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Tuesday, April 04, 2017


Steve Cole ponders thoughts on dinosaurs:
1. Cruralispennia multidonta is a new bird from 131 million years ago found in China. The early evolution of birds (which split from dinosaurs somewhere around 150-154 million years ago) is not well understood, but there were true birds flying 90 million years before T-rex stalked his triceratops prey. This new Chinese bird shows that there were a lot of very different kinds of birds flying only 20 million years after the first bird appeared.
2. Lots of fossil news comes out of China these days for several reasons. One is that the Chinese didn't really start looking for them until 20 years ago, and due to the global fascination with all things dinosaur, the Chinese are determined to find all of their dinosaurs in short order. (It took a century and more for us to find the many well-known North American fossils.) Chinese national pride is at work, as the Chinese government rewards scientists who bring good publicity to the nation.
3. In Siberia there is a region the size of the continental US which is covered in mile-deep lava that was deposited 250 million years ago. These "Siberian Trappes" are what gave the dinosaurs their shot at the big time. (Trappes is a word for "steps" which is sort of what they look like, lots of flat plains bordered by cliffs going up or down to the next flat plain. Usually all of the elevation changes are in one compass direction.) These huge volcanoes (far bigger than Yellowstone) erupted for 100,000  years, poisoning the atmosphere, the rain, and the oceans. The food chains collapsed in most places and 95% of plant and animal species became extinct.  When the eruptions were over, small groups of unusual plants and animals in "special case" areas were all that were left, and these evolved into new types, one of which happened to be a dinosaur.
4. The Archosaurs are a very old group of reptiles from the ancient past. They appeared at the start of the Triassic. Their descendants include crocodiles and birds, as well as extinct lines such as dinosaurs, pterosaurs, and marine lizards.
5. Plesiosaurs are a long-necked marine lizard (think Loch Ness Monster, or a brontosaurus with flippers for legs). A new study of the bones in several nearly complete specimens indicates that in most species the neck primarily bent down, not up or sideways. This may mean that plesiosaurs glided along just above the bottom (or just above a school of fish) and reached down whenever they wanted a snack.
6. Vertebrates (animals with spines, like snakes, lizards, dogs, and humans) started climbing out of the rivers and onto the land about 385 million years ago. And evaluation of several different animals from that time period shows that at this moment in history, the eyes of river fish tripled in size when they became amphibious creatures. The increase in size would have almost no value to a creature living in water, but would make the life of a creature living in air much more workable. Perhaps what happened is that river fish noticed food just above the water (plants, insects, or whatever). Evolutionary theory holds that random mutations happen on their own, and those mutations that prove to be useful create new animals (while those that have no virtue die out). Water animals that had these larger eyes were better suited to grabbing this "just out of reach" food because they could see it. Some of those creatures had another spontaneous (or directed by unknown designers) mutation in which their fins became larger and stronger and could allow the fish to climb up on wet rocks, the better to grab the food.
7. Horseshoe crabs have been around for a very long time, far longer than dinosaurs. Some point to these and say that they are exactly identical and disprove evolution. The reality is that they are clearly of the same family of critters but not the same species, and are not identical. Someone who as not being specific might note that a house cat and a leopard were "identical" and a quick look says they're clearly from the same tribe, but no scientist would call them identical. These ancient crabs only prove that our planet's biological history is as mysterious as it is awe inspiring.
8. Some 78 million years ago (during dinosaur times), a very big rock of some kind struck Iowa. Estimates of the explosive force indicate it could have killed land animals the size of cows up to 650 miles away.
9. One key adaptation that made mammals successful was the three-lobed molar, the chewing teeth at the back. With the ability to both sheer and crush food, the variety of foods that mammals could eat expanded exponentially.
10. Recently, three teeth were found in Mexico that are clearly tyrannosaur and from about the time of T-rex, but they have clear differences and are apparently from an unknown cousin of "the big boy" of the dinosaurs. No skeletons have been found so not much is known.