A researcher of the American Museum of History shows a fossil skull of Chilecebus carrascoenis, a 20-million-year-old primate from the Andes mountains. AFP
In a study published on Wednesday in the journal Science Advances, researchers in China and the US used high resolution imaging to examine the only known fossilized skull of the extinct Chilecebus, a New World monkey that scampered around ancient mountain forests, feeding on leaves and fruit.
One key finding: the brain size of primates, long assumed to have increased progressively over time, now appears to have followed a more roundabout path.
Primates are broadly split into two groups: Old World, from which our own species descended, and New World species of the Americas and Oceania.
"We see multiple episodes of expansion of the brain in each of these major groups, and we see several episodes of actual reduction of relative brain size in certain groups," co-author John Flynn of the American Museum of Natural History said.
The research, led by Xijun Ni, at the Chinese Academy of Sciences, used X-rays and CT scans of the inside of the Chilebus' skull to determine its internal structure.
The fossilized skull has been precisely dated because it was discovered among volcanic rocks, and by placing the species within its bigger family tree, the team was able to infer that cerebral enlargement occurred repeatedly and independently in anthropoid evolution.
Though the Chilecebus was roughly around the size of a modern marmoset or tamarin, in contrast to those monkeys its brain had several grooves known as infolding that suggest a greater degree of cognitive complexity: in other words, brain size is not always linked to advancement.
What's more, in modern primates, the size of the visual and olfactory centers of the brain are inversely related, meaning that species with a strong sense of sight usually have a weaker sense of smell and vice versa.
But the researchers found that a small olfactory bulb in Chilecebus did not result in a stronger olfactory ability, meaning the two abilities aren't coupled as previously thought.
Flynn said the research bore testament to the secrets that could be unlocked from well-preserved ancient fossils.
"We can go out into the mountains and make this remarkable discovery 10,000 feet up in the Andes and be able to make insights about the evolution of our history, be able to test previous hypotheses.. (and) be able to understand the evolution of brain complexity in primates.
"That's a really amazing possibility from the discovery of one really well preserved fossil."
A study published Monday has found that an arachnid species is capable of winding up its web to store up elastic energy, before releasing its grip and catapulting itself at furious speed toward its unsuspecting prey.
A team of scientists in Chile have said that they found a human footprint that dates back more than 15,000 years, the oldest one ever found in the Americas, the media reported on Tuesday.
The latest archaeological excavations on Marawah Island, carried out by specialist teams from the Department of Culture and Tourism – Abu Dhabi (DCT Abu Dhabi), have shed new light on Abu Dhabi’s earliest known settlement, which dates back 8,000 years.
Peering into the lake, the village elder struggled to pinpoint where beneath the hyacinth and mesquite weeds lay the farm he lived in his entire life until the water rose like never before and swallowed everything.
Baby bottles made with polypropylene can release up to 16 million microplastics, and trillions of even smaller nanoplastics, per litre, the study found.
The all-time blockbuster Dilwale Dulhania Le Jayenge (DDLJ) which turned 25 years old on Tuesday, and ace fashion designer Manish Malhotra, who created quite a few style trends in the film, recalled working on the project.
Other changes include increasing prevalence of an additional artery in the forearm, and changes to face shape as jaws become smaller. The study demonstrates that humans are evolving at a faster rate than at any point in the past 250 years.