Fossil Friday, Going Swimmingly
No one guessed what the fossil for this week was. Take a look at the image below and see if you can figure out who this vertebra belongs to before continuing on after the image. As you may have deduced from the title of the post, it is an aquatic animal.
This is not the lizard you’re looking for.Platecarpus. Wikimedia.
This fossil is a really nice dorsal vertebra of a giant marine reptile. Most of the ones usually found in Arkansas are mosasaurs, but this one is different. It lived at the same time as the mosasaurs, placing it in the Late Cretaceous Period. As with all other Late Cretaceous fossils in Arkansas, it was found in the southwest corner. Specifically, it was found near Saratoga, Arkansas in Howard County by local resident Matt Smith. Interestingly, the very same spot has also turned up several nice mosasaur fossils, so it was a popular place in the Cretaceous seas. It shouldn’t be too surprising though, as it was a nearshore environment in a tropical climate much like the Bahamas today, so there would have been lots of good eating for hungry marine predators.
Elasmosaurus
Ok, enough of the teasing. The vertebra we have here is that of a plesiosaur known as Elasmosaurus. These are classic marine reptiles that most people are familiar with to some degree. They have sometimes been described as looking like a snake that swallowed a sea turtle because of the relatively wide bodies with oar-like flippers and a very long neck. They are thought to have spent much of their time slowly cruising the seaways, using their long necks to catch fish unawares. some people have even suggestd that they floated at the surface of the water with their head out of the water, so that fish could not see it, allowing them to plunge their head down into the water and catch fish from above. That is pure speculation though. Right now there is no way to really test such hypotheses, so feeding methods remain in the realm of speculation until such time as someone figures out a way to test it adequately. At the moment, biomechanical tests indicate that either method would have been possible.
Mosasaur vertebrae. Note the rounded left end.
So if you find a vertebra like this, how do you tell whether it is a mosasaur or plesiosaur vertebra? They can both be large, although the one pictured here is the largest one I have ever seen found in Arkansas. The best way to tell is to look at the ends of the centrum, otherwise known as the body of the vertebra. Most of the time, that is all that is preserved, as all the processes that stick out have been broken off, like we see in this one. Plesiosaur vertebra have flat, possibly even slightly concave, or indented ends. Mosasaurs, on the other hand, have what is known as procoelous vertebrae, which have one end convex, a bit more rounded off. These differences make mosasaur vertebrae look more like over-sized lizard or croc vertebrae, whereas plesiosaur vertebebrae look more like the disc-like vertebrae seen in fish. This may mean that plesiosaurs were more adapted for aquatic life than mosasaurs. Both were clearly fully aquatic, what with neithr one of them having legs of any sort, but plesiosaurs appear to have been aquatic for longer, giving their spine to more fully adapt.
Indeed, when we look at the age of the rocks their fossils have been found, mosasaurs are restricted to the late Cretaceous, whereas the plesiosaurs first appeared all the way back in the Triassic (another successful prediction based on evolutionary theory). This means plesiosaurs had well over 100 million years advance on the mosasaurs. It didn’t really help them in the end though. About the time mosasaurs appeared, plesiosaurs were declining. Mosasaurs evolved and spread quickly, becoming the dominant marine predator of the Latest Cretaceous. Does this mean that mosasaurs outcompeted the plesiosaurs? Not necessarily. It has not yet been sufficiently determined whether or not mosasaurs simply filled a niche left open by the plesiosaur decline or competitively excluded them. there is also the argument to be made that they would not have competed at all. The body shapes of mosasaurs and plesiosaurs are quite different, indicating they filled different niches in the marine realm, so they weren’t going after the same food sources. Therefore, there is no particular reason we know of that they could not have existed alongside each other without adversely affecting each other.
Nessie picture collection by Darren Naish, Tetrapod Zoology, July, 2013.
Most people are familiar with them due to the much discussed “Loch Ness Monster”, which has often been said to be a supposed plesiosaur that has somehow survived for 70 million years. Of course, that idea doesn’t make a lot of sense for several reasons. It is highly unlikely that plesiosaurs could have lived for so long without leaving any trace of a fossil record. It does happen occasionally though. The coelacanth is a famous example of that, for a long time having a good 65 million year gap in their fossil record. They were thought to have gone extinct along with the dinosaurs until living specimens were caught. We know more about them now and their fossil record is no longer quite as limited as it once was, but it still has wide gaps in the fossil record. But more serious problems for Nessie arise from the fact that plesiosaurs were large, air-breathing marine reptiles. Coelacanths went unnoticed because they moved to the bottom of the sea, an option not available to plesiosaurs, which were limited to surface waters, and relatively shallow waters at that. That means they lived in exactly the sort of marine environments most visited by humans. That makes it hard for them to hide from people today and puts their bones in prime spots in the past to fossilize. Then of course, there is the problem that Loch Ness is a freshwater lake and plesiosaurs were adapted for saltwater. Not to say a species couldn’t have adapted for freshwater, but it does make it less likely. Finally, there would have to be enough plesiosaurs big enough to support a breeding population and there is simply no way they could all hide within the confines of a lake, especially since they have to live at the surface much of the time.
But what about the supposed bodies that have been found of plesiosaurs? They have all been identified as decomposing backing sharks. Basking sharks are one of the largest sharks known today. they are pretty harmless though, as they are filter feeders, much like the whale shark. When their bodies decompose, the jaws typically fall off pretty quickly. So what has been identified as the head of a “plesiosaur” was actually just the remaining portions of the cartilaginous skull without the large jaws. If you look at the picture of the asking shark here, there isn’t much left after you remove the jaws.
Next week is Labor Day on Monday, so I will likely not post a new fossil next week. I will post something next week, just not a mystery fossil. But there will definitely be one the following week, so please come back to see the next fossil and see if you can guess what it is before Friday. In the meantime, enjoy your vacation.
Mystery Monday Returns
Welcome back! the new school year has started for most, if not all, people by now. Everyone is busily trying to figure out new schedules, new curricula, new people, sometimes even new schools. Changes are everywhere this time of year. Paleoaerie is no exception. We didn’t get quite as much done over the summer as we would have liked (does anyone?), but it was an interesting summer, filled with good and bad. To start with the bad, the UALR web design course that was initially going to work on revamping the website is no more due to unexpected shakeups at the school. Nevertheless, a different course will take a look at the site and see what they can do, although they sadly won’t have as much time to deal with it.
But there was a lot of good that happened. Big news for Paleoaerie is that we are now partnered with the Arkansas STEM Coalition, a nonprofit advocacy group for STEM education within Arkansas. This is really important for us because this means Paleoaerie now operates as an official nonprofit organization. What does this mean for us and you? It means that any donation to the site is tax-deductible. It also means that many grants that we could not apply for before are now within possible reach. Fundraising should be a bit easier from now on, which means we may be able to do much more in the upcoming future. One of the things we will be doing in the near future is a Kickstarter campaign to buy a 3D laser scanner so that we can start adding 3D images of Arkansas fossils onto the website, which will be available for anyone to use. One might ask why not use some of the cheap or even free photographic methods that are available. In a word: resolution. I’ve tried other methods. When one is attempting to make a 3D image of an intricate object only a few centimeters across, they don’t work well. If you want details to show up, you need a better system. Stay tuned for that.
Paleoaerie is also partnering with the Museum of Discovery and the University of Arkansas at Little Rock for a National Fossil Day event on October 11. Make sure to mark your calendars and come out to the museum to see the spectacle and diversity that can be found in Arkansas. There is much more than you think. We are also working with the museum on a new dinosaur traveling exhibit. It is very cool, so watch for it later this fall.
The last big news that happened recently is today’s Mystery Monday fossil. Someone brought me a fossil to examine a couple of weeks ago. The first amazing part of it is that is was actually a fossil. the vast majority of what people show me are just interestingly shaped rocks. This was a bona fide fossil. Not only was it a fossil, but a really cool one. The image below is a vertebra from a little seen animal in Arkansas and not at all for a very long time. The fossil is roughly 100 million years old, putting it in the Cretaceous Period. At that time, Arkansas was on the shoreline of the late Cretaceous Interior Seaway. Take a look at the image below and see if you can figure out what it came from. I’ll let you know what it is Friday. Thanks to Matt Smith for bringing this wonderful fossil to my attention. Come out to the National Fossil Day event and see it for yourself.
Who Ya Gonna Call? Mythbusters?
Adam Savage and Jamie Hyneman of the Mythbusters do a great job of presenting commonly held myths and testing them in a variety of ways, trying and adjusting and retrying experiments. They even sometimes revisit myths with a new point of view and new questions. It is this that I think is the key to their success. They present science as a series of questions and experiments, revising and retesting, a dynamic process. Starting with what people believe and then presenting the evidence to show the real answer is an important part of the educational process. Derek Muller, who runs the Veritasium Youtube channel, did his PhD dissertation on just this topic, showing that simply providing the information did not increase learning. Unless the misconceptions the audience already held were first acknowledged and dealt with, people thought the material was clear and that they understood it, when in fact they had learned nothing at all.
All of this involves asking lots of questions. But what some teachers view as a downside to this approach (although it absolutely is not) is that invariably you will wind up with lots of questions you can’t answer. Your students will ask questions you have no idea what the answer might be. So what do you do in this case?
Hopefully, you already knew which of these options is the better choice. But where do you go to learn more? Some questions can be rather esoteric or have answers that can’t be easily looked up. Fortunately, hordes of scientists are at your beck and call to save the day. Here are four websites where you can ask real scientists any question you like. None of the scientists on these sites will do people’s homework for them, but are enthusiastic about answering questions.
Ask a Scientist has 30 scientists that will answer questions on biology, chemistry, physics, space, earth and environment, health, technology, and science careers. In addition, they have links to videos for some questions. You can look at answers to past questions and ask your own. Even though it is based in the United Kingdom, with all the scientists being from the U.K., they will answer questions from anyone.
This site is also based in the United Kingdom, but has scientists from all over the world. This site is limited to biology and paleontology, but it has over 100 scientists who can answer questions. Some are doctoral students, some are the tops in their field with decades of experience. All of them are experts in what they do and all of them are there to help. They have answered thousands of questions, all of which can be searched and read. If you don’t find what you are looking for, ask your own question. You might even find that you have started a lengthy discussion of your question between several experts, as has happened from time to time.
This Ask A Biologist is a National Science Foundation grantee and is hosted by Arizona State University. Again, it is limited to biology and is run by the biology faculty and graduate students of ASU. So on the one hand, you might think they might be more limited. But ASU has an extensive biology department and this site has much more ancillary material than most of the others. They have activities, stories,coloring pages, tons of images, videos, and links to other information. They have a teacher’s toolbox, providing easy searches for teachers to find exactly what they want, searchable by topic, activity, and grade level. In short, while they have several scientists available to answer questions, that is but one aspect of this educational site.
The Mad Sci Network has a huge amount of information. You can ask a question about anything. The site has experts from world class institutions available to answer questions. They have a searchable archive of over 36,000 questions already answered, so they may have already answered your question. In addition to the search features, they have several categories listed, in which you can pull up all the questions in those categories. They have a “Random Knowledge Generator” if you just want to have fun browsing at random. They also have a series of what they call “Mad Labs”, which are activities and experiments you can do at home or in the classroom. They have links to more information and resources elsewhere, including general science, educational methods and techniques, museums, science fairs, suppliers, and more.
So there you have it. When you are faced with questions you can’t answer, don’t try to bluff your way through. Who ya gonna call? Hundreds of scientists from around the world, that’s who.
How Big Is Your Favorite Dinosaur? Find Out Here
Dinosaurs Life Size
By Darren Naish
Publication Date: 2010
Barrons Educational Series, Inc. ISBN: 978-0-7641-6378-4.
Author: Darren Naish is a well respected paleontologist publishing on all manner of dinosaurs, marine reptiles, pterosaurs, and other extinct animals. While he has published several notable scientific papers, he has also written extensively for the general public, ranging from children’s books to books for the educated layperson. In addition to this book, Naish published Dinosaur Record Breakers, another good book that kids will find interesting. He has also published on cryptozoology, the mostly pseudoscience study of “hidden” creatures, such as Bigfoot and the Loch Ness monster, debunking a variety of mythical creatures and discussing more plausible alternatives. You can also always find him at his highly regarded and widely read blog, Tetrapod Zoology, on the American Scientific blog network.
Dinosaurs Life Size came out a few years ago, but it is still a decent book for kids. I can’t say good for reasons discussed below, but it is better than many and has mostly good information. Don’t get it confused with the book of the same name by David Bergen, which came out in 2004. Naish’s book is much more up-to-date and scientifically accurate, having the advantage of having been written by an active researcher in the field who knows what he’s talking about. Not to criticize Bergen’s book as I haven’t read it, but if you were going to choose a book that was a decade old written by a non-expert or a book a few years old written by an expert who also happened to be a professional writer, which would you choose?
The book begins with a short introduction to dinosaurs and the book. A fold-out timeline follows, which puts all the animals discussed in the book in its appropriate place in time. The timeline includes a brief description of each period within the Mesozoic Era, commonly known as the Age of Dinosaurs. The meat of the book is a generally two page description of 26 different animals. Each animal gets a brief discussion of what it looked like, where it lived, and a few interesting factoids that have been pulled “from the bones” as a section for each animal is called.
Of course, the main draw of the book are the size comparisons. These are handled in two ways. Each animal is illustrated in full view alongside a young kid for scale. Almost all of them also have a drawing of a body part in real size, which really puts into glaring contrast just how big (and tiny) some of these animals were. Herrerosaurus has a hand, Lesothosaurus has its head for scale. At the extreme ends, Sauroposiedon has an eye and Argentinosaurus has a toe while Microraptor and Archaeopteryx are small enough to be drawn in their full glory. Most are covered in two facing pages, so that every turn of the page presents a new animal. A few are presented on fold-out pages, although I am unclear as to why because only one actually takes advantage of the extra space to present its animal. the other one just puts two animals instead of the standard one.
After the animal descriptions is a fold-out page with a dinosaur quiz to test the reader on what they learned. this is followed by a short discussion of what fossils are, how they are formed, how old they can be, how they are found, and a couple of famous fossil examples. The book ends with a glossary and index. All told, there is plenty of solid information for the young reader who will gaze in wonder at the dinosaurs and at least some will enjoy testing themselves on the quiz.
The book has good information. I particularly like the pictures of a globe marking where each one is found. The illustrations of the life size bits give a good indication of the actual size of the animal. I like the pictures of real fossils and the bits of information about what has been found through their study. The book is very visual and should appeal to kids. The book is listed as being most appropriate for kids in grades 2-6, which I think is a pretty fair assessment. Advanced readers in first and second grade will like it, but will be bored by it by the time they get out of elementary school, but most kids in the 3-5 grades will like the book.
There are only SIX dinosaurs here!
I do, unfortunately have some serious complaints about the book. First and foremost, the book is called “Dinosaurs Life Size”. I would prefer books labeled as such stick with dinosaurs. Despite knowing better, Naish chose to include descriptions of Plesiosaurus, Stenopterygius, Liopleurodon, Pterodactylus, and Quetzalcoatlus; none of which happen to be dinosaurs. You may notice that this leaves only 21 actual dinosaurs. A better title would have been Mesozoic Reptiles Life Size, but I can understand that probably wouldn’t sell as well. Still, it is misleading. What I cannot forgive though, is that he does NOT clearly identify them as non-dinosaurs. This is such an unforgivable sin that I am tempted to tell people not to get this book. The only place he indicates they are not dinosaurs is ONE sentence in the introduction. Naish has published research on all of these animals, he certainly knows better, so this is unpardonable.
Yep, even some of these dinosaurs had bristly “feathers”. Mark Witton
The next complaint I have is in the illustrations themselves. Some of the dinosaurs are noticeably absent of feathers. The Gallimimus is bare, except for a tuft at the top of its head. Part of this an be forgiven by the enormous advances that have been made due to new discoveries in the few short years since publication of the book. But even in 2010, we knew more dinosaurs were covered in feathers much more than is shown in this book. It is possible that feathers of some sort were an ancestral condition of ALL dinosaurs, so the bareness of some of these illustrations is wrong, even for the information he had at the time, so why the drawings were done this way is beyond me.
The average human height is 5′ 6.5″. Yes, that’s descriptive of the species.
The last complaint I have is in the sizes. Each description is given a word description of how big each animal is. But the pictorial comparisons with the children are not the best. There is only a rough idea of how big the children are, which one is forced to base entirely on one’s experience with kids as there are no scale bars in any of the pictures. For a book about size, this is an inexcusable oversight. I have personally seen kids of a similar age who were between three feet and five feet. Now imagine extrapolating that difference to an animal that is thirty times that size and you can see the immense errors involved. Admittedly, there is a lot of uncertainty in the actual sizes of many of these animals (there are pretty much no complete sauropod tails, for instance, so determining length is problematic). But this book neither mentions anything about the uncertainties involved and then complicates the issue with further uncertainties in the illustrations while giving exact measurements in the written description.
So, in conclusion, I cannot fully support this book as there are too many serious problems. However, it is still better than many others on the market and does have solid information in the texts. The pictures give a rough idea of sizes, which for the age the book is geared towards is reasonable. But it is inconsistent with the sizes between the text and the illustrations; the illustrations themselves are not always accurate in terms of what we know about feather coverings, thus showing somewhat antiquated pictures of dinosaurs; and the book is really about Mesozoic reptiles, not dinosaurs anyway. Thus, the best I can do is give it maybe 3/5 stars, which pains me deeply because Darren Naish is a truly smart, well-read, and knowledgeable person who otherwise has written lots of great material.
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