Popularity Issues

Astrodon has been the subject of some issues, as we have seen, regarding its name. In Texas as well as in Maryland most of the popularity of this dinosaur comes from the fact that both states were represented by Astrodon (it was Pleurocoelus in Texas until 2009) as official state dinosaurs. Dinosaur Train and Dinosaur King offer us no fun-for-kids cartoons or games this week involving Astrodon and, to this point, I have not found any good toys or stuffed animals. Videos are even sparse; the exception being the episode from Discovery sampled on Monday. If there is ever a consensus reached on the name then that will probably help in adding to the knowledge of this dinosaur by others. Until that time, however, Astrodon will be most popular in Maryland and a few small circles, which is not a terrible thing necessarily. Unfortunately, that probably means no quality toys for a while as well. Joanna Barnum did do a wonderful tattoo design for the animal though that can be purchased as a print on Etsy, so if someone wanted they could carry Astrodon around with them and publicly display it. You could also try to get it tattooed.

Visit Joanna Barnum

Naming Confusions About Astrodon

Astrodon, as has been discussed, was named after a description of a couple of teeth, then renamed Astrodon johnstoni after Leidy inspected a single tooth, then bones named and described as Pleurocoelus were identified by Marsh, and then finally in 1903 John Bell Hatcher put all of the pieces of this puzzle together into one animal which was then placed as a whole under the older name of Astrodon johnstoni. Still, in the early 1990's, the J.S. McIntosh section of The Dinosauria gave the impression that Astrodon was junior to Pleurocoelus, and Texas adopted Pleurocoelus as its state dinosaur. Paul's Field Guide has additionally placed Astrodon within the Pleurocoelus genus and effectively assigned Astrodon to the trash pile. However, working under rules of the ICZN's Principle of Priority Astrodon should still be the genus name because the tooth, though a lowly tooth, was described and named prior to the naming and describing of Pleurocoelus by Marsh. Arguments and special cases can be made of course to get around the Principle of Priority, but in the case of Astrodon I have not run across any debate or discussion about such; it seems that these two authors simply regard the remains to be named Pleurocoelus rather than Astrodon. Recognition by the majority of paleontologists would be a good reason to change this, but in my personal searches it appears that Astrodon is used much more actively than Pleurocoelus by the paleo community, thus shooting down that possibility, for the foreseeable future at least. Regardless of whether your personal opinion is to go with Pleurocoelus or Astrodon for the name of this dinosaur, I think we can all agree that Gil Adams painting of a Pleurocoelus in a very Texan posturing is pretty fantastic; nigh on adorable even:

A  slight addendum:
Upon further searching I have observed a general trend: Maryland and the scientists in the general area typically use Astrodon in reference to the remains and dinosaur in general whereas sources from Texas tend to use Pleurocoelus.

Leidy and Astrodon (Plus A Stegosaur?)

Leidy's "Cretaceous Reptiles of the United States" is a Smithsonian endorsed paper, basically a small book, that has no copyright restrictions, due to age, and is therefore available for download straight from mainstream sources. Typing the name straight into Google gives the book as the first result and it can be downloaded from there (or use the link provided). The section on Astrodon is rather short. Leidy notes that he only has a single tooth to examine, given to him by Johnston, and that the tooth resembles known hadrosaur teeth. As such, it makes a great deal of sense now what I said on Saturday when I mentioned that it was rather odd that Leidy would lump Astrodon teeth together in a plate with hadrosaur teeth. The fact of the matter is that Leidy simply did not have any other remains to compare it to at the time and did not realize that, despite similarities to hadrosaur teeth, he was looking at the tooth of a sauropod. O.C. Marsh would later, again, misrepresent Astrodon by giving discovered bones of Astrodon a different name (Pleurocoelus) but in 1903 John Bell Hatcher would finally pull together the two discoveries and notice that they were the same, making Astrodon the senior synonym of the two (in the east at least; Pleurocoelus, for the time being is still a distinct genus in the western US though it has been speculated to simply be another variation of the Astrodon genus). Apparently Astrodon was also a victim of mistaken identity in Portugal. Teeth discovered in the Kimmeridgian, which is Jurassic, of Portugal were identified initially as belonging to Astrodon but have since been reassigned as belonging to a stegosaur known as Dacentrurus. More study on teeth unearthed worldwide thought to belong to Astrodon is detailed along with the Dacentrurus change in this paper by Peter Galton.

A Little Overestimate

Discovery's Prehistoric Washington DC episode of the Prehistoric City series discussed Astrodon, as we would expect given that it was the first dinosaur discovered in Maryland and one of the first in all of the American East. Thomas Holtz, known Tyrannosaur lover, author, and professor of geology at the University of Maryland, takes on the narration and description of Astrodon in this Discovery clip. The science behind it is well done, with one caveat in an area which almost always sees differing opinions when incomplete dinosaurs are discovered: size. The sizes noted in the clip are significantly larger than the sizes which have been discussed here this week; about 20 feet longer and 10 tons heavier than we have mentioned, to be exact. Different opinions, modelling of living body composition, and theories concerning those models lead us to having different estimates of sizes in dinosaurs and other extinct animals; a topic that has been addressed previously around here. It is not so much an issue as a point to be mindful of. The models used by Discovery are fairly bland sauropods, but they flesh out another dinosaur which has not been represented often in the television or movie world, and they are portrayed accurately, as far as the science we are using is concerned. Therefore, I say go ahead and watch and enjoy thoroughly, for the entire minute or so it lasts.

Starry Teeth For The Kids

Again with the general lack of child related information. I honestly did not expect that in relation to such a well known and interesting sauropod, but I suppose that happens to even the neater animals. Astrodon's info, in "kid level easiness" is outlined below:

Name:

Astrodon (Greek for "star tooth"); pronounced AS-tro-don

johnstoni (named for Christopher Johnston, the initial describer of the genus)

Habitat:

Woodlands of eastern North America; specifically Maryland and the middle range of the US

Historical Period:

Early-Middle Cretaceous (120-110 million years ago)

Size and Weight:

About 50 feet long and 20 tons

Approximately 30 feet tall

Diet:

Plants

Distinguishing Characteristics:

Large size; similarity to Brachiosaurus. It may have been related to, or may even be another example of, Pleurocoelus, a sauropod of Texas.

Technically there is no actual coloring page for Astrodon, but, given the differing versions of Astrodon skull illustrations we could either post a somewhat non-descript Brachiosaur or simple sauropod. I have chosen the simple non-descript sauropod for today. As always, I recommend talking with young loved ones as you color this little guy and enjoying your Sunday.

Lisa Bond

Teeth, Babies, and Borrowed Poses

Joseph Leidy, when describing the teeth of Astrodon johnstoni, described them with a number of other teeth. The other teeth belonged mainly to hadrosaurs; however, the teeth of Astrodon almost do not stick out against the other teeth which were described. Perhaps it was Leidy's art that made them look somewhat similar, or perhaps it was a little mislabeling, that sort of thing happens. The teeth attributed to Astrodon are the four illustrations in the lower left corner of the plate, which, in these angles, look very little like stars. Regardless, Leidy did not describe them as star-like; Christopher Johnston did. These illustrated teeth may have been worn or chipped in the intervening years between the descriptions of Johnston and Leidy. There are many reasons that this could have happened; poor handling, poor storing, dropping of samples. Any number of things would have been possible. The inclusion of the hadrosaurs' teeth points to either a misjudgment of Leidy and Johnston in assuming that the teeth belonged to a hadrosaur, or Leidy had another reason, such as common deposition, for including the teeth together in this way. Considering bones had not yet been discovered, it is fair to assume that Leidy may have supposed the teeth all belonged to forms of hadrosaurs.

Luis Rey painted a wonderful scene not too long ago in which a  pack of Utahraptors were depicted assaulting an Astrodon in an Early Cretaceous plains landscape. Since then, numerous other images that are very much alike have shown up in random places. This is one such imitation of Rey's painting. It is a little less earthy in its color tones and has a bit more of a motion blur added to the fast pace of the action that is taking place whereas Rey's painting is like a well focused freeze frame of life in action. Additionally, Rey's image is a little outdated in terms of feathering in relation to maniraptoriformes and theropods whereas this image is done in what we can consider the latest scientific based style of feathering on a deinonychosaur. This Astrodon appears to be running away with the Utahraptor (I assume it is a Utah raptor with an adult or near adult Astrodon) rather than dashing it against the trees in the scene or tossing it away from its body, which could be disastrously dangerous considering we can imagine the other Utahraptors slowing the Astrodon or this Utahraptor composing itself and doubling back on its body to attack the Astrodon. In the Early Cretaceous there would have been fewer large theropods that would have been willing to attack a full grown sauropod, but it would be refreshing to see that sort of image rather than more and more artists borrowing the "raptor pack" image from Rey with regard to Astrodon.

©Tuomas Koivurinne

Finally, I would like to end on a fun illustration today without having to think up possible destruction scenarios for fossils or trying to explain why they were grouped the way they were. I would also not like to describe more paleo-violence as I end our day of images. Instead, I offer up the artwork of one of my favorite amateur illustrators (and tattoo artists) in a proposed parental care situation, or potentially a herd caring situation depending on one's individual preference, depicting a young juvenile Astrodon playfully chasing the tail of a taller, and therefore most likely older, Astrodon. If that image does not make you smile look at it again. Also, notice the much more Brachiosaur like head on this image than on other images of Astrodon.

Starry Teeth

Big bad East Coast dinosaurs. We took a small trip to South America last week, but we are back in North America and back along the Eastern Seaboard of the United States this week; a perfect jumping off point for next week coincidentally. However, we have a specimen in front of us this week that warrants not jumping the gun. Two teeth, gathered from Maryland (it is astounding how little can be used to describe a species sometimes), were described by a man called Christopher Johnston in 1859. Johnston was reluctant to go more specific than naming a genus so it fell to Joseph Leidy in 1865 to attribute a species to the named genus and the dental remains of the animal. He named the species after Johnston and the generic name, which describes the star shaped teeth, was added to it to create an animal thenceforth known as Astrodon johnstoni. How do we know anything from those teeth? Years later O.C. Marsh was given some bone from the Arundel formation of Maryland, where the teeth had come from, and he named those bones Pleuorcoelus nanus and P. altus. Thanks to subsequent detective work in 1903 by John Bell Hatcher the teeth of Pleurocoelus were recognized as identical to those of Astrodon and, with further corroboration in 1921 by Charles Gilmore, Pleurocoelus was relegated to the history books as a younger, and therefore junior, synonym of Astrodon. I am thankful for this as Astrodon is a much more interesting name in my mind. Astrodon is a relative of Brachiosaurus and resides in the Titanosauridae clade; two distinctions that make it known that this was a big animal. How big? Approximately 9m (30ft) tall and 15 to 18m (50 to 60ft) long. I will get back to everyone on estimated weight, but meandering along the Eastern Seaboard in the Early Cretaceous, this was a large dinosaur, and, though this image does not show it to scale with anything, we can certainly get that sense:

©Dmitry Bogdanov

Making Popularity Work

Sometimes we just have to hope a dinosaur will gain more popularity and, therefore, be more in the public eye making it even more popular. Such is the pursuit of some scientists such as Dave Hone, and Gary Vecchiarelli, to name a couple specific examples (they work on exposing the public, as one aspect of their work, to Daspletosaurus and Dryptosaurus respectively). I suppose I could pick one little known dinosaur and champion its cause as they have done, but I prefer to work in a larger scope and simply continue to promote all dinosaurs; this week the animal being promoted, we all know by now, is the strong armed Tyrannotitan. As we have seen, the forelimb of Tyrannotitan is comparable to that of Acrocanthosaurus; short but robust. Additionally, we know that it was slightly shorter, in femur length, than Giganotosaurus. Popular incarnations of Tyrannotitan that already exist are minimal. We saw that there was a tribute video created and posted on Youtube. There are no animatronic Tyrannotitan that I have found; no video game interpretations; no dedicated books; and no cartoons or video games. Considering that the remains of its relatives are as scant as its remains but that they have become popularized in many media, I feel that it will only be a matter of time before Tyrannotitan becomes as popularized as Giganotosaurus and Carcharodontosaurus. It is far too big an animal, and an interesting animal as well, to not become popular eventually.

Measuring Those Arms

The holotype and paratype of Tyrannotitan were found 1 km apart. The paratype indicated an individual 7% (a somewhat random seeming number) larger than the indicated size of the holotype specimen. The question from yesterday remains; how long were the arms (or forelimbs to be scientifically accurate) of Tyrannotitan? The length of the humerus and ulna recovered for the holotype are not noted in the describing paper (which I have a  copy of now thanks to a friendly reader); however, they are described as composing an arm that is "short and robust" and compared as equivalent to the forelimb of Acrocanthosaurus in size. Strangely the paper notes that the humerus and ulna are shown with size bars in the second figure published. The second figure, though, is a series of views of the dentary from the paratype. Thus, we do not have a size mentioned or shown in scale in figures for the humerus or ulna. Perhaps I will be able to dig that up. The forelimbs, judged to be like those of Acrocanthosaurus, can therefore be asserted to be larger and, as it says they are robust, stronger than those of Tyrannosaurus, but without measurement I cannot possibly say they are either larger or smaller, weaker or stronger, than the arms of its carcharodontosaur family members which appear in the fossil record after it. One positive thing we can assert thanks to the paper is that Acrocanthosaurus, according to the results interpreted by this team, is undeniably removed from the carcharodontosaur family and is, by these authors, allied with Allosaurus. We know now, with this information, that Acrocanthosaurus was not a far northern carcharodontosaur though it did appear to have some similar traits to some of the carcharodontosaurs. We have also learned that the forelimbs of Tyrannotitan were short but strong, though we still cannot compare their size directly to that of related animals without the measurements of the discovered remains.

Additionally, the hindlimbs of Tyrannotitan were described by the authors as having uniquely carcharodontosaurid characteristics; the femoral head projection and the length of the fibula in relation to the femur were the noted characteristics. The hindlimb, the femur in particular, was also noted to be shorter that Giganotosaurus, making the basal Tyrannotitan just a bit shorter than its later relative. The authors phylogenetically placed Tyrannotitan between the family that branched off toward Allosaurus and Acrocanthosaurus at the base of the branch that contains Giganotosaurus and Carcharodontosaurus, as shown below:

From Novas et al., using rooting of Currie and Carpenter 2000

Tyrannotitan In Print

The description of the remaains of Tyrannotitan were concisely written and published in the May 2005 edition of Naturwssenschaften. The article is not available for free (or through my school's JSTOR) and I have, therefore, not been able to read it. The abstract is available, however, and describes Tyrannotitan as an older and basal form of the Carcharodontosauria. The poor condition of remains is pointed out by the team of researchers in almost an apologetic way, but it is not their fault at all that so little is known about the links between the three animals that are typically associated with one another (Tyrannotitan, Giganotosaurus, and Carcharodontosaurus). However, when considered a basal ancestor of Carcharodontosaurus, it does make some sense (though I cannot pull up the argument or final decision of the research team as to how it was related to Carcharodontosaurus) that it could have been a basal ancestor. One question this creates in my mind though is "How do we explain the reduction of forelimb leading into the family and then the subsequent need for that arm to adapt back into a slightly larger forelimb again?" Perhaps I will need to find the measurements of the forelimbs of the two to compare tomorrow so as to be able to discuss just how much the limb changed from one animal to the next. We can see in Tyrannotitan that the arm was of a modest, yet rather small, size:

© Natuurwissenschaften

Dinosaurs Out of Motion

It is always somewhat sad when there is not any kind of video related to the dinosaur for the week. I even like seeing simple interviews with the people that described or discovered the skeleton; even when they are not very long or exceptionally informative. We shall trudge ever onward with only a few small tribute videos though and discuss something else today. The skeleton of Tyrannotitan is very unique in a number of ways that make it looks as though it fits into a number of differentin at this time  families. First there is the small tyrannosaur like arm and scapula that is built much like that of a tyrannosaur. The acromion process, a spur of bone where a number of muscles attach to the shoulder, is roughly perpendicular to the rest of the bone, a trait found more in tyrannosaurids than in the family in which Tyrannotitan is placed (Caracharodontosaurs). Much of the limbs and other bones found are in possession of characters which placed Tyrannotitan in the family it was placed in; however, there are many more differences that pull Tyrannotitan into its own classification away from Giganotosaurs, Carcharodontosaurs, and the Tyrannosaurs they are similar to in many aspects. The teeth are unique, the orbitals are unique (I want to save these for Wednesday) and there are other strange attributes to the skeleton in the vertebrae. The caudal vertebrae possess tall neural spines (in known caudal vertebrae) which would have made the tail rather deep at the base and potentially, as a result of the expanded space, quite muscular. Additionally, in the vertebral column, the sacral and caudal vertebrae lack pneumaticities, or small holes for air, or air sacs, in the centra of these vertebrae; Carcharodontosaurus and other members of the family possess vertebrae with pneumaticities in them in these parts of the body (tail and hips). Why these holes/sacs are absent from Tyrannotitan is not certain at this time given the lack of skeletal material attributed to the dinosaur, but perhaps in time that will change for the better.

Titanic Children's Resources

Not really a titanic day for kid's resources; it is another day where I borrow a little info, reorganize some of it, and make my own fact page actually. Nothing wrong with that, but let us get it going!

Name:

Tyrannotitan (Greek for "giant tyrant"); pronounced tih-RAN-no-TIE-tan

chubutensis; from the Chubut Province in Argentina

Habitat:

Woodlands of South America

Historical Period:

Middle Cretaceous (120-110 million years ago)

Size and Weight:

About 40 feet long; weight unknown but estimated between 4 and 7 tons

Diet:

Meat (carnivore)

Most likely ate sauropods such as Chubutisaurus and Amazonsaurus

Distinguishing Characteristics:

Giant size; small arms

Additionally, Brett Booth, whose drawings were posted yesterday, also had an initial uncolored line drawing of Tyrannotitan on his other blog which could be used for coloring purposes. Also, there is a much less scientifically accurate Tyrannotitan that is available for coloring at this link, but please do follow the illustrator's instructions.

Mr Booth's initial sketch is a little light, but it could be used for coloring.

Clash of the Titan

©Alexander Lovegrove

Tyrannotitan, with its small arms and a tall tail (ventral to dorsal), would be an interesting theropod to view in the wild. Much of its body would have been geared toward the posture of tyrannosaurs, on account of those little arms, but it would have probably had a posture much like other carcharodontosaurids, because it was related quite closely to them. The body postures of the two groups would be slightly different because the two groups were built differently, so how would an animal built much like one of the groups but possessing a similar characteristic of the second group, the small arm of tyrannosaurs, carry its body overall? All said and done, most images of Carcharodontosaurus show an animal that can rush forward and grasp prey, either large or close to the ground, with its head and neck extended to peer forward, giving an overall composition of an animal that holds its back nearly parallel to the ground. Tyrannosaurs, more often than not, are portrayed slightly off the parallel to the ground spectrum due to the fact that their massive heads created a vastly different center of balance; arm reduction or not. Perhaps the massively deep tail balanced the large head and small arm more, shifting the center of balance in Tyrannotitan back more toward that of its family group and allowing it to assume a posture more like Carcharodontosaurus than Tyrannosaurus.

©Brett Booth

The other consideration with small arms, as it has long been in tyrannosaurs with small arms, is feeding. How does an animal with minimalistic arms manage to feed itself? Regardless of the dinosaur-bird connection I find it odd that popularly we do not see more parallelism drawn between the feeding habits of hawks and other raptors with dinosaurs that have reduced forelimbs. My imagination, and it is quite vivid most times, can easily picture a large dinosaur feeding like a hawk (not for the faint of heart) with the exception that the teeth of a large dinosaur are replacing the tearing actions of the beak of the hawk. Much like in this image, a large dinosaur without the capacity to tear meat with is reduced forelimbs, such as those found on Tyrannotitan, could have stood on its prey as it ripped what it wanted away from the other meat on the body. Surely some use could be seen by the arms, but certainly not much in the vein of aiding the feeding process.

©Brett Booth

The other characteristic that really, as far as we know because we do not have the complete skull to help us determine how much of that structure is unique, sets Tyrannotitan apart from other animals of its time period is the extent of the ventral and dorsal chevrons and ribs of the caudal vertebrae. Though not many of these have been recovered those that have been show that the tail was rather broad top to bottom and, in the areas we know of, this would appear, if not paddle-like, then alligator like in its musculature and overall breadth. This indicates, and it may not be the only reason for the tail developing as it has, that Tyrannotitan may have been an adept swimmer. James Field has a rather nice swimming Tyrannotitan illustration. Despite the dangers of the water, perhaps swimming may have helped ambush prey or to simply reach prey living, or perhaps only nesting, in "safer" areas isolated from other types of predators during the vulnerable nesting or mating times of the year. That would be an awfully specific niche to control, but something would certainly prey on dinosaurs at those times and, if secluded by bodies of water was one trait of prey items during those seasons of the year, it would make sense that at least one predator would happen to adapt to gaining access to the secluded nesting and mating grounds. It s a theory I like to imagine has a bit of merit to it, though we may never know if that is true, of course.

Titanic Tyrants

First, I know that should say "A new group" or something, but "A new kingdom" sounds flashier, so that's why I went with that.

Today, and this week, we will look at an animal from the Chubut province of Argentina; Argentina is one of our favorite locations these days obviously. We are looking into the lives of some of the greatest predators of the Aptian age, early Cretaceous; a dinosaur related to both of the giant carnivores Giganotosaurus and Carcharodontosaurus. Reaching an estimated 12.2m (~40ft) and weighing in at an estimated range of 4 - 7 tons, this was a large predator. Thought to be more closely related to, and placed in the family of, Carcharodontosaurus, a fairly good amount of skeletal evidence has been collected in both the type and additional material procured since the type was unearthed; though no complete skeleton exists. The material was given the name Tyrannotitan chubutensis. The material was described in 2005 by Novas, de Valais, Vickers-Rich, and Rich but was a short description consisting of only 4 pages. No other studies have been published since. The type fossil consisted of incomplete dentaries and teeth, proximal tail vertebrae, vertebrae 3-8 and 11-14, most of an arm with a broken scapula, most of a leg (missing the tibia and most of the foot) with a broken femur, parts of the pelvic girdle, and some ribs and chevrons on the tail vertebrae found. Additional material has been found that include sacral vertebrae, more cervical and thoracic vertebrae, more dentary and teeth elements, a jugal (a skull bone), more tail vertebrae, another femur, some toes and fingers, and a couple more ribs. We have quite a bit of material to look at this week, and, given opportunities (such as not having videos on Monday probably), we will get to look most of it over. Say hello to some of Tyrannotitan's known remains:

©Conty

Popular Propanoplosaurus

Propanoplosaurus has basically become popular by being discovered. It has not really gotten into the level of popularity needed to have children's books, toys, games, or anything else of that sort take notice of it. However, it is quite famous in the local area, or was for a little while (perhaps it is not as famous as it was for that short period now in its local area). It is a permanent part of the Smithsonian Dinosaurs in Our Backyard exhibit, as long as that remains a part of the museum, which has its own level of fame. It is also the earliest nodosaur found on the East Coast of the US, which makes it famous for another reason.

The Tiniest Fossil

At 13 centimeters long Propanoplosaurus' type specimen vies for the distinction of world's smallest vertebrate fossil (it has no chance against invertebrates), though it does not win; at the moment the smallest fossil footprints found belong to a Carboniferous era amphibian which would have had to have been tiny to make the impressions. Anyhow, the entire animal probably would have been about 24 centimeters from nose to tail, which still makes it a rather small animal. Considering it was still a baby, it was probably not far from the nest or mama when it died unless 1) nodosaurs were not good mothers and left the babies to raise themselves, 2) some sort of catastrophe separated them, like a flood or a forest fire, or 3) it really was not separated from its herd or family but this is all that has been recovered. Those are the scenarios that come to mind right away, but of course there are a nearly limitless range of possibilities that we can conjure up to explain this fossil. The developing osteoderms present on the skull, regardless of how this baby came to be a fossil, offer a unique view of the early growth stages of nodosaurs; providing that all nodosaurs went through similar growth stages. Hopefully this fossil and its unique cross pattern of bone plates in its skull will shed some more light on how these big armored dinosaurs developed throughout their lives.

Not Much To Write Home About

The first hatchling dinosaur reported in the Eastern US has had a lot of press coverage in its very short known existence. Press coverage is not scientific scrutiny, however. Thus far only one study has been conducted on the remains, the main study which described and named the new species from the impression of the young nodosaur found in the fossil. Unfortunately, for most, that paper is contained in the Journal of Paleontology and is only available online as an abstract (I am not at school so I cannot check my JSTOR access to it today). I will try to get at it some time later today, but I certainly make no promises because you can never tell what you'll have access to sometimes with JSTOR even when the school says I have access to some articles. Anyhow, the abstract states exactly what we have discussed up to now on here. The only thing that we have not been able to discuss, and I hope to present this tomorrow, are the distinguishing characters discovered in the fossil by the study team that led to the naming of this infant as a new species.

A Couple Videos to Share

The Smithsonian's page on amateur paleontologists that contributed to the "Dinosaurs in Our Backyard" exhibit, which is on the first floor of the National Museum of Natural History in Washington D.C., has a video featuring a part of an interview they conducted with Ray Stanford in which he discusses discovering the impressions of Propanoplosaurus. Additionally, there is also another nodosaur trace fossil which Stanford found in the general D.C. area at the Goddard Space Flight Center. Could the adult footprint be in some way, probably not directly of course, related to the infant nodosaur?

Making Your Own Fact Sheet

As to be expected with such a new, rare, and tiny dinosaur, there is no child friendly fact page to simply link to today. Therefore, like last week, I am borrowing from here and there and making my own easy and quick to read fact page for the wee tikes in our lives to glean some quick facts (coloring page material at bottom from Enchanted Learning):

Name:

Propanoplosaurus (Greek for "before Panoplosaurus"); pronounced prop-PAN-oh-ploe-SORE-us

marylandicus; meaning from Maryland

Habitat:

Woodlands of eastern North America; discovered in Maryland, US

Historical Period:

Middle Cretaceous (115-110 million years ago)

Size and Weight:

The baby fossil that was discovered is from an animal about one foot long and a few pounds in weight.

Diet:

Plants (herbivore)

Distinguishing Characteristics:

This baby dinosaur was designed to grow to become an armored adult dinosaur. He or she probably would have had tough bone on its back and head with tough skin covering it and maybe some spikes growing out of its shoulders for more defense. As an adult it would have possibly looked a lot like this:

(On a professional note, let us ignore the Enchanted Learning dinosaur art accuracy for today!)

Drawing An Adult Baby Dinosaur

Courtesy of the Smithsonian Institute

How does an artist, and this is another problem of only having a baby or juvenile dinosaur to use as a model for a species, restore a baby dinosaur that has no record available of an adult of their species? Sketching out the death pose of the unfortunate little dinosaur is not too difficult considering it involves little more than tracing around the bones, but the skull of this nodosaur points to an adult that may, or may not, have been a great deal like the Late Cretaceous' nodosaurs that have been recovered from Montana and parts west of the Mississippi River. How might this unarmored infant have grown to appear as an adult when its skull was so very clearly that of a developing nodosaur and possessed many attributes found in later nodosaurs such as Panoplosaurus?

Uncredited photo

One method is to assume that it would look somewhat as it looked as an infant and simply copy the general body image but add a little dermal armoring. This statue, unfortunately, has no labels and no site of origin, so I cannot for sure say that it would be an artist's rendition of a slightly older, probably not adult but more of a subadult, Propanoplosaurus; however, it fits the general body type well and presents a suitable intermediate growth stage between a completely unarmored infant nodosaur and a fully armored adult nodosaur. The one thing that I have come to love about artists impressions of ankylosaurs and nodosaurs in the past few years that is missing here is the remarkable girth that these dinosaur families have been given in recent illustrations (this is one of my favorite ankylosaur images ever). I do remember a time when ankylosaurs were not so fat and I remember seeing the first of what are now many "wide-load" ankylosaurs and thinking that they looked ridiculous, but I am quite attached to that idea of them now. That said, it makes this skinny little nodosaur look strangely alien and almost like they were going for a hadrosaur, which may be the case; anyone with info on this statue share please!

Courtesy of the Smithsonian Institute

This image accompanies the fossil now on display in the Smithsonian's Museum of Natural History; it is on the placard. Artist information is not available as far as I can tell and this, surprisingly, is not an image of an adult. This illustration of the baby Propanoplosaurus is an illustration of a baby Propanoplosaurus. The fossil showed no evidence of highly structured armoring on the infant, however there is obviously highly structured armor on this infant. The Smithsonian's "Dinosaurs in Our Backyard" website points out the same information and discrepancy between fossil and illustration and offers two hypotheses: 1) Baby nodosaurs are born without armor and 2) This baby nodosaur's skeleton and armored skin became separated prior to fossilization. I have to take issue with hypothesis number 2 on the grounds that anything ripping off the armored scutes and dermal armor of the infant after death- scavenger, water, wind, etc.- probably would have separated the skeletal elements to the four corners of the world as well as that armor was probably attached quite well, especially the bony skeletal protuberances at the shoulder pictured here. My support is with hypothesis 1 on this one.

A Panoply of Dinosauria

Before I begin today, allow me to explain the changes you may have noticed. The banner/cover photo is a little vague for a reason; basically I like surprises of all forms and types. As longtime readers may remember in the past few years at least once a year for a month we explore a different set of paleo-creatures. One time it was birds, we had a month of pterosaurs and a month of ice age mammals also. A few months ago I decided that I wanted to find a suitable time to venture into another part of the paleontological history of the world, and so, for the first time, I am dedicating February and March both to a class of animals that we have not discussed or featured here to date. I am sure a few good guesses can be made at this point, but for the next two Thursdays I will change the banner at the top of the page to give a little bit more of a clue as to where we are going for the unsure and for February and March I will put up an entirely new banner and then afterwards I plan to have an updated dinosaur themed banner back up; the current one has been reminding me of the 80's lately, and things need to change a little bit at least! Now, on to this next week of dinosaurs!

Panoply, in the title, has a lot of meanings, for this week we are going with the old military meaning: A full suit of armor. I cannot say for sure why I keep making the research end of this much more in depth than it needs to be the last few weeks, looking up dinosaurs with very little past, but I am going to do it again this week. An Aptian "pseudofossil," it was an embryonic dinosaur, was discovered by Ray Stanford, an East Coast ichnofossil (trace fossils like footprints and coprolites etc.) phenom; seriously, the man is a "citizen scientist," meaning he is not a PhD guy out doing this professionally, that scours the land and finds fossil trace evidence like he belongs on a Mesozoic version of CSI or Bones and he's been doing this since the late 80's. Pseudofossils are rare enough, and naming a species, in this case Propanoplosaurus marylandicus, after a juvenile is even more rare, because dinosaurs do change over time, like other animals, and naming a species after a juvenile may just create a junior synonym for a known adult which we did not recognize as a later growth model of the juvenile. Propanoplosaurus means "toward or before Panoplosaurus" which in turn means "completely armored lizard." It is a middle Cretaceous nodosaur; Panoplosaurus is a Late Cretaceous dinosaur. Nodosaurs, remember, are armored herbivores, low to the ground with thick bone scutes and dermal thicknesses ("osteoderms") protecting their bodies; they are a subfamily under Ankylosaurs.

This baby (embryo, fetus, etc.) was discovered as an imprint of a good amount of the dinosaur. It is not the actual bones, but a cast of the skull and postcranial skeletons including the ribs, but lacking the pelvic girdle and caudal vertebrae. The word baby evokes oohs and ahhs on its own and Brian Switek even went so far as to call it adorable; I cannot say I disagree that it was probably an adorable little armored tike:

From Stanford, et al. 2011

I look forward to delving into the mystery of this little guy and exploring what he could have grown to be this week!

Laugh At The Partial Skeleton

Sometimes, like the angle of that picture of the casting I posted yesterday, you just have to laugh at dinosaurs. For all the ferociousness another angle of that skeleton captured, that angle was just silly looking, ludicrous almost even. On that note, however, I would still probably soil myself if the real animal were lunging at me in that pose rather than laugh at it. The week is never complete without a few good chuckles at toys or books or something that misrepresents our dinosaurs out in the popular world; not every popular culture reference is fantastically accurate, jaw dropping, and awe inspiring. Today, though, I saved a rather, I almost want to say cute, interesting entry from the world of video games that shows what a creative mind can make and place in an electronic world. Unfortunately I cannot find a suitable Zoo Tycoon model, though I know that people have modeled Appalachiosaurus and placed it into their zoos from forum talk and a download available for people with the game (it has a red face and white body, which is weird). The video I want to share today with everyone is a Spore video, which is probably why "cute" is an apt word for this creator's creatures. It could also be because they are living in his world, and not just shown in the creature creator like so many other videos I share from Spore. Enjoy it:

Calling For Help

A special angle of the position of the mounted skeleton.

Appalachiosaurus, like so many other incomplete skeletons, is a cry for more findings. The legs tell us a good amount of information about the locomotion of Appalachiosaurus and they also tell us a great deal about how those legs were developing compared to other tyrannosaurs; both where they came from and where they were going to in terms of development. A few things that would really help us understand and draw more information overall about the tyrannosaurs (of North America I mean here) would be a discovery of an Appalachiosaurus with more of its skull, at least one hand- arm optional- and some more of its torso including vertebral elements as well as ribs and/or gastralia. Some of the diagnostic characters that would help to assign it solidly in the tyrannosauria are missing because we are missing those elements of its skeleton, additionally, it is always nice to have a nearly complete skeleton of any animal available to study rather than a skeleton that is less than 50% complete. That does not mean that Appalachiosaurus is not going to pass on any great secrets in its current state, just that it would pass on more if it were more complete. That may seem like something that really did not need to be said separately like that, but it can be amazing how many times someone just does not think of some simple truth like that when trying to look at the bigger picture in front of them. One thing, in addition to the cladistic analysis performed using what elements of the skeleton are present, that we can, or Carr et al. did, say for certain is that there was some type of injury which this animal survived to its tail. Two of the vertebrae that were found from the caudal region were fused together, indicating an injury which caused, through healing, the vertebrae to fuse to one another when healing the injury.

Appalachiosaurus Has Papers

The naming/describing paper announcing Appalachiosaurus to the world is available online. I like being able to say that. It is nice that such valuable resources are there for everyone to read and learn and discuss. What I hate having to say following a statement like that is something to the effect of "but you may not be able to view it." Such, sadly, is the case with Appalachiosaurus. Once upon a time the second author, Thomas Williamson, had it hosted through the New Mexico Museum of History and Natural Science, but it is no longer hosted on their website. Where you can get it still, and it does require a membership or a fee to read it, is from Taylor & Francis through the Society of Vertebrate Paleontology. That is correct friends, this paper was originally published in the Journal of Vertebrate Paleontology and is now not hosted anywhere but at the publisher's website. I am not going to knock publishing costs today, mostly because at $15 US for the article is cheap compared to what some articles cost for a single copy.

Regardless, the description in the paper and analysis of the fossils is pretty straightforward, as far as I am concerned. Carr, Williamson, and Schwimmer also included some very nice photos of the fossils and diagrammed out the skull positions of the bones, as well as labeling every possible surface they could. It really is amateur friendly work. Check it out if you can. If you cannot, I wish I could post some fantastic images from their paper, but I am sure I would get into some sort of copyright debacle, so instead, here is a close-up of the skull in the McWane Science Center taken by Ralph Daily (found via Flickr):

An Old Trend

I haven't had to post a "tribute" video for a while on a Monday, but I do today. Appalachiosaurus, in video terms, falls under a few of the "not film ready" dinosaur traps: 1) it is relatively new being described in 2005; 2) it is somewhat unheard of to the general public and thus demand of images of it are lower; 3) there have not been any dinosaur shows or specials that focus on its part of the world  ever, to my knowledge. Like Asian dinosaurs and my constant declaration that we need to have some more videos about Asian fauna in general, the Eastern US is fairly often completely ignored by prehistoric documentaries. The only ones I know of off the top of my head are the Prehistoric city series that Discovery aired a few years back which had episodes on New York and Washington DC. Perhaps, though, that is a stepping stone for future documentaries about the other half of America.

Creating Kid Friendliness

It seems that I may really need to look into making my own child friendly information pages. I may also need a full time, free, coloring page illustrator to do that. You cannot have fun kid oriented learning without fun coloring pages! Because we are lacking in every category that I normally look for in terms of presenting on Sundays, here are some facts that can be shared quickly with the younger bunch in your lives :

Name:

Appalachiosaurus (Greek for "Appalachia lizard"); pronounced ah-pah-LAY-chee-oh-SORE-us

montgomeriensis (for Montgomery County, Alabama)

Habitat:

Swamps of North America

Historical Period:

Late Cretaceous (77 million years ago)

Size and Weight:

The discovered skeleton is estimated to be about 7m (23ft) long and weigh about 600kg (1300lbs) as a living animal!

Diet:

Carnivore. It eats meat.

Discovered:

Appalachiosaurus was discovered in 2005 in Alabama, US.

Bones in Alabama

The bones, finally put into a composite here, that were described by Carr, Williamson, and Schwimmer, were a good portion, compared to some type specimens, of a dinosaur. Enough, obviously, to distinguish separating characters and warrant the creation of a new genus for the remains. This graphic is a little backwards compared to what we normally see when we are looking at a "discovered bone" skeleton. Typically the shaded portions are the bones that have been found but in this illustration it is the white bones that have been discovered and used to name the new species. Carr and his associates decided that, in this description of the remains, Appalachiosaurus is not as basal, i.e. more derived or more "tyrannosaur-like", than Dryptosaurus and thus should be given a seat further up the family tree; though probably still in the trunk and not out on a branch end. The legs and skull are fairly well preserved, the skull not as much obviously, but they certainly make up enough evidence of individuality and separation from other tyrannosaurs. The vertebrae play a part in this as well, and we shall examine that in more detail in time.

Borrowed from Mark Wildman, I assume it is is his photo

The most interesting debate that I can start with, without going into this that and another discussion within the naming paper, is the assumption of hands. Tyrannosaurs have the unenviable position of typically being presented with a lack of digits. In foot related issues this is not a big deal (many dinosaurs and birds alike are "missing" digits on their feet), but when we come to the hands this can be a family tree issue; I know it can be with the feet as well but let us ignore that for today for the sake of argument. Tyrannosaurs as we think of them are missing digits on the hand, specifically digits 4 and 5 without about half of the bones of the third digit ending as a small metacarpal that does not become a fully formed finger/claw. Why is this important? The arms and hands of Appalachiosaurus, to this point have not been recovered. This leads to multiple interpretations of the hands. Were the hands formed as they were, basally, in Dryptosaurus with digits 1-3 expressed as large clawed fingers or were they like those of later tyrannosaurs with digits 1 and 2 expressed as fingers with the third digit being represented by a small section of bone and digits 4 and 5 non-apparent. Perhaps it was intermediate, with three fingers but digit 3 significantly reduced. One can see the multitude of possibilities. For now, at least, the displayed skeleton (in the McWane Science Center of Birmingham, AL) possesses three fingers like Dryptosaurus.

Regardless of the fingers represented, Appalachiosaurus is a tyrannosaur, and that means it was a big theropod. The island continent of Appalachia consisted of, basically, the formed Appalachian mountains bordering the Atlantic Ocean, the beginning of the Great Plains bordering the Western Interior Sea (I would be writing about 200 feet underwater if the geography were the same today!) and stretching from the Arctic circle and Greenland to about middle Alabama/Mississippi/Georgia in the extreme southern reach of the continent. This Appalachiosaurus, then, was found at the southern reach of the continent and Dryptosaurus lived along what would have been the eastern shores. There was still a lot of other land to roam for these two theropods which allowed them to grow to larger sizes than other island dwelling dinosaurs that suffered from the effects of insular dwarfism; a phenomenon that I find fascinating and adorable. The specimen described is thought to be a juvenile, due to unfused skull elements discovered, and would be about the size in the illustration. Adults could have, and most likely did, grown to much larger sizes.

A Good Old Boy

Restoration illustrated by Michael B.H.

If you are not aware of the slang in the title for any reason then you should know that it is typically used as a negative, but at times can be used in a positive way, to discuss Southern US politics or biases. Today, however, I am using it only to refer to a old denizen of the South. Comprised of a number of bones from the skull, vertebral column, pelvic girdle and the majority of its hind limbs, Appalachiosaurus montgomeriensis was discovered in Alabama in Late Cretaceous, approximately 77 million years ago, rocks. Named after Montgomery County and the mountain chain (Appalachian Mountains) and island content (the continent of Appalachia) which also derived its name from the mountain chain,  Appalachiosaurus is a juvenile specimen of an East Coast tyrannosaur species making this the second Eastern US tyrannosaur that has been covered as a dinosaur of the week as well as being the second discovered, though much more recently than the previously discussed Dryptosaurus. The reason that this specimen is thought to be a juvenile has to do with unfused bone, which we will look at later in the week. The remains were first described and named in 2005 and its description left out a few other animals, making its position on the family tree, as it has not been redefined since the discovery of these other tyrannosaurs, rather questionable. However, Appalachiosaurus will certainly get its due going over this week, and as such perhaps we can look into this family tree issue!

We Know Its Name At Least

Amphicoelias, by most accounts, would not qualify, either species, as a popular dinosaur, but people have heard the name. Perhaps not many people outside of paleontology circles, but those that have can at the very least say they have heard it if they know nothing else about it. You simply do not forget a name like Amphicoelias because it takes a while to figure out how to pronounce it. Beyond that, though, there are no cartoons or books or toys or stuffed animals, mentions in video games; basically all of the typical avenues of popular culture that get discussed here on Thursdays are non-existent for Amphicoelias, which is somewhat sad for either species, especially given that one of them has existing material and as such is not debated as to the validity of its existence. The popular images of Amphicoelias, not those of Knight and other earlier artists that depict large sauropods underwater with their necks craning out, have, for what it is worth, popularized tree loving sauropods in areas with at least some forest, but the area in which Amphicoelias was found is thought to have been mostly savannah-like and thus sparsely populated by trees. Even what we have of art, therefore, is not completely congruent with the facts. Some day, hopefully, we will have more remains and know more about this large and magnificent animal. Until then, we can only base our popular images of Amphicoelias off of what little information we have and the illustrations of previous artists.

The Other Species

All this talk about distal femur bits and potentially crumbled into oblivion neural arches in Amphicoelias is slightly deceptive. The only species missing all of its evidence in this discussion is A. fragilimus. There is another, smaller, species described in the genus Amphicoelias: Amphicoelias altus. Amphicoelias altus is actually the type species of the genus and is composed of a number of bones including the scapula, ulna, a tooth, coracoid, pubis, femur, and two vertebra; the type fossil consists of the last three structures mentioned with the first four being found later. Mook, mentioned yesterday, noted that Amphicoelias, based on A. altus, is very similar to Diplodocus; however, the proportions of limb length in A. altus are significantly, relatively speaking, different from those of Diplodocus making it a taller animal though they are of similar length. Due to the similarities some have proposed that Amphicoelias is a senior synonym of Diplodocus, but the overwhelming majority assert that the differences are enough to warrant the occupations of both names as valid and separate genera. Another species has been proposed recently, A. brontodiplodocus, but this species has been refuted by many and the lead author of the unpublished paper, Henry Galiano, has noted that the proposition of the idea of one genus with many growth stages of sauropod represented and currently named as separate genera from the Morrison Formation, the essential theme of the work, is not ready to be published and is not, thereby, ready to be criticized. We shall see if they develop the idea further, but if you are interested in it you can read what has been circulated so far and you can read two analyses by Mike Taylor and Matt Wedel, respectively. As for my opinion of the matter, I reserve the right to review everything and not post it online, as I do not consider myself enough of a sauropod expert to weigh in at this time.

Writing About Sauropods

Cope's writing about Amphicoelias is not readily available online; as is the case with most 19th century science of any kind really. However, H.F. Osborn and C.C. Mook's summation and review of Cope's sauropods s online; if you can get it to download, which takes some patience. It is a large article, being a summation of a life's work in sauropod recovery, description, and the perceived biology of long dead animals. The American Museum of Natural History generously hosts some of its older publications, such as this title (Camarasaurus, Amphicoelias, and other sauropods of Cope) which is not an enormous amount of data (174MB) as far as data storage goes, but it is an enormous article (about enormous dinosaurs, how droll) that encompasses 252 pages of figures, descriptions, tabled lengths, and maps, amongst other things, that review and sum up all of the work of Cope on sauropods he worked on, which for the purpose of Osborn and Mook's review is 6 species. Most of the species mentioned have met diverse fates in terms of their validity; however, at this point Amphicoelias is still, until proven otherwise of course, a valid taxon as well as Camarasaurus, which is discussed and described in amazing detail by Osborn and Mook using Cope's work as well as the existing Camarasaurus fossils. I would not suggest reading it all in one sitting (that much technical scientific writing may make your head explode in a single sitting), but as an interesting review of a prolific paleontologist's work as well as a summation of the Amphicoelias work done by Cope it is without equal and thus a good work to at the very least scan for information. Enjoy your new year people of the world!