Chinese Skull Suggests New Branch on Human Bush

Skull of the ancient hominin from China.
(Wu et al., Journal of Human Evolution, 2023)

At Science Alert, Ancient Skull Found in China Is Unlike Any Human Seen Before

An international team of scientists has described an ancient human fossil in China unlike any other hominin found before. It resembles neither the lineage that split to form Neanderthals, nor Denisovans, nor us, suggesting our current version of the human family tree needs another branch.

The jaw, skull, and leg bones belonging to this yet-to-be classified hominin, labeled HLD 6, were discovered in Hualongdong, in East Asia, in 2019. In the years since, experts at the Chinese Academy of Sciences (CAS) have struggled to match the remains to a known lineage.

The hominin's face is similarly structured to that of the modern human lineage, which split from Homo erectus as far back as 750,000 years ago. But the individual's lack of chin appears more like that of a Denisovan – an extinct species of ancient hominin in Asia that split from Neanderthals more than 400,000 years ago.

Working alongside researchers from China's Xi'an Jiaotong University, the UK's University of York, and Spain's National Research Center on Human Evolution, researchers at CAS think they have uncovered an entirely new lineage – a hybrid between the branch that gave us modern humans and the branch that gave us other ancient hominins in the region, like Denisovans.

Until proven otherwise, I will assume all prehistoric human lines had hot chicks. 

At Eureka Alert!,  A climate-orchestrated early human love story

To unravel when and where human hybridization took place, scientists usually rely on paleo-genomic analysis of extremely rare fossil specimens and their even scarcer ancient DNA content. In the new Science paper, the team of climate experts and paleo-biologists from South Korea and Italy pursued a different approach. Using existing paleo-anthropological evidence, genetic data and supercomputer simulations of past climate, the team found that Neanderthals and Denisovans had different environmental preferences. More specifically, Denisovans were much more adapted to cold environments, characterized by boreal forests and even tundra, compared to their Neanderthal cousins who preferred temperate forests and grassland. “This means that their habitats of choice were separated geographically, with Neanderthals typically preferring southwestern Eurasia and Denisovans the northeast”, says Dr. Jiaoyang Ruan, postdoctoral researcher at the IBS Center for Climate Physics (ICCP), South Korea and lead author of the study.

However, according to their realistic computer simulations the scientists found that in warm interglacial periods, when Earth’s orbit around the Sun was more elliptic and northern hemisphere summer occurred closer to the Sun, the hominin habitats began to overlap geographically. “When Neanderthals and Denisovans shared a common habitat, there were more encounters and interactions among the groups, which would have increased the chance of interbreeding”, adds Prof. Axel Timmermann, corresponding author of the study and director of the ICCP and professor at Pusan National University.

But how did the climate warm without coal-fired power plants and SUVs? 

And just for fun, 5 million-year-old fossils reveal 2 new species of saber-toothed cats in South Africa

Scientists have unearthed the remains of two never-before-seen species of saber-toothed cats that roamed Africa around 5.2 million years ago. The discoveries have changed what researchers previously knew about this group of extinct feline creatures, a new study shows.

The new findings could also shed light on the environmental changes happening at the time, which could help reveal why human ancestors started walking on two legs. researchers say.

The partial remains of the two newfound species, Dinofelis werdelini and Lokotunjailurus chimsamyae, were unearthed alongside the bones of two other known species, Adeilosmilus kabir and Yoshi obscura, near the town of Langebaanweg on the west coast of South Africa. The four species belong to the subfamily Machairodontinae — an extinct group of feline predators that included most species of saber-toothed cats. (The name Machairodontinae means "dagger-tooth.") Most members of this subfamily were equivalent in size to most big cats alive today.

In a new study, published July 20 in the journal iScience, researchers described the remains of all four species. The discovery of D. werdelini was not a surprise to the team, because species from this genus had previously been uncovered in the area and across the globe, including Europe, North America and China. However, the researchers were shocked to discover L. chimsamyae because, until now, members of this genus had only ever been found in Kenya and Chad.

I have seen in the past (don't make me Google) that sabre-tooth species were widespread down through prehistorical times, up until fairly recently, the end of the last glaciation. It's kind of a shame that none of the existing cat species show this trait.

The Wombat has Rule 5 Sunday: Salma Hayek up on time at The Other McCain.