Scientists believed that the Coelophysis dinosaur regularly practiced cannibalism when other food options were scarce. But a study by Sterling Nesbitt from the American Museum of Natural History shows the misunderstood meat-eater was actually snacking on ancient crocodiles.

Coelophysis bones unearthed near Ghost Ranch in New Mexico from 1947 appeared to have the bones of their own young within their stomach cavities. Back then, researchers convicted the 200 million-year-old dinosaur as a cannibal, based on the evidence.

Were they better adapted to their environment than competing species?  Were they more diverse than other species?  Or were they just lucky?

It’s the latter, according to one scientist at New York’s Columbia University.

Steve Brusatte, a Ph.D. student, told the Earth & Sky website that crurotarsans – a species that was at its peak during the Late Triassic period – were more diverse and better adapted to life on Earth than dinosaurs.

“Steve Brusatte said if we were standing in the Late Triassic and someone asked him who would come out on top, he would have bet on the crurotarsans. There must have been a feature that helped the dinosaurs.”

But here’s one theory that takes all the others out with the tide: Change in sea level is the real culprit.

“The expansions and contractions of those environments have pretty profound effects on life on Earth,” says Shanan Peters, a University of Wisconsin-Madison assistant professor and author of the study that explored this new theory.

In particular, it is the ebbs and flows of water and sediment over geologic time that has led to mass extinctions over the past 500 million years. According to Peters, it’s also this change that determines the composition of life in the oceans.

A brief history of mass extinction events
Scientists believe that there may have been as many as 23 mass extinction events since life first began on Earth 3.5 billion years ago. Included in these are the dinosaurs, but also much simpler life forms, such as single-celled micro-organisms.

Consider this: in only the last 540 million-years, there have been five well-documented mass extinctions. Here, marine plants and animals were the major casualties, with as much as 75 to 95 per cent of such species dying-off.

A modern problem
One reason for these shifting tides is that, over hundreds of millions of years, the world’s oceans have responded to the shifting of the Earth’s tectonic plates and to changes in climate.

Experts are quick to point that our own species will bear witness to a rapid change in sea level.

“This breakthrough speaks loudly to the future impending modern shelf extinction due to climate change on Earth,” says Rich Lane, the National Science Foundation (NSF) Program Manager.

Not the only factor
Peters argues, however that while the changing sea level theory doesn’t preclude possible contributors to mass extinctions, it does provide a common link among these events over a significant stretch of the planet’s history.

“The major mass extinctions tend to be treated in isolation by scientists,” Peters says. “This work links them and smaller events…and it also tells us something about who survives and who doesn’t across these boundaries. These results argue for a substantial fraction of change in extinction rates being controlled by just one environmental parameter.”

The study appears in the June 15 edition of the journal Nature.

A dinosaur first found over thirty years ago by a high school teacher was confirmed to be a new species, a herbivore with a bony frill and horns on the back of its skull and bony structures above its eyes.

Philip Currie, the University of Alberta paleontologist who seems to be in the thick of almost every major discovery in Canada, told the Edmonton Journal that “We eventually realized it was not only a pretty rare kind of ceratopsian (horned) dinosaur, it was also a new species…. Horned dinosaurs are pretty weird anyway, and this is probably the most bizarre of all of them.”

The Globe and Mail goes into detail about the find, and the struggle of Al Lakusta, the high school teacher who discovered the fossils, to get the bones taken seriously by authorities.

According to the Globe and Mail:

Pachyrhinosaurus means thick-nosed lizard, but lakustai is in honour of Mr. Lakusta’s determination and hard work. It is also a recognition of the importance of what he unearthed.

The dinosaur bone bed he found is exceptional, and contained 27 individual creatures, including youngsters. They died together 72.5 million years ago, perhaps crossing a river or in a catastrophic flood.

Their necks were long and slender that could look easily on bushes and trees. They can walk in four legs and can rear up on its hind legs to search the higher levels and gain access in higher foliage. The Plateosaurus lived around the area of France, Germany and Switzerland.

When the Triassic Period was about to end, mass extinction happened. The Pangaea or the land mass started to break apart and was divided into two, namely the Laurasia in the north and Gondwanaland in the south. The Antarctica belongs to the Gondwanaland continent and it was united with South America, India, Africa and Australia.

Replica of Eoraptor at Brussels

The Eoraptor was a dinosaur that is about the size of an average modern dog that lived also during the later part of the Triassic Period. The Eoraptor was excavated in 1992 at the Northwestern part of Argentina, what they unearthed was the skull and skeleton that was about 3 ft. long. The Eoraptor had very sharp teeth, probably stood on both three-toed feet and had three-fingered hands. Like the Coelophysis, it is evident that it was a part of the suborder Theropoda or the “meat-eating dinosaurs”.

It inhabited the highland forest areas. Most meat-eaters travel alone or in small groups not like the plant-eaters that live and travel together. Some young Coelophysis remains were found in the ribcages of two adult Coelophysis. This was once thought to be evidence of a live birth rather than egg laying.

However the advanced development of the skeletons indicated that the young Coelophysis were probably eaten by the adults. Therefore cannibalism also occurred in living meat-eaters, especially when food is scarce.

The history of the planet Earth is divided into a bunch of time chunks so whether you’re looking at a time which existed 100 years ago or even as far back as 1000 million years ago you’ll need to learn the lingo used to classify each of these sizable time periods. The most important of these are aeons, eras and periods.

The rest of this article will go onto explain the timeline that the dinosaurs existed in so if you’re not familiar with the terms aeon, era and period we recommend you take a look at our timeline defintions page here, otherwise read on to learn more about the age of the dinosaurs.

The Age Of The Dinosaurs

The Dinosaurs and many of the other large prehistoric reptiles existed in the Mesozoic era of the Phanerozoic aeon. The Mesozoic era ran from about 250 million years ago to 65 million years ago. Thats 185 million years of Dinosaur domination, no wonder the Mesozoic era was commonly referred to as the age of the Dinosaurs.

The Mesozoic era contained three periods known as the Triassic, Jurassic and Cretaceous periods. Over the next few sections we will try to cover the key charcterstics of each period to give you an overall understanding of when and where certain dinosaurs existed as well as smashing some of the common myths and misconceptions surrounding that time period.

The Triassic Period

The Triassic Period is the first phase of the Mesozoic era and spanned for an interval of 35 million years from 250-205 million years ago. Planet Earth was a very different place back then with the most common difference being that all the continents were united to form one huge c shaped land mass or super continent known as Pangaea meaning “all lands”.

The Jurassic Period

The Jurassic Period was the second phase of the Mesozoic Era. The time scale for this famous period is from 205 to 138 MYA (million years ago). This period was named after the Jura Mountains because of the exposure and discovery of the marine lime stones.

The Cretaceous Period

The Cretaceous Period was the last period of the Mesozoic era and marked the end of the dinosaurs. It spanned a time from 138 million to about 65 MYA (million years ago). In this period the continents fully separated. However, Australia and Antarctica were still united. There were important things that happened in this period such as the development of flowering plants like the magnolias and water lilies and the increase in the number of different kinds of insects. This was the beginning of the modern insects such as the ants, butterflies, grasshoppers, termites and aphids.

This dinosaur footprint, including three toes and a heel, is thought to have been made by an upright-walking meat-eater.

More than 1,000 dinosaur footprints along with tail-drag marks have been discovered along the Arizona-Utah border. The incredibly rare concentration of beastly tracks likely belonged to at least four different species of dinosaurs, ranging from youngsters to adults.

The tracks range in length from 1 to 20 inches (2.5 to 51 centimeters).

“The different size tracks may tell us that we are seeing mothers walking around with babies,” said researcher Winston Seiler, a geologist at the University of Utah.

The tracks were laid about 190 million years ago in what is now the Vermilion Cliffs National Monument.

“There must have been more than one kind of dinosaur there,” said researcher Marjorie Chan, professor and chair of geology and geophysics at the University of Utah. “It was a place that attracted a crowd, kind of like a dance floor.”

While the site is covered in sand dunes now, the researchers say the tracks are within what was a network of wet, low watering holes between the dunes.

In fact, the tracks provide more evidence of wet intervals during the Early Jurassic Period, when the U.S. Southwest was covered with a field of sand dunes larger than the Sahara Desert.

Chan and her colleagues, including Seiler, described the dinosaur track site in the October issue of the international paleontology journal Palaios.

By studying the shapes and sizes of the tracks, Seiler suggests four dinosaur species gathered at the watering hole, though the researchers have yet to match the prints with specific species.

Currently, the tracks are named for their particular shapes and include:

Numerous dinosaur track sites have been found in the western United States and elsewhere around the world.

For instance, tracks from a herd of 11 giant sauropod dinosaurs were discovered in the ancient coastal mudflats of Yemen. But the new discovery is rare in the density of tracks.

“Unlike other trackways that may have several to dozens of footprint impressions, this particular surface has more than 1,000,” Seiler and Chan write.

Chan first visited the site of the dinosaur tracks in 2005 with a U.S. Bureau of Land Management ranger who was puzzled by them. Chan initially called them potholes, which are erosion features common in desert sandstone. “But I knew that wasn’t the whole story because of the high concentration and because they weren’t anywhere else nearby but along that one surface.”

One unnamed reviewer of the Palaios study still believes the holes are erosion features, according to a statement released today by the University of Utah.

In 2006, Seiler saw the tracks and had similar thoughts.

“At first glance, they look like weathering pits — a field of odd potholes,” he said. “But within about five minutes of wandering around, I realized these were dinosaur footprints.”