Science Spin March 2009

In search of Africa's lost dinosaurs

By Tom Kennedy

Long before the harsh dry deserts, the entire north end of Africa was a warm, humid delta like environment. Crocodiles swam in shallow waters, flying reptiles spread ten metre wide wings, and dinosaurs grew into giants.

One hundred million years ago during the Cretaceous period, the Sahara teemed with life, and as palaeontologist, Nizar Ibrahim, explained, we humans, who had yet to evolve, would have been dwarfs in that land of monsters. The dinosaurs of Africa were big, and for some as yet unknown reason, most of the other animals in that carbon dioxide enriched environment were scaled to match. We often think of American Tyrannosaurus rex as big, but some of the plant-eating African dinosaurs were actually a lot bigger.

The American dinosaurs are better known to most of us because their fossilized remains are more accessible and easier to find, but as Nizar observed, to get a more balance view of what the Cretaceous period was like, we need to explore and broaden our horizons.

Nizar admits to being a dinosaur enthusiast, and has been as long as he can remember. Even as a small boy, clutching his dino toy, he just knew that he would have to become a palaeontologist. His bemused, but approving parents, made sure to satisfy his growing appetite for suitable books, and when the time came to study, he headed for Bristol where the university, with a long and distingished history in the Earth Sciences, has a strong focus on palaeobiology.

As an undergraduate, Nizar was already impatient to get out into the field, and as he explained, do real hands-on research. A lot of scientists, he said, just visit museums and while there is nothing wrong with that, Nizar did not think this was good enough, and besides he was the sort of student who had, quite literally, played with live snakes as a child. He was well aware that we still know very little about the explosive growth of life during the Cretaceous, and that we know even less about conditions at the time in Africa.

Pictures of an enormous sail backed Spinosarus dinosaur fossil discovered in 1910 by Ernst Stromer in Egypt, and subsequently lost in the World War II bombing of Munich, had made a great impression on Nizar. It is amazing, he said, to realise that this animal, one of the largest ever discovered, once existed, it was real, and not just some illustration in a book.

For his research, Nizar wanted to go out and uncover more evidence to show that this giant was no isolated find, and that if palaeontologists were prepared to go out into the wilderness, they would disover the fossilized remains of an ancient world that stretched right across the northern end of Africa. Nizar likes to get out and about, but he also makes a good argument to explain why scientists should be prepared to get their hands dirty. Many of the fossils in museum collections, he said, were bought from collectors or acquired from secondary sources, and from a scientific point of view, this can limit their value. A palaeontologist, like an archaeologist, can read much more into a find when they know exactly where it came from.

Nizar's ambitious thesis proposal brought him to UCD where he is now a PhD student, busy writing up the results of an expedition to Morocco that last year led him up over the Atlas Mountains and far out into the desert.

Nizar's determination paid off in a big way. The expedition team, led by Nizar and made up of scientists from the University of Portsmouth and the Université Hassan II in Morocco, made a number of remarkable discoveries, including dinosaur tracks, fragments of a flying reptile, and a massive one metre long fossil bone. Two of the finds are likely to be from previously unknown species.

That bone, once part of an enormous plant eating Sauropod dinosaur, was quite a prize, but it was hard won. As Nizar recalled, the expedition group had ventured out into an isolated desert area, well off the beaten track, and close to the border with Algeria. "We had to get permission from the military to go in there," he said, and it is not the sort of place to go into without being prepared for the worst. About a year before two people had driven into the area by car. The car broke down, and the two, isolated and overcome by the intense heat, died.

The expedition had nearly come to an end, when they decided to have a look at one scree covered hill. Impossible to reach by their Land Rover, the party walked for about an hour and a half before clambering up loose, sharp edged stones. People who think the Sahara is just a sea of sand, said Nizar, have the wrong idea. There is a lot of raw rock, and, of course, where there is rock there could be fossils.

Just ten minutes after arriving at the site, which Nizar said was actually more of a mountain than a hill, the scientists noticed an interesting looking fragment. They began digging around it, and much to their surprise, what they had seen at the surface was just the shattered tip of something quite large. As they dug, the complete form of a one metre long bone emerged.

After the initial excitement of discovery died down, the scientists realised that they now had a really big problem. Impossible for one person, yet alone two, to lift, and extremely fragile, so how could they possibly get it out of there?

At first, to keep the surface cracks from spreading, they applied a glue to the bone, but as they realised, this would not be enough to stop it breaking up from its own weight if they attempted to lift it out of the ground. The bone needed to be encased in plaster, and where was plaster, and the water to mix it in, to come from in the middle of the Sahara?

Nizar, and Darren Martill, a palaeontologist from the University of Portsmouth, who had offered his Land Rover provided some of his students could come on the expedition, decided to back-track to the nearest town in search of plaster. After driving through most of the night they came across a man, making his way towards the town. Worries about what this man was doing wandering about soon evaporated as Nizar explained in Arabic what they were looking for.

The scientists had been thinking of finding a clinic or hospital where plaster of Paris might be used, appropriately enough, for mending broken bones, but their grateful passenger gave them a more realistic, down to earth lead. He told them where the local builders went to get their plaster. Not quite the same, but at a push, it would certainly do.

A day later, Nizar and Darren arrived back to camp with the supplies, much to the relief of the others. Expedition finances were so tight that any idea of mobile communications had been ruled out of the question, so the safe return of their transport was something to celebrate. At this late stage, the Moroccans in the team had returned to Casablanka, taking one of the two Land Rovers.

Now the work of plastering could begin, and tee-shirts were sacrificed as strips were torn off to bind the cast. The plaster, said Nizar, was not the best, and as precious time began to run out, they waited with growing anxiety for the cast to set. Anxiety began to grow into desperation the following morning when probing fingers revealed that the plaster was still soft.

They concluded that heat would help, so they gathered up their papers, and scoured the surroundings for enough sparse and thorny vegetation to build a fire around the cast. At least, that was the intention. In true boy scout style, they attempted to light the fire using sparks from the car battery. So much for theory. It didn't work, and so one unlucky volunteer had to trudge one and a half hours to the Land Rover and one and a half hours back again bearing a box of matches.

This time everything went according to plan. The fires blazed and the plaster set, but even as the cast cooled, the five remaining scientists were wondering what to do next. The bone, now in its cast, was heavier than ever, the Land Rover was some distance away, and it was difficult to clamber down the rocky hillside. There was some debate, but Nizar made it clear that he was certainly not prepared to abandon their fossil. "If the bone stays," he declared, "I stay!"

Two planks, which they were lucky to have, were fetched from the Land Rover and bound together to make a stretcher. Then, a safe path had to be made down the hillside. "We moved thousands of rocks," said Nizar, and it took all their strength to navigate their way down to the Land Rover, which was then so heavily loaded that its wheels kept sinking into the sand. Every so often, said Nizar, we all had to get out and help the Land Rover along.

Eventually they made their way out of the area and on reaching a surfaced road had their hopes of a smooth passage back to Casablanca dashed by, of all things, a snowstorm. Compared to the trials and tribulations they had gone through out in the desert, this was no more than an unexpected inconvenience, and a reminder of how much the world, like climate, never ceases to change.

Making tracks

As animals move around they leave tracks, and on rare occasions these become covered in fine sediment to be preserved as fossil impressions. The expedition came across a number of dinosaur footprints, and as Nizar explained, they often show a distinctive pattern, created by three claws pressing into the ground as the animal crouched down. Dozens of dinosaur footprints were found, but Nizar said he would like to have found even more. If tracks can be shown to belong to individual animals, a lot can be deduced about their gait. Most of the time, he said, the traces would be from dinosaurs leisurly wandering about because this is what animals spend most of their time doing.

Matching

One of the field-working skills is an ability to distinguish fossils from the surrounding stones. The skill, explained Nizar, gets better with practice, and he now has no problem picking up two similar looking fragments and identifying one as from a crocodile, and the other as a dinosaur. The crocodile, he noted, is rougher and heavier, while the dinosaur typically has many fine channels. From the collection brought back from Morocco, he picks up another fossil, and the first impression is that it is some form of tooth. So it is, but not a tooth as we might imagine. The tooth, he can say with complete confidence, came from the cutting edge of a giant sawfish. The long snouts of these monster creatures were lined externally with two rows of sharp cutting teeth, tipped with nasty looking barbs, clearly capable of inflicting terrible flesh tearing wounds.

Determining what species a fossil belongs to is more difficult, and given the immense periods of time involved, our ideas of what constitutes a species in living animals could be too rigid, so matching up fragments, unless they all occur together, is not at all easy. Identifying a fossil bone can involved a lengthy literature search before it can be matched with known species, and when differences occur, chances are that the species is actually new.

The crocodile and sawfish infested delta was no Garden of Eden, and among the fossils in Nizar's collection is a big back bone, a vertebra with flat dorsal extensions, which stuck up like a great sail along the back of a dinosaur. One of the extensions had been broken off before the bone became a fossil, and as Nizar speculated, this may well have been from the dinosaur's final fight.

That particular fossil, he said, would have come from one of the largest of the dinosaurs, similar, or perhaps even the same as the Spinosaurus monster that survived as a fossil for millions of years only to come to grief in the bombing of Munich. This dinosaur with its enormous sail-like appendage was a spectacular find, amazingly intact, so the loss of the fossilised skeleton was unfortunate. However, as Nizar observed, the exploration of Africa has hardly begun, and who knows what will turn up over the coming years.

More than likely, Nizar will be making some of those finds. This was his second trip out to Morocco, and as far as he is concerned, this is just the beginning. His first trip was a short visit to get the lie of the land and to meet colleagues from Morocco, including the mammal palaeontologist, Professor Samir Zouhri, and a structural geologist, Iahssen Baidder, who participated in the second, but first "real" expedition.

For Darren Martill, Nizar Ibrahim's expedition was also a dream come true. For twenty-five years, Darren, who is reader in Palaeobiology at the University of Portsmouth, had been waiting for an opportunity to explore the area.

Going home

The giant Sauropod bone arrived back in Dublin during January, and it now rests on its bed of plaster encrusted newspapers surrounded by boxes crammed with fragmentary fossils. The bone came from a plant eating Sauropod, believed to have been about 20 metres long.

Nizar is keen to create a display based on these finds so that everyone can share his enthuiasm for dinosaurs, but ultimately, he said, those fossils must go back to Morocco. Ironically, he said, the palaeontologists who work at the Université Hassan II in Casablanca, and are closest to this fossil rich area, often have less funding than scientists from abroad. A museum for these Cretaceous fossils is planned, and when this opens, it is likely to create a shift in focus towards the lost dinosaurs of north Africa.

The exact dating of the Moroccan fossils, explained Nizar, is hard to pin down because many of the usual indicator species, particularly the ammonites, are missing. However, there is a lot of evidence to show that what we see in Morocco is just one part of a vast sweep of delta deposits, with many of the same species appearing right across the range.

Flying reptiles

Among the numerous finds were beak fragments from a flying Pterosaur reptile. Some of these, said Nizar, had a wingspan of over ten metres. At present only two or three specimens of this flying giant are known from Africa, but Nizar observed they appear to have been quite common. A number of beak fragments were gathered, and Nizar believes that these survived because they were the toughest part of the body. Of necessity, bones in flying animals are light, but for pecking for food, the tip of the beak would have been hard and resilient.