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| Confuciusornis, an early bird/theropod dinosaur from 125-120 mya |
- Dinosaur biogeography - with the increased number of described dinosaur species (now over 1000) and continuing new discoveries, researchers have the detail to do metanalyses of biogeography and paleoecology.
- A better understanding of the timeline for dinosaur evolution - new dinosaur trackways in Poland push back the appearance of dinosaurs to just after the great Permian/Triassic extinction.
- Dinosaur physiology - many examples in this area, including:
- Recovery of soft tissues in tyrannosaurids and hadrosaurs (duck-billed dinosaurs), including the collection of collagen and protein sequences.
- The discovery of bone-embedded air sacs indicating that theropod dinosaurs used one-way flow through their lungs like birds.
- The recent identification of melanosomes in dinosaur feathers, the organelles that produce feather coloration. This study suggests that the theropod dinosaur Sinosauropteryx had reddish-brown stripes on its tail.
- Did I mention feathers? This past decade has seen tons of research describing the wide distribution of feathers, at different evolutionary stages, across dinosaur phylogeny, including ornithischians (the taxon not closely related to birds). And a new paper has just described the developmental changes that occurred in dinosaur feathers, and suggests that dinosaurs had a wider range of feather types during development than modern birds.
Two legged dinosaurs are portrayed in museums and television with their bodies held horizontally and their legs vertical. This is not at all possible because their center of gravity is above their hip bone (or forward of the hip when the body is horizontal). If they had attempted to walk horizontally with their legs vertical they would have toppled forward and protected themselves from impact with the upper part of their huge head. Almost certainly they walked almost erect, but at least at a 45 degree angle, often with the tail held aloft in order to prevent tripping by thrusting it back and to prevent an assailant from jumping on their back. To see a discussion of this see http://charles_w.tripod.com/dinosaur.html or in this journal article http://gsjournal.net/Science-Journals/Essays-Paleontology/Download/4718 . If you see any errors in them, please let me know. You may also see an explanation why vertebrate size, extent of bone, and teeth declined during the Cretaceous on the savannas in http://www.angelfire.com/nc/isoptera/termites.html as caused by a phosphorus famine produced by Amitermitinae plant smothering termites starting probably in late Jurassic Australia. Loss of teeth was probably much accented in birds and pterosaurs because of the young eating termite mating insects which had iron oxide and bauxite in their guts.
ReplyDeleteSincerely, Charles Weber