Dinosaur Evolutionary Tree Is All Wrong
Oops… The dinosaur evolutionary tree is all wrong!
A new study has revolutionized the dinosaur evolutionary tree, producing “the biggest change to dinosaur tree in 130 years” (New Scientist. March 25, 2017, p. 9). The old theory classified dinosaurs into two significantly distinct dinosaur families, those with bird-like hips that point downwards and towards the tail, called the ornithischians, and those with lizard-like hips that point downwards and to the front, called the saurischians. The new theory was based both on newer dinosaur findings that were not available earlier and a newer analysis of dinosaur traits. Instead of focusing on the pelvic bone, as in the old system, Baron and his team analyzed 457 characteristics in 74 species (Baron et al. 2017. A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature 453(7646):501-506; K. Padian. 2017 Dividing the Dinosaurs. Nature. 543(7646):494).
These findings forced development of a new dinosaur family tree.
They found that the 21 anatomical features they selected can be used to divide the dinosaurs very differently than the older system. As there is no correct way of selecting traits used to classify, selection of other traits could be used to divide dinosaurs into an even different evolutionary tree. Based on these features, the new tree puts T. rex and other theropods on the side of the “bird-hipped” creatures, and the sauropods with those related to Herrerasaurus, a South American bipedal carnivore. These findings forced development of a new dinosaur family tree. This revolution is not unusual in evolutionary biology, and illustrates the tenuousness of classifying life, a field termed taxonomy. Using one set of traits one can produce one taxonomy, and using another different set can produce a very different taxonomy. Thus, taxonomy classifications are somewhat tenuous.
The taxon Dinosauria was named in 1842 by paleontologist Sir Richard Owen (1804 -1892), a creationist. Richard Owen was one of the strongest scientific opponents of Darwinism during the age of Darwin. The term dinosaur means terrible lizard due to their size and assumed ferociousness. Paleontologists admit they know almost nothing “about the early evolution of these creatures, and in particular, the evolution of the dinosaurs before the [putative] saurishian-ornithischian split (C. Forster. 2000. “The First Dinosaurs” chapter 2 pp. 41-52 in R. Silverberg. editor, The Ultimate Dinosaur, New York, Simon and Schuster). Thus, new discoveries can revolutionize their conclusions, as occurred in this case. Taxonomy is not only used to determine evolutionary trees, but also to differentiate one species from another. The problem is the species concept is an imperfect and problematic method to classify life. As Cornell trained taxonomist Carol Yoon wrote, species classification was the “gray area of the field” and, more problematically “it was a moving target,” as this new dinosaur study shows (C. Yoon, 2009, Naming Nature: The Clash Between Instinct and Science. New York: Norton. pp. 104-105).