The prototype starfish, which has features in common with both sea lilies and modern-day starfish, is a missing link for scientists trying to piece together its early evolutionary history.

The exceptionally preserved fossil, named Cantabrigiaster fezouataensis, was discovered in Morroco’s Anti-Atlas mountain range. Its intricate design — with feathery arms akin to a lacework — has been frozen in time for roughly 480 million years.

The new species is unusual because it doesn’t have many of the key features of its contemporary relatives, lacking roughly 60% of a modern starfish’s body plan.

The fossil’s features are instead a hybrid between those of a starfish and a sea lily or crinoid — not a plant but a wavy-armed filter feeder which fixes itself to the seabed via a cylindrical ‘stem’.

The discovery, reported in Biology Letters, captures the early evolutionary steps of the animal at a time in Earth’s history when life suddenly expanded, a period known as the Ordovician Biodiversification Event.

The find also means scientists can now use the new find as a template to work out how it evolved from this more basic form to the complexity of their contemporaries.

“Finding this missing link to their ancestors is incredibly exciting. If you went back in time and put your head under the sea in the Ordovician then you wouldn’t recognize any of the marine organisms — except the starfish, they are one of the first modern animals,” said lead author Dr Aaron Hunter, a visiting postdoctoral researcher in the Department of Earth Sciences.

Modern starfish and brittle stars are part of a family of spiny-skinned animals called the echinoderms which, although they don’t have a backbone, are one of the closest group of animals to vertebrates. Crinoids, and otherworldly creatures like the sea urchins and sea cucumbers are all echinoderms.

The origin of starfish has eluded scientists for decades. But the new species is so well preserved that its body can finally be mapped in detail and its evolution understood. “The level of detail in the fossil is amazing — its structure is so complex that it took us a while to unravel its significance,” said Hunter.

It was Hunter’s work on both living and fossil echinoderms that helped him spot its hybrid features. “I was looking at a modern crinoid in one of the collections at the Western Australian Museum and I realised the arms looked really familiar, they reminded me of this unusual fossil that I had found years earlier in Morocco but had found difficult to work with,” he said.

Fezouata in Morocco is something of a holy grail for palaeontologists — the new fossil is just one of the many remarkably well preserved soft-bodied animals uncovered from the site.

Hunter and co-author Dr Javier Ortega-Hernández, who was previously based at Cambridge’s Department of Zoology and is now based at Harvard University, named the species Cantabrigiaster in honour of the long history of echinoderm research at their respective institutions.

Hunter and Ortega-Hernández examined their new species alongside a catalogue of hundreds starfish-like animals. They indexed all of their body structures and features, building a road map of the echinoderm skeleton which they could use to assess how Cantabrigiaster was related to other family members.

Modern echinoderms come in many shapes and sizes, so it can be difficult to work out how they are related to one another. The new analysis, which uses extra-axial theory — a biology model usually only applied to living species — meant that Hunter and Ortega-Hernández could identify similarities and differences between the body plan of modern echinoderms and then figure out how each family member was linked to their Cambrian ancestors.

They found that only the key or axial part of the body, the food groove — which funnels food along each of the starfish’s arms — was present in Cantabrigiaster. Everything outside this, the extra-axial body parts, were added later.

The authors plan to expand their work in search of early echinoderms. “One thing we hope to answer in the future is why starfish developed their five arms,” said Hunter. “It seems to be a stable shape for them to adopt — but we don’t yet know why. We still need to keep searching for the fossil that gives us that particular connection, but by going right back to the early ancestors like Cantabrigiaster we are getting closer to that answer.”

While most people with MS are first diagnosed with relapsing-remitting MS, marked by symptom flare-ups followed by periods of remission, many people with relapsing-remitting MS eventually transition to secondary progressive MS, which does not have wide swings in symptoms but instead a slow, steady worsening of the disease.

The study involved autologous hematopoietic stem cell transplants, which use healthy blood stem cells from the participant’s own body to replace diseased cells.

“So far, conventional treatments have prevented people with MS from experiencing more attacks and worsening symptoms, but not in the long term,” said study author Matilde Inglese, M.D., Ph.D., of the University of Genoa in Italy and a member of the American Academy of Neurology. “Previous research shows more than half of the people with MS who take medication for their disease still get worse over a 10-year period. Our results are exciting because they show hematopoietic stem cell transplants may prevent someone’s MS disabilities from getting worse over the longer term.”

The study looked at 210 people with MS who received stem cell transplants from 1997 to 2019. Their average age was 35. Of those people, 122 had relapsing-remitting MS and 86 had secondary progressive MS and two had primary progressive MS.

Researchers assessed participants at six months, five years and 10 years after their transplants.

Five years into the study, researchers found that 80% of the people experienced no worsening of their MS disability. At the 10-year mark, 66% still had not experienced a worsening of disability.

When looking at just the people with the most common form of MS, researchers found 86% of them experienced no worsening of their disability five years after their transplant. Ten years later, 71% still experienced no worsening of their disability.

Also, people with progressive MS benefited from stem cell transplants. Researchers found that 71% of the people with this type of MS experienced no worsening of their disability five years after their transplants. Ten years later, 57% experienced no worsening of their disability.

“Our study demonstrates that intense immunosuppression followed by hematopoietic stem cell transplants should be considered as a treatment for people with MS, especially those who don’t respond to conventional therapy,” Inglese said.

Limitations of the study include that it was retrospective, did not include a control group and the clinicians who helped measure participants’ disability were aware that they had received stem cell transplants, so that could have led to bias. Inglese said these limitations will be addressed in future research.

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Idiopathic intracranial hypertension is when the pressure in the fluid surrounding the brain rises. It can mimic the symptoms of a brain tumor, causing chronic, disabling headaches, vision problems and in rare cases, vision loss. It is most often diagnosed in women of childbearing age. Treatment is often weight loss. In some cases, surgery may be required.

“The considerable increase in idiopathic intracranial hypertension we found may be due to many factors but likely mostly due to rising obesity rates,” said study author William Owen Pickrell, Ph.D., M.R.C.P., of Swansea University in Wales in the United Kingdom and a member of the American Academy of Neurology. “What is more surprising from our research is that women who experience poverty or other socioeconomic disadvantages may also have an increased risk independent of obesity.”

For the study, researchers used a national healthcare database in Wales to analyze 35 million patient years of data over a 15-year period, between 2003 and 2017. They identified 1,765 people with idiopathic intracranial hypertension during that time. Of the group, 85% were women. Researchers recorded body mass index measurements for study participants. Body mass index is calculated by dividing weight by height. For every one person with the disorder, researchers compared three people without it who were matched for gender, age and socioeconomic status.

The socioeconomic status of each person with the disorder was determined by where they live, using a national scoring system that considers factors like income, employment, health, education and access to services. People in the study were then divided into five groups ranging from those with the fewest socioeconomic advantages to those with the most.

Overall, researchers found a six-fold increase in the number of cases of the disorder over the course of the study. In 2003, for every 100,000 people, 12 were living with the disorder, compared to 76 people in 2017. Also, in 2013, for every 100,000 people, two were diagnosed during that year, compared to eight people in 2017.

Researchers found that the increasing number of people living with the disorder corresponded to rising obesity rates in Wales during the study, with 29% of the population being obese in 2003 compared to 40% in 2017.

“The worldwide prevalence of obesity nearly tripled between 1975 and 2016, so while our research looked specifically at people in Wales, our results may also have global relevance,” said Pickrell.

There were strong links for both men and women between body mass index and risk of the disorder. For women, there were 180 cases per 100,000 people during the study for those with high body mass index compared to 13 women with a body mass index considered to be ideal. For men, there were 21 cases per 100,000 among those with a high body mass index compared to eight cases for those with an ideal body mass index.

Researchers also found that for women only, socioeconomic factors were linked to risk. There were 452 women in the group with the fewest socioeconomic advantages compared to 197 in the group with the most. The women in the group with the fewest had a 1.5 times greater risk of developing the disorder than women in the group with the most, even after adjusting for body mass index.

“Of the five socioeconomic groups of our study participants, women in the lowest two groups made up more than half of the female participants in the study,” said Pickrell. “More research is needed to determine which socioeconomic factors such as diet, pollution, smoking or stress may play a role in increasing a woman’s risk of developing this disorder.”

A limitation of the study was that researchers identified the socioeconomic status of participants by the regions in which they lived instead of obtaining individual socioeconomic information for each participant.