Ancient squid-like creatures are not squid after all, study finds

THEY ARE SEA SERPENTS

University of Bristol

Facebook

WeChatMessageWhatsAppEmail

 

image: 

Reconstruction of Nektognathus, swimming in the Cambrian Sea. Image Credit, Bob Nicholls

view more 

Credit: Bob Nicholls

Remarkable fossils found in North Greenland have helped researchers solve a 500-million-year-old puzzle surrounding squid-like ancestors.

It was previously thought ancient organisms called nectocaridids, which bear a resemblance to squid, were a type of cephalopod – marine molluscs with tentacles and a prominent head. But scientists, co-led by the University of Bristol, have now shown these creatures are actually an early descendent of arrow worms, also known as chaetognaths.

This surprising discovery means the rather simple marine arrow worms had ancestors with much more complex anatomies and a predatory role higher up in the food chain.

The study, in partnership with palaeontologists at the Korean Polar Research Institute and University of Copenhagen, is the culmination of a series of excavation expeditions to Sirius Passet in North Greenland, which began nine years ago. The locality is famous for its extreme exceptional preservation of marine organisms from the Early Cambrian around 518 million years ago.

Co-lead author Dr Jakob Vinther, Associate Professor in Macroevolution at the University of Bristol, said: “Sirius Passet is a treasure trove of fossils from the Cambrian Explosion. We not only find delicate soft-bodied fossils but also their digestive systems, musculature and sometimes even their nervous system.

“Around 15 years ago a research paper, based on fossils from the famous Burgess Shale, claimed nectocaridids were cephalopods. It never really made sense to me, as the hypothesis would upend everything we otherwise know about cephalopods and their anatomy didn’t closely match cephalopods when you looked carefully.”

The research team’s excitement grew as fossils of the mysterious nectocaridids were unearthed in Sirius Passet for the first time.

By analysing 25 fossil specimens, the researchers were able to pinpoint where nectocaridids fit into the tree of life. The solution came from Sirius Passets’ unique preservation conditions resulting in their nervous systems commonly remaining intact.

“We discovered our nectocaridids preserve parts of their nervous system as paired mineralised structures, and that was a giveaway as to where these animals sit in the tree of life,” Dr Vinther explained.

Recently, the team uncovered fossils in Sirius Passet belonging to another branch of the animal tree – a small group of swimming worms called arrow worms or chaetognaths.

“These fossils all preserve a unique feature, distinct for arrow worms, called the ventral ganglion,” said co-lead author Dr Tae-Yoon Park of the Korean Polar Institute.

The ventral ganglion is a large mass of nerves situated on the belly of living arrow worms, which is unique to this type of creature. The unique anatomy of the organ combined with the special preservation conditions means it sometimes is replaced by phosphate minerals during decay.

Dr Park added: “We now had a smoking gun to resolve the nectocaridid controversy. Nectocaridids share a number of features with some of the other fossils that also belong to the arrow worm stem lineage. Many of these features are superficially squid-like and reflect simple adaptations to an active swimming mode of life in invertebrates, just like whales and ancient marine reptiles end up looking like fish when they evolve such a mode of life.”

The discovery helps reveal clues about arrow worms and their past.

“Nectocaridids have complex camera eyes just like ours. Living arrow worms can hardly form an image beyond working out roughly where the sun shines. So, the ancestors of arrow worms were really complex predators, just like the squids that only evolved about 400 million years later,” Dr Vinther added.

“We can therefore show how arrow worms used to occupy a role much higher in the food chain. Our fossils can be much bigger than a typical living arrow worm and combined with their swimming apparatus, eyes and long antennae, they must have been formidable and stealthy predators.”

As further evidence for nectocaridids being swimming carnivores, the researchers found several specimens with the carapaces of a swimming arthropod, called Isoxys, inside their digestive tract.

The fossil is named Nektognathus evasmithae. The species name honours Professor Eva Smith, the first female professor of law in Denmark and renowned human rights advocate.

Dr Vinther said: “My decision to name our fossil after Eva, is that this animal was a smart and stealthy fighter just like she is.”

The holotype specimen of Nektognathus from Sirius Passet

Credit

Tae Yoon Park

The holotype specimen of Nektognathus from Sirius Passet imaged with Electron Probe microanalysis for its carbon content

Credit

Mirinae Lee and Chankun Park

Specimen of Nektognathus as it was found in the field at Sirius Passet, North Greenland

Credit

Tae Yoon Park

Modern chaetognath from Antarctica

Credit

Tae Yoon Park

---

Journal

Science Advances

DOI

10.1126/sciadv.adu6990 

Article Title

A fossilized ventral ganglion reveals a chaetognath affinity for Cambrian nectocaridids

Article Publication Date

23-Jul-2025

Molecular hope: tiny ocean creatures reveal dual paths to climate resilience

University of Vermont

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

University of Vermont Professor Melissa Pespeni led a research team that explored how tiny sea creatures evolve. Her discovery provides hope that organisms in the ocean my be more resilient to the onslaught of climate change than previously known.

view more 

Credit: Joshua Brown/UVM

In a first-of-its-kind experiment tracing evolution across 25 generations, scientists have discovered that marine copepods—the tiny crustaceans at the heart of the ocean food web—rely on a largely unknown biological toolkit to survive the stresses of climate change.

Published July 15, 2025, in the Proceedings of the National Academy of Sciences, the study reveals that it’s not only genetic changes (permanent alterations to DNA) that help these animals adapt to warming and acidifying ocean conditions. In addition, little-known epigenetic changes (temporary “on/off” chemical modifications to parts of DNA) play a crucial role too. Remarkably, the researchers discovered that the two mechanisms operate independently but in concert, offering what they call a “two-pronged strategy” for long-term resilience.

“This is a story of molecular hope in the face of a rapidly changing planet,” said senior author Melissa Pespeni, associate professor of biology at the University of Vermont. “We found that evolution is not working from one toolbox, but two—and they’re complementary.” 

Until now, few studies have tracked genetic and epigenetic changes in tandem over many generations. This experiment is one of the first to do so in a long-term, replicated evolution study—offering some of the strongest evidence yet that epigenetic change can help populations survive and perhaps even allow future genetic adaptation.

Which means that copepods may be tougher under the stresses of a warming ocean than scientists previously would have predicted. And that could be good news for the many fish species who eat copepods as their primary prey—and for the many other creatures, including humans, who eat fish.

Copepods are tiny crustaceans, barely visible to the naked eye, but beautiful under a microscope and hugely important to life on Earth. They're found in nearly every freshwater and marine habitat—and they may be the most abundant animals in the ocean. (Photo: Andrei Savitsky)

Evolution in a Bucket

To conduct this study, Pespeni and colleagues at GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany and at the University of Connecticut, raised populations of Acartia tonsa—a foundational marine copepod species—in carefully controlled laboratory buckets. Some buckets were warmed, others acidified, and some experienced both. Over a year, these fast-reproducing animals cycled through 25 generations.

The team measured their response not only at the organismal level—how many eggs the copepods laid, their thermal tolerance, development rates, and survival—but also at the molecular level. Using state-of-the-art sequencing, the researchers mapped changes in the animals’ genome (genetic adaptation), epigenome (molecular markers that influence gene expression), and transcriptome (which genes were turned on and off).

They found striking and consistent epigenetic and genetic changes across the treatment groups—but, surprisingly, these changes occurred in different regions of the genome.

“That’s really powerful,” said Pespeni. “It shows that the epigenetic variation was not just dragged along with the genetic variation. These are independent mechanisms that the organism is using to cope.”

Evolution’s Dynamic Duo

In genetics, variation provides the raw material for evolution. Populations with more genetic variation are generally better equipped to respond to environmental change. But what happens when genetic variation runs low—or change happens too fast for slow-moving genetic mutations to keep up?

That’s where epigenetics comes in.

“Epigenetic changes can happen within an individual’s lifetime and don’t require a new mutation,” said Pespeni. “They’re reversible and fast.” Exactly what a copepod wants when facing a heat wave or a spike in ocean acidification.

The study found that regions of the copepod genome with high epigenetic divergence—like shifts in methylation—had two to two-and-a-half times lower genetic divergence, suggesting that these mechanisms may inhibit each other or target different functions. But both types of changes mattered.

Epigenetic divergence was particularly concentrated in genes involved in stress responses and the regulation of transposable elements— bits of "jumping" DNA that can reshuffle the genome. And importantly, these epigenetic changes were correlated with changes in gene expression, directly shaping how the organism functions.

“Together, these results show that genetic and epigenetic variation are not redundant,” Pespeni explained. “They are evolution’s dynamic duo—providing two independent toolkits for organisms facing rapid global change.”

A Shift in Evolutionary Thinking

The findings have profound implications for how scientists understand evolution and resilience in the Anthropocene.

“Epigenetics is not just a side note in biology,” said Pespeni. “It’s important. We’re not rewriting Darwin, but we are expanding the Modern Synthesis to include this player.”

“This might sound like neo-Lamarckian heresy,” Pespeni said with a laugh, referencing the discredited idea that traits acquired during a lifetime can be passed to future generations. (Because you spent years in the garden and developed rough calloused hands doesn’t mean your child will be born with “gardener’s hands” or a love of lettuce.) “But what we’re seeing is that molecular and physiological phenotypes—like how an organism responds to temperature stress—can be passed down to future generations through epigenetic means, at least temporarily.”

Why Copepods Matter

Tiny as they are, Acartia tonsa and other copepods play a massive role in the ocean ecosystem and global carbon cycle. They’re the base of the marine food web, sustaining fish, whales, and seabirds. They also help cycle nutrients and carbon in the ocean.

“Without copepods, you don’t have fish, you don’t have whales, you don’t have the ocean system we know,” said Pespeni. “And they are arguably the most abundant animal on Earth.”

The fact that copepods can survive and quickly adapt across generations—say, during a short, intense heat wave—could make a long-term difference in maintaining biodiversity and ecosystem function in a warming world.

“Allowing an organism to survive a few extra generations during a stress event could preserve genetic diversity and buy time for longer-term adaptation,” said Pespeni. 

Hope in the Genome

This research may offer new optimism to the grim tale of global changes. While genetic diversity has long been seen as the well of evolutionary potential, this study suggests that epigenetic diversity might offer a hidden reserve of strength—one that can be tapped quickly, flexibly, and repeatedly. “And that's important,” Pespeni says, “because it shows these organisms may be more resilient than previously expected.”

---

DOI

10.1073/pnas.242278212 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Complementary genetic and epigenetic changes facilitate rapid adaptation to multiple global change stressors

Article Publication Date

25-Jul-2025

Antibiotic-resistant bacteria found in southern ocean

Higher Education Press

Facebook

XLinkedIWeChatBlueskyMessageWhatsApp\Email

 

image: 

Antibiotic resistance profiling of Staphylococcus saprophyticus

view more 

Credit: Jiangnan University

Antibiotic resistance has increasingly become a significant concern for the environment and public health. Researchers isolated Staphylococcus saprophyticus strain from the Southern Ocean within the Antarctic circle.

Antibiotic susceptibility profiling of S. saprophyticus revealed complete resistance to Cefixime, Norfloxacin, Azithromycin, and Metronidazole. Comparative genomics revealed the presence of drug resistance genes across various strains of S. saprophyticus, with the vanY gene in the vanM cluster being the most common, followed by sdrM and sepA genes. The drug resistance genes will alter the antibiotic targets of the strain and enhance the excretion of antibiotic drugs. 

The Southern Ocean is one of the pristine and isolated ecosystems on Earth and is regarded as an untouched area. However, this study confirmed that human activities have already affected the Antarctic ecosystem and may cause greater public health damage through the interaction of the food chain and ecology.

The work entitled “Antibiotic resistance profiling and comparative genomics of cold-adapted Staphylococcus saprophyticus from the Southern Ocean” was published on Systems Microbiology and Biomanufacturing (published on May 28, 2025).

---

Journal

Systems Microbiology and Biomanufacturing

DOI

10.1007/s43393-025-00374-z 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Antibiotic resistance profiling and comparative genomics of cold-adapted Staphylococcus saprophyticus from the Southern Ocean

Article Publication Date

24-Jun-2025

 

Record-breaking ‘gigantic’ deep-sea limpet species named after ONE PIECE character

Pensoft Publishers

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Bathylepeta wadatsumi and “Large Monk” Wadatsumi. 

view more 

Credit: Limpet photograph: Chen et al.; Illustration: ONE PIECE (TV series) Toei Animation.

Researchers from Japan Agency for Marine-Earth Science and Technology (JAMSTEC) have discovered a deep-sea limpet species 5,922 metres beneath the northwestern Pacific Ocean, marking the deepest known habitat for any true limpet (subclass Patellogastropoda).

Described as a new species in the open-access journal Zoosystematics and Evolution, the limpet was found on hard volcanic rock 500 kilometres southeast of Tokyo, Japan. The gastropod measures up to 40.5 mm in shell length, a remarkably large size for a true limpet from such depths.

The new species was named Bathylepeta wadatsumi, a reference to Wadatsumi, the god of the sea in Japanese mythology, and the character “Large Monk” Wadatsumi, from the manga series ONE PIECE. The character’s enormous size mirrors that of the newly discovered limpet.

The researchers behind the discovery paid further homage to the world’s most popular manga series in their acknowledgements, writing:

“We also take this opportunity to salute Eiichiro Oda for continuing to chart the epic voyage of ONE PIECE (1997–), which reminds us that the greatest voyages are driven by freedom, camaraderie, and an insatiable thirst for discovery.”

The new species was collected using the crewed submersible DSV Shinkai 6500, making it the first time a member of the genus Bathylepeta has been observed and photographed live on its natural rocky substrate, rather than being dredged using a net. The use of submersibles is instrumental in accessing these habitats, allowing for direct observation and collection of previously overlooked organisms. 

Dr. Chong Chen, lead author of the research paper, said: “Even in an age of sophisticated remotely operated vehicles, there’s often an edge to the human eye on the seafloor. Crewed submersibles like Shinkai 6500 let us explore with intention and nuance—spotting lifeforms like Bathylepeta wadatsumi that might otherwise be missed entirely.” 

Beyond its taxonomic significance, the study has broader ecological implications as B. wadatsumi appears to graze on sediment layers over rock, indicating a specialised role in processing organic matter in deep-sea ecosystems.

The findings underscore the need for more comprehensive explorations of rocky abyssal habitats using submersibles to reveal the true diversity and distribution of Bathylepeta and other animals relying on such habitats.

Original source

Chen C, Tsuda M, Ishitani Y (2025) A new large-sized lepetid limpet from the abyssal northwestern Pacific is the deepest known patellogastropod. Zoosystematics and Evolution 101(3): 1249-1058. https://doi.org/10.3897/zse.101.156207

Habitus of Bathylepeta wadatsumi with a clear feeding trail behind.

Bathylepeta wadatsumi holotype. A. Dorsal view; B. Ventral view; C. Ventral view with the soft parts removed; D. Lateral view from the left; E. Lateral view from the right.

Credit

Chen et al.

Journal

Zoosystematics and Evolution

DOI

10.3897/zse.101.156207 

Article Publication Date

24-Jul-2025

 

 

Potential trade-offs of proposed cuts to the NIH

JAMA Health Forum

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

About The Study: 

The results of this qualitative analysis using systems modeling suggest that National Institutes of Health (NIH) budget reductions may have far-reaching implications for scientific progress, the biomedical innovation environment, and health care costs. Beyond immediate budgetary impacts, systemic interactions shaping long-term biomedical research and public health must be considered in funding policies.

Corresponding Author: To contact the corresponding author, Mohammad S. Jalali, Ph,D,, email msjalali@mgh.harvard.edu.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi: 10.1001/jamahealthforum.2025.2228)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

#  #  #

Embed this link to provide your readers free access to the full-text article 

 https://jamanetwork.com/journals/jama-health-forum/fullarticle/10.1001/jamahealthforum.2025.2228?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=072525

About JAMA Health Forum: JAMA Health Forum is an international, peer-reviewed, online, open access journal that addresses health policy and strategies affecting medicine, health and health care. The journal publishes original research, evidence-based reports and opinion about national and global health policy; innovative approaches to health care delivery; and health care economics, access, quality, safety, equity and reform. Its distribution will be solely digital and all content will be freely available for anyone to read.

---

Journal

JAMA Health Forum