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I was reading a post by Brian Switek on his blog Laelops—which by the way, if you aren’t reading it, you should—about interpreting injuries on dinosaur bones. It’s an interesting read, but what caught my eye was a problem that I have seen in more places than I can count. He included this picture in his post. Take at look at the front limbs.
The “hands” are pointed inwards. To get in this position, the elbows have to be turned outwards, using a rotation in the shoulders. But it also requires the hands to be pronated. To get what I mean by that, hold your hands forward with the palms up. When you do this, the two bones in your forearms—the ulna and the radius—are positioned side by side.
This position is called supination. Pronation requires the radius to rotate so that it crosses over the ulna. This can be done because of the construction of the elbow. The ulna is essentially the entire elbow joint, making it a hinge type joint. The radius is, for the most part, just along for the ride at the elbow. The head—the part at the elbow—is round, with a shallow indentation, which is surrounded by what is called the annular ligament. That ligament wraps around the radius, attaching it to the ulna, but never actually attaching to the radius itself, allowing the head to spin in the sling. It is that shape of the radius and the annular ligament that allows it to rotate freely, which makes our level of pronation possible.
Importantly, all tetrapods have the same bones. It was set in place from the first fish that developed bones to support their fins and remains that way all through the hundreds of millions of years to us today. However, not all animals have the same shape of the radial head. Some animals appear to not have both bones, but in reality, they do. They have just fused the bones together. But that fusion has consequences, just like altering the shape of the radial head.
Before we move on to dinosaurs and those consequences, it would be reasonable to ask about other animals to see if they show the same pattern. Let’s take a look at proboscideans, the family of elephants. They are large animals that have their palms facing downward.
This is an elephant skeleton on display at the Manchester Museum. They have a radius and ulna, just like humans. Theirs, however, do not swivel. Nevertheless, it is rotated so that the bones are not in parallel, but the two ends are twisted so that the radius is twisted over the ulna. Their forelimbs are in permanent pronation.
So what about dinosaurs? Let’s look at Dreadnaughtus, the giant sauropod.
This is Figure 2 from Lacovara et al. 2014. The radius and ulna are massive, as befits a giant quadruped. They are also incapable of rotating to pronate the foot. It has been said by some that some degree of pronation is required for efficient quadrupedal locomotion, but that is not really accurate. It does mean though, that the first digit, what would be our thumb, is going to face forward or at most slightly inward while the remaining digits will be angled outward (anterolaterally). They will not be situated directly forward without shifting the arms at the shoulder. As an example, here is a figure showing a sauropod trackway. Note the direction of the toes.
This is a figure from Falkingham, et al. 2010. As can be seen, the toes are not forward, but pointing outward. The level of pronation is minor and can be achieved with only rotation at the shoulder and a minimal shift or the forelimb. VanBuren and Bonnan (2013) found this was true in all quadrupedal dinosaurs.
This is a best case for pronation in dinosaurs and they can’t do the full pronation needed for bunny hands, much less the bizarre inward facing hands of the Plateosaurus above. So let’s look at theropods, where we see bunny hands all the time. For instance, in Jurassic Park pretty much all the dinosaurs have bunny hands.
The palms are downward with the arms close in, requiring a full pronation to achieve that position. So could they do it? To the bones. This is the radius of Neuquenraptor, as published by Novas and Pol in 2005. It is an unenlagiin, in the family Dromaeosauridae, along with Velociraptor, Deinonychus, and all those other raptor dinosaurs.
These radius is fairly straight, and if you look at the head, it is not the shallowly indented round cup we see in mammals. It is more angular, which is typical of theropods. That relative angularity would prevent the radius from rotating as ours do, in effect locking it into a small range of motion, preventing them from placing their hands palm down.
In point of fact, VanBuren and Bonnan didn’t just look at sauropods. They looked at all types of dinosaurs. They found that no dinosaur had the ability to cross the radius over the ulna, which means that at best, they had very limited ability to pronate their forearms. That means no known dinosaur could have characteristically held their arms close in with their palms facing downward, aka bunny hands.
It is a little more complicated than this. Studies have shown that if the arm is fully extended, the hands can be more pronated, by using the entire length of the arm to rotate, but even that is not going to be fully pronated like we can, or bunnies can. And if you think about the living dinosaurs, the birds, when was the last time you saw a bird put its wings flat on the ground in front of them? They can clap, but they can’t type or play basketball.
Of course, the wrist bones of the maniraptors—those dinosaurs leading up to birds—did have what is called a semilunate carpal bone, allowing them to move their hands to insane degrees side to side, which is what allowed them to develop the ability to fold their wings like they do, and they can flex and extend their hands to a remarkable degree. But they cannot rotate their wrist. Try it yourself. See what movements you can make with your hand without moving your forearm, just your hand. However far you can move your hand that way, these dinosaurs have you beat in spades. But once you move that forearm, you have a serious advantage over them.
There are a number of things going on in the Arkansas legislature right now that deserve attention here. The first thing I want to mention is that Arkansas now has its own official state dinosaur.
On February 17, 2017, Governor Asa Hutchinson approved House Resolution 1003 to list Arkansaurus fridayi as the official state dinosaur. This bill was pushed by a high school kid named Cypress Oury and sponsored by Greg Leding, AR House representative for District 86. As those of you who have been here before may remember, Arkansaurus is the informal name of the only dinosaur ever found in Arkansas.
Unfortunately, we only have half of one foot, so identification has proved elusive. The best that can be said is that it is some kind of primitive coelurosaurian theropod. It is not as derived as tyrannosaurids and certainly not a maniraptoran theropod or any of the others near to the avian line. Thus, while the new drawing by Brian Engh above is better than previous versions, it is highly speculative. The arms are almost assuredly wrong and should be longer. We don’t know if it had feathers or not. It likely did, but those feathers would have been unlikely to be as long as those shown in the drawing. They would more likely have been shorter and fuzzier. This is not to say the feathers Brian Engh drew are wrong, they are certainly plausible, but a bit more advanced than is likely for a coelurosaurian that far down the family tree.
When picking a state dinosaur, Arkansaurus is certainly the most likely candidate, being the only one with an actual body fossil. But it was not the only candidate. Arkansas is known for having some spectacular dinosaur trackways. The tracks include two types. The very great majority are from a large sauropod, possibly Sauroposeidon (or depending on the taxonomy one follows, Pleurocoelus or Paluxysaurus, which may or may not be all the same or all different). Since Sauroposeidon is one of the largest known dinosaurs, this would have made a fine candidate, but the taxonomic uncertainties and the lack of actual body fossil material make it less viable. The other possibility if Acrocanthosaurus, an almost sail-backed theropod related to Allosaurus. Unfortunately, while we have footprints, we have no actual bones of this one either. We only presume it was the track maker because there have been fossils of it found in both Oklahoma and Texas and it is the only theropod of the right size known in the general area.
That is the good news. Sadly, there is also bad news. The Arkansas legislature is on a religious kick these days, proposing a number of unconstitutional bills. One such bill is HB 2050, “An act to amend the Arkansas code to allow public school teachers to teach creationism and intelligent design as theories alongside the teaching of the origins of the earth and the theory of evolution; and for other purposes.” They always add “and for other purposes,” no matter what the bill is, just to cover their butts. This bill is clearly unconstitutional, as already decided by McLean vs. Arkansas Board of Education in 1982 and Ktzmiller vs. Dover Area School District in 2005. As Judge Overton said in 1982, “No group, no matter how large or small, may use the organs of government, of which the public schools are the most conspicuous and influential, to foist its religious beliefs on others.” The theory of evolution is one of the best supported by mountains of evidence and exhaustive, thorough research of any scientific theory currently accepted by science, whereas creationism and intelligent design fail all efforts to make them remotely scientifically plausible. The idea they can stand side by side with the theory of evolution as valid scientific explanations in a science classroom is an insult to all thinking people.
Then there is SJR7, by Senator Jason Rapert (the same man who, among other things, was responsible for the Ten Commandments monument being built on the Capital grounds), calling for Congress to propose an amendment to define marriage as between one man and one woman. Because the Supreme Court of the United States has already made same-sex marriage legal throughout the country, the Arkansas legislature wants Congress to overturn their ruling. This is based on their religious beliefs and ignores a number of facts, such as it not actually being supported by the Bible, it violates the First Amendment by pushing a specific religious view onto everyone, and most importantly for our purposes here, ignores biological reality (and why I am talking about it here). Humans are not just male and female. There are several ways that genetics and development can intertwine that cause a mixture of male and female, making separation into a binary sex impossible. This bill would make it illegal for them to marry at all. Moreover, the bill does not define “man” or “woman,” making it ambiguous whether people who are biologically one sex, yet identify as the other, are banned from marriage. Considering that what gender one identifies with and is attracted to has a strong biological underpinning and is not a “lifestyle choice,” there is little to make this bill viable through any explanation other than prejudice.
In relation to that bill is SB346, by Senators Greg Standridge and Gary Stubblefield is a bill to require people in public schools to use the bathrooms that match their biological sex. To begin with, these two senators do not know the difference between gender (sociological) and sex (biological). Secondly, they have no answer for intersex individuals who cannot be easily classified as male or female other than they are not allowed to go to the bathroom at all, which has been the unfortunate situation at some schools for transgender children. This bill was pulled, but another was filed by Senator Linda Collins’ Smith targeting government buildings. Apparently, the backlash from the state LGBT supporters, business owners, and the governor were not sufficient to dissuade the legislature they needed to act against an imaginary scourge.
And of course, this list would not be complete without trying to make the Bible the official state book, as attempted by Rep. Tosh in HR 1047. He, of course, touts the myth that “the Bible form the basis upon which our modern civilization is structured,” pretending that he is simply supporting the Bible for purely historical reasons. He goes on to say that the Bible is “considered by many to be a book of truth,.. is widely read,” and why not throw in that we have a bunch of other state symbols, why not a religious book too?
All of these bills at the very least face constitutional challenges and have already been ruled as unconstitutional in other court battles. All this will do is cost the state a fortune in legal bills and drive away tax dollars as businesses leave the state and tourists opt to go elsewhere. Moreover, it seriously harms science education as we continuously have to battle this form of ignorance.
UPDATE: Now that the legislature has finished this session, how much damage did they get done? In terms of what has been mentioned here, not a lot, thankfully.
HB 2050: This bill to allow creationism in the schools died on the vine. It was referred to committee, but the author of the bill never provided a full bill for the committee to read, so the session ended without further progress, meaning that the process will need to be started from scratch next year. WIN
SJR7: This resolution to ask the US Congress to approve an amendment to the constitution making marriage as between one man and one woman failed to pass after three attempts. The truly scary thing is that it got 50 votes, only 1 short of passing. WIN
SB346: The notorious bathroom bill never made it out of committee. WIN
HR 1047: The House resolution to make the Bible the official state book passed the House with a unanimous vote. Yes, you read that right. Not a single representative voted against it. Thankfully, this was only a resolution with no legal authority and the Senate will not vote on it until the next session, but still. Of course, what can one expect in a state which still says in the state constitution that an atheist cannot hold public office nor be considered competent to testify in court? LOSE.
In other news, HB 1040 prohibiting Sharia law from being enforced passed both houses of the legislature and signed by the Governor. The irony of this is that it was never legal in the first place. Our legal system just doesn’t work that way. This was just another bill to demonize Muslims. LOSE.
If you are teaching in a college, pay close attention to your students and don’t rile them up. A new law passed by the legislature and signed into law allows students to carry guns on campus, but good news, they still are not allowed to bring them into football stadiums because allowing them to do so might jeopardize Arkansas’s standing in the Sun Belt conference. Seriously.
A couple of weeks ago, I visited Dodd Elementary in Little Rock. After I left, the students wanted more information and sent me several questions. I thought, rather than respond to them individually, I would post the answers here.
Did saber-toothed tigers live at the same time as mammoths in the Ice Age? How old are mammoths?
Yes, they did! They even lived together in Arkansas during the Ice Ages, along with the more commonly found mastodons (which were like the mammoths, but a bit smaller (about the size of modern elephants) and were more adapted for forests than the grassy plains preferred by the mammoths.
What most people refer to as the Ice Age was in fact a series of almost a dozen times in which the glaciers expanded to cover much more land than they do now. This period lasted from about a million years ago to 11-12,000 years ago during what is called the Pleistocene Epoch.
There were actually many different species of saber-toothed cats. The most commonly known is one called Smilodon, which lived between 2,500.000 years ago to about 10-12,000 years ago.
The first mammoths appeared around 6,000,000 years ago, but the Woolly mammoths and the Columbian mammoths (the type that lived in Arkansas), first appeared about 400,000 years ago. They came south from Canada into the United States about 100,000 years ago. While they died out in North America almost 12,000 years ago, there were a few that lived on Wrangel Island near Russia until less than 5,000 years ago.
I wanted to know if cavemen were alive because didn’t the dinosaurs eat them?
All the dinosaurs (except birds) died out over 65,000,000 years ago, but the first humans only appeared around 200,000 years ago. So humans and dinosaurs were separated by an enormous amount of time and never lived together. Humans did live alongside the mammoths and saber-toothed cats during the Ice Ages, though. Humans killed and ate mammoths and humans and saber-toothed cats killed each other (we don’t know if humans ate the saber-toothed cats, but we’re pretty sure they ate us).
How old is coral?
Coral is very, very, old. The first corals appeared over 500,000,000 years ago. However, none of these early types of coral still exist. They all went extinct (died out) and were replaced by types of coral that evolved (descended) from them. The modern corals that you can see today first appeared in the Triassic Period roughly 200,000,000 years ago (the first dinosaurs appeared about 240,000,000 years ago).
How big is a T. rex egg?
No one knows! No T. rex eggs have ever been found. We can guess they were up to a foot long and up to five inches wide, but that is just a guess based on what we know of eggs that have been found from its distant relatives. What we do know is that T. rex babies were a lot smaller than the adults would have been no bigger than a small turkey.
How long is a sea spider?
Sea spiders, or pycnogonids (pic-no-go-nids), can grow up to 25 cm (10″). They can be found in the southern oceans today. Fossils of sea spiders are rare, but have been found as far back as the Cambrian Period almost 500,000,000 years ago. Even though they look something like spiders, while they are arthropods like spiders, they are not really spiders and occupy their own group within the arthropods. They are very strange animals, with most of their organs in their legs.
I think you may have been referring to a different animal though, the sea scorpions, which was part of the fossil collection we saw in class. Even though they are called scorpions, they are not true scorpions, although they are related to them. These animals, called eurypterids (your-ip-tur-ids), were mostly no more than 30 cm (12″), but could get almost 2.5 meters (8′), making them the biggest arthropods ever known. The earliest fossils we have found were dated at 467,000,000 years, but they may have first appeared over 500,000,000 years ago. They died out at the end of the Permian Period just over 250,000,000 years ago, along with most of the life on the planet at the time.
What is the shortest sea dinosaur?
While there were sea-going reptiles, there were no sea-going dinosaurs that we know of. The closest that we know of right now were the spinosaurs, which spent much of its time wading in relatively shallow water. These dinosaurs were huge, some of them approaching 15 m (50′) or more, with the smallest ones only a modest 8 m (26′).
Of the sea-going reptiles, the most common ones were the dolphin-shaped ichthyosaurs (ick-the-o-sores), the lizards called mosasaurs (literally lizard, they evolved from monitor lizards like the Komodo dragon), the generally short-necked and big-headed pliosaurs (ply-o-sores), and the long-necked plesiosaurs (please-e-o-sores, for the purists, plesiosaur can also refer to both pliosaurs and the more traditional plesiosaurs because the larger group containing pliosaurs and plesiosaurs is named after the plesiosaurs. yes, it is a bit confusing). And of course we can’t forget the sea-going crocodiles called metriorhynchids (met-re-o-rine-kids).
The smallest ichthyosaur, or “fish-lizard” named Cartorhynchus (cart-0-rine-cuss) was less than 0.5 m (15″) long. it was also the oldest known one at almost 250,000,000 years old. You may notice that the picture below says the smallest was 70 cm, but an even smaller one was found.
Dallasaurus (“Dallas lizard”), the earliest known mosasaur, was also the smallest mosasaur at no more than 1 m (3′).
The smallest plesiosaur was just over 1 m (3′).
Thalassiodracon, or “sea dragon”, probably the smallest known and most primitive pliosaur, was 1.5-2 m (5-6.5′), so slightly bigger than its relatives, the plesiosaurs. All of the marine (sea-going) crocodilians were more than 2 m (6 ‘) and would have eaten the others, so we can rule them out for shortest marine reptile from the Mesozoic Era during the age of dinosaurs.
There is another group of marine reptiles that was also common during the Mesozoic, although they are not so widely known. The thallatosaurs, which literally means “ocean lizard” were as small as 1 m (3′). Finally, there was a sea turtle-like group called placodonts, of which the smallest were just under 1 m (3′).
Notice that most of them all start off at roughly 1 m, except for the ichthyosaurs, which started off at less than half of that, so the winner for shortest sea reptile of the dinosaur age is the ichthyosaur named Cartorhynchus.
What is the longest sea dinosaur?
The undisputed king of the marine reptiles was the ichthyosaur named Shonosaurus, also known as Shastasaurus, which reached 23 meters (75 feet).
The longest mosasaur is, coincidentally, Mosasaurus itself, potentially reaching lengths of 18 meters (59 feet), so not as big as Shonosaurus. This animal used to live in Arkansas. According to the most official statements, the mosasaur in Jurassic World was 22 meters (72 feet), so bigger than the real ones, but not by a terribly large degree, and still smaller than Shonisaurus.
The longest pliosaur was no more than 18 meters (59 feet), while the longest plesiosaur was no more than 15 meters (49 feet), so none of them come close.
How did they breathe underwater?
It does seem like animals who live in the sea should be able to breathe underwater, doesn’t it? But the aquatic (a fancy word for living in the water) reptiles didn’t. Like all reptiles, they had to come up to the surface to breathe. This is true for any reptile that swims in the ocean, including sea turtles and marine iguanas. The same is true for their distant relatives, the birds. Penguins have to breathe air, even though they can dive deep. It is also true for all mammals, such as whales and dolphins. So how do they dive underwater and stay underwater for so long? They hold their breath, just like we do when we swim. Only they are much better at it than we are and can hold their breathe for a long time.
What is the longest land dinosaur?
That is an excellent question. The problem is that we have no fully complete skeletons of the largest dinosaurs, so we have to estimate their sizes from the bones we have.
As you can see on the chart above, there are several dinosaurs that are similar sized. Diplodocus and Supersaurus got up to 33.5 meters (110 feet). Argentinosaurus got upwards of 35 meters (115 feet) or more. Bruhathkayosaurus (Bru-hath-kay-o-sore-us) was possibly around this size as well, but the fossil material is too little to get a good estimate and what we had has disappeared. However, the American Museum of Natural History in New York has recently put on display the largest dinosaur ever displayed and possibly the largest dinosaur ever known at over 37 meters (122 feet).It doesn’t even have a name yet and is just called the AMNH titanosaur. Of course, the biggest dinosaur ever found is so little known that it has become almost mythical. Amphicoelias has been estimated to have been as long as 58 meters (190 feet). Unfortunately, all that was found of this animal was a few bones, including a vertebra that stood 2.7 meters (8.9 feet) tall. The bones were very fragile, in very poor condition, and were preserved in mudstone, which crumbled easily. All of the fossils vanished (possibly crumbled away and swept out), so all we have left is a few drawings and measurements of the bones.
How big was Apatosaurus?
According to the fossils we have, Apatosaurus typically got around 22 meters (72 feet), but could have gotten as long as 27.5 meters (90 feet). Weight is a very difficult thing to estimate for many reasons, but most estimates place an adult Apatosaurus somewhere between 20-40 tons (40,000-80,000 pounds, 18000-36000 kg), or about the weight of 4-8 adult elephants.
What is the shortest land dinosaur? What is the smallest dinosaur?
That depends on what you consider a dinosaur. Anchiornis was estimated to be 34 cm (13″) long, but was a young adult, so probably got at least 38 cm (15″). But some consider Anchiornis to be an avialan, the earliest group of birds. Parvicursor is the smallest known adult dinosaur that is definitely not a bird according to some people, at 39 cm. Epidextipteryx was only 44 cm (17″) if you include the tail feathers, but only 25 cm(10″) if you don’t include them. However, Scansoriopteryx, also known as Epidendrosaurus, was only about 16 cm (6″), but we only have young ones that would have grown larger, but we don’t know how much larger. Epidextipteryx and Scansoriopteryx may look like birds, but were actually in a different group of dinosaurs. If you consider modern birds, the bee hummingbird takes the prize as the smallest known dinosaur at less than 6 cm (2.5″) and weighing less than 2 grams, just over the weight of a single penny.
But if you are talking about shortest, meaning how tall they stood, that is harder to work out because it would depend on how they stood, but none of these animals would have stood taller than 20cm (8″) at most.
For comparison, these dinosaurs were about the size of a common crow or perhaps even smaller.
Can an 8 feet tall person be as tall as a dinosaur?
A person standing 8 feet tall would be taller than a lot of dinosaurs. A baby just learning to walk would be bigger than some dinosaurs. If we include modern birds, which are also dinosaurs, there are some dinosaurs that a new born baby could hold in their hands (the bee hummingbird is less than 2.5″ long and more than an inch of that is taken up by the beak and tail feathers).
When did the dinosaurs live? When were they born?
The earliest known dinosaur is Nyasaurus, which was found in rocks thought to be 243,000,000 million years old during the Triassic Period, the first part of the Mesozoic Era. There is some uncertainty if this was an actual dinosaur, so if it wasn’t, that would make dinosaurs like Herrerosaurus and Eorapter (both of which looked similar to Nyasaurus) the oldest dinosaurs at about 230,000,000 years old.
When did the dinosaurs die?
Everything that most people call dinosaurs died out at the end of the Cretaceous Period, the third part of the Mesozoic Era, about 65,500,000 years ago. However, they didn’t all die out. One small group of dinosaurs survived, which are the birds. Today, birds are the most diverse group of terrestrial vertebrates (animals with a backbone living on land), so dinosaurs are alive and thriving.
How long did the dinosaurs live?
Dinosaurs were on earth for a very long time. From their beginnings over 240 million years ago to the end of the Cretaceous Period, they lived for around 175,000,000 years. If you include the birds, they have lived for over 240,000,000 years and are still going strong.
If you are talking about individual dinosaurs, they have varied lifespans. Just as you can find mammals that live no more than a year or so to mammals like us that can live over a hundred years old (the oldest known person lived to 122), you can find dinosaurs that lived like that. Some species of hummingbirds only live a few years, so we can expect that some other dinosaurs may have only lived a few years as well. The giant, long-necked sauropods were adults by their teens and may have lived as long or longer than we do. We reall
How old are T. rexes?
If you mean how long ago did they live, Tyrannosaurus rex lived at the very end of the Cretaceous Period, the last period of the Mesozoic Era, 68,000,000-65,500,000 years ago. If you wanted to know how old an individual T. rex could get, They did most of their growing when they were between 14-18 years old, reaching maturity between 16-18 years old. But they didn’t live long after that. All of them that we know of died before they were 30. Of course, whether or not they could have lived longer than that, we don’t know, but that is the ages of the fossils that we have.
How did the dinosaurs die?
Most of the dinosaurs died out at the end of the Cretaceous Period about 65,500,000 years ago when two major events happened. The first was eruption of one of the largest volcanic events in the history of the Earth. The volcanoes that formed the Deccan Traps in India were so massive, the rocks from the lava put out by these volcanoes are over 6000 feet deep. These eruptions happened over tens of thousands of years, maybe even millions of years.
But that wasn’t the worst thing. An asteroid hit in Mexico at the same time as the volcanic eruptions were taking place. It was estimated to be about 10 kilometers (6 miles) across and left a crater more than 100 miles across. Remnants of the crater can still be seen in Chicxulub, Mexico. If all the nuclear bombs in the world were exploded at the same time, it would not be as powerful as the impact of that asteroid.
Did some animals live after the volcano and meteor?
Amazingly enough, yes. If they had not, we would not be here. Every form of animal suffered heavy losses, but most did not die out completely. One small group of dinosaurs survived, which became the birds. A lot of mammals died out, but a lot also survived. Amphibians and crocodilians did reasonably well. Anything small, able to take shelter, and lie dormant (like squirrels hibernating in the winter) to conserve their energy and ride out the tough times did ok. In the oceans, anything large, needing a lot of food, or having shells had a hard time.All the large sea-going reptiles died out. Virtually all the shelled cephalopods (squid relatives) went extinct, but their unshelled relatives survived. Tiny organisms called plankton that lived in the ocean and made their shells out of calcium carbonate died out and were replaced by types that used silicon for shells. During the Cretaceous, the ones with carbonate shells were so common, when they died, their shells piled up and became huge layers of chalk, forming what became the famous White Cliffs of Dover in England and the chalk beds in southwestern Arkansas, among other places. But they almost all died out during the volcano and meteor impact and never became nearly as abundant ever again. The reason for this is because the asteroid and volcanoes released so much carbon dioxide and sulfur into the air that was soaked up by the oceans that the oceans became very acidic and lost a lot of oxygen. So anim
Of course, insects of all sorts survived, as did a variety of invertebrate animals like snails, clams, starfish and the like. But all of them took severe losses, especially those that were specialized to eat only certain plants or animals. One that had a more varied diet managed to survive.
How was it there? Was it dusty or cold there?
During the Mesozoic Era, the time of the dinosaurs, it was, in general, warmer than it is now and the temperature differences between seasons were not as extreme as today. The north and south poles were not permanently frozen over during this time like they are now. But much like today, there were all types of weather and environments. It was hot and dry in some places, it snowed in other places. There were swamps and prairies, forests, deserts, almost any environment you can think of existed then. The only environment you might not find would be glaciers, but you could probably even find them near the tops of mountains at times. Of course, they didn’t exist in the same place on earth and there were different dinosaurs that lived in different areas.
Also remember that the Mesozoic covered an immense span of time, so the earth changed during this time.
Why didn’t the dinosaurs need to fly?
Some dinosaurs did fly, but most didn’t. Most animals today don’t fly either. I expect most animals would if they could, but it takes a lot of changes to evolve the ability to fly. As animals evolve, they can’t decide they are going to develop flight. Small changes will appear in individuals from time to time and if those changes are helpful (or at least not harmful), then they get passed on and can spread through the population. To develop flight, a large number of changes have to happen, so only a few types of animals have evolved in the right way to develop flight. Once they did though, it was very effective, which we can tell by looking at the large number of birds and insects and even bats that can fly.
Is it true that fish had sting rays?
There are some fish called stingrays and they do indeed have venomous spines on the tail, which can be painful and occasionally deadly if they sting someone. They only use them in self defense though, so they won’t hurt anyone unless they feel threatened.
Stingrays are common today and can be seen in many aquariums. But they are also found as fossils and have been around for millions of years. We have even found fossils of stingrays in Arkansas. They do not have bones like we do, but we do find lots of their teeth, which look like flat rectangles. They use these flat teeth for crushing shells of clams and other animals.
What was the tiny thing at the bottom of the smart board?
I’m sorry, I don’t know what you are referring to. Was it on the timeline? Please let me know and we can figure it out.
How many bones have you found?
I have found lots of shells and crinoids. I have found a handful of shark teeth. But I haven’t found too many bones. When I was on a dig in Argentina, I did find a pelvis (hip bones) of a sauropod (the giant, long-necked dinosaurs). I also found part of a skeleton of an archosauromorph (the ancestors of crocodiles and dinosaurs). When I worked in Wyoming and Colorado, I found several fossil turtle shells and part of the horn of what may have been a uintathere or some similar animal (rhino-like mammals with knobby horns and bumps on their heads). I also found several tiny bones of rat-sized mammals. I don’t know what they were, but I remember one place where the bones looked like turquoise (a greenish-blue gemstone).
What I would really like to find would be a dinosaur in southwestern Arkansas, although the skull of a mosasaur or elasmosaurus would be a close second. There are opportunities for finding fossils in most of the state, so keep looking and let me know if you find something!
Aliki Brandenberg, known mostly simply as Aliki, has written several popular books for children in the Let’s-Read-And-Find-Out Science series published by Harper Collins. Among these books are ones about fossils and dinosaurs written for 5 to 9-year -olds (I think 4-8 would be a better range, as many 4-year-olds will like the books and most nine-year-olds will have moved on to books with more information). When they came out in the 1980s, they were widely regarded as excellent books for children. The books were voluminously illustrated with colored pencil drawings of fossils and people studying them. The main text was supplemented with word balloons for the human characters, supplying interesting tidbits and additional information, so should not be ignored. Unlike many books of the time, these were about as accurate as one could expect to get without going into so much detail that a person of that reading level would feel overwhelmed.But it has been 25 years or more since then. We’ve learned a lot since then. How have they held up? Surprisingly well, for the most part, better than the majority of books published at the same time. I will review four of them here, two in this post and two in a following post. Some people might find the reviews a bit lengthy, so here they are in a nutshell: still good reads for kids, even better with a few additional comments to update them and correct a few misconceptions that kids might get from the simplicity needed to pare down complicated subjects into something that would fit the space constraints and interest levels.
Fossils Tell of Long Ago
Publication Date: 1972, revised 1990.
Harper Collins Publishers. ISBN: 978-0-06-4455093-5
AR Book Level: 3.6
Fossils Tell of Long Ago endeavors to explain what fossils are, how they form, and what they can tell us. In a quick 32 pages, Aliki provides a wealth of information well written for the intended reading level of early elementary kids.
Fossils starts off describing what fossils are and how they are formed. The description of the fossilization process is simplistic and doesn’t get into the microbes precipitating minerals around the bones during decomposition, but that was not known when the book was written and the description in the book is sufficiently accurate for the level of reader at which the book is aimed. I do like the use of the famous Xiphactinus fossil as the lead example as it is a fascinating fossil in its own right and thus a good fossil with which to hook readers. Aliki’s description of coal as a fossil is great. She does a good job of introducing different types of fossils, even including different pieces of information that may be gleaned from fossil footprints.
Aliki then goes on to talk about mammoths in ice, amber, and how fossils can tell us about the environments when the rocks were deposited, introducing many more types of fossils along the way. She ends the section by reinforcing the utility of fossils to tell us about past environments and organisms that no longer exist, even putting in a plug for museums.
The book ends with showing how to make your own fossil track and thoughts about how people in the future may interpret it. Best of all, she ends on a positive, encouraging note that anyone can find fossils, even the kid reading the book, and discover something no one else in the world knows. And that is a powerful motivator.
All in all, the Fossils book stands up very well and can still be recommended as a great book for kids.
Publication Date: 1988 (Amazon lists the publication date as 1990, which differs from what is printed in the book).
Harper Collins Publishers, ISBN: 978-0-06-445077-5.
AR Book level: 3.7
“Dinosaur Bones” tells about the early history of the study of dinosaurs and briefly discusses dinosaurs and the world of the Mesozoic. This book does not hold up quite as well as the “Fossils” book and shows its age by being out-of-date in some places, but is still reasonably accurate a good read for young kids. It provides an interesting glimpse at the beginnings of the modern studies of dinosaurs (dinosaur bones have been found for millenia, but modern scientific study is much more recent) and a very brief introduction to dinosaurs and their world.
This book, like almost every other book, has a European bias. On the very first page, it says the Dr. Robert Plot was the first person to describe a dinosaur bone in 1676. He had no idea what it was and he described it as possibly a giant human thigh bone or some other such animal. He was hardly the first to find dinosaur fossils and try to describe them though. Native Americans, ancient Greeks, and many others found them far earlier. They just did not recognize them as dinosaurs. Fossil Legends of the First Americans and The First Fossil Hunters:Paleontology in Greek and Roman Times, both by Adrienne Mayor, are filled with accounts of early fossil hunters.
The book begins by describing how she was introduced to dinosaurs and her curiosity about how scientists know what we do about past life, which she begins to answer by talking about people finding fossils. The book provides an excellent short history of the early scientific study of dinosaurs by Europeans, hitting all the famous highlights. The best part of this section is her emphasis on early ideas changing with new fossils and new data. She presents dinosaur paleontology as a dynamic process, with ideas being revisited and revised in the face of new evidence, which is a great thing to put into a book for kids.
The book then delves into the world of the dinosaurs, showing that the world was much different than it is today. I like that this was included and I realize there were space limitations, but I have a small problem with this section. The Mesozoic Era, what is commonly known as the time of the dinosaurs, lasted for over 200 million years. That is a huge time. In general, the description of the continents being joined together into one land mass was accurate for a good bit of that time, but it broke up during the Mesozoic,which had important effects on the evolution of the dinosaurs. The temperatures were also only warm everywhere, as stated in the book, if one considered temperatures warmer than current “warm.” Neither the Arctic nor Antarctic were covered in glaciers, but it was still cold enough to snow and reach frigid temperatures at night in the poles. Basically, it is not possible to compress the diversity of climate and landforms of 200 million years across the entire world into two pages and six sentences. But given that constraint, she did the best that could be done. At the very least, she presented the concept of great changes in the globe over great expanses of time, which is a substantial achievement for a book aimed at elementary kids.
Following this section are two pages describing how fossils are formed and geologic time. She mentions the important concept of dinosaurs evolving. For the space available and the intended audience, the book does remarkably well. For the purpose of just introducing the concepts to kids, they are handled succinctly and clearly. The biggest place where it falls down is saying that scientists tell time by looking at the order of the fossils. This is indeed one way, but if that were the ONLY way, it would be a circular argument. You can’t use the fossils to date the rocks and the rocks to date the fossils at the same time without additional evidence. This method also only provides relative dating, there is no way to really tell how old the rocks and fossils are this way, only the order they were laid down. There are some rocks though, such as ancient lava flows or ash beds, for which we can get absolute dates using radiometric techniques. Between the two dating methods and comparing rock units from different areas to each other, we can get reliable dates for all the rock layers. Having said that, the major geologic time units were devised by looking at the order of fossils. It was only later that we learned how to provide the absolute dates, which told us how old the rocks really were. I would have preferred a simple change of wording to say that finding fossils is ONE of the methods scientists use to tell time and not make it look like it is the only way. The change may not look like much, but it really does make a big difference and many kids will pick up on the distinction so long as adults don’t give them misinformation.
The final few pages describe the history of the dinosaurs in a few sentences. The Triassic Period is done well for the allotted three sentences and the illustrations provide examples of some of the dinosaurs. The only problem here is the description of Heterodontosaurus, which is out of date (for cool information on this unusual animal, go here and here… no, really, check it out).
The Jurassic Period is a bit problematic in that it has the giant, long-necked sauropods tromping around what look to be swamps and dragging their tails, which is no longer considered accurate. Interstingly, all the carnivores are shown in dynamic, tails-up poses. The Cretaceous Period starts with saying “dinosaurs had taken over.” Dinosaurs were dominant throughout the Jurassic Period, long before the Cretaceous. The dinosaurs are also drawn too much in the old, upright positions. More than any other page, this one looks like a throwback to an earlier artistic era. In the entire section, the dinosaurs are drawn very simply and generically, despite the fact that they are named with specific names.
The final page starts with “Then suddenly, they all died out. No one knows why.” This is followed by several things scientists don’t know about dinosaurs. By and large, it is true, but we have made great progress and can now provide at least partial answers to all of them now. We now have some very good ideas about why they died out. There is also considerable debate about how “suddenly” it was. Most notably, dinosaurs didn’t all die out, just most of them. Birds are directly descended from the Mesozoic dinosaurs and are the most diverse group of vertebrates that live on land. Scientists are also making strides to answer the final questions the book states about their colors, what sounds they made, and their metabolism. While there are still many gaps, we have made much progress on those questions. As a result, I would recommend that anyone reading this book to kids mention how old the book is and that a lot of work has been done since then to find answers to those questions, but there is still much more to do.
The National Fossil Day event at the Museum of Discovery is almost here.Here are a few more things you might see at the event. Here is a cast of a coelacanth, a lobe-finned fish that is closely related to the fish that started the trek onto land, and a mesosaur, an early reptile before reptiles and mammals went their separate ways.
Want something with a bite to it? How about some teeth? Like Megalodon teeth, and a nodosaurid dinosaur, and how about the tooth of a giant ground sloth? What about primitive horse and rhino teeth?
Lots more to see. Come out and have a look. Bring your fossils and compare.
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.
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.
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 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.
Last Friday I posted clues to a mystery fossil. The clues were 1) I lived in AR during the Mississippian Period roughly 330 million years ago and am a very common fossil to find here. 2) Many people think I’m a coral, but I’m not. 3) I am named after a famous Greek mathematician and inventor. Who, or more precisely, what am I? Allie Valtakis got the right answer as the bryozoan, Archimedes. Here is what the Arkansas Geological Survey says about it.
The Bryozoa grow attached to the sea-floor as do corals, but they differ significantly from corals in terms of soft-part anatomy. The bryozoans are exclusively colonial and fall into two broad groups, the lacy colonies and the twig-shaped colonies. Individual “houses” (zooeciums) lack the radial partitions found in corals, but they are divided transversely by partitions called diaphragms (Fossils of Arkansas). Bryozoans can also grow as incrustations on the shells of other organisms and are commonly associated with reef structures.
“Bryozoans are tiny colonial marine animals that are present in marine and fresh water today. They are sessile benthonic animals (fixed to seabed) that are filter feeders and prefer shallow seas, living fairly close to shore (neritic). One bryozoan called Archimedes (see picture below) is abundant in Mississippian age rocks in Arkansas and is so plentiful that one of the rock formations called the Pitkin Limestone was once referred to as the “Archimedes Limestone”. Generally, only small pieces of bryozoans that resemble “fronds” are preserved in Mississippian and Pennsylvanian age rocks in the Ozark Plateaus Region.
Freeman, Tom, 1966, Fossils of Arkansas: Arkansas Geological Commission
Bulletin 22, 53 p., 12 pls., 15 figs., 1 map.
Way to go, Allie!
Can you guess this week’s fossil? I will do things a bit differently this time. Unlike previous fossils, in which I told people on the Facebook page as soon as someone provided the correct answer, I will not reveal the answer until Friday, so you have plenty of time to give it a try. In addition to the picture (note the scale) below, I will provide one clue every day until Friday. Good luck!
Clue 1: It’s from the Cretaceous.
Clue 2: It’s modern day relatives are widely considered a delicacy.
Clue 3: This is no wilting lily. This creature is big and bold. It shows how twisted it is on the outside for all the world to see. Dude, that’s heavy.
Come back tomorrow for the answer! You can also find it on the Facebook page.
Walking with Dinosaurs 3D movie review
I went to see Walking With Dinosaurs 3D this weekend. My kids were interested in seeing the movie and I liked the BBC “Walking with Dinosaurs” TV mini-series, so we were all eagerly anticipating the movie. I had read a few reviews of the movie, some by paleo people, who said the dinosaurs were great, but the voices were terrible, which gave me pause, but it’s a BBC movie on dinosaurs, how bad could it be, right?
Sad to say, I have to agree with most of the reviewers. This movie may be much more enjoyable if you can’t hear it. To begin with, whatever expectations you may have, forget them. If you are going in expecting to see a big screen version of the BBC “Walking with Dinosaurs,” you will be disappointed by the cartoon voices and plot. If you are looking for light entertainment for little kids, you might be a bit surprised by the rather jarring breaks providing a subpar, documentary-style educational interlude which will kick everyone out of the story.
The film reminded me nothing so much as a cross between the BBC documentary-style series and The Land Before Time movie series, failing at both. I think the reason for this is because it seemed to clearly start off with the idea of it being a kid-friendly movie along the lines of the TV series, but some executive decided after it was made that it was not going to draw enough kids. So the movie was recut and really bad dialogue added to it instead of the normal narration one would expect in a nature documentary, along with completely superfluous modern scenes bookending the film, wasting the talents of otherwise fine actors. The voices were obviously added as an afterthought because the dinosaurs do not act like they are speaking. I could even occasionally hear the original dinosaurian bleating and honking in the background even as they are supposedly talking. The dialogue, as Brian Switek noted in his review, destroyed any emotion that may have been evoked by the scenes that were supposed to be emotionally powerful. What should have been poignant, heart-tugging scenes were drained of any impact by juvenile pratterings that never ceased. I found myself wishing for the dinosaurs to just shut up once in a while. As a result, it is a movie that may be enjoyable for a little kid, but eminently forgettable. Bambi was a much more riveting emotional experience, not to mention more educational about the lives of deer.
The story line was inconsistent with the idea of a nature documentary and a poor choice for a dinosaur movie. Whether or not the worst aspects of it were in the original script, I don’t know, but the final plot, while suitable for a cartoon Land Before Time, was wholly inappropriate for a nature “fauxmentary.” For a film that was supposedly educational, it pushed moral viewpoints which are only valid in human cultural environments and completely invalid in the natural world. The idea that intelligence and courage will overcome the thoughtless, testosterone-fueled belligerence of the larger alpha males is a noble sentiment and may work in a human context, but not in the depicted dinosaur society. Control of a herd of large herbivores that have evolved extravagant displays will never pass to the runt of a litter because he saves the herd in a time crisis due to his quick thinking. The plot line for the movie is far more appropriate to an after-school special involving actual, human children, not dinosaurs. As such, it completely destroys any educational effectiveness of the movie. The only education that remains is that dinosaurs lived in a snowy Alaska and that some dinosaurs had feathers, particularly the smaller theropod carnivores. I really like this aspect of the movie, but its authenticity in these aspects was completely undermined by the silliness of the rest of the movie.
To make it even more confusing in terms of genre plotting, the movie shows that females in the herd are dominated by the alpha male, but glosses over what that means in terms of sexual dominance. In a kid-based movie, this understandably only goes as far as hanging out with each other. In the natural world (and post-adolescent human worlds), as every adult in the audience will understand, it means the female submits to the alpha male’s sexual advances. In terms of a human kid’s movie, it sends very poor messages about the role of females in society. In terms of an educational nature show, it is intentionally misleading to spare the typical parental sensibilities of what is appropriate for kids to see.
In short, if you go to see this movie (which I would really recommend waiting until a rental, as it is not worth spending the price for a 3D movie), go expecting to see a mindless 80 minutes of passable, but forgettable, entertainment for children with no real educational value other than to say look, aren’t dinosaurs neat? Enjoy the graphics, ignore the rest.
The Big Golden Book of Dinosaurs
By Dr. Robert T. Bakker
Ilustrated by Luis V. Rey
Publication date: 2013. 61 pg.
Golden Books, Randomhouse. ISBN: 978-0-375-96679-8.
Do these books look familiar? One is the classic book that most people old enough to be parents grew up on, first published in 1960 and continuing through 1981. The second is the new, Big Golden Book of Dinosaurs, a new, totally updated edition that came out in 2013. The book is written by Dr. Robert Bakker, known by many as the bushy-bearded, cowboy hat-wearing paleontologist of many documentaries and the author of such books as the Dinosaur Heresies and Raptor Red. Illustrations are by Luis Rey, a talented artist already mentioned here due to his work illustrating Dr. Holtz’s Dinosaurs book. Dr.Holtz’s book was written for a wide audience, geared towards children of middle school age and upwards. This book, like its predecessor, is geared for elementary kids. So it is not as detailed, but it is even more lavishly illustrated and will definitely hold the interest of younger kids.
From the front cover to the last page, those who know and love the original book, will find it echoed here, but updated with the latest information. inside the front cover is a map of the world as it existed in the Triassic and early Jurassic, with dinosaurs dotting the landscape, showing where various dinosaurs have been found. The map is matched on the inside of the back cover with a Cretaceous map. Both maps have the names of each of the dinosaurs illustrated so you know what you are looking at. There is also an index and handy pronunciation guide for all the animal names.
While the book is of course heavily weighted towards dinosaurs, like the previous book, it does not focus entirely upon them. In the brief introduction, it makes a point to place the dinosaurs in context as part of an evolving ecosystem, not as isolated creatures. The book then dives into the Devonian seas,introducing us to the fish that began the walk towards becoming landlubbing tetrapods (animals with four legs). It continues with a few pages on the Carboniferous and Permian Periods, with giant insects, early amphibians and reptiles, and even animals like the iconic Dimetrodon, properly identifying its kin as ancestral to modern mammals, even explaining key features showing it’s related to us. Only then do we get to the Triassic, the beginning of the Age of Dinosaurs and even then, it starts the discussion with pterosaurs and the ancestors of crocodylians. After a mention of the earliest dinosaurs, it then mentions the proto-mammals.
Finally, we reach the Jurassic Period and it is here that dinosaurs take center stage, with gigantic, long-necked sauropods and other well-known dinosaurs. Even so, they don’t forget the small, mouse-like early mammals under foot. After a brief interlude to discuss the great sea reptiles that appeared during this time, as well as the pterosaurs, that were now much bigger and diverse than in the Triassic, they return to a discussion of dinosaurs, this time focusing on a bit of history explaining how our views have changed over the decades.
The book moves then into the Cretaceous, showing how dinosaurs adapted to diverse environments, such as the sand dunes of central Asia to the snows of the poles. There is a chapter on different ways dinosaurs communicated with each other, including singing, after a fashion, much like birds and animals call to each other today, although he goes a bit overboard in this area and speculates beyond what most in the field would say is reasonable. Of course, no elementary book would be complete without a chapter devoted to Tyrannosaurus rex and its battle with an armored herbivore, in this case, the ankylosaurid Euoplocephalus and a battle with Triceratops. While the book makes much of the use of horns and frill by the Triceratops in battling T. rex, they were almost assuredly evolved to battle other Triceratops as dominance displays, like bison or antelope today, although that of course, doesn’t rule out their use as defensive weaponry against predators.
There is the required chapter on dinosaur extinction and it does a good job of mentioning several possibilities. However, it gives a bit of short shrift to the most accepted asteroid hypothesis and a bit more space to Bakker’s favorite hypothesis of disease, which is almost assuredly not true as a hypothesis of widespread extinctions on such a large scale. To his credit, he ends with the likely possibility that no one hypothesis is sufficient for explaining everything.
The book ends with what animals actually benefited from the extinction, that being mammals. The book ends with noting that not all dinosaurs died out and acknowledging the influence that dinosaurs had on the evolution of early mammals, thereby connecting the story of the dinosaurs to us. Besides the great illustrations, that I think, is the key strength of this book, never letting the reader forget that dinosaurs were but a part (a big, incredibly impressive part) of a bigger ecosystem, with each piece influencing the others. No group was isolated from the others, all are interconnected.
Overall, while I had a few minor quibbles, as i mentioned above, I can definitely recommend this book for any elementary library. Some middle school kids will like it too, although those older than that will likely be reading it for nostalgia of the original book, who will find this version a worthy successor.
Other than the image of the 1960 book, all images are illustrations from the book.
Day 4 and the last day at SVP. After this, we will return to our regularly scheduled sorts of posts.Another day of talks and poster sessions, the last chance to meet friends and colleagues and discuss what you’ve heard and what people are doing. Although frankly, I think most people are tired and ready to go home by this point. Some people thrive on the highs of shared creativity and knowledge and find the end of the meeting and going back to regular work depressing, I think the most common reaction is the feeling of being rejuvenated by the meeting, so that you can’t wait to go back and start developing the new ideas created at the meeting, the chance to put those creative juices to work before the distractions of everyday life dry them up.
A lot of people don’t like having their talks on the last day. People are going home, they are tired, their attention flags, but this meeting showed a strong turnout for the last set of talks. The symposium scheduled for today was “Patterns from the poles: biodiversity and paleoecology of high latitude fossil vertebrates,” which I, at least, found interesting and worth attending. I didn’t attend too many of the talks though, because there was also a session on the evolution of early birds, which I found even more interesting, as well as a session on mammals, which had several talks discussing how different mammal groups adapted to climate change in the past. Several talks introduced new fossils and what they contributed to our knowledge of evolution within those groups, such as a new Devonian fish from Siberia, the first pterosaur from Antarctica, a new sauropodomorph (early versions of animals that would become sauropods, the oldest mammal from Antarctic and a new Arctic camel, new birds, seals, sirens, dolphins, and whales. All in all, good reasons to stick around.
Rui Pei reported on a new specimen of Anchiornis, the first animal in which fossil evidence in the feathers was used to determine coloration. Anchiornis lived 10 million years before Archaeopteryx and there has been some debate about whether it was a true bird or still a non-avian dinosaur. Pei’s analysis of the new specimen indicated that Anchiornis was a troodontid, so not quite yet a bird. This is another great example that the transition between birds and other dinosaurs is so well documented that the line is an arbitrary classification with no biological relevance. Speaking of feather colors, William Gearty found new ways to study the melanosomes in the feathers providing colors, finding that, in addition to color, he could tell color gradients as well. he also concluded that melanosomes stiffened the feathers, making them more resistant to wear, but also carried more bacteria, thus representing an additional resource cost for the animals (some of this work can be found online at PLOS One).. Justin Hall found that feather asymmetry, long thought to be important for flight, turned out not to have the aerodynamic significance we thought, as it didn’t really affect the ability to fly. Ashley Heers found trade-offs in locomotor ability: the more investment in wings, the less was put into the legs, and this trade-off could change as the bird grew so that chicks may emphasize the wings or legs while the adults emphasized the other.
Several studies showed the difficulties inherent in paleoecology interpretation. Peter Makovicky found that the horned ceratopsids showed different growth rates between northern and southern populations, the duck-billed ornithopods did not, and the carnivorous theropod Cryolophosaurus showed different growth rates in different areas of the same body in the northern individuals, but not in the southern individuals. According to Bergman’s rule, we should expect to see animals get bigger and stockier the farther north they are found. Anthony Fiorillo found that the small troodontids followed the rule, but northern individuals of the large tyrannosaurs were only 40% the size of the southern ones. In this case, it is likely that resource supply kept the tyrannosaurs smaller. Patrick Druckenmiller reported on a diverse Arctic dinosaur fauna including toodontids, dromaeosaurs, thescelosaurs, hadrosaurs, pachycephalosaurs, and tyrannosaurs, despite mean annual temperatures near freezing. While similar to southern forms, all the species were different, indicating a discrete, provincial ecosystem. John Tarduno argued that the presence of champsosaurs (a type of early crocodylian) and turtles indicated the weather was too warm for ice to be present even during winter, but as proven by an earlier talk, we know this is incorrect (a great example of science correcting itself). He proposed volcanism forming a series of shallow, freshwater connections between North America and Asia during the latest Cretaceous allowing interchange between the continents, which will need more study to determine if that proposal is true. Judd Case found that even though modern fish fauna show a drop in diversity with lower temperatures, thisi was not the case in the Cretaceous. As the temperature in the Cretaceous dropped 8-10 C in the Antarctic oceans, the fish didn’t really change, although marine reptiles increased in diversity while the ammonite diversity dropped.
Rodrigo Figueiredo presenting evidence that predators who pursue their prey (as opposed to ambush predators attacking large prey and those that pounce on smaller prey) may not have evolved to go after herbivores, but to prey on the pounce predators themselves, much like wolves will sometimes hunt foxes and weasels. Michael Greshko presented a study finding that herbivores known as generalists (able to eat a wide variety of plants) mostly consist of different individual specialists who eat only a narrow range of foods. This is rather like why a pizza buffet needs to stock a lot of different types of pizza even though any particular customer may only eat one or two different types. Speaking of eating, Emily Rayfield gave a possible answer to why mammals reduced the number of bones in the mandible to just one, as opposed to having several bones in the lower jaw like other groups of animals. Using Finite Element Analysis, an engineering method designed to test mechanical strength of materials, found that the one bone provided a stronger bite while reducing stress. Alistair Evans used a program called GEOMAGIC to study tooth shape in early mammals and predict what tooth shape should be like to help sort out all the isolated teeth for which we have no idea what they belong to. in this way, he is making predictions of fossils that have not yet been discovered.
In addition to the software programs mentioned previously, several others were mentioned in talks this day. Most biogeography methods these days are done using phylogenetic methods to help inform how animals spread out across the globe, but Chris Sidor presented Bipartite Occurrence Networks (BON), using Gephi to visualize the patterns, which just uses locality connectedness and found that therapsids (proto-mammals, aka mammal-like repties) were pretty widespread and cosmopolitan before the Permian extinction event, but became much more provincial and limited in range afterwards. Paul Upchurch used TREEFITTER to map pterosaur biogeography, finding support for sympatry (speciation within the same region) with an origin in eastern Asia. Diego Pol used Ancestral Area Reconstruction methods to conclude that dinosaurs probably originated in South America, along with most, but not all, mammals, but crocodylamorphs originated in China. Graeme Lloyd used GEIGER to study evolutionary rates and Akinobu Watanabe used PERDA (Polymorphic Entry replacement Data Analysis, a script running in TNT, a phylogenetics analysis program) to simulate poor sampling of phylogenetic data, finding that if a trait, or character, has multiple possibilities within a single species, it seriously messes up results unless multiple individuals covering all the possibilities are included in the analysis. John Alroy found that no current method is very good for finding the first appearance of taxa, but Bayes Theorem methods, such as used in MrBayes, produce better estimates of extinction times.
The last two talks I would like to mention are from Robert Sansom and David Grossnickle. Sansom found that loss of soft tissue characteristics resulted in changes in cladograms drawn from the data for vertebrates, but not for invertebrates. In other words, if one only looked at hard parts, the evolutionary relationships changed, and more often than not, made the animal appear to be more ancestral than it really was. This occurred even if the characters were recorded as unknowns and not simply listed as absent. Grossnickle looked at morphological disparity in Mesozoic mammals, i.e. the diversity of body form. What he found was that most Mesozoic mammals were carnivorous/omnivorous, with a low level of diversity which gradually increased until the middle Cretaceous. At some point in there, they hit a botttleneck. Their diversity crashed and, while it did start going up again,never reached the previous diversity levels until after the K-T extinction event. What is interesting about this is that pretty much everything else was diversifying, while mammmals were not. Another interesting thing about this is that according to molecular data, mammals were diversifying, so the apparent diversification did not show up as morphological diversity.
This is the end of my discussion about the science presented at SVP. There were so many more talks and posters that I did not mention and i make no claim that the ones I mentioned are even the best or most important, nor are they even all the ones I attended and learned something from, but it would take me until the next meeting to discuss all of them. The point is that meetings like this are incredibly fascinating places to see what is going on in science right now. Anyone who thinks science is a bunch of stale facts in textbooks or that scientists even pretend to have all the answers is seriously mistaken. The search for truth is asymptotic, you can get ever closer to a totally clear understanding of reality, but you will never reach it. Science is all about going over the data, tossing out ideas that don’t succeed and developing ones that do, with each step opening up new avenues of exploration.
I will end this discussion with the awards banquet held on the evening of the last day. During this banquet, we are told how much the auction collected to support the society, important news, memorials for those we lost recently, and people are recognized for their hard work and contributions to the field of vertebrate paleontology. Students are awarded their prizes and scholarships they have won, artists are awarded for best art in different categories, and people are recognized for outstanding careers that have progressed the field. This year, one of the biggest awards went not to a scientist, but to a science advocate. Perhaps because the meeting took place in Los Angeles, special recognition went to Steven Spielberg, for the money he has donated to the Jurassic Foundation and other places to support paleontology research and education and for the Jurassic Park movies, which brought paleontology to the center of the public eye and has inspired many to enter the field and make their own contributions. Officially, the meeting ended here. There was an after-hours celebration, which is always fun from what I hear, but I was beat and had a plane to catch early in the morning, so I called it a day. Until next year!
Another day at SVP, another boatload of information. Some may be wondering why I am devoting several posts to this meeting,when it may seem not as relevant to the general public. Fair question. people not actually doing science in an academic setting rarely get a chance to see anything about what it is like. Science is often presented as a list of facts, but that is only part of the story. Science is a dynamic endeavor, never being satisfied with an answer, always working on the things we don’t know and revisiting the things we thought we knew to see if they still hold up under the new information. Science gets things wrong all the time, but this process of study and review and critical examination reduces the margins of error. Not all things that are wrong are equally wrong, rejecting evolution in its totality is a whole other category of wrong compared to disagreements about the rates of evolution in a particular lineage. No one in science who examines the evidence seriously disputes evolution or that dinosaurs existed, but exactly how evolution works, how dinosaurs lived, exactly who is related to whom; these are questions that people struggle with. With each new study, the path moves closer and closer to the truth, each time having the possibility of opening up whole new avenues of exploration we had never thought of before. That is what these meetings are all about, bringing minds together for new solutions to old questions and for finding new questions to ask about old solutions. What goes on at meetings is a glimpse behind the curtain of published papers and distilled textbooks, putting human faces onto that quest, faces that are, more often than not, students working together and with more experienced people. Most science is done not by white-haired old men in the lab, but by young, energetic students with a zest for learning. And there is so much more to do.
In the previous two days, there were collections of talks called symposiums, devoted to specific topics, such as on ontogeny and the la Brea tar pits, including a preparators symposium on fossil collection and preparation techniques. Friday included a special symposium on the tempo of evolution and dating the fossil record. Samuel Bowring presented the EARTH-TIME Initiative, an opportunity to date the stratigraphic record to a precision never before seen, allowing measurements as refined as +/- 20,000 years all the way back to Triassic times (>200,000,000 years ago). That is a resolution of 0.01%. The remaining talks were about research on specific areas and times contributing to that increased precision.
Terry Gates looked at cranial ornamentation in theropod dinosaurs, finding only larger theropods used bony ornamentation and that if a lineage developed it, the lineage quickly developed larger species. So the question now is why were bony cranial ornaments only selected for larger body sizes? Yuong-Nam Lee reported on new fossils of Deinocheirus, an enigmatic fossil previously known only from one set of huge arms, which allowed them to determine it was the largest ornithomimosaur ever found, sporting a large sail on its back near the hips, something like a small spinosaur sail. Picture a giraffe-sized ostrich, with a sail on its back, giant arms with huge claws, and a big,chunky tail. On second thought, maybe not so much like an ostrich, after all.
Other dinosaur reports include Ashley Morhardt, who reported that Troodon had the largest encephalization quotient of any non-avian dinosaur (i.e. it had a big brain). Most of its brain was made of the cerebrum, which not only makes a reasonable case for it being the smartest dinosaur, but supports a mosaic model of brain evolution, meaning that different parts of the brain evolved at different rates. Amy Balanoff discussed the evolution of oviraptorosaur skulls and brains, showing larger cerebrums than most other dinosaurs, but reduced olfactory tracts, so they were similar to birds in having a relatively poor sense of smell. Walter Persons reported on fossils showing that Microraptor ate mostly fish, as well as small mammals and birds.
A session devoted to mammals had several interesting talks, such as one by one by Ross Secord, who concluded from his research that the body size increase seen in horses was related to warmer temperatures allowing an longer growing season causing increased availability of grasses, making up for the lesser nutritive value of grasses compared to other plants. I would argue however, that a shift to eating hard-to-digest grasses would result in increased body size not through increased availability, but to increase digestion efficiency. Horses are what is known as hind-gut fermentors, which is less efficient than the foregut fermentation seen in ruminants such as cows. This mode of digestion is more efficient at higher body sizes, allowing more time for digestion. Lindsey Yann found that horses were too much of generalist feeders to be useful for paleoclimate reconstructions, but different camel species were more specialized and could used to make determinations of relative aridity and plant cover. Rebecca Terry found that interactions between mouse species had at least as large an effect on population sizes as climate, with different species reacting differently to resource changes. Thus, there is no easy answer to predicting how species will react to climate changes because they cannot be looked at without understanding interactions throughout the entire ecosystem. Much of this sort of work uses MIOMAP and FAUNMAP, which are similar paleontology databases to the Paleobiology Database, but limited to mammals in North America and so may be more complete for these types of studies.
Brady Foreman discussed ways to interpret the completeness of the fossil record based on river deposition patterns and Patrica Holroyd discussed the “missing marsupial problem,” finding that because most eutherian mammal fossils are identified to species level and most marsupial fossils cannot identified beyond “marsupial,” there is a taxonomic identification bias in the literature and thus, species diversity studies.
Three other studies I would like to mention are about archosaurs, the “ruling reptiles,” including crocodilians, dinosaurs, and birds. Brandon Peecook looked at the bone microsturucture of Nyasaurus, which was either the earliest known dinosaur or the closest basal archosaur to it, and found that it had elevated growth rates compared to other reptiles, indicating that all dinosaurs may have had faster growth rates from the beginning. John Sarrazin reported that crocodilians and birds both use unidirectional air flow through lungs,as opposed to bidirectional like mammals, which uses a completely aerodynamically controlled system with no structural valves, so in all likelihood, the ancestral archosaur had these characteristics as well. Finally, Jennifer Nestler found that cold weather is not what limits the range of alligators. Rainfall contributed more than 60% to range limitations, most of the rest comes from warm weather during the summer providing long breeding seasons. Only 0.4% of the factors limiting their range could be attributed to cold weather limitations. Something to think about as global warming causes longer summers with elevated rainfall in the eastern United States.
At the end of the day, after the talks and the poster sessions, this is the day for the annual auction, to raise funds for the organization that can be used to fund research and travel grants for students in the upcoming year. The auction consists of two parts, a silent auction and a live auction. In the silent auction, everyone has two hours on which to bid on the objects they want and the last bidder wins, much like alive version of eBay. The auction is filled with a wide array of donated items, everything from rare books and artwork to hand-knitted dino-themed baby socks, whatever people are willing to donate. After the silent auction comes the live auction, usually filled with more expensive, one-of-a-kind items, such as original artwork or the original copy of O.C. Marsh’s dinosaur monographs. I have even seen the services of a field cook and her personal field kitchen for a season get auctioned off. The auctioneers always have fun with it, usually dressing up in costumes. you never know who is going to be serving as auctioneer, it could be a zombie, King Tut, or Superman, but regardless, it is an entertaining spectacle.
An end to another day, only one more day to go, before everyone packs up to go home, or off to their next meeting, or a museum to do research, wherever their path leads them.