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Adding a new name to the family tree

Palaeoanthropologists have just announced the name of a new species of human, Homo bodoensis, which lived in Africa in the Middle Pleistocene around 500,000 years ago. It was a direct ancestor of modern humans, Homo sapiens, which emerged as a distinct species around 200,000 years ago.

The Middle Pleistocene is an important chapter in human evolution, but a muddled one. H. bodoensis was named based on the reassessment of fossils from Africa and Eurasia, which had previously been assigned to other, poorly defined species: Homo heidelbergensis and Homo rhodesiensis.

“Talking about human evolution during this time period became impossible due to the lack of proper terminology that acknowledges human geographic variation,” says University of Winnipeg palaeoanthropologist Dr Mirjana Roksandic, lead author of the study.

Introducing the name H. bodoensis is aimed at “cutting the Gordian knot and allowing us to communicate clearly about this important period in human evolution,” says another author, Christopher Bae from the University of Hawai’i at Manoa.

The study was published in Evolutionary Anthropology Issues News and Reviews.

Whale shark ancestors were voyagers

In more ancestor-related news, researchers have shed light on the migrations of the world’s largest fish – the whale shark.

The research team, led by the Smithsonian Tropical Research Institute, collected tissue samples from 21 sharks in Panama. Genetic analysis showed that the whales were highly diverse, bearing similarities to other populations across the world, from the Arabian Gulf to Mexico to the Western Indian Ocean to the Gulf of California. This does not mean that an individual whale shark travelled from these places, but rather populations may have shifted over generations. This study helps us understand the genetic diversity of this species and how different populations are connected.

“Imagine Qatar: a possible journey of more than 27,000 kilometres from Panama for this species,” says Hector Guzman, lead author of the paper in Frontiers in Marine Science.

“This observed connectivity amazed us, revealing a real political challenge for the protection and conservation of whale sharks. It seems no longer a local or regional concern, but a global issue.”

Satellite images reveal coastal conservation

Coastal wetlands are among the most heavily degraded ecosystems in the world, facing threats like sea-level rise and encroachment by humans – with 2.4 billion people worldwide living within 100 kilometres of the coast.

Research has previously shown that China, for example, lost 50% of its coastal wetlands between 1950 and 2000 due to urbanisation, industrialisation and population growth.

Now, an international research team has used satellite imagery to study the changes in China’s coastal ecosystems over the last 40 years.

“Because coastal wetlands provide diverse important ecosystem goods and services, their loss has reduced biodiversity, affecting water quality, carbon storage and coastal protection from storm events and increased regional vulnerability to sea-level rise which, together, pose threats to human health and coastal sustainability,” explains lead researcher Xiangming Xiao, from the University of Oklahoma.

The study, published in Nature Sustainability, used 62,000 high-resolution satellite images to track coastal changes between 1984 and 2018. It found that between 1984 and 2011, wetland areas significantly decreased.

But in recent years, things have changed.

“We found a substantial increase in saltmarsh area and a stable trend of tidal flat areas after 2012, driven by decreased anthropogenic activities (pollution) and increased conservation and restoration efforts,” says Xiao.

“To achieve the sustainability of coastal wetlands, China must continue to give top priority to conservation and the restoration of coastal wetlands and their ecosystem services.”

Alien signal turns out to be interference

In 2019, astronomers at the Parkes Observatory’s Murriyang radio telescope thought they’d spotted intelligent life beyond Earth – but now they’ve reported that the signals were just human interference.

The strange signal, dubbed BLC1, occurred in one narrow band of frequencies, and slowly drifted in frequency over a five-hour period. This means it didn’t match up with any known astrophysical event or Earth-based activity, so astronomers speculated that it might have been made by alien technology. Even more tantalisingly, BLC1 came from the direction of Proxima Centauri, the closest star to our Solar System.

But in two papers just published in Nature Astronomy, the astronomers have explained that by following up on the signal to perform verification tests, they have found that BCL1 isn’t a sign of intelligence life – instead, it’s most likely radio interference from right here on Earth.

“Our best guess is that BLC1 and the lookalikes are generated by a process called intermodulation, where two frequencies mix together to create new interference,” Curtin University’s Danny Price, co-author of the paper, said in The Conversation.

“Regardless of what caused BLC1, it was not the technosignature we were looking for. It did, however, make for an excellent case study, and showed that our detection pipelines are working and picking up unusual signals.”

How do you take the pulse of a fly?

A new study has revealed that fly hearts respond to danger just like human hearts do – with their heartbeat racing faster.

“We were quite surprised by this result,” says lead researcher Marta Moita, from the Champalimaud Centre for the Unknown in Lisbon, Portugal.

“We know that when vertebrates face a threat, their autonomic nervous system kicks into action, generating the changes in cardiac activity that we are all familiar with. However, this system doesn’t exist in insects, and so it was unclear whether they would exhibit similar cardiac alterations.” 

The team used fluorescent molecules to light up hearts cells, then followed the activity through its transparent exoskeleton. When a fly faced a danger, they could watch how the heartbeat changed.

“Amazingly, just like in humans, the fly’s heart changed its activity depending on which defence response is assumed,” says co-author Natalia Barrios. “If the fly decided to escape, the heart accelerated, but if the fly froze in place for a sustained period of time, its heart slowed down.”

Next, the team aim to find out what mechanism causes this, such as whether flies have an autonomic-nervous-system-like structure.

The research appears in Current Biology.