Rare Fossil Discovery Sheds Light on Ancient Life in New York
A newly published scientific paper is highlighting a remarkable discovery from the New York State Museum’s paleontology collection: a 420-million-year-old fossil from the Silurian Period, identified as Naraoia bertiensis. This incredibly rare specimen is one of only two known fossils of its kind ever found from this era, offering groundbreaking insights into the evolution and distribution of early marine life.
Naraoia were soft-bodied arthropods that once roamed the sea floor. During the Silurian Period, the region we now call New York was located south of the equator and submerged under a shallow tropical sea—ideal conditions for ancient marine ecosystems. However, due to their delicate, flexible exoskeletons, Naraoia fossils could only form under exceptional conditions, making discoveries like this exceedingly uncommon.
The fossil was found on private property near Herkimer, New York, though the exact date of its discovery is unknown. Its presence in the Museum’s collection has now provided scientists with critical new data on the species’ geographic range and survival into the Silurian, long after its peak in the Cambrian Period.
The study, titled Novel evidence for the youngest Naraoia and a reassessment of naraoiid paleobiogeography, was co-authored by Dr. Lisa Amati, New York State Paleontologist, along with researchers from the American Museum of Natural History and the Czech Republic. Their work highlights how even a single fossil can offer key insights into the history of life on Earth.
This discovery also underscores the importance of museum collections in supporting cutting-edge research. Behind the scenes, Museum scientists continue to reveal hidden stories from New York’s deep past—stories that help us better understand the ancient world and the ever-evolving history of life on our planet.
Scientists Are Pretty Close to Replicating the First Thing That Ever Lived
Where did we all come from? It’s a question that has lit fires of curiosity in philosophers, theologians, and more recently (at least, historically speaking) scientists for millennia. While the the older guard of high thought used stories or metaphors to derive life’s origin story, scientists instead learn about the inner workings of life’s smallest building blocks in an attempt to understand how they first formed life billions of years ago.
This long scientific exploration has led most evolutionary biologists to the conclusion that, for at least 400 million years, Earth was an “RNA World.” The hypothesis suggests that life first took form due to self-replicating RNA, before the evolutionary arrival of DNA or even proteins.
But there’s a couple problems.
First, there’s no trace of this “first replicator” in known biology. And second, scientists have failed to convincingly replicate RNA in an environment similar to early Earth. While scientists are very much still on the hunt for evidence that validates the first of these two issues, a team from University College of London (UCL) is closing in on solving the second problem.
Published in the journal Nature Chemistry, a team of UCL scientists (along with experts from the MRC Laboratory of Molecular Biology in Cambridge) used three-letter “triplet” RNA building blocks subjected to acid and heat in water. This separated the RNA double-helix—the structure that makes replication so difficult—and scientists froze the solution.
What occurred next is possibly an intimate glimpse of how life first formed on Earth—between the liquid gaps of the ice crystals, these building blocks coated the RNA strands and prevented them from zipping back together. After the scientists thawed the solution and and made adjustments to pH and temperature, the RNA replicated again and again. Eventually, the strand was so long that these structures could perform biological functions.
“The triplet or three-letter building blocks of RNA we used, called trinucleotides, do not occur in biology today, but they allow for much easier replication. The earliest forms of life are likely to have been quite different from any life that we know about,” James Attwater, lead author of the study from UCL, said in a press statement. “The changing conditions we engineered can occur naturally, for instance with night and day cycles of temperature, or in geothermal environments where hot rocks meet a cold atmosphere.”
UCL has long been involved in constructing the play-by-play of life’s origins on Earth. In 2017, for example, a study analyzed the chemistry that provided Earth with the very nucleotides necessary to construct the first RNA structures. This new study now attempts to understand, in a lab setting, how those ancient RNA first began replication, a process that’s essential to understanding the foundation of life.
“Life is separated from pure chemistry by information, a molecular memory encoded in the genetic material that is transmitted from one generation to the next,” Philipp Holliger, the senior author of the study from MRC Laboratory of Molecular Biology, said in a press statement. “For this process to occur, the information must be copied, i.e. replicated, to be passed on.”
Currently, the researchers have only been able to replicate roughly 17 percent of the RNA strand (roughly 30 out of 180 letters), but the team says there’s no reason they won’t achieve complete replication with improved enzyme efficiency. The researchers also note that this reaction can’t occur in saltwater (the salt disrupts the freezing process), but geothermal freshwater lakes or ponds would be the perfect chemical setting for RNA replication to take hold.
Although many questions remain, Earth’s ancient RNA World could have actually had the capacity for self-replication. It’s an intriguing step forward, but the scientific journey continues.
Giant ground sloths evolved three different times for the same reason
A cooling, drying climate turned sloths into giants – before humans potentially drove the huge animals to extinction.
Today’s sloths are small, famously sluggish herbivores that move through the tropical canopies of rainforests. But for tens of millions of years, South America was home to a dizzying diversity of sloths. Many were ground-dwelling giants, with some behemoths approaching 5 tonnes in weight.
That staggering size range is of particular interest to Alberto Boscaini at the University of Buenos Aires in Argentina and his colleagues.
“Body size correlates with everything in the biological traits of an animal,” says Boscaini. “This was a promising way of studying [sloth] evolution.”
Boscaini and his colleagues compiled data on the physical features, DNA and proteins of 67 extinct and living sloth genera – groups of closely related species – to develop a family tree showing their evolutionary relationships.
The researchers then took this evolutionary history, which covered a span of 35 million years, and added information about each sloth’s habitat, diet and lifestyle. They also studied trends in body-size evolution, making body mass estimates of 49 of the ancient and modern sloth groups.
The results suggest sloth body-size evolution was heavily influenced by climatic and habitat changes. For instance, some sloth genera began living in trees – similar to today’s sloths – and shrank in body size as they did so.
Meanwhile, three different lineages of sloths independently evolved elephantine proportions – and it seems they did this within the last several million years, as the planet cooled and the growth of the Andes mountains made South America more arid.
“Gigantism is more closely associated with cold and dry climates,” says team member Daniel Casali at the University of São Paulo, Brazil.
Many of these diverse sloths disappeared during two stages: one around 12,000 years ago and the other around 6000 years ago, says Boscaini.
“This matches with the expansion of Homo sapiens, first over the entire American supercontinent, and later in the Caribbean,” he says — which is where some giant sloths lived. Notably, the only surviving sloth species live in trees so are much harder for humans to hunt than massive ground sloths.
The idea that humans were the death blow for ancient megafauna is well-supported, says Thaís Rabito Pansani at the University of New Mexico, who wasn’t involved in the study.
“However, in science, we need several lines of evidence to reinforce our hypotheses, especially in unresolved and highly debated issues such as the extinction of megafauna,” she says. The new evidence shores up this story.
“Sloths were thriving for most of their history,” says Casali. “[The findings] teach us how a very successful [group] can become so vulnerable very quickly.”
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