A remarkably complete skeleton uncovered along the UK’s Jurassic Coast has been identified as a previously unknown species of ichthyosaur — a group of prehistoric marine reptiles that once dominated the world’s oceans.
The dolphin-sized creature, named Xiphodracon goldencapensis and nicknamed the “Sword Dragon of Dorset,” is the only known specimen of its species. Its discovery helps close a major gap in the fossil record and offers new insight into ichthyosaur evolution.
For more than two centuries, the Jurassic Coast has yielded thousands of ichthyosaur fossils, ever since pioneering fossil hunter Mary Anning began making historic finds there. However, this marks the first new genus of Early Jurassic ichthyosaur described from the region in more than 100 years.
Exceptionally Preserved 190-Million-Year-Old Fossil
The fossil was found near Golden Cap in 2001 by Dorset collector Chris Moore. Preserved in nearly perfect three-dimensional detail, the skeleton includes a skull with a huge eye socket and an elongated, sword-like snout. Researchers estimate the animal measured about three meters long and likely fed on fish and squid. There may even be traces of its final meal preserved within the remains. It is thought to be the most complete prehistoric reptile ever discovered from the Pliensbachian period.
The research was carried out by an international team of paleontologists led by ichthyosaur specialist Dr. Dean Lomax, an Honorary Research Fellow at The University of Manchester and an 1851 Research Fellow at the University of Bristol. Their findings appear in the journal Papers in Palaeontology.
Dr. Lomax said: “I remember seeing the skeleton for the first time in 2016. Back then, I knew it was unusual, but I did not expect it to play such a pivotal role in helping to fill a gap in our understanding of a complex faunal turnover during the Pliensbachian. This time is pretty crucial for ichthyosaurs as several families went extinct and new families emerged, yet Xiphodracon is something you might call a “missing piece of the ichthyosaur puzzle.” It is more closely related to species in the later Early Jurassic (in the Toarcian), and its discovery helps pinpoint when the faunal turnover occurred, being much earlier than expected.”
Solving an Evolutionary Mystery
After it was collected in 2001, the skeleton was acquired by the Royal Ontario Museum in Canada, where it joined one of the world’s largest ichthyosaur collections. Despite its importance, it had remained unstudied until now.
Ichthyosaurs from the Pliensbachian (193-184 million years ago) are extremely rare, making this specimen especially valuable. Scientists have long known that ichthyosaur species before and after this time period were very different from one another, even though they occupied similar ecological roles.
Co-author Professor Judy Massare of the State University of NY at Brockport explained: “Thousands of complete or nearly complete ichthyosaur skeletons are known from strata before and after the Pliensbachian. The two faunas are quite distinct, with no species in common, even though the overall ecology is similar. Clearly, a major change in species diversity occurred sometime in the Pliensbachian. Xiphodracon helps to determine when the change occurred, but we still don’t know why.”
Evidence of Injury and a Violent End
The skeleton also provides clues about the challenges of life in Jurassic seas. According to co-author Dr. Erin Maxwell of the State Museum of Natural History Stuttgart, several limb bones and teeth show abnormalities that suggest the animal suffered serious injury or illness while it was alive. The skull also appears to bear bite marks from a much larger predator — likely another large ichthyosaur — which may have caused its death.
Dr. Maxwell said: “This skeleton provides critical information for understanding ichthyosaur evolution, but also contributes to our understanding of what life must have been like in the Jurassic seas of Britain. The limb bones and teeth are malformed in such a way that points to serious injury or disease while the animal was still alive, and the skull appears to have been bitten by a large predator — likely another much larger species of ichthyosaur — giving us a cause of death for this individual. Life in the Mesozoic oceans was a dangerous prospect.”
Unique Features and a Fitting Name
Researchers identified several anatomical traits in Xiphodracon that have never been documented in any other ichthyosaur. One of the most unusual features is a distinctive bone near the nostril (called a lacrimal) that includes prong-like projections.
Dr. Lomax, author of the recent book “The Secret Lives of Dinosaurs,” said: “One of the coolest things about identifying a new species is that you get to name it! We opted for Xiphodracon because of the long, sword-like snout (xipho from Greek xiphos for sword) and dracon (Greek and Latin for dragon) in reference to ichthyosaurs being referred to as “sea dragons” for over 200 years.”
The study was published in the international journal Papers in Palaeontology. The fossil is expected to go on public display at the Royal Ontario Museum in Toronto, Canada.
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