Channels, Spring 2018

Page 70 Oldham • A Four-Legged Megalosaurus Mantell’s reptilian beasts. His own comparative study of the Iguanodon and Megalosaurus led him to a different estimation of size. The calculations came out with more believable sizes. Iguanodon went from the preposterous size of two-hundred feet to a humble twenty- eight feet long. Megalosaurus also was scaled down to about thirty feet long and this time being slightly larger than its equivalent. Since the animals were, just a little bigger than an elephant Owen reconstructed them as such. Iguanodon and Megalosaurus become elephantine cold-blooded reptiles (Figure 2). In 1841, Owen put these monsters into his new clade dinosauria. He believed that Iguanodon, Megalosaurus, and Hylaeosaurus marked the apex of the reptilian class. Owen hoped this was the final nail in the Lamarckian, and even Darwinian evolution, coffin. In Owen’s mind, The superiority of the dinosaurs, living in a glorious “Age of Reptiles”, was a direct act of divine Creation. Species did not transmute into one another but were placed on the earth by Design and if they appeared to form a succession, it was a result of divine planning rather than evolution. (Desmond, 1990 pg. 21) In light of their obviously complex nature and seemingly apparent superiority as compared to their modern reptilian relatives, dinosaurs should have been better adapted to survive to the modern era. Yet, they did not survive, and the question was why? According to Owen, it was not that they had evolved, but rather were divinely created. Owen’s idea would later fall by the wayside as the paradigm shifted from special creation and catastrophism to evolution and uniformitarianism. His new clade of dinosauria would continue to survive, and his concept of elephantine reptiles would endure as well. Leaping Laelaps: Dinosaurs as Giant Kangaroos A discovery in the New Jersey marl by William Foulke and Joseph Leidy would completely overturn Owen’s reconstructions. Leidy called the new dinosaur Hadrosaurus and noticed that his new creature was similar to the Iguanodon of England. He also noticed that, The great disproportion in size between the fore and back parts of the skeleton of Hadrosaurus leads me to suspect that this great extinct herbivorous lizard may have been in the habit of browsing, sustaining itself, kangaroo-like, in an erect position on its back extremities and the tail. (Foulke, Leidy, 1858) After the discovery of Hadrosaurus and before the bone wars waged in the western U.S., E.D. Cope found another set of remains among the marl. Cope named his new dinosaur Laelaps (now Dryptosaurus ). With his new skeleton Cope noticed that the creature could not have possibly walked quadrupedally. He said this about Laelaps posture, They must also have been very much flexed under ordinary circumstances, since the indications derivable from the two humeri, or arm bones, are, that the forelimbs were not more than one-third the length of the posterior pair. This relation, conjoined with the massive tail, points to a semi-erect position like that of