STL Science Center

STL Science Center

28 February 2013

A Positive Bias Fossil

Bias in the records, rock and fossil, are always of paramount concern to paleontologists and a positive bias, while not always a good thing, is far more welcome than a negative bias typically. Xiphactinus has been discovered in so many places, pieces, and configurations that it is a small but massively important positive bias center of the fossil record. This translates into a fairly large impact on popular culture. Xiphactinus appears in two major documentaries, Walking with Dinosaurs: Sea Monsters and Sea Monsters, as well as in video games such as Zoo Tycoon; it has been modded in. In true human/prehistoric animal interaction as seen with other Nigel Marvin/WwD BBC shows, Xiphactinus attempts to attack a person. At least the model used was fairly accurate though if not the premise of the episode. The Sea Monsters National Geographic movie is best described as a documentary that possessed highly qualified and wonderful technical/scientific advisers, but fell victim, in parts, to the Hollywood bug; as explained earlier this week by Mr. Everhart in response to a still from the movie "We tried to get the producer to NOT use the schooling X-fish scene... but he was after a dramatic effect, not scientific accuracy."

Xiphactinus does show up in collector's collections as well as statues and smaller figures. There is also a lot of artwork that features Xiphactinus; a simple Google image search or even going straight to a site such as DeviantArt and searching for Xiphactinus will show a rather long list of illustrations and paintings; some of which are fantastically beautiful.

27 February 2013

Xiphactinus The Swallower

As mentioned previously, the gluttony of Xiphactinus has been to our benefit as a paleontologist community. Finds of Xiphactinus that are fully articulated tend to be quite often associated with other animals stuck in their gullets. There have been plenty of other finds that are simply heads or fins, teeth are popular also, and these remains can be distinguished from other members of the family (Ichthyodectidae) to which Xiphactinus belongs primarily by the fact that Xiphactinus is simply a larger fish than other members of the family (the genera Gillicus and Ichthyodectes). In addition to whole monster fish discovered with stomach contents, or throat contents in some specimens that died while eating, and scavenged remains, there have also been a few Xiphactinus remains discovered as stomach contents themselves in the bellies of larger predators such as the shark Cretoxyrhina; Cretoxyrhina teeth have been discovered in Xiphactinus vertebrae also. Being the largest fish in the sea, the largest bony fish at least, allowed for fairly good preservation and thus discovery of Xiphactinus specimens over the past 150 years in Kansas, in particular, and the remainder of North America that was covered by the Western Interior Seaway.

26 February 2013

Fish of Many Letters

My favorite papers are always the older papers, with rare exception. It is not because I am a traditionalist or that I find current science to be less educated or informed, it is totally the language used. Scientific papers are dry by nature, something that will probably never change, but the language of the earlier paleontologists is from a different time and, in my opinion, makes the reading that much more interesting despite its dry nature. With that in mind, I picked out two papers- out of a virtual stack not to mention a good portion of Oceans of Kansas' chapter on fish- one of which is from 1997 and the other 99 years older, from 1898, that redescribes and makes new observations on Xiphactinus.

The 1997 paper, by Schwimmer, Stewart, and Williams, discusses the different Xiphactinus discoveries in North America and the distribution of the species Xiphactinus vetus in the Eastern US. The paper is a short communication and thus is not very highly in depth, but it does address some questions of distribution and poses a question near the end of what kind of evolutionary relationship existed between the two species of Xiphactinus.

The older paper, O.P. Hay's 1898 observations and redscription, does exactly what it says it is going to do; Hay makes observations on Cope's and Leidy's  two "distinct" genera of fish. Hay goes on to talk about multiple species but does make an important note that Cope's genus, Portheus, and Leidy's genus, Xiphactinus, possess "no serious discrepancy between Cope's description of his Portheus thaumas and my specimen [Leidy's Xiphactinus]." Additionally, as has been made often here, Hay compares Xiphactinus with extant tarpon regularly throughout the paper. It is a fairly good read.

25 February 2013

Swimming with Xiphactinus

As has been mentioned in some of the Facebook posts (not necessarily on the blog posts) National Geographic's Xiphactinus is not spectacular due to television standardization; meaning sometimes the science gets sidelined by showmanship for interest purposes. However, almost every television show in existence has ignored facts here and there as it pleases them in order to air a show which will generate interest. This is a paradox that we have seen many times in looking at documentaries through our dinosaur vision, so we are used to it to a point; should the show be entertaining at the sake of some scientific fact or should it contain only scientific fact at the sake of entertainment? Entertainment purposes may generate scientific interest where lack of entertainment may cause people to "tune out" and all the science in the world may be wasted on having an effectively non-existent audience. It is a wrestling match as old as documentaries themselves. Regardless, I have two videos to share today, neither of which is a full scale documentary (more on the two documentaries which feature Xiphactinus on Thursday this week).

One shows a proposed swimming posture of Xiphactinus, which appears a bit rigid as far as I am concerned.

The other is a short documentary on the exhibit of Xiphactinus at the Hastings Museum in Nebraska.

24 February 2013

Xiphactinus For Kids


Xiphactinus (combination Latin and Greek for "sword ray"); pronounced zih-FACK-tih-nuss
X. audax
X. vestus


Shallow waters of North America, Europe, Australia

Historical Period:

Late Cretaceous (90-65 million years ago)

Size and Weight:

Up to 20 feet long and 500-1,000 pounds



Distinguishing Characteristics:

Large size; prominent teeth
 This week we have an awesome coloring page, all things considered, of Xiphactinus. Today is an easy day. Share the facts, color the mean looking fish, enjoy some snow outside (if you have it)

23 February 2013

Bulldog Fish

©Dmitry Bogdanov
Xiphactinus is sometimes referred to as a bulldog looking fish, which makes sense when we look at the jaws of the fish and how they are turned upward at the same time as they are jutting out into space ahead of and below the eyes. The length of the fish was imposing even without the teeth; the longest estimates reach approximately 20 feet while many known specimens reach at least 16 feet. That much fish was probably difficult to turn, however, with the body build that the big bony fish had and the lack of maneuverability probably allowed more than one smaller fish to elude the grasping and deadly maw of this large fish. The only dangers left in the water to a fish this big would have been sharks and mosasaurs, and size would be the only protection against mosasaurs while agility would be the best defense against sharks of near equal size; Xiphactinus apparently was not adapted to outperform either exceptionally well however.

I think, given the size and lack of agility apparent, though we said nothing of speed and I am willing to lay down a small bet that Xiphactinus had a barracuda like surge of power at least inherent in its physiology, that a school such as this would have been rare or non-existent with the exception of breeding season movements to spawning grounds. Considering we know so little about the early stages of the life cycles of these fish anything is possible, including mass movements of the fish during the spawning season to a seasonal spawning ground. Looking at their size and the lack, so far, of evidence of any freshwater habitation, we can conclude for the time being that these were not salmon like in their need to return to a river system to breed, but where then, would a school of Xiphactinus go to breed, if they did ever "school"? Either way, these Xiphactinus are on some kind of mission and are very intent on making it to wherever it is they are going.

Borrowed from Mr. Everhart's Oceans of Kansas
Probably one of the most famous, if not the most famous of Xiphactinus fossils, is the fish within a fish. Discovered by George Sternberg. The fish in its gullet is a Gillicus, a 6 foot fish that, the main theory holds, writhed in its death throes and ended up effectively suffocating the larger Xiphactinus. The only way for the preservation to be as fantastic as it is, honestly, is very quick burial within the sediments at the bottom of the ocean. Had the burial been slower or the corpse not drifted to the bottom of the ocean quickly then it would have certainly been scavenged, torn apart, and not as fantastic a fossil as it is now, obviously.

22 February 2013

One Fish, Two Fish

Not to be made angry
Xiphactinus audax (and Xiphactinus vetus) were some big scary old fish. Reaching estimated lengths of nearly 20 feet (6m), these fish were truly monsters of the deep ocean. In fact, they simply look as though they would be highly willing to eat, or at least maim, any creature slow, dumb, brazen, or unfortunate enough end up within striking distance of that terrible set of teeth. Stomach contents of these big mean fish are testaments to the amount of horror they imposed upon the oceans of their day; approximately a dozen remains have been discovered with items such as a fish nearly 6 feet long as well as appendages from other larger animals like plesiosaurs, potentially scavenged, have been found with the bones of Xiphactinus specimens. Most of these fish have died with their prey barely digested or even stuck in their gullets, as though the writing prey killed their killer in their death throes. Big and mean and prone to biting off more than it should attempt to swallow. As well known as the stomach contents, and actual fish, are known, there is little to nothing known about Xiphactinus' life cycle. We have evidence of their deaths, as scavenged morsels in the bellies of sharks such as Squalicorax and Cretoxyrhina. Xiphactinus skeletons are well preserved throughout the US at the limits of the Western Interior Seaway and also globally as far from the Western Interior Seaway as the middle of Europe and Australian fossil beds.

21 February 2013

The Most Popular Reptile in the Sea

Tylosaurus is found in many aspects of popular culture. Books, YouTube videos, toys; we know they all exist. Mr. Everhart loves Tylosaurus- I have gathered that from his frequent and very useful comments and links this week in addition to the amount of information addressing Tylosaurus in his book- and a fellow graduate student I know is working on isotope analysis in mosasaurs; he has not mentioned specifically a genus of study, but chances are fairly good that it is a Tylosaurus vertebral column which he is analyzing. Additionally, as I always enjoy finding- in part because I love Zoo Tycoon and in part because I like seeing prehistoric animals in video games- I have found an add on that places a Tylosaurus in the menagerie of animals available for display in a player's zoo. There are a few Tylosaurus add ons, but this seems to be the original model that made its way online.
Zoo Tycoon 2 Tylosaurus

20 February 2013

Gastrointestinal Wonders

Tylosaurus, as a genus not any individual species, seems to have had a habit of dining and dying. Quite a few specimens, and this is in part thanks to the preservative nature of the ocean sediments as well, have been unearthed with lunch intact or in various stages of digestion. Items found in the stomach area (sadly no stomachs have been discovered preserved as yet) include fish, sharks (most mentions seem to be of digested teeth), mosasaurs (ex. Clidastes), diving birds (such as Hesperornis), and plesiosaurs. The diversity of diet gives us a glimpse into the diversity of habitats that Tylosaurs inhabited. They have been unearthed in Alabama, Kansas, and other western states. The locations in which they are found represent both near-shore deposits deep ocean areas. Assuming that Tylosaurs wanted to live in these areas and were not driven to near-shore environments in search of food, or to deep ocean environments in desperate searches for food, we can use this as evidence that Tylosaurus was indeed an apex predator that had free reign over much, if not all, of the Western Interior Seaway at the height of its development. The wealth of remains has helped in suggesting and supporting this hypothesis, but the remains were unfortunately mired in controversy when they first appeared.

Due to our ever popular topic of the Marsh/Cope feud, Tylosaurus was known by far too many names when it was originally discovered. Cope proposed the name Macrosaurus only to change his description of the material's placement within the English mosasaur genus Liodon. Then Marsh proposed the name Rhinosaurus from another specimen. Cope decided he liked Rhamposaurus because Rhinosaurus was an occupied name, as Marsh discovered. Rhamposaurus, too, was taken, and Marsh, therefore, changed the name once again to Tylosaurus. Thankfully, that has stayed the name of the genus for about 141 years now. Hopefully it will remain the name for at least another 141 years!
Smithsonian Tylosaurus, which was found with plesiosaur stomach contents (not pictured), and a Hesperornis following it.

19 February 2013

Paper Everywhere

Tylosaurus is one of the most studied genera of the Western Interior Seaway. There are papers written about it all over the place and many of them are quite current, or at least recent if the science is not entirely current; I honestly do not have the time to read every single paper on Tylosaurus right now, that is how many are out there. Many of the most recent papers are authored, or at least coauthored by Michael Everhart, who also wrote a very detailed book, Oceans of Kansas, on the parts of the Western Interior Seaway that covered Kansas at different times. A good part of the chapter on mosasaurs in Everhart's book covers Tylosaurus specimens. Anyone with interest in Kansas, the Western Interior Seaway, or mosasaurs really should do themselves the favor of reading his book. My recommendation for reading today, if anyone has a desire to read a particular paper, but cannot pick up the aforementioned book, is to either look through this list here or read this 2005 Everhart article on a new species identified from the Niobrara in Kansas. Also, enjoy this Dan Varner image:

18 February 2013

Tylosaurus Fights?

Most videos that have to do with Tylosaurus, of any species, are speculative fighting videos. What I mean by that is that they are self made videos that theorize battles between Tylosaurus an other marine animals of the Late Cretaceous, whether they were present in the Western Interior Seaway or not. One video is an exhibition of clay model that someone created, which is fairly accurate and pretty neat looking, to be honest. It is not exactly professional toy grade, but it is pretty good for someone just making a clay model of a Tylosaurus for fun. Good old Canada's Courtenay Museum in the Comox Valley of British Columbia put up a short video with Richard Ross, a board member of the museum, announcing and discussing the addition of a Tylosaurus fossil to the Courtenay Museum's collection earlier this year. What follows in the clip are some closeups of the fossil that, for today, are the best video evidence I can share today.

17 February 2013

Making A Fact Page

I have to borrow a fact page template from About, as I do sometimes. Strangely, Tylosaurus does not have a fact page on on kid related sites, which is, to me of course, sad and unfortunate. Borrowed and adapted from Bob Strauss' fact page on Tylosaurus.


Tylosaurus (Greek for "knob lizard"); pronounced TIE-low-SORE-us
Multiple species are recognized. These include: T. proriger, T. nepaeolicus,T. kansasensis, T. capensis, T. pembinensis, T. saskatchewanensis


Shallow seas of Central America (by "Central America" the original author of this, Bob Strauss, means the overall area of what was once the Western Interior Seaway).

Historical Period:

Late Cretaceous (85-80 million years ago)

Size and Weight:

Up to 49 feet long and 7 tons


Fish, turtles and other marine reptiles

Distinguishing Characteristics:

Long, sleek body; narrow, well-muscled jaws
Additionally, I have found high quality models, usually at Target, of Tylosaurus. These make good toys, if you have the funds (Amazon distributes Safari Ltd. models for $12). A cheaper Safari model exists but you do get what you pay for. Middle ground is achieved by Safari as well with their TOOB collections that are smaller versions of their higher quality models. Books also exist, the newest being a short Tylosaurus only book, that is a little vague, by Gerry Bailey. Finally, there are a few "coloring sheets" out there. The best, though I will not post them today (no express permission), is the property of Osvaldo Cortes. It would make a wonderful coloring page.

16 February 2013

Tylosaurus Swims Again

Older images of Tylosaurus, as I said yesterday, are quite fantastic. This image, from the turn of the 20th Century, is fairly typical of older drawings. The dragon-like appearance of older Tylosaurus drawings is not usually exactly like this in one very special aspect: the hairy appearance of the dorsal ridge. The backs of Tylosaurus were originally drawn with large flowing "manes" of thin skin that undulated while the body moved, snake-like, through the water, propelling itself through the water with its tail. In that aspect of motion ideas have not changed very much over the years; the tail is still proposed to be the main propelling force for mosasaurs such as Tylosaurus with the fins acting as stabilizers more than as paddles. Snake-like motion is probably a bit of an exaggeration, though related to snakes, as only the tail would have been really needed for propelling Tylosaurs through the water. The most un-reptilian mane of hair has not actually been documented on Tylosaurus (nor has there been any feathering) so the mane can be interpreted as purely an artistic interpretation.

Fast forward a few years to Charles Knight's interpretation of Tylosaurus and we see the exact same ecological positioning of Tylosaurs; it is chasing down some rather large and tasty looking morsels in the Late Cretaceous seas. This turbulent ocean landscape is a little bit more evolved, so to speak, in terms of Tylosaurus. This Tylosaurus has no exaggerated dorsal ridges, though the spinal ridge is still highly visible. Another strange bit of this illustration is that the Tylosaurus has chased the fish it is attempting to eat directly out of the ocean and is continuing to pursue them above the waves. Tylosaurus most likely would not have been too excited about chasing its food out of the water. It was most likely not an extremely fast or agile swimmer; it more thank likely surprised its prey from below.

That makes this image even more shocking and unrealistic. While the accuracy of an attack from below is probably better than a Tylosaurus attempting to chase down fast moving fish- the fish above are smaller faster movers than the large predatory fish of the ancient sea, such as the Squalicorax shark that this Tylosaurus has surprised and tossed out of the water- the attack from below makes much more sense in terms of how a Tylosaurus actually would have hunted its prey with the highest success rate. The unlikely part of this image is that the Tylosaurus is nearly halfway (which would be about 27feet of reptile) out of the water, which would require an amazing amount of energy and quite a bit of speed; a highly inefficient method of stalking and killing prey when the predator in question has a less than perfect kill per hunt record. In reality a shark like this would more than likely have been bitten completely in half by the large powerful jaws of this Tylosaurus.

I do not even have anything to say to this illustration really. I think it is attacking a plesiosaur, but it looks like some sort of weirdly exaggerated duck. Also, its tail is extremely hyperbolic in terms of being shown as a paddle. Seriously, just soak this one in. Supposedly it was a print that was sold in Germany in the late 19th Century.

15 February 2013

The Mighty Tyler... uhh, Tylosaurus!

Tylosaurus proriger was, and still is, an amazing reptile of the ancient oceans of the world. Older depictions of Tylosaurus, which we will examine tomorrow, were quite snakelike in their appearance but since that the first half of last century they have become slightly less streamlined and bulky. In essence, Tylosaurus has been given the equivalent of lifetime of body building exercises in its newer form. The fossil evidence supports a bulky Tylosaurus, an animal capable of slow (modern trends concerning marine reptiles all seem to be much slower than they used to be portrayed) but powerful swimming, with enormous jaws capable of crunching down on sharks and absolutely destroying their cartilaginous bodies.

Six species of Tylosaurus are now recognized and have been found throughout the interior of North America, as Tylosaurus was the penultimate genus of mosasaur evolution and an apex predator that dominated the later Cretaceous of the Western Interior Seaway. At more than 45 feet from tail to nose, it was an enormous apex predator, longer than a school bus, and possessed a very distinct premaxilla; the name Tylosaurus refers to the protuberance of the premaxilla which was very long in proportion to the overall skull. The effect is a very long predator with a great deal of power and a very large mouth. The only negative aspect of Tylosaurus, other than sheer size, is that it was an air breathing reptile related, most closely, to extant (living) monitor lizards such as the Komodo Dragon (and my favorite monitor the Nile Monitor) and snakes. There is a wealth of information to share on Tylosaurus, and this will, therefore, be a very full week.

14 February 2013

Archelon Meets Cavemen

I wanted very badly to embed a clip put up by TCM (that's Turner Classic Movies for those that do not know) on YouTube from the Hammer Film's- great British "cheesy" movies most of the time- remake of One Million Years B.C. that features an Archelon fighting some cavemen. Unfortunately, TCM does not allow embedding of that clip. I love Ray Harryhausen's stop motion work on films like this though; it is ancient compared to computer graphics, but it is so wonderful to see the work that went into making the models and positioning them and everything else involved in the process. Also, if this is not the best page of stop motion gifs ever, and I am linking directly to the Archelon gif, then I do not know who is topping it, but I want to see it. Archelon, as we have seen, also appears in story books, including a newer one, and in many different images. One image that I have not shared until today is a U-Haul trailer image:
U-Haul; educating Americans about the past one truck or trailer at a time.

13 February 2013

Interesting Archelon Facts

The Western Interior Seaway of North America was rife with life, this is a known fact from the wealth of fossil evidence that was collected between the 1860's and the present day. Archelon, as we know, is one of those lifeforms that has been shown to have existed in some abundance (in terms of a rather large turtle at least). A lot of the Archelon specimen material that has been collected within the confines of what was once the ocean resides in what is now South Dakota. A number of other turtle species have been discovered within the extent of the now extinct ocean. Kansas turtles have also been collected- Kansas was a plesiosaur and mosasaur hunting ground but turtles and fish are found in good abundance here as well- but where and when they were collected are not well documented, sadly. Archelon was not a high population, in terms of specimen material, animal in the area that is now Kansas, but it is thought to have lived throughout the seaway; missing evidence of its living in any given area is subject to pretty much every type of fossil record bias one can think of.

Wieland, the author of the initial description of Archelon, thought, based on the raptorial curve of the turtle's beak, that Archelon was an entirely carnivorous animal and that it could catch slow moving prey. This narrows down diet to jellyfish, as in some extant sea turtles, and slow moving fishes and, perhaps, sedentary mollusks. The raptorial nature of the beak, rather than the tough crushing beak of, say, a seed crunching bird, was not necessarily built for crunching down on clams and other inoceramids. That raptorial beak would be a good defensive tool as well.

Tylosaurus, a big mean mosasaur, would have loved to have made a snack of smaller Archelon, typically juveniles, but that beak could have been used, in addition to the protective shell, to survive attacks from giant mosasaurs such as Tylosaurus. Use your imagination in finishing out the drama of this image sold by Great American Media Services and through a few museums as an info card or poster:
Artist unknown (so far)

12 February 2013

The Scholarly Sea Turtle

This is clearly not an image of Archelon. It is one of the best images of a "scholarly turtle" that turns up on Google, in my opinion. Most scholarly papers on Archelon have the unfortunate distinction of being written prior to the internet days; in the first decade or so of the 20th century to be precise. Some more recent papers focus on growth and development of sea turtles and redescriptions of bones attributed to dinosaurs that actually are those of Archelon. I find, more interestingly, papers on turtle evolution (Kear and Lee) and paper/activities about proposed nesting structures of giant extinct turtles (Bishop).

Kear and Lee describe a primitive protostegid (ancient marine turtles) discovered in Australia and relate this new, basal, turtle to its descendents (note: descendant with an "a" refers to specific descending organisms whereas with an "e" at the end refers to derived groups descending from other groups). In terms of history and discussion pertaining to how animals such as Archelon came about and reigned in their respective turtle niches, this paper is quite good but also short at the same time meaning that it lacks some information; it is not an entirely in depth venture into turtle evolution.

Bishop's Archelon nesting proposal activity is a fun read that looks at analogous, we and Bishop hope, extant turtles such as Loggerheads. Bishop's discussion of extant turtle trackways (both Loggerhead and Leatherback) includes graphics to help illustrate the struggle up the beach for females; it allows for the imagination to envision Archelon trackways on a beach as well, I think. After a description of Archelon, mostly drawing from other sources, Bishop goes in to her rationale of how and why Archelon would have nested the way she says it would. The activities allow for others to draw their own conclusions about the exact nature of Archelon nesting habits; it is interactive science.

The activity included is interactive science at its best for schools. It shows living examples, describes and extinct species, and then encourages teachers and students to go out to a real beach and investigate and recreate what an Archelon female may have done out on the beach in order to crawl from the ocean, create an egg mound, lay eggs, cover them up, and then retreat back into the ocean. I know it is not a traditional scholarly paper, but I think the history in it warrants reading and the activity is well worth investigating with students, adult or child, in a museum outreach or for fun.

11 February 2013

Archelon and the Sea Dragon

There are a few videos with Archelon in them. One of them is not so much a video as a narrated book, which is pretty fantastic as you get an entire story, rare for books still within copyright (which this book should still be though it is out of print at this time), and it gets read to you; admit it, even as an adult we like to hear a story told or read to us every now and then. The video for that is posted below.
The story is pretty accurate as far as what we think was the ecological niche and behaviors of Archelon. The illustrations of Archelon are also fairly well done. Given the date of publication, and thus illustration, the illustrations of the other animals in the book are fairly well done. Since the book was originally written and published, though, the images of plesiosaurs, pterosaurs, and mosasaurs have been updated and made the illustrations within the book look quite out of date. Tylosaurus in particular is rather out dated, but that is quite fine considering that the science, at the time, was actually quite accurate. I do not want to comment on the end of the story, because that kind of ruins it, but it gets a little silly for a while there, as we know more about marine creatures these days than the author did in the 1970's. I do like that the story includes a small snippet of the modern turtle egg laying journey (I assume that revealing this part of the end of the story does not ruin the book for anyone!).

As stated, other videos exist, but I want to save some of those for Thursday, if I can find good clips and not just stills. For today, enjoy a good, but older, book.

10 February 2013

Fun Times To Come

Dinosaurs are not the same as Archelon. Technically I should say Archelon is not a dinosaur- though it does show up on the Dinosaur For Kids fact site- but it is all the same. It does not appear, to my knowledge, to be a part of the Dinosaur King universe at this time, though it will (WILL) shortly be a character in the Dinosaur Train world. I feel somewhat like I am giving a free advertisement today, but starting February 18th Dinosaur Train is going to have a number of episodes in a "Dinosaur Submarine" rather than on a train. One of those scheduled episodes is set to have an Archelon character. If you can watch PBS keep an eye out for it in the near future! Not much exists in the toy or book for children sections of the world. There is one image at least that could be used for coloring purposes, which is nice at least. It is located here, but I am not going to post it itself as I did not ask to do so.

09 February 2013

Archelon, Giant Turtle of Awesome

Type specimen (YPM 3000)
Sometimes it is really hard to find exciting illustrations and paintings of some of the animals which we discuss here for Saturday mornings. Today, talking about a giant, plodding, deep in thought turtle of ancient Earth history, that is quite an accurate description of the challenge. Archelon was a giant sea turtle. As a giant sea turtle it was, as stated above, a slow moving animal- slower than Elasmosaurus certainly- and plodded through the oceans at a nice steady pace, its size being its largest defense. The size, pictured here in the type specimen, was an astounding find for a turtle, or any other entire fossil at that time. The lack of only one flipper (in terms of major appendages and parts of the skeleton anyhow) is pretty fantastic really, considering how many fossil animals are "discovered" and named using only small parts of the skeleton such as teeth or claws alone. The "shell" structure is easily seen here as well. We can see the struts over which the leathery or bony carapace would have been stretched; the shells of modern turtles are solid carapaces with their strength in the shell itself, not as trusses and struts. We can actually think of the shell of Archelon in terms of support beams in a house; strong beams in key points to best defend, in this case, the inner "living area."

©Dmitry Bogdanov
The fleshed out Archelon is, as is every fossil animal, always open to some sort of interpretation. The shell is the most open part of the skeleton to interpretation, I think, for artists. Flippers are open to some interpretation, however, they are fairly solid and non-changing and their structure delineates what they would have looked like fleshed out nearly perfectly given our understanding of extant turtles, and other animals with flippers. The flesh of the neck and the fore and hind limbs are also open to a bit of interpretation, but it is definitely the shell that we are most interested in. The shell in this illustration is not entirely tightened over the shell ribs that are seen in the fossil, but some depressions of the area between the ribs are clearly evident.

©Nobu Tamura
 Another version of the shell, illustrated here, shows a much more bony carapace than a leathery carapace stretched over the shell ribs. The bony carapace strengthens the ribs and emphasizes the struts. With the bony carapace stretched over the ribs the depressions between the ribs are not as pronounced; this could have the ability to additionally protect the turtle much better than the leathery carapace which, when stretched, still "sagged" between the ribs. The argument could also be made, though, that the more taunt and therefore less giving carapace in a bony format like this would be more easily punctured as it would have no or very little flexibility in the areas not protected by the dorsal ribs.

08 February 2013

Not Quite Stupendemys

Stupendemys, for those of the readers not in the know, is a genus of turtle, extinct, that is now considered the largest in the history of the world. This week we will cover what is now the second largest turtle, also extinct (for this blog? of course!), called Archelon ischyros. A major difference between these two turtles, besides size, is that Stupendemys was a fresh water turtle whereas Archelon was a sea turtle. Archelon was not the first sea turtle, and obviously not the last, but it still is the largest marine turtle and at over 4m (13ft) tip of the beak to tip of the tail and just about 4.9m (16ft) from flipper-tip to flipper-tip, it may have weighed over 2,200kg (4,900lbs). To put that in perspective, the largest living turtle, the Leatherback sea turtle (Dermochelys coriacea) is at its largest 2.2 m (7.2 ft) from beak to tail, 1.75m (5.74 ft) from flipper to flipper, and weighs up to 700 kg (1,500 lb). That makes Archelon a little more than twice as long, nearly three times as wide, and three times as heavy as the largest living turtle!

Oh, hi! from Wallace Building on the University of Manitoba campus, Winnipeg, Manitoba Canada (Photo by: Mike Beauregard, taken from Wikicommons)
Archelon was unusual amongst turtles in that its shell was not a shell; rather it was a scaffold of strong bony struts that supported a leathery/bony (debatable point here) carapace above it. It has large flippers, a nice sharp looking beak with an overbite almost more akin to a parrot than an extant turtle, and is thought to have used that beak to crush mollusks. Leatherbacks dine on jellyfish and other related pelagic goodies, but their ancient suborder (both Archelon and Leatherbacks belong to the Cryptodira suborder of Testudines) cousins were crunching enormous squid and possibly ammonites. More to come on shells, beaks, and the size of this behemoth!

07 February 2013

Nessie and Playsets

Where to start with the popular culture entry for the week? Elasmosaurus is an amazingly popular animal. Though most of the time packages for toys or generic books, or anything else of that type of thing, says simply "Plesiosaur" on it, it typically refers to a long necked Elasmosaurus. Once in a great while we see a box that says Elasmosaurus, but sadly, often those boxes contain what I refer to as "angry toys." Angry toys are those magnificently strange models we often see given to children in which the dinosaurs, dragons, and other creatures are portrayed as malevolent looking beasts that were definitely modeled in a tear you up posture with gnashing teeth and a scowl. Such as this:
Where to start on the awful inaccuracies here? I understand the toy maker's mantra these days; I find it to be universal throughout the toy industry that "make more money" is the typical war cry (Papo and other higher quality fossil animal modelers being an exception as they include "be accurate" in there as well). Regardless, do we start by the implication of a caveman/plesiosaur interaction? Labeling it a dinosaur? The neck position? Teeth? The awful forelimbs? The only thing a child would gather from this modelling of Elasmosaurus is that it was a terrible monster with a lot of deformities.

Let us look at something better here. There is always Spore, talking about inaccuracies. However, despite its inaccuracies, the majority of Spore creations tended to be made with the best intentions by creative folks attempting to push their artistic abilities and boundaries. Also, this is a pretty good model, except for that ever common neck. Type in "Spore Elasmosaurus" in YouTube, you get quite a few models; I just picked one that I thought was the best.
One last thing before I go. Nessie, the Loch Ness Monster, or The Monster of The Loch, depending on your preference, would most likely be something akin to an Elasmosaurus. Many cryptozoology fanatics and websites attribute Elasmosaurus survival to the identity of the Loch Ness Monster. Is it the truth and does it exist? That is your decision to make.

06 February 2013

Some Facts About Elasmosaurus

There are tons of little factoids about Elasmosaurus that get lost in the funny history of Elasmosaurus. In fact, it almost seems as though the debacle of Cope is the main focus of many mentions of Elasmosaurus. However, there are a whole bunch (really scientific of me) of neat things about Elasmosaurus. As we have noted the neck of Elasmosaurus is extremely long. Possessing 71 cervical vertebrae (you, myself, and giraffes all have 7 cervical vertebrae), the neck was not simply a string of elongated vertebrae; it was actually just that long a neck. The vertebrae are an average size for an animal of the time, the centrum of the anterior most cervical is 2.5cm (1in.) in diameter, and they  articulated as we expect vertebrae to articulate (proper overlaps of processes anterior and posterior of the neural spine). Additionally, something we have not spent time on this week which is wonderful about Elasmosaurus, is the locomotive appendages of this large graceful (but slow of course) whale-like animal. The theoretical locomotive abilities of Elasmosaurus, and plesiosaurs in general, are very succinctly and accurately described by Adam Smith on his website. I strongly encourage reading the page. He also mentions the likelihood, there is very little to none, of plesiosaurs "walking" on land.

An image I love, though snake necked (which is just fine for the cartoon-like appearance here), that shows how streamlined the body of Elasmosaurus could be when it did get some speed. Despite all the "slow" and "whale-like" talk I think that Elasmosaurus could certainly build up some speed when it needed to; a Humpback Whale which is of comparable size can generate bursts of speed up to 16.5mph (26.5kph) when in danger. Though the locomotive abilities are not comparable it is possible, and plausible, that an Elasmosaurus could have built up some speed and would not always plod slowly through the oceans. Therefore, I really like the streamline qualities of this illustration as it shows some speed ability on the part of Elasmosaurus:
©Liz Temple

05 February 2013

Scholarly Elasmosaurs

Cope's paper on Elasmosaurus, as we all know, was originally describing an animal that was constructed in reverse in relation to how it should be represented. This appeared like this in his paper:
Academy of Natural Sciences
Cope then corrected, though he did not correct all of the paper leaving in many typographical errors and errors in reference to directions (proximal/anterior) of body parts, the image. The corrected image appeared in this manner:
Academy of Natural Sciences
Since that time other papers have come out on Elasmosaurus (Everhart 2005, Sachs 2005, Davidson 2002; to name a few recent articles) Most of these papers review other Elasmosaurus finds but some also review Cope's work and one, the Davidson paper, attempts to answer the question "How did he make that big a mistake anyhow?" Basically, the idea of that paper is that there was plenty of evidence at the time, including other known plesiosaurs, that there is not plausible reason that Cope would not have been able to put Elasmosaurus together correctly the first time. Sachs' paper redescribes Elasmosaurus while Everhart's describes characters that were missing from the type specimen using newer elements of Elasmosaurus not yet described at the time. Everhart's paper is free online; Sachs may require contacting the publisher; and Davidson's is available through BioOne with subscription to their services (my school has access that I can use).

04 February 2013

Motion Capture Elasmosaurus

King Kong. A name not often synonymous with Elasmosaurus. However, of all the battles fought by King Kong and his progeny, the battle fought against Elasmosaurus, by his "son" of course, in 1933's Son of Kong is probably one of the least talked about but most stylized in terms of the "that's a very odd animal fight" reaction of movie going audiences. The Elasmosaurus depicted was based, we can tell by the model and the combat, pretty much entirely from Charles Knight's locomotive styling in the 1897 painting he published which was shared here on Saturday. Movie clips from 1933 are hard to find sadly, so I have to make due today sharing this fantastic still:
Tail choked!
Elasmosaurus has appeared in many "hoax" films, "Nessie" of Loch Ness fame, amongst a few other worldwide cryptic species, are considered to potentially be Elasmosaurs, and has also appeared in cartoons, such as Dinosaur Train (Netflix link to the specific episode here). The Dinosaur Train episode features an Elasmosaurus named Elmer and, in terms of cartoons, is fairly accurate with concern to the current scientific views of Elasmosaurus. Elmer does still have quite a vertical neck range though that is not correct in current views. In true modern kid's cartoon fashion, there is a song that goes along with the episode:
I do love the accuracy of the teeth on the Elasmosaurus. All in all, it's a good learning experience, as far as I am concerned (I know there are some that do not like Dinosaur Train much in terms of scientific accuracy), for the sharing of information with children about Elasmosaurus. "Dr. Scott" does a great job adding in things we have discussed about Elasmosaurus after the vignette of Elasmosaurus ends.

03 February 2013

Swim With Elasmosaurus

If only we could swim with Elasmosaurus (without getting bitten I should add). Elasmosaurus has been a popular creature since it was first made known to the public (even before the corrected reprint) and as such has garnered, over the past 145 years, many, many roles in the veins of popular "dinosaurs." Unfortunately, Elasmosaurus has been considered just that, a dinosaur, for many of those years and it has taken quite a long time for the general public to even hear the phrase "marine reptile" without automatically becoming lost in conversation when the term dinosaur is not applied. Considering even I grew up hearing the term dinosaur applied to aquatic reptiles of the Mesozoic, it is not much of a surprise, but I feel we should make all efforts to make sure that even though they, the children, are reading a page called KidsDigDinos they are reading about an ancient animal that is not a dinosaur. Additionally, there is a little factoid on that page stating the flippers may have helped in terrestrial locomotion; currently it is held to be highly doubtable that any of the Plesiosauria would have been on land for any reason (other than being beached). Enchanted Learning presents Elasmosaurus without this little factoid and is actually a little more complex in its information presentation, which is nice; having more than one level of information means I get to present a more challenging fact page for good readers. There are also toys and films/cartoons that have built up over the years from highly inaccurate portrayals to fairly scientifically correct portrayals (in light of current science).

Coloring pages for today are more than plentiful. I have found accurate and inaccurate images of Elasmosaurus. I am going to say that the most accurate image that could be used for coloring belongs to Josep Zacarias (ask him if you want to use it!). However, I am just going to post the rest of the images and everyone that wants to color can choose what they want to color:

02 February 2013

Drawing Necks

One of the greatest tasks for marine reptile paleontologists since 1868 has been deducing the use of a neck like the lengthy one we find attached to the body of Elasmosaurus. Just like with sauropods, the neck of Elasmosaurus has been discussed, debated, and drawn many different ways over the past 145 years. The mystery has slowly unraveled over that time, but today we shall briefly look at the history of the interesting apparatus that is the long necked plesiosaur's neck (short necked plesiousars, examples of these are found in the polycotylid and pliosaur families, are visibly different from the long necked plesiosaurs).

Cope's original illustrations of Laelaps, Elasmosaurus, and Hadrosaurus appear nearly comical these days. The Mosasaur in the background we will leave for another day, however, the Elasmosaurus gives us plenty to talk about right now. Cope's Elasmosaurus, in his illustration, possesses the original configuration which Cope published erroneously. The exceedingly long tail is stupendous and, prior to looking at other illustrations, it is fairly easy to understand why Cope would assume that so long a column of vertebrae would be found in a tail rather than a neck. The eyes were fairly accurately portrayed in terms of position, but even the small neck would not have been as flexible as Cope portrayed it to be. The strangely small forelimbs and the fact that it is floating on the top of the ocean water are equally erroneous. That turtle right behind Elasmosaurus sure looks happy though.

Charles R. Knight 1897
Move forward nearly 30 years to Charles R. Knight, one of the most prolific wildlife (though prehistoric) painters in American history. Knight, using the readjusted skeleton of Elasmosaurus, painted this wonderful plate for a magazine published in black and white in 1897. The body, overall, is accurate even today, with the exception, once again, of that grossly exaggerated neck flexibility. It has, fairly recently, been proven and shown through models (fossil bones are usually far too fragile to actually string and grind together) that the neck of a plesiosaur, especially this very long neck of Elasmosaurus, was not able to perform the snake-like strikes that are often depicted in older illustrations such as this one. The vertical position of the body of the second Elasmosaurus is also quite odd, though of course it would be able to swim vertically at times. The strike posture it seems to be taking in this image, though, is rather bird-like or snake-like and would probably have been difficult to maintain for any length of time (not to mention the inability of the animal to strike like a snake as previously mentioned).

Find me an artist, win a cookie!
Enter the modern era. Elasmosaurus and other plesiosaurs have been updated from the dolphin like ballerina-swimmers making quick snake like strikes to graceful, yet slower, swimmers which possessed long but horizontally inflexible necks; vertical flexibility was a bit larger in range, though not as much as Knight and Cope depicted. Now Elasmosaurus is thought to have catch small fish and, by some, crunch down on some small shelled animals. Its slow but graceful swimming habits have been described many ways, as there are many models of the swimming mechanism which may have been present in these large plesiosaurs. Often, though, it is depicted as a rowing motion, a penguin-like flapping, or even a hummingbird-like figure eight motion. Regardless of which version of locomotion is favorable, catching fish like a plesiosaur would have involved a bit of stealth in striking from below, using the long neck as a way to get the head close without the body being seen by the prey. A concerted effort of many plesiosaurs circling and balling up prey to invoke a "feeding ball" (if anyone else has used the term I do not know of it so I am claiming it as my own for now) is another alternative means of feeding. This would involve a gathering of fish forced  into a large living and writhing mass by circling predators which the plesiosaurs could then dart into, at their slow speed even, and grab fish.

01 February 2013

Your Head Is On Backwards

Starting this set of months off correctly. As a background for those of you who do not know what I am doing these days, I am in graduate school, changing careers a bit, and working on getting a master's degree in biology. My project is describing and identifying a series of vertebrae which were unearthed in southern Kansas. Due to the nature of Kansas during the Cretaceous, these are most likely marine reptile vertebrae, and, to celebrate the arrival of the specimen and beginning of my work on them, the next two months will all be about marine reptiles and fish.

©Michael Skrepnick
The first skeleton of Elasmosaurus platyurus was unearthed and delivered to E.D. Cope in 1868. Cope, in his excitement, and the absolute secrecy with which he examined the skeleton, at the revelation of the skeleton, originally placed the skull on the caudal vertebrae and left the cervical vertebrae to stretch out "behind" the animal as an exceedingly lengthy tail. Contrary to popular belief Cope actually caught his mistake at about the same time as Joseph Leidy (Leidy did not discuss his revisions of the specimen with Cope) and attempted to rush a reprinting of his announcement of the skeleton and its official description. The reprinted, and filled with errors, republication was even in circulation prior to the Marsh publication on Elasmosaurus which many attribute to the popular myth of Cope being embarrassed by Marsh about Elasmosaurus. Regardless, the long thin neck of Elasmosaurus is somewhat cryptic as a neck as is; it is far more slender than one would expect for a long organism like Elasmosaurus is and could be fairly easily mistaken for a tail (Everhart 2005). The long neck, in fact, possessed 71 cervical vertebrae; nearly 4 times the amount of vertebrae belonging to the tail (there are 18 caudal vertebrae). At approximately 12m (40ft) Elasmosaurus could have weighed in at nearly 2000kg (2.2tons).

Elasmosaurus, being a long necked plesiosaur, was a carnivorous creature living in a near shore environment in the Western Interior Seaway of what is now North America. At the time the Western Interior Seaway cut what is now North America in half, creating two continents (Appalachia in the east and Laramidia in the west) and the shallow ocean was the home of a multitude of species. This large number of species, especially of smaller (and hence lower on the food chain) fish and invertebrates, led to an explosion in larger predators as well, of which Elasmosaurus was one. How is it such a successful predator? We shall examine this over the next week, starting tomorrow morning.

Everhart, M. J. (2005). Oceans of Kansas - A Natural History of the Western Interior Sea. Indiana University Press, Bloomington, Indiana, 344 pp.