Well-preserved fossils help scientists unravel a puzzle about the origins of early animals that baffled Charles Darwin.
Analysis of the 547 million-year-old remains enabled researchers to trace the origins of some of the world’s oldest animals back more than ever.
Their study revealed the first known link between animals that evolved during the so-called Cambrian explosion about 540 million years ago and one of their early ancestors.
Until recently, little was known about the origins of the animals that evolved during the Cambrian event due to a lack of well-preserved fossil evidence.
The mysterious origins of the animals that evolved at this time – when the diversity of life on Earth increased rapidly, giving rise to almost all modern animal groups – baffled the nineteenth-century naturalist Charles Darwin. It is often referred to as Darwin’s Dilemma.
Prior to the new study, it proved difficult to trace links with past animals because their soft tissues – which provide vital clues about the animals’ ancestors – almost always break down over time.
During fieldwork in Namibia, scientists from the University of Edinburgh discovered fossil remains of small animals – known as Namakalatus – that resemble a pin pad attached to a short leg.
Using X-ray imaging technology, the team found some properly preserved animal soft tissues inside the fossils with a mineral called pyrite. So far, scientists have only identified the remains of a skeleton of a Namacallathus.
The study of soft tissues – and their comparison with those in later-evolving animals – revealed that Namakalathus was an early precursor to the species that appeared during the Cambrian explosion. Among them are prehistoric species of worms and mollusks.
The study published in the journal Science advances, Funded by the Natural Environment Research Council. Also co-working is a researcher from Lomonosov Moscow State University, Russia.
Professor Rachel Wood, from the University of Edinburgh’s School of Geosciences, said: “These are exceptional fossils, they give us a glimpse into the biological convergence of some of the oldest animals.
“It helps us trace the roots of the Cambrian explosion and the origins of modern animal populations. This preservation opens many new avenues for research into the history of life that was previously not possible.”