The fossilised remains of sharks and other marine animals have also been found in Angola, lodged in the rocks where there used to be sea
By Louise Redvers
BBC News, Luanda
In the past, most people who went to Angola were searching for oil, diamonds or landmines.
Now, the country is also proving a big draw for fossil hunters - known in the scientific community as palaeontologists - who have described Angola as a "museum in the ground".
Angola was closed off for many years because of its three-decade long civil war, which only ended in 2002, so few scientists have had the chance to visit.
Those getting the chance now are not leaving disappointed. Louis Jacobs, of the Southern Methodist University in Dallas, says:
"Angola is the final frontier for palaeontology. Due to the war, there has been little research carried out... but now we are getting in finally and there is so much to find.
"In some areas there are literally fossils sticking out of the rocks, it is like a museum in the ground."
Louis Jacobs is part of the "PaleoAngola" project whose biggest find to date was in 2005, when five bones from the front-left leg of a sauropod dinosaur were discovered on a cliff at Iembe, around 65 km (40 miles) north of the capital, Luanda.
Fossils just stick out of the rocks in some parts of Angola
Since then, the majority of the skulls and skeletons uncovered by the team have been from turtles, sharks, plesiosaurs and mosasaurs, of which there is even an angolasauras species.
Plesiosaurs and mosasaurs are not technically terrestrial dinosaurs at all but marine reptiles related to lizards and snakes.
Yet according to Octavio Mateus, from the Lisbon's New University, the bones of the sauropod are just the beginning.
"We believe there are more dinosaurs to be found, we just need the facilities and means to dig for them," he says.
"Angola is amazing for fossils. Some of the places here are the best in the world in terms of fossil [remains], we keep finding new animals so it is always exciting to be here."
As well as unearthing interesting fossils, the study of palaeontology is also about understanding how the Earth was transformed tens of millions of years ago.
For example, when South America split from Africa and the southern Atlantic was formed.
"Fossils can date how animals migrated from one place to another and how continents moved through time," Mr Mateus says.
"From [studying] fossils we can work out when terrestrial animals were no longer able to cross from Africa to South America and when marine animals were present," he says.
The rocks are also a reference point for the time when creatures like dinosaurs were thought to have been made extinct.
Fossilised rock sits below ancient black lava, that once flowed into open waters
The scientific community largely accepts the theory that a massive asteroid hit the Earth 68 million years ago, slamming into the sea somewhere near Mexico.
"You can see where lava has flown into wet sand and then to where it has flown over dry land. That gives us an indication of when different things were happening millions of years ago," Mr Mateus explains.
The PaleoAngola project, with funding from the National Geographical Society and the Petroleum Research Foundation of America, is also working in collaboration with universities in Luanda, Lubango and in Maastricht in the Netherlands.
The Angola digs have focussed on Iembe and also at the coast of Bentiaba, in the southern desert province of Namibe, on the border with Namibia.
"As well as doing this research, the idea is to train Angolan scientists so in the long-term they can run the show," Louis Jacobs, a former head of Kenya's National Palentology Museum, says.
"Angola should be able to use its own unique resources in museums to teach future generations about their country and the world.
"And who knows, in the much longer term, it could prove to be a tourist attraction."