A Glimpse at the Most Detailed Fossils in the World and What They Tell Us
Scales, skin, or feathers?
Prior to the 1990s all depictions of dinosaurs were of large reptilian creatures with scales growing on their skin like you'd see on an iguana. Sometimes a particularly forward thinking artist might make them with beaded skin like a python or textured skin like a bearded dragon. Once or twice some really rebellious artists may have put feathers on their creations. Still we didn't know what they really looked like and there was a lot of debate. Archeopteryx was discovered in the 1800's. It seemed to be an animal that was halfway between a dinosaur and a bird. It was covered in feathers but had a long tooth-filled snout and lizard-like tail. There had been a lot of debate about raptors, a type of predatory dinosaur that seemed to share a lot in common with birds. However the debate was more about whether or not they were cold blooded like a lizard or hot blooded like a bird. Feathers didn't come into the debate until some remarkable discoveries in China started to hit the news. Here small predatory dinosaurs started to be unearthed that had feathers... but curiously enough most did not have functioning wings. Their feathers were far too short, even stranger some of them wore nothing but down feathers, they type you'd find on a newly hatched chicken. Were they for display? To keep warm? To deflect rain? Or for some other purpose? Theories abounded and it became the new in thing to depict at least raptors with feathers. There is still no evidence other dinosaurs were feathered but a lack of evidence doesn't always mean they weren't. We will just have to wait and see to anyone else shows up in a boa.
Mini Microraptor Documentary
For many years dinosaurs got painted in only green and gray. It was a bleak colorless world for the paleo-artist. I am not entirely sure why this was but since these days there has been increasing speculation on what dinosaurs and other extinct creatures actually looked like. It is true that on very rare occasions fossils can be found with imprints of skin texture or feathers but they don't also capture color... that is until someone found out how to tease the color out of them. Jakob Vinther, who was studying at Yale at the time, was looking at a squid fossil when he realized that when the ink sack of the squid was seen through a microscope he could see molecules that could have been what made up the color of the ink. Curious he turned his attention to a fossil feather and realized it too had these pigment molecules. So what color was this feathered dinosaur? Black with an iridescent sheen, probably much like the grackle pictured below. Since this discovery others have worked on the issue and they are now pioneering new techniques using a scanning electron microscope. In fact they have even determined the entire body color pattern of Anchiornis.
For many years people thought dinosaurs must have lived to great ages in order to grow so big. Some thought they might live like a tortoise with 200 years to claim on the earth. Argentinosaurus could grow 120 feet long and weigh over 100 tons but hatched out of an egg vaguely the size of a soccer ball. How could it pack that much growing in without having a long time to do so? It seemed an impossible idea and yet, dinosaurs lived fast and died young according to new studies.
It has been found that bones show growth much like trees do, with rings in their center. This wasn't discovered earlier because it is generally not a good idea to saw a perfectly good fossilized bone in half and yet it was done to the world's most famous T-rex, Sue of the Field Museum in Chicago. Sue was already a sensation having shown evidence of living past a leg injury that would have made hunting impossible (thus proving she had at the very least a mate feeding her, if not an entire pack.) Sue was as large as she could have gotten, a complete adult, and was already showing the wear and tear of an elderly animal and yet she turned out to be only 28 years of age. Further study on other T-rex specimens showed that they maintained three growth spurts in their lives, the biggest being in their teen years where they could gain four and a half pounds a day for several years. They would be effectively full grown by twenty and were more than lucky to still be alive at thirty. It was an astonishing find.
What's for lunch?
the diet of extinct animals has largely been a massive guessing game based on the teeth of said animals. For instance a mammoth has the large grinding teeth similar to an elephant so we know they, as well as other large herbivores before them, probably shared a similar diet. Fish eaters tended to have sharp straight teeth and carnivores preying on land animals had a tendency to have long, sharp, curved teeth that resembled daggers. Still some animals have odd teeth, or no teeth at all. The farther back you go in time the more foreign and bizarre creatures get. The main predator in the Cambrian era was anomalocaris, an animal so weird that fragments of its fossils were thought to be three distinct animals. Only when a complete fossil was found could paleontologists put the big picture together. So how are we to tell for certain what an animal ate?
Fortuneately there are a very few fossils that have saved the soft tissue matter of these animals. Every once in a while fish fossils will be found with other fish in their belly and on even rarer occasions a dinosaur will be found that looks like an X-ray. In China an 8 foot long Sinocalliopteryx ate two primitive birds before its demise, as shown by the leg bones in its stomach.
Girl or Boy?
The sex of a fossilized animal was usually a guess determined by comparing it to similar living animals. For instance in species that had horns the ones with the larger horns were generally considered to be the males just like the moose, bulls, and big horn sheep of our day. Sometimes larger reptilian animals like T-rex were considered females because many lizards and snakes grow larger females than males. At other times the width of the hips was considered because females would have to lay eggs or give birth and needed wider hips to do the job. However these were educated guesses, not fact until recently. Paleontologists at the Museum of the Rockies in Montana devised a way to tell for sure if their dinosaurs were wearing the pants of the family or a skirt. They studied the thighbones of several specimens to see if they could find evidence of medullary bone, a substance that is found in female birds that gives them the calcium and other compounds needed to create egg shells. Sure enough the first specimen they tested, named Bob, was discovered to in fact be a Bobbette.
What did they sound like?
When parasaurolophus was first discovered paleontologists thought his long head crest was used as a snorkel so he could swim under water. This was some imaginative speculation but was completely wrong. Further discoveries showed the crest had no hole in the top that would allow for such a use and future generations of paleontologists realized this animal was not an animal that lived in or near the water either. So what was the head crest for? As it turns out it was a horn. With the help of expanding computer technology paleontologists were able to recreate the call these dinosaurs likely made to each other.
Recently cricket fossils from the Jurassic era were studied in order to discover what they sounded like. Just like modern day crickets they may have created noise using something called a stridulating organ. These crickets sounded much different than today's with very high frequency pings that only lasted for one note.
The Call of a Parasaurolophus
Some dinosaurs may have appeared so different as babies and adolescents that they have been identified as completely different species than their adult counterparts. Baby triceratops for instance hatched with little nubs instead of horns and frilled ridges around their head crest that would later disappear as they got older. We know triceratops of all ages look different because we've found them all in herds. This isn't so easy when you're looking at a dinosaur that is not found in herds of different ages.
Dracorex Hogwartsia sounds like a joke name but it is a real and stunning animal whose head could very easily be confused with that of a dragon. There is debate about whether or not it is its own species or is just the awkward teenage stage of a pachyecephalosaurus.
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