palaeontologist uses the generic term ‘dinosaurs’ in conversation, they are generally referring to non-avian dinosaurs.
Dinosaurs were divided into two orders by the British palaeontologist Harry Seeley in 1888: the saurischians and the ornithischians. Seeley characterized these orders (or lineages) by the arrangement of the bones in the hip. The saurischians, which have a pubic bone that slopes down and forward, were named ‘lizard-hipped’ because their hip structure resembled that of a lizard. The ornithischians, which have a pubic bone that slopes down and backwards, were named ‘bird-hipped’. Despite the fact that ornithischians were named bird-hipped because their hip structure was similar to birds, Seeley did not identify any similarity to birds. In fact, further study determined that modern birds actually evolved from the lizard-hipped saurischian dinosaurs, not the bird-hipped ornithischians.
The saurischians include two major dinosaur groups, the sauropods (large herbivores such as Apatosaurus and Diplodocus) and the theropods (meat-eaters such as Velociraptor and Tyrannosaurus). The ornithischians include armoured dinosaurs (such as Ankylosaurus), horned dinosaurs (ceratopsia), and duckbilled dinosaurs (hadrosaurs). Though scientists have concluded that the oldest dinosaurs were 225 million years old, they do not know how much earlier in time the common ancestor of the lizard-hipped and bird-hipped dinosaurs lived.
As with most areas of the study of dinosaur science, there is also a major controversy about the extinction of what we commonly call dinosaurs. Did dinosaurs die out catastrophically as a result the Cretaceous–Tertiary extinction event that occurred 65 million years ago, or did they die out gradually over a long period of time due to climate changes or environmental forces? There is quite a bit of evidence to suggest that an asteroid hit the earth 65 million years ago and that not only wiped out dinosaurs but a great numbers of other animals and plants as well. Except for a few explainable aberrations, there are no non-avian dinosaur fossils above the Cretaceous–Tertiary boundary in rocks younger than 65 million years old.
Like many palaeontologists, Currie believes that when the asteroid hit natural selection was already at work. By the end of the Late Cretaceous period, temperature shifts on the planet were becoming extreme. He points to the rocks along Alberta’s Red Deer River that stretch into Dinosaur Provincial Park as evidence that factors such as climate change were already at work phasing out certain species.
‘If you look at 10 to 15 million years before the asteroid hit, you have more than 40 species of dinosaurs in this region,’ he explains. ‘By 5 million years before dinosaurs became extinct, you have about 25 species of dinosaurs. The rocks that were laid down a million or so years before the end of the Cretaceous along the Red Deer River have fewer than a dozen species of dinosaurs. That is telling me loud and clear that there was something else going on to reduce their diversity, and I suspect it was climatic.’
‘There is no black or white in palaeontology, only differing shades of grey.’
Further, Currie argues, if an asteroid hit and simultaneously wiped out all the dinosaurs, then there should be an abundance of fossils present on the Cretaceous–Tertiary boundary. However, the preserved evidence does not show this. In North America, the fossil record shows that only a few dinosaurs, including Ankylosaurus, Triceratops and Tyrannosaurus, lived until the end of the Cretaceous period. Studying the succession of faunas over a 10-or 15-million-year period shows that species’ diversity was dropping off.
‘Prior to the asteroid hitting, something else was going on,’ Currie reasons. ‘It’s like everything: as humans what we do is try to come up with a simple answer, but in nature there is not necessarily a simple answer.’ He acknowledges that this is just one of many theories on extinction. ‘It’s very easy to come up with a new theory for dinosaur extinction; it’s not so easy to go out and get the evidence. The problem is that it takes years and years of collecting evidence.’
The same can be said about almost all dinosaur theories. There is no black and white in palaeontology, only differing shades of grey. Short of having a time machine to travel back to the Jurassic or Cretaceous periods, palaeontologists must take to the field and dig for evidence, and then hold new fossil finds up against existing ones. Eureka moments are very rare. Discoveries take years to be prepared, studied and then scientifically described before they are presented to the public for further debate. Even under the best of circumstances, they are met with doubting eyes and contradictory theories rather than front-page headlines.
chapter 2
the dino hunters
The special group of palaeontologists loosely known as dinosaur hunters are detectives who spend their lives trying to put together pieces of an ancient mystery that may never be fully solved. The dino hunter is part historian, part explorer, part scientist. He attempts to reconstruct history which dates back more than 65 million years – or 60 million years before the first human – through a combination of research, fieldwork and lab work. To do so he must raise public and private money to fund expeditions, navigate foreign government bureaucracies to gain access to critical sites, endure the harsh conditions of some of the most brutal climates on earth, outsmart poachers looking to make a buck on the black market, and recruit young palaeontologists to assist in the field and the lab.
Dinosaur finds can be traced to the ancient times of the Western Jin Dynasty of China, when they were thought of as ‘dragon bones’, although the first identified dinosaur find occurred in 1676, in England. Part of a large bone was found in a limestone quarry at Cornwall and described the following year by Oxford professor Robert Plot as the femur of a large animal like an elephant. However, some people concluded later that it must have belonged to a giant human like those written about in the Bible. It wasn’t until 1824 that the first scientific description of a dinosaur was written by another Oxford professor, William Buckland. After collecting a large number of dinosaur bones over a nine-year period, Buckland determined they were all from a related animal that resembled a giant lizard, and he published a scientific paper describing a great fossilized lizard that he named Megalosaurus. Although this was the first dinosaur described, the term ‘dinosaur’ wasn’t coined until 1842 when Richard Owen recognized that the remains shared a number of features and therefore should be grouped together taxonomically.
An artist’s impression of the duckbilled dinosaur Corythosaurus.
Jaime Chirinos/Science Photo Library
The first recorded North American dinosaur find was made in 1838 by John Estaugh Hopkins in a mudstone quarry on the Cooper River in Haddonfield, New Jersey. Hopkins displayed in his house the bones he found, where they were seen by his friend William P. Foulke, a part-time geologist. Foulke returned to the quarry and discovered most of a skeleton, which he asked palaeontologist Joseph Leidy to help him extract and study. Leidy scientifically described the find and named it Hadrosaurus foulkii, or ‘bulky reptile’. The Hadrosaurus find would lead to what became known as the ‘bone wars’ which erupted between dinosaur hunters Othniel Charles Marsh and Edward Drinker Cope, who were both mentored by Leidy.
Marsh, of Yale University’s Peabody Museum of Natural History, and Cope, of the Academy of Natural Sciences in Philadelphia, were initially cordial and shared information on their finds. But a dispute broke out over a fossil site that was discovered by Cope just south of the Haddonfield site. Cope was having the site’s new finds sent to him for examination, but when Marsh realized there were an untold number of bones to be recovered, he began paying those digging the site to divert the finds to him. Cope found out about Marsh’s underhanded tactics, and the gloves came off.
For the next 20-plus years, Marsh and Cope used all means available – including bribery and theft – to outdo one another in the search for dinosaur bones. Both men spent considerable sums of money trying
