RANDOM THOUGHTS #281

Steve Cole ponders thoughts on dinosaurs:
       

1. The Morrison Formation is a large geological area including the current Colorado plateau. Scientists have found more turtles and crocodiles (150 total specimens) in the east and north than in the south and west, indicating that during dinosaur times, those areas were wetter, perhaps mostly swamp. These eastern and northern areas have relatively greater abundance of limestone and mudstone, things that are created in oceans and swamps.
        

2. There is a large impact crater in Ukraine known as the Boltysh structure. It dates from (best guess) a few thousand years before the Chicxulub crater, although geological dates are squishy and it could be anywhere within a million years either way (in a similar orbit and just hit a few loops around the solar system earlier or later) or even on the same day (fragment of the same asteroid). This impact has not been adequately studied so far.
  

3. During the dinosaur period (the Mesozoic, which includes the Triassic, Jurassic, and Cretaceous) the earth was rotating faster and days were shorter, around 22 hours at the start of the Triassic (385 days in a year) and 23 at the end of the Cretaceous (375 days in a year). The year lasted about the same number of hours but had more and shorter days.
      

4. Birds don¹t use lungs like mammals do. In a mammal, there is one pipe into the lung, and air flows alternately in and out by way of that one pipe. In a bird, air is taken all the way down and put into the bottom of the lungs, then flows up and out a separate pathway, so the airflow only goes one direction. This is more efficient and without this (and a lot of other bio-engineering) birds could not fly. Apparently, meat-eating dinosaurs and saraupods (the biggest ones, like Brontosaurus) did the same thing. It gets better. Birds, meat-eating dinosaurs, and sauropods had hollow spaces in some of their bones, and these were actually part of the air circulation system.
    

5. Dinosaurs come in two types: bird-hips (stegosaurus, duckbill, triceratops) and lizard-hips (birds, meat-eaters, and sauropods). This is defined by the shape of the bones in their hips.
    

6. One relatively new field of the study of dinosaurs is brain endocasts. These are castings made from the empty skulls of dinosaurs (or any animal) to create a rough model of the brain. This has become much easier since scans and 3d model technology allows this to be done without destroying the invaluable skull. Scientists are, often, able to identify major brain structures (fore-brain, mid-brain, hind-brain). Comparing this to existing animals yields important clues into the intelligence and behavior of the dinosaur. It is often possible to identify the areas linked to sight and to smell, and the relative size of these areas indicates how the animal hunted (or avoided being hunted).
   

7. A new study of the later years of dinosaurs (just a few million years before the big rock hit Mexico) shows the appearance of new species of large snakes and large birds which preyed on dinosaur eggs. This probably does not mean that egg thieves were the cause of dinosaur extinction, but it is unclear what it does mean beyond the later times of the dinosaur era having new threats and dangers.
  

8. One way we learn more about dinosaurs is trackways. These happen when a dinosaur walks across a muddy flat area just before a sandstorm or volcanic ash cover everything up. The trick is, unless you find the dead dinosaur at the end of the tracks, you really have no idea which species made them. (We have never found the aforementioned dead dinosaur, but scientists continue to hope.) Dinosaur fossils rarely have any skin or tissue left, so footprint identification is a matter of which skeletal foot is close. Consider also that we might logically know as little as 1/3 of all the dinosaur genera that ever lived, so the tracks you find might not connect to any known dinosaur. Tracks can be measured but it's hard to tell what speed the dinosaur was going when he made the tracks, but there are mathematical guesses. This probably results in the normal walking speed, not the fastest running speed, but at least in theory we'd know from the shape of the tracks if the dinosaur was running.

        
9. THE LOST WORLD by Arthur Conan Doyle was inspired by some huge fossil dinosaur teeth he saw. Funny thing is, these were later identified correctly as crocodile teeth. (Crocodiles back there were three times the current size.)
    
10. You might assume that the south pole was always cold, but during the Cretaceous it was covered with open forests and a rich diversity of dinosaur types and sizes, including some not found anywhere else.