66 million years ago, the last dinosaurs vanished from Earth. We’re still trying to understand why. New fossils of abelisaurs – distant relatives of the tyrannosaurs – from north Africa suggest that African dinosaurs remained diverse up to the very end. And that suggests their demise came suddenly, with the impact of a giant asteroid.
The causes of the mass extinction have been debated for two centuries. Georges Cuvier, the father of palaeontology, thought extinction was driven by catastrophes. Charles Darwin thought gradual changes in the environment and competition between species slowly drove lineages extinct.
As our understanding of the fossil record improved, it became clear that the Cretaceous period (145 million years to 66 million years ago) ended with an extraordinary wave of extinction. Huge numbers of species disappeared, worldwide, in a brief period. The discovery of the 180km-wide Chixculub asteroid impact crater in Mexico suggested a sudden extinction of dinosaurs and other species, driven by the impact. But others have argued that a long, slow decline in dinosaur diversity contributed to their extinction.
Piecing together the story is hard. It’s not just that dinosaur fossils are so rare; the fossil record is also patchy.
Most of what we know about the dinosaurs’ final days is the result of intensive study of a few places in the United States, Canada and Mongolia. Far less is known about dinosaurs of the southern landmasses – South America, India, Madagascar, Australia, Antarctica, New Zealand.
Partly that’s down to geography; it’s hard to find dinosaurs in rainforests. Partly there have, historically, just been more palaeontologists and museums in the northern hemisphere. The question is whether the picture is biased.
Because it’s such a huge landmass, Africa probably had far more dinosaur species than North America. Yet until recently we’ve known hardly anything about Africa’s end-Cretaceous dinosaurs. Africa has few terrestrial rocks from this period. That’s because high levels of volcanic activity pushed sea levels up, submerging much of Africa under shallow seas. Dinosaurs, being terrestrial, rarely occur in marine rocks. But rarely doesn’t mean never. Study enough marine fossils, you eventually find a dinosaur.
And in Morocco, we’ve studied lots of marine fossils.
What we’ve found
The phosphate deposits of Morocco are the remains of an ancient seabed, dating to the final million years of the dinosaur era. They’re full of fish bones and scales, shark teeth and marine reptiles. Vast numbers of marine reptiles – mosasaurs, plesiosaurs, sea turtles.
But once in a while, dinosaurs turn up.
It’s not clear how dinosaur bones ended up in marine sediments. Dinosaurs may have swum out to islands searching for food, as deer and elephants do today, and some might have drowned. Other dinosaurs might have been washed out to sea by floods or storms, or drowned in rivers that carried them downstream to the ocean. Still others may have died on the shoreline before being carried out on a high tide. But some improbable series of events transported dinosaurs into the ocean.
The dinosaurs of the late Maastrichtian of Morocco. By Nick Longrich.
And so, studying marine beds, and working over many years, we’ve slowly put together a picture of Africa’s last dinosaurs, bone by bone.
Africa’s last dinosaurs included titanosaurian sauropods, long-necked plant-eaters the size of elephants. Horse-sized duckbill dinosaurs filled the herbivore niche. But the carnivores are particularly interesting. Sitting at the top of the food chain, they tell us a lot about the ecosystem. And African predatory dinosaurs were diverse, implying diverse herbivores, and lots of them.
The African duckbill dinosaur, Ajnabia odysseus. By Raul Martin.
The top predator was a ten-metre-long animal called Chenanisaurus barbaricus. So far Chenanisaurus is known from just a jawbone, but this tells us it was part of the Abelisauridae, a bizarre family of carnivores found in South America, India, Madagascar and Europe, while tyrannosaurs dominated in the north. Abelisaurs had short, bulldog snouts, and sometimes horns, and they had bizarre, stumpy little arms that make the arms of T. rex look massive by comparison.
Now, fossils of two new abelisaurs have appeared in Morocco.
One is known from a tibia, a shin bone. It was smaller than Chenanisaurus, about five metres long – small by dinosaur standards, but large compared to modern predators. Curiously, it resembles abelisaurs found in South America. It’s possible this marks an ancient land connection that existed between the continents 100 million years ago. Or, abelisaurs may have swum the narrow seaway separating the continents.
Tibia of a new abelisaurid from Sidi Chennane, in Morocco. Nick Longrich.
Another bone is from the foot of an even smaller abelisaurid, just three metres long. Similar small abelisaurids occur in Europe; it may be related to them.
In recent months, more dinosaur fossils and more species have turned up. We’re still writing these fossils up, so we can’t say much now, but finding so many species in a handful of fossils tells us we’re sampling from a highly diverse fauna.
While fossils from the Great Plains in North America may record a decline in dinosaur diversity, this may be a local phenomenon, not a global one. It’s possible global cooling in the latest Cretaceous hit higher-latitude environments hard, reducing diversity. But the African dinosaur fauna hints that at low latitudes, dinosaurs were thriving, even diversifying. If so, that means dinosaurs were cut down in their prime; burning out rather than fading away.
Foot bone of a small abelisaurid from Sidi Daoui, Morocco. Nick Longr.
What our findings show
Africa’s last dinosaurs, especially its diverse predatory dinosaurs, suggest that immediately before their extinction, the dinosaurs thrived.
For over 100 million years, they evolved and diversified, producing a remarkable range of species: predators, herbivores, aquatic species, even flying forms, the birds. Then in a single, catastrophic moment, everything was wiped out in the months of darkness caused by dust and soot from the impact. Everything, except a half-dozen or so bird species.
Evolution is driven by rare, improbable events like asteroid impacts. Curiously, science is often driven forward by improbable events as well – like the unlikely discovery of dinosaurs buried millions of years ago, at the bottom of the sea.
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
