus as the antagonist in Disney's Dinosaur. It also lost out to Majungasaurus in a variety of documentaries that touched on Abelisaurids. However, we know that it featured in Planet Dinosaur's take on Abelisaurids and we have seen it hunting Saltasaurus in said program. A YouTube user listing himself as Shaban Interactive has posted a number of lighting and modeling tests using Aucasaurus, though some are very inaccurate models of the dinosaur. They are not all bad, except the very inaccurate models. There are also many tributes and stock illustrations online, but I do not think we need to post links to those up here as they are easily found in a quick Google search. National Geographic, where the original highlighted image of the week came from, published an article that discussed Aucasaurus and what was then current dinosaur research at the time, which is worth reading. Their lack of popular material aside, Argentina can be proud of one of the most complete and well known Abelisaurids... even if it does have sad little arms.

Fights and Skulls

The skull of Aucasaurus is damaged. Perhaps not all of their skulls ever, but the type specimen is most definitely damaged. This damage has lead to speculation that the animal in question was in a fight prior to its death and that the fight may even be the cause of the death of this dinosaur. Despite the damage done and the speculation surrounding the skull of Aucasaurus, an article that was published in Acta Paleontologica Polonica only a few weeks ago contains scans of the braincase of Aucasaurus and discusses inner ear morphology and endocranial morphology of Aucasaurus. The ear and brain scans reveal a dinosaur that was capable of moving its head about quite a bit more than other Abelisaurids without sever consequences. I forgot about this paper yesterday, but then remembered that I had the image of the brain scan on my desktop. It can be read online at the link provided above and is very much worth the time it takes to read it.

Ariana Paulina-Carabajal and Cecilia Succar

Quick Read

Not much to read about today. There are a number of papers, most any paper that references Aucasaurus would be a candidate today, that are about Patagonia and that mention Abelisaurids. However, the only paper that really is of great interest to someone wanting to read specifically about Aucasaurus would be the naming paper from Coria, Chiappe, and Dingus. Unfortunately, without JVP or SVP access the article is not accessible. It is worth a read if it can be accessed however, and I highly recommend it as it details the skeleton of the animal.

Hunting Long-Necks

Saltasaurus probably was often a meal for Aucasaurus, but we see them eating Titanosaurus chicks more often. Saltasaurus would have been more of a snack that Aucasaurus could teach its young to hunt. The almost comical depiction of the little hands of Aucasaurus belays their ferocity, as we can see in the full Dinosaur Planet episode. If one can find it online to watch today, take some time out for oneself and watch it!

Playing Nice With Others

Aucasaurus may be one of the best known of the Abelisaurids to science, but that does not translate exceptionally well to how popular a dinosaur is with paleontologists of younger ages, as we well know by now. The best places to see this dinosaur for readers of different levels are internet mainstream links, such as the London Natural History Museum's Dino Directory and About.com's dinosaur pages. Like much of the internet's knowledge about Aucasaurus, however, the pickings here are a bit sparse. Published materials that are good sources include National Geographic's Kids Ultimate Dinopedia; online versions of the material are incomplete but the link is to a page that mentions the dinosaur at least. Josep Zacarias, as always ask permission to use his artwork, has a very nice line drawing of Aucasaurus that could be used for coloring, if one were so inclined.

Always Snacking

Work attributed to Conty

According to the artistic interpretation of much of the paleo-artist community, Aucasaurus ate nothing but baby Titanosaurs. The small morsels would have been easier to eat for a dinosaur with a posterior facing forelimb that was not much help in grabbing and holding prey. Despite the longer, but shallower and possibly weaker jaw, in comparison with Carnotaurus, Aucasaurus was probably capable of bringing down larger prey than an infant Titanosaur. Adult Titanosaur was probably a difficult meal to acquire for a solitary animal, but it was most likely on the menu at any life stage; it may have required a lot more effort as a larger animal to a certain point with old age lowering the effort put in by these Abelisaurid hunters.

©Mariana Ruiz

The forelimb of Aucasaurus is not as reduced as it appears in this series of illustrations. The very bird-like appearance of the hindlimbs is rather interesting for sure; the scaled foot and an almost booted tarsus look to the leg itself allows for a rather interesting interpretation of the fossil animal. The neck is elongate and the snout is a little shorter than we anticipate from the fossils. The representation here is presented not for analysis, but mostly because the body shape is well defined and appropriately expressed and therefore represents fairly well what this dinosaur would have looked like in life.

Never Cry In Argentina

Do not cry for Argentina when it comes to dinosaurs; I may be one of the few people I run around with that remembers Madonna had a big hit related to Argentina way back when and that that counts as a pun (I am oh so old these days). My terrible puns aside, this week's dinosaur is one of those very well known and prominent denizens of Mesozoic Argentina. Its remains are well described and, in part, has certainly put Argentina on the map as a carnivore's paradise and one of the most dangerous lands on the Late Cretaceous globe. Aucasaurus garridoi was one of the largest Abelisaurids included in the exclusive Carnotaurini tribe of little armed, big headed, beefy carnivores that ran what is now South America near the end times of dinosaur reign. Aucasaurus was smaller than Carnotaurus but possessed equally fearsome stout jaws, bony protuberances of the skull, and four metacarpals in its small posteriorly direct forelimbs. This strangeness and the oddly long snout, for an Abelisaurid, in addition to the fact that the type specimen is nearly complete from snout to 13th caudal vertebra, make this dinosaur very unique and important to Argentinian paleontology. You will get to see why this week.

Spore and More

Spore's version of Beipiaosaurus, or at least the one that is available online, is not very feathered looking, but is certainly an admirable imitation of the original from 124 mya. Books, while containing some resources related to Beipiaosaurus, are not very common information resources. The most useful would happen to be The Dinosauria but there are also books for other levels of readers including the casual dinosaur enthusiast like Bambiraptor and Feathered Dinosaurs as well as Riddle of the Feathered Dragons which explores the history of feathered Chinese dinosaurs. 

Big Coelurosaurs

©Oyvind M. Padron

Just like Yutyrannus, Beipiaosaurus was a coelurosaur of giant proportions. Being the largest feathered dinosaur so far discovered is not really an honor, but certainly could be considered one. Beipiaosaurus does still have the honor of being the largest herbivorous feathered dinosaur. At 2.2 m in length, Yutyrannus measured 9 m, was a fairly good meal for its contemporary. Beipiaosaurus was kind of a big turkey dinner also. The caudal vertebrae were fused into a pygostyle. It was a big-headed turkey though, with the skull as long as the thigh.

Papers Are Like Fossil Feathers

Papers regarding Beipiaosaurus are somewhat rare. The papers that are out there include a paper on the EBFF structures. This paper is short, but available online, and discusses the EBFF structure as well as providing a short synopsis of the early evolution of feathers. Xu has studied Beipiaosaurus for a rather long time, thankfully, bringing us the paper mentioned above in addition to the original naming paper and a paper that discusses a pygostyle structure that was recovered from fossils of Beipiaosaurus. Unfortunately, that naming paper appeared in Nature. Nature is a well known and widely read journal, but it is also highly protective of the work published within it. That original abstract is available online for anyone to read, but it is only an abstract and some of it is therefore lacking.

Beipiaosaurus Videos

As usual, with this tribute expect music that you may or may not like. The news articles of 2009 loving or hating Beipiaosaurus have genuinely disappeared by now. Most documentaries have a tendency to relate information about smaller dinosaurs with feathers or larger; these rather unique theropod herbivores are ignored or lost in the world of dinosaurs for the most part. We are left, then, with the video from yesterday and tributes like this one. There are also some other random videos out there, but I think today looking at many models and pictures of Beipiaosaurus may be rather beneficial for those of us out there not exactly sure what we are looking for.

Feathered Movies

There are actually few sources for kids on Beipiaosaurus. One of them traces back to a Creationism blog that says paleontologists are making up evidence of feathers and interpreting fossils in the best way to support their "party line". Rather than dealing with that and separating out the arguments for and against and all of that jazz about kids links, here's a video:

Feathered Fossil

From Xu, et al. 2009

The long and short filamentous fiber of Beipiaosaurus are quite clearly evident in the fossil remains. The downy layer of insulation feathering as hollow filaments are partially preserved in the fossil in the carbon film layer that halos the neck, tail, and hindlimbs especially. The longer, elongated broad filamentous fibers (EBFFs) make up a considerable amount of the halo and individual fibers are clearly visible within the halo. The length of the fibers is substantial, measuring between 100 and 150 mm (3-4 in) which is nearly half the length of the neck itself. These feathers are broad as well, of course, measuring up to 3 mm wide. The widest feather fibers in Sinosauropteryx, for comparison purposes are approximately 0.2 mm. This wider feather fiber allowed for the EBFFs of Beipiaosaurus to be a great deal more rigid than typical feathers. None of the fossilized fibers are bent or curved unnaturally or in a manner that indicates the shafts were coerced into their present positions by other forces. The rigidity of these feathers adds support to the hypothesis that these feathers would have been used as signalling or display structures rather than as air trapping insulatory structures as we find with the downy feathering layers.

Therizinosaurs and EBFF's

©Pavel Riha

Going backwards in the history of feather discoveries we hit the previously largest known feathered dinosaur. Elongate Broad Filamentous Feathers, the type of feathers discovered along the fossilized remains of Beipiaosaurus inexpectus, were long simple feathers rising beyond the down feathers. These longer feathers were most likely used for signalling and display while the down feathers were used to insulate the body; though Xing Xu stated that the team did not want to make any idle speculations. Therizinosaurs like Beipiaosaurus were theropods that, unlike many of their cousins, were herbivores. We have discussed these herbivores before, so there should not be too much background information to go over on therizinosaurs to begin with. What we can focus on, instead, is the Chinese dinosaur in question that was once the largest feathered dinosaur, before the discovery of Yutyrannus.

Google Is Obsessed

Every time I type in Yutyrannus the Jurassic Park Facebook game pops up before anything else; apparently popular culture is obsessed with Yutyrannus' presence on Facebook. Outside of that I have found mention in books, as noted previously, and one model on Spore (it must be losing its hold on people's imaginations these days). It is actually a little sad that it is not more popular, given the media attention it has garnered in the past couple of years. However, such is the life of a dinosaur!

Feathers Where?

The holotype of Yutyrannus had feathering evident on the pelvic and pes areas of the fossil. A specimen known as ZCDM V5000 was discovered with feathers facing posteriorly on the tail. The feathers come off of the tail at an angle nearing 30 degrees. All of the feathers were short, compared to the overall body size of the animal, but varied in length depending on the area of the body in which they were encountered. Neck feathers on the smallest discovered specimen consisted of filaments measuring nearly 20 cm in length with 16 cm long filaments discovered on the forelimbs (upper arm only). Two hypotheses have formed around these feathers. One hypothesis concerns the idea that the feathers that have been discovered are the only feathers to be found on Yutyrannus and are therefore only display features of the dinosaur. The second hypothesis states that these are merely the only evidenced feathers and that a thin coating of these somewhat long filaments covered the body entirely. This would coincide with the fact that the landscape at the time was a bit colder and Yutyrannus required the insulation layer that only such feathers could provide.

Creating and Reporting

I have been told in the past to be very careful in reading and discussing Creationist accounts of paleontology in the past by other academics. However, I think it is very important to be able to read such accounts and discuss and refute them in a logical and scientific manner rather than by means of sarcasm and inappropriate mocking. I say that only as a preemptive warning for the fact that Yutyrannus has garnered a lot of interest in communities other than the strictly scientific kind; like the letter to Nature introducing Yutyrannus. While we have some good "mostly science" books out there that already mention Yutyrannus in reference to Tyrannosaurus' relatives, there are plenty of bits of literature that are not as science friendly. The Christian Science Monitor is a little more scientific-inquiry-friendly (I made up a phrase and I do not apologize) than some other Christian websites and news sources and actually treated the discovery and a related article pondering the relatedness of PBS' Barney and Yutyrannus fairly neutrally (as we expect a news source should). Their description of their site and service speaks to their dedication as a news source first (it is owned by the The First Church of Christ, Scientist which has a beautiful headquarters in Boston, MA but we are not here to discuss architecture):

The Christian Science Monitor is an independent international news organization that delivers thoughtful, global coverage. We want to inspire people to think about what they've read long after they've left the page. To share what they've learned with others. And to do something that makes a difference. (Emphasis taken from the original source)

 This is in strict opposition to the self blurb of the Institute for Creation Research, the largest condemner, to my knowledge, of Yutyrannus and the idea of dinosaur to bird evolution:

For over four decades, the Institute for Creation Research has equipped believers with evidence of the Bible's accuracy and authority through scientific research, educational programs, and media presentations, all conducted within a thoroughly biblical framework.

Acknowledging your bias is not in itself a condemnation of reliability. Misinterpretation of facts and citing other articles written within the same agency with the same bias and misinterpretation of papers does not help your cause though. Hardly any scientist in the world would accept the Bible as an adequate reference for a scientific article also; granted this article is only quoting the Bible, not using it as evidence per se. I recommend reading it and making one's own judgments rather than my interpretation being pushed out on everyone; however, if reading that sort of thing makes one angry or agitated, it should probably be skipped and only the scientific papers should be read.

Monday, Right?

My days melt together sometimes and Monday and Tuesday are extraordinarily busy. I tell all the readers this only because these entries will probably not be written until after 5pm local time on those days and will assuredly be published later than normal.

Regardless, Yutyrannus is a semi-news star, not a movie star, and still has some videos for me to share today. Most of them are not documentaries and very few are "legitimate" news videos, but some, like this one, can be considered news related. More often we see tribute videos and non-reliable news sources. Stick with the tribute videos today though if not the nearly legitimate "news" source above.

Feathered Kids

One of the benefits of paleontology being popularized is that there are more resources for kids, and the rest of us. Time for Kids featured an article in April 2012 that is still available online, which is nice for younger readers. There are not any dedicated children's sites for Yutyrannus though. In fact, there are no fact files or coloring sheets, as we normally share on Sundays.

Feathered in Degrees

It may have appeared that there was an argument against feathering with Yutyrannus, but that was certainly not intended. The fact is that there is evidence that there are feathers and they definitely are there. The extent of feathering that is portrayed in illustrations are, obviously, rather different depending on the artist and their interpretations of the fossils. The amount of feathering is variable in illustration from this rather downy looking individual to the extra fuzzy looking individuals shown yesterday. A downy coating like this may have been sufficient for insulation, but it may be lacking entirely in the display aspect of feathering that usually comes to mind; though not all birds, for instance, are flashy feathered individuals. Feathers for insulation rather than used as display markers in dinosaurs could be the more primitive condition and that may be what this interpretation is showing.