About 130 yrs ago, Harry Govier Seeley, a paleontologist trained in Cambridge, classified dinosaurs into two distinct groups, or clades, depending on the kind of their pelvic bones. The “reptile-hipped” saurischians included carnivorous theropods such as the Tyrannosaurus Rex (T-Rex), while the “bird-hipped” ornithischians comprised herbivores such as the Stegosaurus and Triceratops. Looking for dinosaur fossils were found, one third group, dubbed sauropodomorphs, was established. In 1887, Seeley figured that the long-necked herbivorous sauropods, much like the Brontosaurus, were in connection with theropods and classified them as saurischians.
The broad groupings had not been entirely satisfactory given that researchers later found some ornithischians that displayed theropod-like behavior: these people were bipeds and carnivorous. However, in spite of the shortcomings, the classification never was questioned alternatives when a team in the University of Cambridge and Natural History Museum made a decision to revisit the decades-old dinosaur family tree.
University of Cambridge paleobiologist Matthew Baron along with his colleagues David Norman and Paul Barrett spent few years examining 74 species, most of which lived throughout the first 100 million a great deal of the dinosaur era. Then they analyzed the differences and similarities in over 457 anatomical attributes of these ancient creatures.
Their investigation generated the conclusion that it is the ornithischians and saurischians which can be related as well as the sauropodmorphs which need to be separate. The study developed a new dinosaur tree, grouping the first kind two within new classification – ornithoscelidan – and giving the sauropods their particular category.
As an effect, the meat-eating T-Rex as well as the vegetarian Stegosaurus now belong to the same family. This arrangement eliminates the confusion on the previous classification since all the people the ornithoscelidan, which mean “bird-limbed,” possess common physical characteristics just like the kind of their skulls and hind-limbs.
Baron, who led the learning, says, “When we started our analysis, we puzzled that explain why some ancient ornithischians appeared anatomically a lot like theropods. Our fresh study suggested the two groups were indeed area of the same clade. This conclusion came as a good shock considering that it ran counter to everything we’d learned.”
The researchers also assert the first dinosaurs could have inhabited earth slightly prior 243 million a long time ago and report that contrary to popular belief, that they’ve originated from what exactly is now North America, not Gondwana C the southern portion of the supercontinent Pangaea.
Study co-author Barrett on the Natural History Museum says: “This study radically redraws the dinosaur family tree, providing a completely new framework for unraveling the evolution of their total key features, biology, and distribution through time. If we’re correct, it explains away many prior inconsistencies with our familiarity with dinosaur anatomy and relationships, and it likewise highlights several new questions relating to the pace and geographical setting of dinosaur origins.”
It will, of course, take a great deal of debate before experts accept or reject the latest theory. So don’t toss out of the social studies textbooks yet!
Resources: nature.com, phys.org, guardian.co.uk