Category: 7. Science

A human species arrived on a major Indonesian island more than 800,000 years earlier than previously known.

Stone tools have been found on one of the world’s largest islands, Sulawesi, which is part of a distinct region known as Wallacea. This scattering of islands between Borneo and Australia have a unique roster of animals and plants that is different from the continents that lie either side.

Wallacea’s distinct biodiversity has developed because of the deep-water channels that separate it from the larger landmasses nearby, providing hard barriers that few species can cross. This included our own, Homo sapiens, which only overcame them in the past 100,000 years.

But a recently discovered archaeological site on Sulawesi known as Calio shows that other human species made this journey much earlier. The tools found there have been dated at between 1–1.5 million years old, much older than the next oldest tools from about 194,000 years ago.

Professor Adam Brumm, who co-authored the new research, says that the region plays an important part in understanding how our distant relatives spread across the world.

“This discovery adds to our understanding of the movement of extinct humans across the Wallace Line, a transitional zone beyond which unique and often quite peculiar animal species evolved in isolation,” Adam says.

“It’s a significant piece of the puzzle, but the Calio site has yet to yield any hominin fossils. So, while we now know there were toolmakers on Sulawesi a million years ago, their identity remains a mystery.”

The findings of the study were published in the journal Nature.

What was found on Sulawesi?

Calio was first excavated in 2019 after a large stone flake was found in a cornfield near the village of Ujung. Digs over the following years revealed that the area was a place where ancient humans lived, hunted and made tools.

In total, seven tools were discovered at the site, which are thought to have been made from large pebbles found in nearby riverbeds. Though they might look natural at first glance, closer study reveals that these tools have been specifically shaped by removing certain parts of the stone to make them useful for a range of purposes.

Eventually, the tools ended up in a nearby river, where they were quickly buried in the sediment alongside crocodile and shark teeth and the jawbone of a pig-like animal called Celebochoerus. This jawbone was crucial to help date the site through methods known as uranium series dating (USD) and electron-spin resonance (ESR).

USD uses the proportion of uranium isotopes in the bone to provide an age for a fossil, but only provides a minimum estimate. ESR helps to narrow it down by examining the radiation dose that the fossil has experienced while it’s been buried.

The Celebochoerus was found to have lived at some point from 1.04–1.48 million years ago. This means that ancient humans must also have been living in Sulawesi at this time.

Who made the Calio tools?

The discovery of these artefacts brings Sulawesi into line with the island of Flores to its south, where million-year-old tools have also been discovered. Both sets of tools show that ancient humans were living in Wallacea in the distant past, but identifying a species is difficult without fossils.

While miniature human species such as Homo floresiensis and Homo luzonensis once lived on the islands of southeast Asia, they were around too recently to have made these tools. However, Professor Chris Stringer, one of our experts in human evolution, explains that their relatives are a possible candidate.

“Over one million years ago, it’s possible that the ancestors or relatives of species like H. floresiensis and H. luzonensis might have been living on Sulawesi,” Chris says. “Although it’s often thought that H. floresiensis’ ancestors dispersed via Java, ancient oceans currents would probably have favoured dispersal from northern islands such as from Sulawesi.”

“Alternatively, a species known as Homo erectus was living in regions like Java when those Sulawesi toolswere produced. So, they could have made them as well.”

Just as the identity of the toolmakers remains a mystery, so does the way these humans got to Sulawesi in the first place. It’s possible they had some knowledge of raft building to make the journey between islands and built up resources to survive the trip.

Alternatively, they might have been carried across on rafts of vegetation during severe storms or tsunamis, which is believed to have helped other animals and plants disperse across the region.

To find out more about these ancient pioneers, the next step would be to find human fossils on Sulawesi from over a million years ago. Though the humid climate generally stops remains being preserved, the island’s mountainous interior contains many caves that could have allowed teeth and bone to survive.

Time: August 12th, 11AM PDT/2PM EDT

JOIN THE AI/ML SEMINAR SERIES

Everyone is invited to the monthly artificial intelligence and machine learning virtual seminar hosted by the Exobiology Branch at the NASA Ames Research Center. Previously recorded seminars can be found on the AI-ML Astrobiology YouTube channel.

The speaker for this event will be Dr. Walt Alvarado, from the Space Biosciences Research Branch at the NASA Ames Research Center.

Title: An AI-Powered Platform for Standardizing Scientific Data

Abstract:

Biological datasets are often heterogeneous and unstructured, making it challenging to compare findings, aggregate results, or reuse data across experiments. Over the past year, we’ve built and launched a generative AI-powered tool designed around a curator-in-the-loop approach, enabling subject matter experts to collaborate directly with large language models (LLMs) for more efficient data standardization and interpretation.

Leveraging multiple LLMs, the system automatically generates structured summaries from unstructured files, supports header-level data inference, and accelerates the population of curated pages on NASA’s Open Science Data Repository (OSDR). The platform integrates seamlessly with NASA data workflows but is adaptable to other scientific repositories, improving both the accessibility and consistency of technical metadata, while a companion conversational agent enables data exploration and efficient retrieval of curated content. These efforts advance NASA’s goals of transparency and collaboration across the research community.

Astrobiology,

In a groundbreaking scientific breakthrough, researchers have successfully reconstructed the prehistoric atmosphere using fossilized dinosaur teeth. This achievement could reshape our understanding of Earth’s ancient climate. Led by geochemist Dingsu Feng of the University of Göttingen, the international team analyzed oxygen isotopes preserved in the enamel of teeth from the Cretaceous and Jurassic periods. Their findings reveal not only the composition of the air dinosaurs once breathed but also hint at sudden, massive CO2 spikes likely linked to volcanic activity. The results provide a new method to study climate dynamics over deep time and understand extinction events.

How dinosaur teeth preserve ancient atmospheric clues

The study focused on the analysis of oxygen-17, a rare isotope that leaves behind telltale chemical signatures when inhaled by air-breathing vertebrates. Over millions of years, these signals remain preserved in durable tissues such as tooth enamel. Because teeth are less susceptible to environmental contamination, they serve as reliable time capsules of ancient biology and atmospheric conditions.Researchers examined previously collected tooth enamel powders from museum specimens across Europe, including those of Tyrannosaurus rex and Kaatedocus, a sauropod dinosaur. These samples held valuable information about oxygen ratios, which correlate with atmospheric CO2 concentrations.

CO2 levels in the age of dinosaurs

Based on the isotope readings, scientists determined that atmospheric CO2 levels were far higher during the Mesozoic era than today. In the late Jurassic, CO2 concentrations reached about 1,200 parts per million (ppm). During the late Cretaceous, this figure dropped slightly to around 750 ppm. For comparison, modern atmospheric CO2 levels hover around 430 ppm.This confirms previous models suggesting that dinosaurs lived in a hotter, more carbon-rich world, largely influenced by natural processes such as plate tectonics and sustained volcanic activity.

Volcanic activity and sudden climate changes

A particularly fascinating discovery was the spike in isotope anomalies in two specific teeth—one from a T. rex and another from a Kaatedocus. These anomalies suggest short-lived but significant surges in atmospheric CO2. Scientists believe these may be linked to massive volcanic eruptions, such as flood basalt events, which released enormous amounts of CO2 in a short geological timeframe.Such findings support the idea that volcanic CO2 emissions played a major role in driving rapid climate changes, which may have affected ecosystems and evolutionary pressures on land-dwelling vertebrates.

Implications for modern climate science

The ability to reconstruct prehistoric air with such precision opens new doors for understanding both past and future climate patterns. By identifying CO2 fluctuations during the age of dinosaurs, researchers can refine models that predict how modern ecosystems might respond to accelerated carbon emissions.This study also highlights the potential of fossilized remains as archives of environmental data, giving scientists tools to trace how life and climate have co-evolved over hundreds of millions of years.

Next target: The Great Dying

Buoyed by their success, the team now plans to apply the same method to fossils from the Permian-Triassic extinction event, known as the Great Dying, which occurred 252 million years ago. This catastrophic period saw the extinction of over 90% of marine species and 70% of terrestrial life, likely due to prolonged volcanic eruptions in what is now Siberia.By analyzing teeth from this period, researchers hope to uncover how atmospheric CO2 behaved before, during, and after this global extinction, offering new clues into Earth’s resilience and recovery mechanisms.From volcanic eruptions to global extinction events, dinosaur teeth have revealed more than just what these creatures ate. They’ve opened a window into the very air they breathed. This pioneering research underscores the power of modern geochemistry and paleontology to unravel the secrets of Earth’s deep past, with implications that stretch far into the planet’s uncertain climatic future.

Researchers at the Francis Crick Institute have discovered that the heart’s own contractions trigger biological signals that guide the formation of a functional beating heart.

Their study in zebrafish highlights the heart’s ability to remodel and adapt to physiological demands and could also reveal what goes wrong during congenital heart conditions.

The heart is one of the first organs to form so that it can supply a developing embryo with the oxygen and nutrients critical to grow and survive. However, how the heart transforms from a simple tube into a complex, three-dimensional pump is still not fully understood.

As part of their study, published today in Developmental Cell, the research team followed the early development of the heart’s muscular structures, called trabeculae, in zebrafish. Zebrafish hearts share key structural and genetic features with human hearts, but with the added advantage of transparency, making it possible to see the heart grow at minute details in real time.

They used live 4D imaging of the zebrafish hearts to study biological processes at different scales, from individual cell behaviours to changes in organ shape and size.

They observed that trabeculae don’t grow and develop by cell division, as previously thought. Instead, neighbouring cells are recruited to build trabecular complexity, thus increasing heart’s muscle mass and contractile efficiency.

Setting the right pace

The team also uncovered a feedback mechanism between heart contraction and its own development. As the trabeculae develop and the heart contracts more strongly, this initiates mechanical signal that makes cells ‘softer’ enabling them to stretch and increase their size. This allows the heart to expand its volume by 90% and maximise its blood filling capacity.

Crucially, this feedback systems dictates a healthy pace of growth, because as heart cells stretch, they lose their ability to get recruited, thereby stabilizing trabecular growth.

The heartbeat is synonymous with life, and although we’ve observed its structure for centuries, how it grows to the right shape and size is still mysterious. What we’re uncovering is that the heart’s structure isn’t hardwired, instead it intelligently adapts to changes in animal physiology. Understanding the biology behind this flexibility could form the basis of future treatments for heart disease.”

Toby Andrews, postdoctoral fellow and first author of the study

The team now plans to delve deeper into trabeculae development, as it transforms into an ever more complex sponge-like 3D mesh of muscular ridges. They hope to identify how trabecular ridges regulate blood flow and which cellular processes and molecular mechanisms shape these complex structures.

Rashmi Priya, head of the Crick’s Organ Morphodynamics Lab, said, “Although we’ve made progress in understanding the molecular pathways involved in heart diseases or ‘cardiomyopathies’, we still know very little about how trabeculae form and how defects in these structures affect heart function. This underscores the importance of dissecting the developmental mechanisms that sculpt these structures and give rise to one of nature’s most efficient pumps-the heart.”

This work is funded by the British Heart Foundation.

After more than ten years of searching, scientists say they have finally solved the mystery behind a catastrophic epidemic that wiped out over five billion sea stars along the Pacific coast of North America. A newly identified bacterium is believed to be responsible, marking a breakthrough in efforts to save these iconic marine animals.Since 2013, a rapidly spreading illness known as sea star wasting disease has caused massive die-offs from Mexico to Alaska, affecting more than 20 different species. The sunflower sea star was among the worst hit, its population declined by about 90% within the first five years of the outbreak.“It’s really quite gruesome,” said Alyssa Gehman, a marine disease ecologist at the Hakai Institute in British Columbia, Canada, who helped identify the cause. She described how healthy sea stars usually have “puffy arms sticking straight out,” but once infected, they develop lesions and eventually “their arms actually fall off.”The answer, finally published in the journal Nature Ecology and Evolution, points to a bacterium, Vibrio pectenicida, which is also known to infect shellfish. The findings represent “a long-standing question about a very serious disease in the ocean,” said Rebecca Vega Thurber, a marine microbiologist at the University of California, Santa Barbara, who was not part of the study.

Identifying the true culprit wasn’t easy. According to Melanie Prentice of the Hakai Institute, a co-author of the study, earlier efforts were misled by a densovirus, which researchers initially thought was the cause. That virus, however, turned out to be a normal resident of healthy sea stars.Another problem with previous studies was that they often used tissue samples from dead sea stars, which no longer contained coelomic fluid, the bodily fluid surrounding internal organs where the disease agent would be active.This latest research took a different approach. Scientists focused on analysing that specific coelomic fluid, and it was there that they discovered the bacterium Vibrio pectenicida.Blake Ushijima, a microbiologist at the University of North Carolina, Wilmington, who was not involved in the study, praised the team’s “really smart and significant” detective work. He acknowledged the unique challenge of identifying marine pathogens, saying it is “immensely difficult” to trace environmental disease sources, “especially underwater.”

Now that the root cause has been pinpointed, scientists hope they can act to prevent further losses. Prentice said researchers might now begin testing the remaining sea stars for overall health. They’re also considering captive breeding or relocating healthy individuals to regions where sunflower sea stars have disappeared.Scientists are also exploring whether certain populations may have natural immunity, or whether treatments such as probiotics could help strengthen resistance to the disease.The stakes go far beyond just the sea stars themselves. These creatures are key predators in kelp forest ecosystems. Their disappearance has led to ripple effects throughout the food web, as kelp forests provide shelter and food for fish, sea otters, and seals. Restoring sea star populations could help regrow what Thurber described as “the rainforests of the ocean.”

Understanding the mechanisms of protein preservation in extreme environments is essential for identifying potential molecular biosignatures on Mars.

In this study, we investigated five sabkha sedimentary samples from the Abu Dhabi coast, spanning from the present day to ~11,000 years before present (BP), to assess how mineralogy and environmental conditions influence long-term protein stability.

Using LC-MS/MS and direct Data-independent Acquisition (DIA) proteomic analysis, we identified 722 protein groups and 1300 peptides, revealing a strong correlation between preservation and matrix composition. Carbonate- and silica-rich samples favored the retention of DNA-binding and metal-coordinating proteins via mineral–protein interactions, while halite- and gypsum-dominated facies showed lower recovery due to extreme salinity and reduced biomass input.

Functional profiling revealed a shift from metabolic dominance in modern samples to genome maintenance strategies in ancient ones, indicating microbial adaptation to prolonged environmental stress.

Contrary to expectations, some ancient samples preserved large, multi-domain proteins, suggesting that early mineral encapsulation can stabilize structurally complex biomolecules over millennial timescales. Taxonomic reconstruction based on preserved proteins showed broad archaeal diversity, including Thaumarchaeota and thermophilic lineages, expanding our understanding of microbial ecology in hypersaline systems.

These findings highlight sabkhas as valuable analogs for Martian evaporitic environments and suggest that carbonate–silica matrices on Mars may offer optimal conditions for preserving ancient molecular traces of life.

Comparing Protein Stability in Modern and Ancient Sabkha Environments: Implications for Molecular Remnants on Ancient Mars, Int J Mol Sci via PubMed

Astrobiology,