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STL Science Center

26 May 2017

Polacanthus Presents Itself

©Rodrigo Vega
There are a number of different interpretations of Polacanthus in a number of different views. There are also a number of different actions being undertaken by these interpretations of Polacanthus ranging from sleeping to evading and actively engaging predatory dinosaurs or intraspecific rivals. The type of action in which the Polacanthus in any given interpretation does not necessarily relate how intriguing or impressive the individual piece is; a sleeping Polacanthus has exactly as much potential as a running animal. I would actually go so far as to say that the sleeping Polacanthus image shared here today is almost more dynamic than the second image.Rodrigo Vega's sleeping Polacanthus is the centerpiece of a rather dark image. Two small Hypsilophodon occupy the cliff protecting the large sleeping ankylosaur from above. The Polacanthus itself is quiet and almost appears to be somewhat contemplative. Though I have described it as asleep, it almost appears awake but with its eyes closed which is a very real possibility of course. This, like many ankylosaur illustrations, is a solitary animal living a lonely life. The Hypsiolophodons above the animal may have acted as a portion of a surrogate herd, as animals like Polacanthus are hypothesized to have lived solitary lives except at points where they needed to be around their own kind (i.e. during mating seasons). There is the possibility that this kind of behavior would be related to poor eyesight  on the part of the ankylosaur; essentially it would have used its non-conspecific herd members as its eyes to be aware of predatory dinosaurs.

©Will Brennan
This could be the exact circumstance of the second illustration of a much more awake Polacanthus. This Will Brennan image might be portraying a similar herding behavior in which Polacanthus has adopted a group of Iguanadon as surrogate herd members in the place of other Polacanthus (and smaller animals like Hypsilophodon). The Polacanthus in this image is actually a part of the foreground and is a secondary character of the image. The illustration itself draws the eye to the center with the light in the distant forest and the central Iguanodon braying or calling the herd together. Assuming that the herd is being called together and Polacanthus is a member of the herd that understands this call, that would mean that are smaller ankylosaur was willing to separate itself from the herd in deeper woods, allowing the safety of numbers to be minimized in this situation.

All of these interpretations are, of course, my personal speculation based on the speculation of artist interpretation of events that may or may not have occurred and may or may not have some kind of scientific evidence underlying them. The most important thing to do with these illustrations is to enjoy them, appreciate them, and create your own ideas about what is happening in them.

24 May 2017

Pelvic Polacanthus

Tuesday there was a paper describing the pelvic armors of different ankylosaurs and Polacanthus was one of the ankylosaurs that was specifically mentioned because it possessed very unique pelvic dermal armors. Most ankylosaurs have somewhat uniform sheets, scutes, or patches of dermal bone that protect their dorsal surfaces. Polacanthus also has dermal armor along its back; however, the dermal armor along the pelvic region is uniquely constructed and protective of the dinosaur's pelvis and hips. Assuming that, as many ankylosaurs are thought to have defended themselves, Polacanthus made itself small when threats loomed, making it difficult to get at its soft underbelly, the expansive pelvic armor was capable of protecting the hips of the animal quite well as it would have served as an armored roof to that area. In many illustrations it appears as though the hips are still exposed (such as that below); however, in the skeletal reconstructions of Polacanthus we can see fairly well that the actual hip socket lies medial and ventral to the armored shelf of bone resting on the pelvis. In some line illustrations this has been exaggerated slightly, such as in the Nopsca drawing which pulls the shelf more laterally than some others, but these small errors in representation do not change the fact that the armored shelf protected the hips of Polacanthus very well and probably kept the dinosaur safe from most direct bites, slashes, and kicks to the hindlimb which, as we saw with Edmontonia, was most likely used to pivot the front shoulder spikes of Polacanthus in threatening displays or actual offensive strikes at rivals and predators.
©SADistikKnight (Robert)

23 May 2017

Polacanthus the Printed

Not surprisingly, there are a lot of papers on the armor of Polacanthus and its configuration. Of course, we should start with the original descriptions of Polacanthus fossils but there is only one of those available online. The first few description papers are short and largely unimportant; however, Hulke's 1881 description, featuring a number of quality line drawings of the known fossils to that time, is online and is worth reading. This was followed up approximately 20 years later by a review of English dinosaurs by Franz Nopsca with a dedicated chapter and new descriptions of Polacanthus. This trend of description has continued off and on through a number of different publications, researchers, and specific foci of research in general. The latest descriptive paper of Polacanthus actually describes a number of ankylosaurs and, specifically, focuses on the pelvic armor and its variations across all ankylosaurs.

22 May 2017

Park Darling

Polacanthus has appeared in a number of documentaries (including two episodes of Walking with Dinosaurs) as a major figure. However, the bulk of non-amateur created videos of Polacanthus are documented interactions of visitors to animatronic dinosaur parks with the statues at the parks. Not all of these moving statues are accurately built, meaning there are a lot of versions of this dinosaur at parks and "fossil zoos" that do not accurately portray the animal. The best model is the one shown below, though this clearly has some interesting individuality sculpted into it.

21 May 2017

Learn Your Polacanthus

Polacanthus is a bit more popular than a large number of other ankylosaurs and, by being one of those more famous and known dinosaurs, has a lot more pages and videos dedicated to it online than others. These include sites like KidsDinos and Age of Dinosaurs. As we know, most websites contain similarities and work with the same set of information to build their fact files and paragraphs of information. The same can be said for most videos. The prime example of this is the WizScience video series that relates the same information over a series of images of the fossil animal in question. Strangely, there is no cartoon for Polacanthus like the I'm A Dinosaur series; given its popularity this is a little strange.

20 May 2017

More Ankylosaurs

During the past week I made mention of different types of ankylosaurs including their namesake group, nodosaurs, and polacanthids. This week to continue painting that picture and better understand what makes each kind of ankylosaur fit into that familial relationship, we will discuss the polacanthid Polacanthus foxii, the namesake of its subfamily. Polacanthus was originally discovered by the Reverend William Fox of the Isle of Wight in 1865; hence the specific epithet. This came about because the reverend, disliking a name given by Lord Alfred Tennyson (Euacanthus Vectianus), the first describer of the fossil, presented the fossil to Richard Owen with the new name in tow; this information is attributed to an anonymous pair of 1865 sources thought to be by Owen, Fox's own 1866 writings naming Owen, Huxley's 1867, and Hulke 1881. Regardless, Polacanthus was an ankylosaur of respectable size, measuring in at approximately 5 m (16 ft) and weight estimates of approximately 2 tonnes. Featuring armor and spikes similar to other ankylosaurs, Polacanthus was not a typical armored dinosaur and possessed unique armors, especially over the pelvis, that separated it from its closest relatives in unique ways.
Model in Sandown, Isle of Wight, Photo ©Henry Burrows

Special Edition - Save the Fossils and Their Land!

peak out for fossils! Executive order 13792 mandates a review of the boundaries of 21 US national monuments, including two whose express purpose includes protecting vertebrate fossils -- Bears Ears and Grand-Staircase Escalante. Both monuments are in southern Utah and both contain rich vertebrate fossil resources.

Please consider commenting that the boundaries of Grand Staircase-Escalante Monument should be maintained and and those of Bears Ears expanded.

Comment submission form: https://www.regulations.gov/document?D=DOI-2017-0002-0001

Deadline for comments on Bears Ears and Grand Staircase-Escalante is May 26.

18 May 2017

Famous Dinosaurs

The popularity of Edmontonia is rooted mostly in its representation in the fossil record. Some very popular and well known dinosaurs have not been well represented in the fossil record, so we can certainly say that it is possible to be poorly represented but very well known. Edmontonia is one of those dinosaurs that is both well known and well represented. Due to this popularity it appears in video games, card games, documentaries (announced simply as "an ankylosaur" in the linked video), cartoons, books (too many to list), and almost any other medium one can think about. I like to share, when they are available, these images from information cards on dinosaurs because they re the kind of things that I used to love when I was a kid and really got me into dinosaurs (of course I am a huge nerd though). These summarize some of the things we know about Edmontonia at the same time as making the animal appear dynamic and interesting to people that would consider themselves dinosaur enthusiasts. They serve the purpose of a popular culture outlet in that way exceedingly well, and are therefore an important resource for popularity day here.

17 May 2017

Dermal Armor and Spikes

E. rugosidens, specimen AMNH 5665
Photo ©Shriram Rajagopalan from Vancouver, Canada
The armor of nodosaurs is generally similar across taxa with variation changing sizes, shapes, and numbers of plates and spikes depending on not only the genus or species, but also the individual animal. Edmontonia, for the most part as a genus, possesses armor that is constituted of flat, mostly smoothed, dermal plates starting with laid out rounded rectangles in organized rows from the neck into the tail. The skull and head lack dermal plating entirely. Over the pelvic and pectoral girdle the dermal plating is significantly different, making the armor patterns similar over the torso and abdomen and pelvis and tail. The torso and abdomen pattern consists of large oval plates guarding large areas of the rostral back (dorsum) of the animal whereas from the pelvis to the caudal-most plates the shape of the plates is more spherical and the shapes are more populated. This causes the armor to leave smaller gaps, possibly providing greater overall protection from crushing bites and injuries than the more rostral armor. The trade-off is in the sizes of spikes and mobility; not to mention Carpenter's hypotheses of sexual dimorphism and/or age as judged from the sizes of shoulder spikes. Nodosaurs do not have tail clubs like ankylosauridae genera nor do they have vertical spikes or sheets of armor across their pelves like some polacanthinidae genera. Instead, nodosaurs like Edmontonia possess large lateral spikes across their shoulders with smaller spikes trailing down to the pelvis, a trait that has led to many representations of nodosaurs hopping about to thrust their shoulder spikes at attacking predatory dinosaurs. The smaller links of armor around the pelvis would enable such movements as the plates would not take up as much space and could be compressed well as the animal twisted and turned. Additionally, the large plates could be similarly manipulated to manipulate the shoulders, but larger plates need more space between one another to move in a similar fashion, which could account, in part, for the large gaps between plates in the torso area. These large gaps could have also enabled the animal to look upward at a slight degree as the spacing between rows could be compressed as the head and neck pushed the extreme rostral rows of dermal plates back toward the shoulders.

Please remember that these are hypotheses based on looking at fossils, the papers of others, and generally restating shown interpretations of the animal already distributed via film and screen and that we still have many unanswered questions about these very interesting animals. When traits like spikes and armor plating are highlighted everyone automatically (it seems) thinks of two possibilities: defense or mating. The defensive capabilities of nodosaurs like Edmontonia are fairly clear in looking at the skeleton and associate spikes and dermal plates: a large, but squat, animal with hardened scales on its back and large sharp protrusions of bone was probably very good at getting low and defending itself regardless of how it actually managed it. If its shoulder spikes were used as offensive weapons they were probably used mainly to intimidate as they would otherwise need to be picked up, moved with speed, and very accurately aimed. Any movement that elevated and sped up the body of this animal would have left the unprotected underbelly exposed long enough that it could have been tragic. This leaves us with two possibilities, as I see it: Edmontonia was much more turtle-like in its defense of itself or it was a brash and intimidating animal that attempted to scare away predatory dinosaurs rather than actually fight them. Both of these possibilities are intriguing and the behaviors behind both could be fascinating. Please feel free to discuss the likelihood of either or both scenarios. I enjoy these kinds of conversations and thoughts.

16 May 2017

Edmontonia the Northern Dinosaur

Whenever we hear and see discoveries from the extreme northern or southern areas of the globe there is a certain amount of amazement not only because of the remoteness of the discoveries, but also because of the idea that dinosaurs lived in colder areas. This, of course, is regardless of the current climate in these areas. There are hypotheses of the climate, seasonal change, and temperatures of places like Antarctica and Alaska. These are discussed in the literature concerning Edmontonia on a fairly regular basis because many examples of the animal have been discovered at higher latitudes in both Canada and Alaska. New species of Edmontonia were hypothesized from Alaska during the 1990's, such as in this Gangloff article from 1993 calling the remains the first ankylosaur remains of their kind from Alaska. A great deal of the Edmontonia articles do not reach as far north but stop with remains from Dinosaur Provincial Park in Alberta, which has held a wealth of Edmontonia remains that have been recovered. This has led to many studies revealing more about cranial anatomy, flexibility in naturally occurring dermal armors, or even the teeth of Edmontonia (or whatever ankylosaur you are personally interested in).

15 May 2017

Watching A Drawing

Sometimes my favorite videos are not portions of documentaries or news stories. Some of my absolute favorites are actually sped up art videos. Whereas I have a few not-so-good documentary clips and one fairly nice time-lapse artwork image, I choose to share the artwork today instead of the weak documentaries. There are nodosaurs in documentaries that are based off of Edmontonia more than any other nodosaurs; however, given that these are only based on the dinosaur and do not expressly discuss the animal, the artwork video is still a slightly better choice for sharing today. Enjoy!

14 May 2017

Nodosaur Facts

For Sunday's fact entry, I am choosing to link a few videos. The I Know Dino podcast about Edmontonia says anything and everything I could in a nice quick format. I Know Dino is run by a team of dinosaur enthusiasts that has made digging up and presenting information about dinosaurs their number one goal.

The Dinosaur Diversity lecture in University of Alberta's Coursera lecture series also discusses, and shows, Edmontonia and the anatomy of the dinosaur. This lecture can be found here.

13 May 2017

Edmonton's Nodosaur

In the news lately there has been a lot of talk about a nodosaur mummy. This week, therefore, I thought it would be prudent to discuss a nodosaur, though honestly a totally different nodosaur than the fossil mummy. This week's nodosaur is known as Edmontonia and the genus contains two species: E. longiceps and E. rugosidens. Nodosaurs like Edmontonia were covered in osteoderms and armor that we will see plenty of this week. Known from materials originally discovered in 1915 from the Edmonton formation of Southwestern Alberta. Specimens have been discovered as recently as 2010 and the taxonomic history of the genus is interesting and complicated. A lot is known about Edmontonia and so we will have a lot to discuss this week, but before we do, appreciate some art based on the original finds.
©E.M. Fulda, 1922; based on the 1915 AMNH specimen

12 May 2017

A Busy Day

Yesterday was busy, so here is Friday's artwork on Saturday afternoon (I will get you all a new dinosaur/fossil within the next few hours). The artwork I shared the other day was a brilliant family portrait of a Troodon and three young animals on a beach. I could easily put another well done family illustration as there are plenty of them online; Troodon families are apparently a very popular motif in the paleoart world such as Blair Sampson's woodland family illustration. This extends not only to young animals but also to eggs and groups of adults as well. Groups of Troodon are, simply stated, popular topics for people to draw and paint. As long time readers know, I prefer well thought out or imagined artworks that challenge our preconceptions or show active and energetic animals. Unfortunately, there are a lot of Troodon images online that are one or the other but not very often both active and imaginative. This image comes from BBC's Prehistoric Planet, which shows the dinosaur in many active and imaginative situations. The feathering that was placed on this Troodon is rather extensive, but looks very well thought out, not simply plugged in to make a completely feathered dinosaur.
©BBC, Prehistoric Planet

11 May 2017

Seen on Video

Dale Russell and Ron Seguin, 1982 
Canadian Museum of Nature, Ottawa, Canada
Troodon has appeared in so many popular venues from books to video games to movies to toys that it is nearly impossible to focus on any single area of the dinosaur's sphere of influence. Instead, we should look a little closer at Dale Russell's interpretation of Troodon evolution and the hypothesis of its continued and increasing intelligence. This hypothesized animal was dubbed Troodon sapiens by Russell and was given form by sculptor Ron Seguin in 1982. I remember seeing it when I was young and being impressed and a little confused. The idea that other forms of animals could take on humanoid forms in the course of their evolution was very odd but not out of the realm of possibility. An intelligent dinosaur, like Troodon, that had been able to evolve (without a major extinction event limiting them), would have potentially been capable of evolving large heads and changing their posture. Therefore, Russell's hypothetical "Dinosauroid Man" was not, and is not, actually all that bizarre. Though any dinosaurs, intelligent or otherwise, could have potentially evolved into more upright, tail-less, postures over millions of years. The fact that someone put that idea into a solid form and wrote a paper about that idea is bold, but that did not endear Russell to everyone. Though I do not know how controversial the "thought experiment" was or still is, it was apparently controversial enough that many disliked it. One of the chief complaints, and what makes it so eerie, is the extent of the antrhopomorphic characteristics of this evolutionary experiment. As I mentioned on Monday (or Tuesday because I mixed up my days), discuss this sculpture, but do not lose friends over it!

10 May 2017

Anatomy of A Stereotypical Dinosaur

Troodon is nothing if plain looking in terms of dinosaur morphology. In modern terms that even includes the inclusion of feathers along both limbs and the majority of its body. The more numerous, and older, portrayals of Troodon are still out and flooding the internet with gracile dinosaurs that look emaciated and a strange oily green-black skin. That skin was typically portrayed as smooth rather than scaly but it is not overly important, considering that the interpretation and knowledge of what Troodon probably looked like has changed and become so much more feathered. Troodon was not, as we tend to see stereotypical gracile dinosaurs thought of, a small animal either. The dinosaur was approximately 2.4 m (7.9 ft) long and tall enough to rival the average human, though at 50 kg (110 lbs) it was the weight of a large dog, which many of us know does not need to be tall to knock down an average sized human being. Exhibiting eyes that face partially forward, indicating depth perception capabilities, that were rather large proportionally, indicating a potentially nocturnal lifestyle, and a brain that was equally proportionally large for its size, Troodon was most likely a very intelligent animal. Intelligence has been debated for a long time in fossils, but Troodon, for many years now, has been generally accepted as an intelligent dinosaur that was capable of manipulating its manual claws, i.e. that it was able to grasp and manipulate objects. This has many implications, including the idea that intelligence and social behavior often go hand-in-hand. That idea specifically has led to many great interpretations of the dinosaur and its capabilities and has told us a great deal about the intelligence of these animals once thought of as slow, stupid, and mostly solitary outside of herds.
©Taena Doman

09 May 2017

Monday on Tuesday

I happened to think yesterday was Tuesday apparently for some reason. The post related to Tuesday and literature therefore appeared yesterday which means that today we will look at some videos concerning, describing, and generally about Troodon. These videos are informational, educational, and entertaining, sometimes all at the same time and sometimes one way at a time or a combination of these. When searching Troodon online it is important to skip a few pages of results, as the only items on the first few pages relate to the ARK video game and videos that are made using its models. The first documentary that appears is an old Discovery documentary discussing, specifically, the intelligence of Troodon including Dale Russel's hypothesized Troodon evolution; for those not acquainted this is a very humanoid version of a highly evolved dinosaur which is shown and discussed at length in the documentary. Troodon also appears in many other documentaries, but for tonite, the single documentary will suffice. It leaves a lot to be discussed between friends and colleagues and can lead to many happy discussions (or terrible angry ones if you choose that path).

08 May 2017

Smart Dinosaurs and Their Eggs

In the case of Troodon there are a lot of research studies and fossil discoveries centered around both the animal's intelligence and its nests. These studies of eggs are not relegated to the egg itself, but have even discussed embryos and nesting ichnofossils. The adult, and juveniles, have also been studied extensively. This includes their teeth, the microstructure of their bones, and their famous intelligence. This, of course, has led to many studies of the braincase and the endocast of the skull. The brain has not received any single treatise that demands attention and is also hosted online anywhere I can find it.

07 May 2017

Facts in Video Form

Today we have a short video about Troodon that goes over some facts about the dinosaur as told by the one of the dinosaurs. There are many other videos as well, but I think this video wraps up a good majority of the facts and presents it in a rather fun way.

06 May 2017

More Surprise Dinosaurs

©Greg Heartsfield, Perot Museum
Creative Commons Attribution 2.0 Generic
There are relatively few times these days when we encounter a dinosaur that we probably should have discussed previously but somehow we missed in the past. This week I noticed that we have somehow skipped a rather prominent dinosaur: Troodon formosus. Dated from 77 MA and originally recovered from the Judith River Formation of Montana. The first fossil was a tooth found in 1856 and described by Joseph Leidy (under the spelling Troödon), making Troodon one of the first North American dinosaurs found and described by Leidy, let alone anyone on the continent. These teeth were described as the teeth of a lizard initially. It was not until 1877 that the dental remains were redescribed and assigned to a place in the dinosaur family tree. The first skeletal remains recognizable as a dinosaur were discovered in the 1930's by Charles M. Sternberg in Alberta, Canada. Since that time many other skeletons and clutches of eggs attributed to Troodon have been discovered, recovered, and have been prepared. These remains have been discovered from a geographic range that includes Alaska, Wyoming, and potentially Texas or New Mexico; these finds are not conclusive at this time however.

05 May 2017

Not A Glamour Shot

This week has flashed by somewhat quickly. Typically, if available, I show a size comparison of the fossil animal to modern humans at some point during the week and I noticed that I have not done so this week. Anyone that has seen a Glyptodon fossil in a museum can very much appreciate the size of this fossil relative of armadillos without seeing such a size comparison. However, those that have not can view the first image shown here and begin to really gauge what this animal may have looked like up close. Despite being an herbivore, and most likely a relatively calm one at that, the sheer size of the animal and its carapace are daunting and, this is my speculation, would be terrifying to view with only a few feet or yards between the animal and an average sized human.

Moving away from the size comparison to look at a unique view of Glyptodon in comparison, we find this armadillo-like version of the ancestor to armadillos. Daniel Eskridge purposely and knowingly stresses that his art is art before it is paleo-art. Sharing this distinction straight away means that we can simply enjoy his interpretation of Glyptodon without complaining about how he got aspects of the animal "wrong" according to modern convention (not saying I think he did, just that some forums tend to focus on these things). These topics can still be broached, but appreciating the familiar looking snout of an armadillo morphed into an ancestral state on the body of Glyptodon makes this animal look less like a prehistoric creature and more like an animal that we could see in the modern wild. This sort of interpretation and believable subject is not uncommon in paleo-art, nor is it entirely frowned upon, but more and more the push for separating interpretation and scientific based representation, I think, is causing people to ignore some of the best endeavors of artists of the past in trying to recreate or interpret interesting soft tissue anatomy. Aside from this, the alert look of the Glyptodon and its head posture make it look curious but frightened at the same time. This gives the animal a somewhat innocent look as well. At the same time I think it underlies a very firm grasp on wildlife behaviors and how an animal that was interrupted at the stream might look at whatever (us in this case) interrupted his drink. As everyone knows, I appreciate paleo-art that is a little different and shares an intriguing new view of the animals we discuss here. This piece certainly does that.
©Daniel Eskridge; @deskridge;
www.DanielEskridge.com

03 May 2017

Anatomy of the Glyptodon

Fossil specimen at the Naturhistorisches Museum, Vienna
The anatomy of Glyptodon has been described over and over again and, because of this and the large number of known specimens, we can break down and describe this anatomy very easily. The vertebral column, eyesight, and skull and associated musculature are of great interest and we could spend a great deal of time on any or all of those individual areas. However, this post is going to specifically treat the most easily recognizable features of Glyptodon: the carapace and tail. The carapace and tail are both covered in osteoderms. Tracing the development of the osteoderms actually coincides with the evolutionary lineage of the species in the genus Glyptodon with specific patterns and sizes of osteoderms appearing across not only the tail and carapace but along the face, legs, and abdomen during the Pleistocene. Osteoderms began appearing in Glyptodon shortly after the North and South American continents were bridged. The current thought is that the osteoderms began becoming more regular and denser as a defensive response to more predatory mammals entering South America from North America. Prior to osteoderm enlargements, the Glyptodon carapace and tail were entirely smooth in appearance. This makes interpretations of Glyptodon somewhat confusing as Late Pleistocene Glyptodon, such as in the first image, are smoother in appearance and very Early Holocene Glyptodon appear to be rough, as in the second image.
Hungarian Natural History Museum

02 May 2017

Glyptodon on Paper

As one of the longer known fossil animals, a lot of articles, lectures, and descriptions of Glyptodon have been published. These have been published in peer reviewed journals and in annals of older collections of lectures and presentations. The older articles include descriptions of osteology by Huxley in 1865 as well as the dentition and partial skeletons of Glyptodon as reported by Owen in 1841. Glyptodon has never been solely an English find; as we saw yesterday the animal is known from South America also. Some works like Nodot's 1856 book (French) or Chavez-Aponte's 2008 article (Spanish) have made Glyptodon an internationally known fossil animal in multiple languages. As the years have gone by the articles have become more and more scientific, which is both a blessing and a little sad. Observation papers like Burmeister's 1864 paper on museum specimen observations have left us, but it was replaced by papers like Osborn's 1903 paper and more recent, more in depth and rigorous investigations. These include fetal remains, protein structures, and even estimations of body size based on limb proportions.

01 May 2017

The Movie Star Glyptodon

A number of Glyptodon videos are produced and published by amateur fossil enthusiasts. While these are good quality videos and worth mentioning, we have far too many videos of this peculiar mammal to share them all let alone discuss, fully, the few that we will share here. A few of the really interesting ones that are worth an extra look and the description that we will post here today include a news story about a fossil find, and an animatronic version of the big mammal. The news story comes to us from Ezeiza (Ezeiza Partido, Argentina) where a farmer, walking about in his fields, noticed an excavated area and the large fossil of the carapace-like structure of the Glyptodon sitting in the hole. Some have speculated that the shell of the animal may have been a hoax, mostly based on the hole in the shell, but Adrian Lister of the Natural History Museum of London was quoted as saying that the hole likely resulted from "wear and tear" and did not necessarily indicate"where the head or tail went".

The video of the animatronic Glyptodon was posted by the Sichuan Lituo Landscape Science & Technology Co., Ltd which manufactured the robotic mammals. These versions of the animals are possibly the most realistic animatronic versions that have been manufactured and put on display. There are others with odd mustaches and toupees and there is even one that walks very slowly and without bending its knees.

30 April 2017

Glyptodon Facts

The facts about Glyptodon are posted in many different places online and in a variety of videos. As I stated yesterday, many people recognize Glyptodon right away even if they do not or cannot recall the name of this large armored mammal. Because none of the videos that are posted about the animal show unique facts or interpretations of those facts that are not presented on the fact websites I will save the use of any websites until later. That, however, leaves us with copious amounts of literature to read about this interesting and odd shaped animal. The sites ThoughtCo and Prehistoric Wildlife present facts and detail some of what we know about the animal including its relationship to near contemporary animals and its descendants. These insights are, of course, useful in determining life histories, ecologies, and general life facts about Glyptodon. The Enchanted Learning site presents similar, but less, information about Glyptodon. It does, however, offer us a coloring sheet, something I have not posted in many months for our Sunday posts. Enjoy reading and coloring today!

29 April 2017

A Mammalian Tank

Good evening sports fans (I have been watching hockey today) and dinosaur fans. We are going to get back to dinosaurs soon, but this week we are going to look at a well armored mammal that I saw, remembered, and noticed I have never discussed on here at the Field Museum on Monday. A genus of the curious Xenarthran animals of South America, Glyptodons are armored animals with large curved teeth and an armadillo-like shell around its body. This should not be a surprise when I say that armadillos are close living relatives of the now extinct Glyptodons. Regardless of name recognition, the visual of a Glyptodon is typically quickly and readily identifiable; this may be the first time for some being able to place a name with the animal. Glyptodon tails are different across the genus, but we will see that their thoracoabdominal armor is fairly conservative across time and evolution.

19 April 2017

A Load of Anatomy

Petrolacosaurus kansensis was discovered in a smoothed layer of shale in eastern Kansas. The discovery included a skull with two temporal fenestrae (part of the defining characteristics of diapsids), a large orbit and teeth. It also included over 60 caudal vertebrae, 7 cervical vertebrae, the pectoral girdle, radius, ulna, fibula, and articulated tibia and astragalus. This articulation tells us a lot about the morphology and development of the reptilian astragalus and ankle joint, which is why many papers have been written on this specific aspect of the fossil remains. Manual and pedal phalanges were also discovered, allowing researchers to know the arrangement of the digits; this is actually quite important evolutionarily as digit order and retention has changed over time (some animals have presented with certain digits lost and sometimes knowing which digits were retained or lost can inform evolutionary relationships). These characteristics have helped to inform the position on the reptilian and diapsid family tree that Petrolacosaurus currently maintains. Further finds of this animal and others will help to refine that positioning further of course, but at this moment we have a good idea of where the animal is phylogenetically and what its position means for the origins of specific regions and parts of the reptilian body plan, making this an extremely important animal.

18 April 2017

Old Literature

From Reisz 1977
Some days, as we all know here, the reading list for older discoveries is very small indeed. This is of course thanks to the fact that not everything ever written has been scanned or re-typed and posted online. This is not just an ancient writings problem either; I have had difficulty getting articles from as recent as 1999 online without contacting authors directly. This is important because there are numerous articles on Petrolacosaurus and some of them are slightly older articles. Remember that the small reptile was discovered in Kansas in 1932 but was not described until 1945. There were no field notes associated with the find other than the general locality of Garnett, Kansas; approximately 50 miles south of Lawrence and the University of Kansas. Having worked on a specimen from the University of Kansas Vertebrate Paleontology collections I can attest to the mountain of field records and their sometimes cryptic nature (the specimen I looked at was given the location "locality #12" but no other information) but I have not seen any completely lost field notes in my experience. Regardless of the completeness of field notes, Petrolacosaurus has been described and assigned and somewhat fawned over for decades now as the oldest known diapsid showing transitional characters. Reisz's 1977 article re-describing this old reptile and first diapsid possesses a very iconic, though general appearing, line drawing of the skull of this reptile which could easily stand in for any and all early diapsids and might be confused by some to represent a modern lizard of some kind. Petrolacosaurus has been used to describe the evolution of not only reptiles as a whole, but also in describing the origin of one of the bones making up the ankle joint, the astragalus (known as the talus in humans). This Peabody paper from 1951 is not only interesting, but important in understanding the evolutionary origins of a bone that was important for reptiles, crocodiles, pterosaurs, and dinosaurs and birds. Petrolacosaurus is a very important animal in the history of evolution despite its small size and these papers make that quite evident. Enjoy reading them and discovering more about the origin of reptiles!

17 April 2017

Walking with Monsters

There are many animals known only from the screen for many people. Petrolacosaurus is a prominent member of this group of animals as many only know it from its appearance in the Walking with Monsters series. Despite its dinosaur-like name, Petrolacosaurus was a small reptile and, as we can see from the first clip featuring it, at the mercy of many other animals like the enormous amphibians, arthropods, and insects it was contemporaneous with. The second clip shows that not all of these interactions went poorly for Petrolacosaurus though. The small predatory reptile was the beneficiary of tragic natural events like forest fires (as shown) and was capable of running down prey smaller than itself.

16 April 2017

Know Your Early Diapsids

One of Dr. John Merck's online lectures for one of his geology classes summarizes some aspects of diapsida and specifically references the characters of Petrolacosaurus that have caused it to be assigned to the base of the diapsid family tree. Other sites have information on Petrolacosaurus as well. These include Prehistoric Wildlife which has a short paragraph describing what is known about the small reptile. A more extensive entry and probably the most comprehensive and easy to read entry outside of the Wikipedia article or a scholarly journal entry is that found on the Walking with Monsters version of the wiki sites.

15 April 2017

Dawn of the Reptiles

We have discussed the dawn of the dinosaurs, multiple times depending on the taxa discussed in any given week, the dawn of mammals, birds, amphibians, and a number of other introductory taxa. Some of these have been composed of disarticulated nearly complete skeletons and some have included single limbs or even single bones. One of the most complete purported "first" taxa is one of the earliest diapsids, a small reptile with two holes in its lateral skull wall (from which we gather the meaning of the word diapsid). Discovered in 1932, the fossil of Petrolacosaurus kansanensis (Lane 1945) comes from the Pennsylvanian age of the Carboniferous (approximately 302 MA) and includes the skull, pectoral girdle, elements of the hind and fore limbs, and a large portion, if not the entirety, of the axial or vertebral skeleton.

14 April 2017

The Artistic Crinoid

Murals and large scale paintings of ocean scenes often include Crinoids. Despite their lower population now, comparison to the Permian, these odd animals have always been prevalent members of the ocean.This level of involvement in the ecosystem makes the inclusion of such creatures in artwork almost essential, especially in panoramas of more ancient subject matter. Some good images that include Crinoids can be found at this link (some may be erased in the future, FYI). Crinoids have been the subject of professional as well as amateur art for a very long time. They have been main subjects as often as they have been background animals actually. Line drawings of Crinoids have populated the notes of scientists since before natural history was even considered a legitimate profession (scientific history is one of my favorite side hobbies and I promise that the history of natural history is very interesting). The best Crinoid-centric image I have found this evening is presented below. This image is older, as we can tell by its artist, Heinrich Harder, but is one of the best Crinoid centered images that can be found online. The image shows a variety of Crinoids, or as Harder called them "seelilien", swaying gently in a current and anchored into the sandy bottom of the ocean. The colors have faded over the years, but imagining the brilliance of the reds, yellows, and purples of the Crinoids one can really see the beauty of these strange animals from Harder's perspective.
©Heinrich Harder

13 April 2017

Forgotten but Popular

Crinoids possess a fairly simple appearance from an external view. A large stalk or stem, a calyx, and a feathery appendage are used for stability and locomotion, feeding and reproducing, and directing food into the mouth respectively. We can think of Crinoids as upside down starfish with the stalk growing out of what would be the dorsal surface of the starfish and a sucker or root-like tendrils anchoring the animal when it does not want to float on the currents. Some of these root structures are comprised almost entirely of the cirri that originate in the stalk. Their tough fibrous nature allows certain Crinoids to use the cirri as small and mostly inefficient legs as well, moving the Crinoid slowly from area to area. It is this stalk that is so often discovered by amateur fossil hunters in roadcuts in places like Missouri and Kansas; in case you find the shear number of fossils hard to believe consider these links please: (Missouri state fossil and Crinoid Stonehenge Model). The calyx is also frequently found, complete with the feathery arms, but is still not as regularly discovered as the stalk by amateurs. The calyx has, like other echinoderms, mouth, reproductive organs, and anus in close proximity to one another; if this sounds confusing, consult this graphic to the right. The feathery arms of the animal are called Pinnules and are ciliated, or covered in small hair-like structures called cilia that are capable of moving gathered food items toward the oral cavity of the animal. Crinoids add even more amazingness to their life history in that they are pentaradial echinoderms. Echinoderms are unique in that they begin life as bilaterally symmetric ("mirrored") larvae and during their life cycle grow to be pentaradial, or having five main segments arranged at 72º intervals around the mouth. Consider the ontogenetic image below to better visualize this change.

11 April 2017

Researching Crinoids

Crinoid papers are everywhere. Crinoids are everywhere. The Crinoids have been researched across time in the Lower Mississipian, and in geographic regions like the Antarctic, and the western Atlantic. Character traits of various Crinoids have been research, described, and cataloged, with specific interests apparently heavily invested in morphology (including microstructures of endoskeleton), ontogeny, physiology, and even locomotion. Topics like the Permian extinction event are given special attention as well, as it justifiably deserves considering that this event was extremely significant in the overall evolution of this class of animals. These papers are, of course, just a very select few of the the published works concerning Crinoids and do not even begin to scratch the surface, but there are far too many works to read in a single week at this point in the history of Crinoid research. Enjoy the readings presented here and, if so inclined, go beyond through your own literature searches.

10 April 2017

Living Fossil

The term "living fossil" is thrown out as a saying far more often than it ought to be used; it should almost never be used to be honest, but we cannot stop everyone from using odd phrases like that. Regardless, a documentary called Living Fossils produced an entire episode on Crinoids that is pretty well done and informational. Enjoy this video today:

09 April 2017

Fossils and Extant Crinoids

Videos of extant Crinoid groups are often given fantastic titles like "Amazing Free Swimming Feathers!" and descriptions like "mesmerizing video". These videos are not heavily inundated with facts and interesting trivial bits as we try to disseminate on Sundays, but there are plenty of dedicated websites to garner facts from. Fossil Facts, Fossil Era, and Kids Search are prime websites for reading short paragraphs loaded with all kinds of facts about these interesting animals. More official sites also present fact files and quite a few photographs of fossil specimens. These fossils come directly from Kansas, in the case of the Kansas Geological Survey and a variety of localities in teh case of the UCMP at Berkeley.

08 April 2017

Overlooked Animals

One of the most populous and overlooked animals in the ocean since at least the Ordovician is the group of over 500 extant species in the genus Articulata. Also known as Crinoids, these strange animals belong to the class Crinoidea, live in areas from the shallows to at least 9,000 m deep, and have a historical range in three additional genera (all extinct) that spans the globe leaving fossils in a large range of geographic areas and geological time zones. The fossils of these passive filter feeding animals have been found attached to fossilized driftwood, the bottoms of ancient oceans, and in lengths in excess of 40 m. As single stalked echinoderms that were enormously successful, Crinoids underwent two explosive radiations early in their evolution in both the Ordovician, when they first definitively appear in the fossil record, and during the very early Triassic, after an extinction event near the end of the Permian initially bottle-necked the Crinoid record for a short period. This second radiation lacked morphological diversity previously seen in Crinoids, but did exhibit some of the longest individuals with Pentacrinites reaching lengths of approximately 40 m (130 ft).

Given that there are hundreds of species and somewhat fewer genera, the reason that Crinoids have been lumped together for this week is because the wealth of information for any one individual species is actually quite limited, online, and there are a number that are not even mentioned anywhere online aside from acknowledgement that they existed. Talking about the entire group together we can discuss a large number of morphologies all at once and compare them. Be prepared for a lot of talk about stalks and plant-like morphologies. These are very unique animals that are often mistaken for plants. Be amazed, or perhaps underwhelmed, by their looks!
Photo uploaded by Berengi; GNU Free Documentation License, Version 1.2

07 April 2017

Today is Something Different

The diet of cave lions was much like the diet of modern lions in that these were large apex predators capable of subduing and preying upon equally large animals. Some of these lions have been found in the dens of bears, suggesting that they were capable of taking bears but that some may have perished in the act; conversely, these remains found in bear caves may have been successful and commandeered the cave for itself. Other known prey items included bison, reindeer (as seen previously), and even saiga antelope; a family of Eurasian antelope that possess rather well insulated nasal passages. Despite never being mentioned, the human imagination likes to imagine that all apex predators would like to get a good meal of human flesh and therefore there are indeed illustrations, like the one below, that shows a "caveman" returning with dinner to find a cave lion devouring his female partner. Be very careful in showing this image as it has no real basis in the evidence we have of cave lion diet or their interactions with humans.

06 April 2017

The Mythology of Lions

Lions, cave or otherwise, have been revered as royal, strong, proud cats for a very long time in the human world and extending some of the myths, legends, and beliefs that are lion-centric to cave lions is not a far stretch of the imagination. One of the early standouts of human literature is the Nemean Lion which was said to prowl Nemea in Greece and is within the historical range of both cave lion and modern lion but only the temporal range of the modern lion. Cave lion remains may have influenced the story of a lion so large and fierce that only the great Heracles could stop it from terrorizing the Greek peninsula. Origin stories in the myths of ancient Greece credit the abnormally sized lion as having been the offspring of titans or having originated and then fallen from the moon. Accounting for abnormal size in such ways certainly suggests that the story's antagonist may have been based on sub-fossil evidence of a large lion. The additional story detail that the animal lived in a cave could suggest either creative story-telling or literally finding the remains of a cave dwelling lion (a common occurrence from which the common name of Pathera leo spelaea originates).

Prior to the Greek, Persian, and classical Chinese (to mention a few cultures) mythos of lions, Eurasian Cave Lions were depicted in early cave art. The American Cave Lion has been depicted on various media in native North American cultures in various forms. Many of these appear more cougar-like (the North American cougar or puma has been referred to as the American Lion by many different source) and may actually be confused with the other cat. Considering that these more recent works were likely created in the likeness of cougars, the depictions of the American Cave Lion may actually be lower in number than the internet would have anyone believe.
Panel of the Lions, Chauvet Cave

05 April 2017

Geography of Lions

Extant lions are restricted to the African continent in the modern day. The extant populations of lions representing a number of recognized subspecies are dotted across the continent in areas that represent a very minor proportion of their historic range across Africa, Southern Europe, and Southwestern Asia. If we were to consider the cave lions as subspecies of the extant lions, as many have described their phylogeny, then the historic range of lions actually covered the majority of Europe, Asia, and portions of North America. We know the extent of their range because Eurasian Cave Lions have been recovered in various places and are well represented in cave art in a variety of locations across Europe and Asia. The North American subspecies (hereafter today I will refer to them as the American Lion) has been recovered in similar ways: as fossils, from glacial deposits, and a large population has been recovered from tar pits as well. The American Lion is known from a shorter temporal range than the Eurasian Cave Lion (340,000 - 11,000 years vs. 370,000 - 10,000 years respectively) and is considered endemic to North America. The American Lion, despite a smaller range and a shorter temporal span, was approximately 25% larger than extant Lions and 15% larger than Eurasian Cave Lions (which are in turn 10% larger than extant Lions) making it the largest of the lions, including the closest common ancestor between American and Eurasian lions, Panthera leo fossilis. This also means that the American Lion is, as many of these lions are, one of the largest known cats in the history of known felids. The size of the cat enabled it to take prey like the reindeer shown below, usually taken in the modern age by large bears or packs of wolves, for example.
©Heinrich Harder

04 April 2017

Genetics and Lions

Ice Age animals have a long, in the somewhat short time that it has been available, history of genetic and isotope research. The reason for this is that the thawed cubs mentioned yesterday have generated not only a lot of sensation but have provided scientists with intact remains that preserved the majority of the soft tissues and organs of the animals. This of course has led to chemical, microbiological, and genetic work being carried out using the preserved tissues of the animals. Some of these studies include molecular phylogeny (Burger, et al. 2004), diet inquiries using isotopes (Bocherens, et al. 2011), and studies of genetic diversity (Ersmark, et al. 2015). Some might be asking "How does one study diversity from a single litter of cubs?" and this is not without its caveats and misgivings; however, it is important to note that we have not discussed all of the populations of known cave lion with some tissue preservation. Many American Cave Lions have been recovered from the tar pits of Rancho La Brea in Southern California and these could add to the genetic diversity of known populations. However, the destructive nature of tar pits has hampered DNA recovery but that is not to say that there have been no efforts to recover DNA. These efforts have been largely unsuccessful unfortunately. This leaves us hoping there are other soft tissue deposits to back up these studies on genetic diversity that have not been mentioned here this week. There are, in fact, soft tissue preserved specimens from across Eurasia and many known from Alaska and Northwest Canada that are mentioned in the paper linked above. These are not entire cubs as we saw yesterday, and are therefore less famous, but are nonetheless quite important in terms of genetic studies of cave lion populations and diversity.

Non-genetic, chemical, or microbiological study is also important in the history of cave lions. These have included phylogenetic studies based on skeletal tissue, specifically cranial and dental characters (Sotnikova and Nikolskiy, 2006), as well as a detailed timeline of the extinction processes that affected and eliminated the Eurasian and American (Stuart and Lister, 2011) Cave Lions from their respective habitats. Though we have been discussing the American Cave Lion in conjunction with its Eurasian relatives seamlessly, there is mitochondrial evidence (see the linked molecular phylogeny paper above by Burger, et. al.) that this population split early enough in their evolution that it has been argued that these represent merely a "lion-like cat" with a very popular misnomer. This phrase was first prominently used in 1969 by C. R. Harington as far as I can tell, but his paper suggests that the North American and Eurasian animals were likely conspecific (Harington, 1969).

03 April 2017

Monday's Movies

One of the most important discoveries in the past few years was the retrieval of two frozen Eurasian Lions after glacial melt in Siberia. This discovery has led to discussions about cloning and the paleobiology of the animals. Cave Lions have also been recreated and animated in documentaries. These include a lot of different documentaries actually, but the one linked here (from Walking with Beasts) is shown stalking a mammoth, and is fairly compelling to watch.

02 April 2017

Things to Know About Cave Lions

A lot of people love Cave Lions as well as extant lions. This has spurred a lot of websites to host information on Cave Lions and even a 20 minute video which was self-produced that discusses what one amateur fossil enthusiast knows about the large cats. This video is spoken over a few artistic recreations of a few populations of Cave Lions. There is also a shortened video from WizScience that goes over a shorter version of some of the same information. Fact pages that we visit often are also well-represented with Prehistoric Wildlife and ThoughtCo (formerly hosted on About).

01 April 2017

Subspecies of Lions

The list of subspecies attributed to lions actually encompasses some of the fossil species of lion that we are going to discuss this week. Rather than discuss the three distinct groups of cave lion separately (Panthera leo spelaea, P. leo fossilis, and P. leo atrox), we will lump the three species together in the sense that we will discuss them as individual populations distributed globally and officially labeled as subspecies of the extant species of lion. "Cave lion", used as a generalized term, refers to European (P. leo fossilis), Eurasian (Panthera leo spelaea), and North American or American Lion (P. leo atrox) populations of large carnivorous felids of the Pleistocene. These animals were not excessively morphologically disparate from extant lions, but distinctions can be seen and observed between the extant and the extinct. These small distinctions add up to larger lions than the extant species, as seen below.
©Roman Uchytel

30 March 2017

A Famous Archosaur

Lagosuchus is well known throughout the paleontology and throughout the popular dinosaur and fossil enthusiast circles. The general public may have heard the name of the archosaur, but not as regularly as any other fossil and less than many more. Despite this unsteady popularity Lagosuchus has appeared in a number of different popular streams, books, and cartoons. These include a brief appearance in the original The Land Before Time, though it appears as an announced and non-descript small reptile running around the sauropod next in the opening scenes, but is radically out of temporal context. This version of the reptile is also a victim of the 1980's illustrative process that made most dinosaurs look emaciated and a terrible green color. Lagosuchus has also appeared in a number of texts and popular paintings. Possibly one of the most well-known paintings is one by Douglas Henderson that still looks very lizard-like. This painting is shared on Henderson's website, though it has also leaked onto the internet elsewhere, unfortunately.

29 March 2017

Incomplete Remains

The known remains that are still attributed to Lagosuchus are comprised of a single hind leg, a few vertebrae, and a scapula. The hindleg is gracile and slender, indicating that the basal archosaur was lightly built and possibly well adapted for a running life. The vertebrae and scapula are not as indicative in the life history as the hindleg appears to be, but are important in describing the animal. These elements when analyzed together indicate that Lagosuchus was actually capable of running bipedally for short periods of time only, being a facultative biped. Quadrupedality appears to have been the most basic form of locomotion for basal archosaurs, making Lagosuchus a typical early archosaur.

28 March 2017

Descriptions and Opinions

Lagosuchus remains, questionable and otherwise, have been described and analyzed many times over. Due to the controversial nature of the remains and phylogeny of Lagosuchus there are not many articles on the animal aside from descriptions of the original materials. These are not hosted online in easily accessible ways because they are slightly older documents from the early 1970's. New material descriptions are available online however, allowing us to look at the known materials and understand how much Lagosuchus material is known to science. There are a lot of papers that use Lagosuchus and the family that was named after it (Lagosuchidae) to describe and discuss archosaur phylogeny. Key in these papers are articles discussing the ankle joint and whether or not there is even any consensus on what the ankle and the accepted basal archosaur tree mean to overall archosaur phylogeny.

26 March 2017

Quick Lists of Facts

Lagosuchus, dubious name or not, has a lot of pages dedicated to it online describing the animal or relaying short lists of facts. Today I will simply share a video that summarizes what many of these pages summarize over and over again. It is a somewhat less exciting video than we might normally share for facts, but it does discuss a lot about what we know of Lagosuchus.

25 March 2017

Early Archosaurs of the Triassic

Pavel.Riha.CB at the English language Wikipedia
Lagosuchus talampayensis is an early archosaur recovered from the Triassic rocks of Argentina. The Chañares Formation represents the Middle Triassic (230 MA) and, barring recent publications until their results can be independently verified, the some of the earliest remains of archosaurs representing the earliest dinosaurs. Discovered in the 1970's and initially described by Romer in 1971, it has been described by many as a nomen dubium by many. A second species was reassigned in 1994, making the description and known material to be even more questionable. That material is somewhat minuscule in nature as well, which does not help. Instead, we will look at what is known about Lagosuchus, its relatives and what its relationships mean for the current phylogeny of archosaurs.

24 March 2017

Everyone's Arkansaurus

There are only a very few widely circulated recreations and illustrations of the little known dinosaur Arkansaurus. The majority of these are variations on a dinosaur that looks very much like the Gallimimus that ran around in the original Jurassic Park movie. A more modern version of the illustrations by Brian Engh does exist that not only updates the general look of Arkansaurus but also adds feathering and a little weight.

20 March 2017

Short News Piece Day

Movie Monday is not going to have a movie or a documentary today. Arkansaurus was not, and is not, famous enough to have influenced any documentaries or movies despite its status as a symbol for a state. The only videos about the dinosaur are news coverage of the state's legislative debate over adopting the symbol. There was not a lot of debate actually, but it is a nice little news piece to watch.

19 March 2017

Arkansas Geological Survey Facts

The Arkansas Geological Survey (AGS) has a large number of publications and fact sheets describing the state dinosaur and other geological wonders of the state. As a somewhat obscure dinosaur, there are few references online that are more popular. However, aside from sites like Cool Dino Facts and the AGS there are also Arkansas based sites that discuss Arkansaurus. These include Paleoaerie, an evolution and education resource site based in Arkansas (AERIE = Arkansas Educational Resource Initiative for Evolution). Another important site hosting a nice post about Arkansaurus today is Arkansas Life Magazine.

18 March 2017

Legislative Dinosaurs

Photo provided to Arkansas Geological Society by ReBecca K. Hunt-Foster
In the past few months there have been a lot of dinosaur stories circulating in the popular news and one of the most relevant to the middle of the United States is the announcement of a new state dinosaur. That dinosaur is named Arkansaurus fridayi and is known from a few bones found by a farmer searching for a cow. In 1972 a man named J. B. Friday was searching his farm in southwest Arkansas and stumbled, almost literally, over a fossil dinosaur foot in the remains of a road cut, which is problematic. Any remaining fossil material may have been destroyed in the construction efforts, by water flow before or after burial, or scavenging prior to burial. The remains were initially described by members of the 1973 SVP meeting as an Ornithomimus which would represent the oldest member  of the species ever recovered. The animal remained informally named Arkansaurus fridayi for 30 years before it was re-described by ReBecca K. Hunt-Foster (published as an abstract under her maiden name; ReBecca K. Hunt). Considering this is the only publication of any type describing these dinosaur remains we will refer to the animal this week with italics rather than quotations; a difference typically separating formally described and accepted genera and species from those used informally. This remains a controversial name, but in defiance (or disregarding the informal nature of the name) the state of Arkansas recently passed a bill making the only dinosaur material known from the state the state's official dinosaur fossil. There is more significance than just naming Arkansaurus the state dinosaur; Arkansaurus is now the 25th official state symbol and Arkansas was the 25th state admitted to the United States.

17 March 2017

Too Much Titanoboa

©Jason Bourque
To finish out the past week we need to look at some of the beautiful paintings and sculptures of Titanoboa. The artistic interpretations and scientific recreations of the snake show the animal in typical snake postures and some are stunningly detailed. One of the more tame interpretations of the snake actually shows Titanoboa participating in one of the most common behaviors of snakes or any other animal: casually sunning itself or possibly moving from one place to another. A large dryosaur and turtle help populate the background of this painting and dryosaurs actually figure into more than one Titanoboa representation. The most well known sculpture, the Titanoboa featured in the Smithsonian exhibit for the giant snake, shows a Titanoboa in the process of swallowing a dryosaur. The dryosaur's distinctive tail is sticking out of the snake's mouth as it aligns itself perpendicular to the ground. This seems odd for two reasons: 1) the post hoc knowledge that the hypothesized diet of Titanoboa is composed of fish almost entirely and 2) lifting an animal as large as a dryosaur vertically into the air to swallow it would, it seems, be extremely taxing and difficult even for an enormous snake like this.
Photo by Ryan Quick

16 March 2017

The Charmer Snake

Through no mistake has Titanoboa become a popular fossil snake. The sheer size alone is enough to make people ooh and ahh over the giant reptile and the popularity that followed is entirely expected. This popularity can be seen in the number of sites online hosting facts and images of the snake as well as the fact that the snake had a one hour documentary dedicated entirely to the single taxon. In the vein of many internet speculation sites, the Smithsonian's work on Titanoboa even allowed for the fairly ludicrous time traveling fight between a Tyrannosaurus and Titanoboa, giving into the popularity of online forums that pose "what if" encounters between apex predators. We now hypothesize that Titanoboa was piscivorous and not really an apex predator, so many of these sensationalist popular views can be thrown out anyhow. thankfully, without linking a lot of books, we have other popular outlets. The most visible of these is video games and, again, ARK manages to include more fossil animals in the game. ARK tends to err on the side of intrigue ever so slightly when re-creating fossil animals and with Titanoboa the designers managed to find something, even on a snake, to indulge their creativity and the fantasy of the game. The snake looks surly and vicious and manages to do so sporting an almost hairy looking frill:

15 March 2017

The Long Remains

Jonathon Bloch with Titanoboa and Anaconda vertebrae. ©Natural History Magazine
The finding of Titanoboa was significant for vertebrate, South American, and herpetological paleontology to name just a few areas and disciplines that benefited greatly from the discovery. Climate studies were another area that has been mentioned a great deal here in the last few days. To truly understand how large the snake is though requires a significant amount of knowledge of extant snakes and how their morphology relates to the size of their overall body. In order to estimate size and weight of extinct snake biologists need to know how the bones and bodies of living snakes are related and then apply the resulting ratios and formulae to the recovered extinct material. Vertebrae, such as those shown from Titanoboa and a 17 foot Anaconda, are often useful in estimating length and weight of fossil animals. Titanoboa was found with a significant number of these vertebrae, which can be rare for snakes. What made estimating the size of Titanoboa easier was not the number and completeness of vertebrae, bones of the spinal column that can make estimating length a bit easier, but the recovery of the skull of the snake. A snake's skull is rarely recovered in extant animal remains, let alone in fossil remains. The reason for this is that snakes are animals with extremely mobile heads. Their heads are capable of moving to extreme degrees and they do so by having very interesting connections between the bones of the skull that are not so much loose as they are workable and even supple. This often leads to the skulls of snakes simply falling apart as the flesh, muscles, ligaments, and tendons decompose and water, wind, and animals scurry about moving the bones. The skull alone is, therefore, a very intriguing find. That makes a very intriguing snake with a very rare skull and an immense body that has captivated millions; not a bad find in a Colombian coal mine.