Future fossil discoveries in the Arabian Peninsula could hold answers to some of the most pressing questions about the evolution and extinction of the dinosaurs, palaeontologists working in the Middle East believe.
The region remains one of the most under-explored on the world’s fossil map, but scientists say countries such as Saudi Arabia, Yemen and Oman – and possibly even the UAE – could be crucial to expanding what we know about the Late Cretaceous period, between 100 and 66 million years ago, before the dinosaurs disappeared.
"It is very important to fill these gaps in our knowledge, and I am sure that renewed interest in the ancient past of the Middle East is going to lead to some pivotal discoveries," Nizar Ibrahim, a palaeontologist at the University of Detroit Mercy, told The National. "We are seeing some tantalising clues already, in the form of dinosaur bones from Oman, Saudi Arabia and Syria, or fossil trackways from Yemen."
Dinosaurs roamed Earth for more than 165 million years before a giant asteroid slammed into waters near today's Yucatan Peninsula in Mexico, unleashing apocalyptic conditions which theoretically wiped out most living creatures and cleared the path for the evolution of humans.
Now what appears to be the most complete fossil evidence to date in support of the asteroid impact hypothesis for their rapid demise has been discovered at an American dig site.
The excavation at the Tanis site in North Dakota's Hell Creek Formation contains a "mother lode of exquisitely preserved animal and fish fossils", according to a paper published in the Proceedings of the Academy of Natural Sciences this week.
The “tangled mass” of freshwater fish, terrestrial vertebrates, trees, branches, logs, marine ammonites and other creatures is believed to be the result of a seismic surge, caused by the asteroid, that triggered a torrent of water and debris from an inland sea.
"We look at moment-by-moment records of one of the most notable impact events in Earth's history. No other site has a record quite like that," the report’s lead author Robert DePalma, a graduate student and curator of the Palm Beach Museum of Natural History in Florida, told news agencies.
“This particular event is tied directly to all of us – to every mammal on Earth, in fact. Because this is essentially where we inherited the planet. Nothing was the same after that impact. It became a planet of mammals rather than a planet of dinosaurs."
Potentially one of the most outstanding finds in recent years, the report comes amid a golden era in fossil discoveries from around the world that is shining light on the Mesozoic Era – the time of the dinosaurs, which is formed of three periods known as the Triassic, Jurassic and Cretaceous – and even earlier.
In China, for example, fossil discoveries are booming. The huge volume of well-preserved feathered dinosaur specimens dug up in Liaoning province since the 1990s has given scientists unique insight into the evolution of birds from dinosaurs in the early Cretaceous period.
And just weeks before the North Dakota discovery was reported, a “mind-blowing” trove of primitive creatures including jellyfish, sponges and anemones dating back more than 500 million years – to the dawn of animal life – was reported to have been unearthed from the banks of the Danshui river in Southern China’s Hubei province.
Dinosaurs in the Middle East and North Africa
In the Middle East and North Africa progress has been much slower, often hampered by lack of access, fewer research facilities and sometimes geopolitical issues, including conflict. But palaeontology is gaining traction, with an increasing number of discoveries in countries such as Egypt and Morocco in recent years.
Scientists believe fossils found in the region could be particularly important for filling in some of the final chapters of dinosaur existence, when the Earth was settling into its current land formations after the break-up of the super-continent of Pangaea, with one fossil find already upsetting the prevailing theory that Africa’s dinosaurs were isolated from the rest of the world.
In 2018 a team from the Vertebrate Palaeontology Centre at Egypt's Mansoura University published findings about a species of Titanosaurus from the late Cretaceous period, which they named the Mansourasaurus shahinae. The long-necked plant-eater was considered to be a critical piece of the puzzle because its remains suggested a similar anatomy to European dinosaurs.
Hesham Sallam, the director of the centre, said they now had several more discoveries awaiting further research and publication.
“In the Middle East we have outcrops that are full of wonderful fossils and are just waiting for us to take up,” he said. “There are so many of them.”
Dr Sallam, who has also previously worked in the area of North Dakota where the new fossil trove was discovered, said more field work in the region could also reveal details of the asteroid's impact farther afield.
“Because the impact was global and the effect was global, of course there is evidence of what happened still in the Middle East,” he said. “We just need to have a strategy and more work to know more about it. I am sure a lot of questions can be answered.”
Dr Ibrahim, whose work has been focused on North Africa, led a team which uncovered rare bones from the skeleton of the predatory Spinosaurus in the 250kilometre-long Cretaceous formation known as the Kem Kem beds on the border of Morocco and Algeria.
He said the apparent golden age for palaeontology meant that new dinosaurs were being found at an “astonishing rate” around the world and scientists were spending more time exploring previously neglected regions, including the Middle East.
“In addition, a small but determined group of [often] young palaeontologists in countries like Egypt or Algeria has emerged and they are ready to usher in a new chapter of exploration,” Dr Ibrahim said.
The Middle East is of direct relevance to some major paleogeographical events, he added.
“Some slices of time, like the Late Cretaceous, record major evolutionary transitions and events in the history of vertebrates,” Dr Ibrahim said. “Discoveries from the Middle East and Gulf regions might provide new insights into these major events.”
Dinosaurs in the Gulf
In the Arabian Peninsula, which has leaped ahead with archaeological field work in recent years, palaeontology has been slower to take off, with just a handful of significant fossil finds in Yemen, Saudi Arabia and Oman.
Much of the what is now land would have been covered by the sea, making marine creatures more common, but there are some areas with potential for land-dwelling dinosaurs, as well as places where they could have been washed down rivers and encased in sand banks that are now exposed sandstone outcrops.
It was one of these deposits on the edge of the mountainous Hejaz, where a team led by Benjamin Kear, a palaeontologist at Uppsala University in Sweden, found the first confirmed dinosaur bones in Saudi Arabia – a plant-eating Titanosaur and a carnivorous Abelisaurid – in 2014.
While the dinosaurs appeared to be a rarer find, giant marine reptiles from the Cretaceous period are plentiful and Dr Kear said it would be just a “matter of time” before more significant discoveries are made in Saudi Arabia and elsewhere in the region.
“The Arabian Peninsula is one of these great undiscovered bits of land when it comes to fossils and fossil history," he said. "There’s a handful of dinosaurs that have been identified, but it’s probably largely because there has not been much work done.”
“If you walk right up from Riyadh to Jordan, there is prolific fossils everywhere, you can’t miss them. There’s ammonites, rich reef systems, all sorts of things. And of course there is marine reptiles, marine turtles, giant marine lizards called Mosasaurs, Plesiosaurs are there.”
Detailed geological mapping carried out for oil exploration, as well as the desert landscapes which make surveys much easier than land covered in vegetation, often make for favourable conditions.
“The beauty of the Arabian Peninsula, because it has no vegetation on it, or not much, is that you can transect these huge amounts of time and track the evolution of different organisms across this time frame,” Dr Kear said. “It’s really, really interesting and it’s a great spot to go if you want to look for fossils.”
Anne Schulp, a palaeontologist from the Naturalis Biodiversity Centre museum in Leiden, was among a team who described the first dinosaur footprints discovered in the Arabian Peninsula in 2008 – north of Sana'a in Yemen – and is now doing fieldwork in Oman, where several types of dinosaurs have been found, including the first evidence of the duck-billed Hadrosaurs, previously thought to be limited to northern parts.
Dr Schulp said the finds, like others around the Middle East, were from the Late Cretaceous period and represented some of the last dinosaurs to have walked the Earth, much like their counterparts in North Dakota.
He said potential in some Gulf countries was limited by geology as the right kind of rock layers from the right age were needed for preserving dinosaur bones, and it could be very hard work to find material, but there was “much more to be discovered, much more to be learned”.
“The visibility, interest, and attention is growing, so new discoveries will certainly follow,” he said.