‘Wessie’ the micro-monster discovered on Dinosaur Island

A new species of feisty amphibian that lived in the shadows of dinosaurs has been discovered by a researcher at the University of Portsmouth.

Illustration of the Wesserpeton by Dr Mark Witton, honorary research fellow at the University of Portsmouth

The discovery fills a gap in the evolutionary history of a now extinct group, the albanerpetontids.

Wesserpeton, nicknamed ‘Wessie’, was tiny, about the size of a small, modern-day newt. Unlike most amphibians, albanerpetontids had a scaly skin and eyelids showing that they spent most of their time on land. Details of the skeleton also suggest that they were well adapted to burrowing.

The creature lived on the Isle of Wight, often called Dinosaur Island, about 130 million years ago during the Early Cretaceous, at the same time as dinosaurs such as Neovenator, Iguanodon and giant, long-necked sauropods.

Broken but healed jaws among the bones suggest Wessie was a fiesty creature. Like some modern-day salamanders it probably engaged in fierce battles for mates and territory, and sharp chisel-like teeth indicate that it was a predator.

Wessie was about the size of a modern-day newt

Lead researcher, Dr Steve Sweetman, said: “When I started looking for the little animals that lived with the dinosaurs a Wessie jaw was the first thing I found and I can still remember how excited I was. I also remember thinking that ‘albanerpetontid’ was a heck of a mouthful for such a tiny creature.

“Of the 50 or so new four legged animals I have now found, Wessie bones are the most common and it was clearly well adapted to the ancient floodplain environment in which it lived.”

The researchers have no complete skeletons of Wessie but they have a large number of isolated bones representing almost all parts of the animal.

Dr Sweetman and his co-author, Dr Jim Gardner of the Royal Tyrrell Museum of Palaeontology, Canada, named the animal Wesserpeton because its bones come from rocks known as the Wessex Formation.

Dr Sweetman said: “It is a pure coincidence that the nickname rhymes with another well-known monster.”

The discovery of Wessie neatly fills an evolutionary gap. Albanerpetontids are first found in rocks of Middle Jurassic age and their last occurrence is in the Late Pliocene. During this period of more than 165 million years, skull bones known as frontals gradually changed from bell-shaped to triangular. Until now, part of this transition was missing from the fossil record.

Dr Sweetman said: “Until the discovery of Wesserpeton there appeared to be an abrupt transition from the more primitive elongated and bell-shaped frontals of the early albanerpetontids to the triangle shaped frontals of later forms. The frontals of Wesserpeton are elongated but they are also triangular, neatly filling the gap between the two.”

Palaeoherpetologist and albanerpetontid specialist Dr Jim Gardner from the Royal Tyrrell Museum of Palaeontology travelled to the UK to work on the project and Dr Steve Sweetman from the University of Portsmouth’s School of Earth and Environmental Sciences made the journey in the opposite direction to work on material held in the Royal Tyrrell’s collections.

The Wessex Formation is unique as it contains plant debris beds of a type so far not recorded anywhere else in the world. Decaying plant material in the sediment removed oxygen and provided ideal conditions for the preservation of bones.

Dr Sweetman said: “From the plant debris beds we have bones of some of the largest creatures to have walked the earth during the Early Cretaceous mixed with those of some of the smallest, including those of Wessie. This is really quite remarkable and it is what makes the dinosaur-bearing rocks of the Isle of Wight so special.”

The discovery is published online in the journal Acta Palaeontologica Polonica.

2 total comments on this postSubmit yours
  1. This is amazing – so interesting and so important.
    I moved to the Dinosaur Island last year and its incredible that scientists are still finding remains.
    Can you comment on why you think that there is this numerous and continuing catchment area of a variety of remains. Did it happen once the island became isolated from the mainland and therefore could not sustain the population, or is there a theory of some event?
    Thank you.

  2. Hi Jan,

    All the things I am working on relate to the dinosaurs and the little creatures that lived with them. On the Isle of Wight the remains of these animals are between 125 and 130 million years old. At that time the land on which the dinosaur bearing rocks were deposited was located about where Gibraltar is today. Partly because of this and because of extreme global warming at the time the climate was very hot during the summer. Occasionally wild fires ignited by lightning strikes would burn vegetation on what was at that time a wide river floodplain and very occasionally after that there was a severe rain storm which produced a flash flood. With open forest canopies and no vegetation on the ground the floods eroded floodplain sediments turning the flood water into something resembling mixed concrete. This moving mixture was powerful enough to pick up tree trunks and the bones of the largest dinosaurs and transport them across terrestrial, lake and river habitats where the flood also picked up small bones and teeth of animals from both terrestrial and aquatic habitats mixing them with the large ones. Quite soon these floods ‘ran out of steam’ depositing the mud, bones and plant remains. Decaying plant material in the sediment removed oxygen that might otherwise led to the decay of the bones and what we are left with is a jumbled up snapshot of life at the time of each flood. This is quite remarkable and so far I have not been able to find anywhere else in the world where similar deposits occur. It is these deposits known as plant debris beds which make the island so special and why the remains of so many different creatures have been found here.

    So far as the Isle of Wight as an island is concerned, you might be surprised to know that it only became an island about seven thousand years ago when a chalk ridge extending from the what are now the Needles to Old Harry Rocks was breached by the sea.

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