Remarkable Isle Of Wight Fossil Reveals Dinosaur-Era Shellfish Cared For Their Young

A remarkable fossil discovered on the Isle of Wight has provided the oldest known evidence of shellfish caring for their young during the age of dinosaurs.

Scientists studying fossils dating back more than 125 million years have uncovered preserved embryos and larvae inside the gills of an ancient freshwater bivalve – a group of animals that includes modern-day mussels, clams and oysters.

The discovery, published in the journal Scientific Reports, suggests that these shellfish were already protecting and incubating their offspring during the Early Cretaceous Period, making it the earliest known fossil evidence of maternal care in the group.

Researchers made the find while examining fossils of Margaritifera valdensis, a freshwater bivalve discovered on the Isle of Wight, which is renowned internationally for its rich collection of dinosaur-era fossils.

What makes the discovery particularly significant is the preservation of soft tissues, which would normally decay shortly after death. Alongside the shell itself, scientists identified fossilised reproductive structures, gill tissues and embryos at different stages of development.

Dr Martin Munt, a visiting academic at the University of Portsmouth and specialist in fossil molluscs, said:

"This is the earliest known fossil evidence that these shellfish cared for and protected their developing young.

"Not only does this discovery provide a rare glimpse into how ancient freshwater shellfish reproduced, but it also helps explain how these animals successfully adapted to life in rivers and lakes millions of years ago."

The international research team also found evidence that the ancient shellfish supplied calcium to their developing young, helping them build their shells in a similar way to freshwater mussels living today.

Dr Aleksandra Skawina, a fossil bivalve specialist from the University of Warsaw, said the fossils show this complex reproductive strategy had already evolved by the Early Cretaceous.

The study also sheds new light on a mysterious dark material known as "molluskite", first described in the 19th century by renowned palaeontologist Gideon Mantell.

Researchers now believe the material is made up of exceptionally preserved fossilised soft tissues and reproductive structures.

The project involved scientists from the University of Portsmouth, the University of Warsaw in Poland and the Geological and Mining Institute of Spain.

Researchers say the discovery offers a rare window into the origins of freshwater mussels, a group of animals that continues to play a vital role in ecosystems around the world but is now among the most threatened on Earth.