Dean Lomax, a palaeontologist at the University of Manchester, along with his team, has unveiled a new genus and species of leptonectid ichthyosaur based on fossil remains found in Dorset, England.
The near-complete skeleton of this dolphin-sized ichthyosaur was unearthed near Golden Cap in 2001 by fossil collector Chris Moore from Dorset.
This specimen features a skull with large eye sockets and a long, sword-like snout, marking it as a new genus and species.
Dating back to the Pliensbachian period of the Early Jurassic, the fossil is estimated to be between 193 and 184 million years old.
“I vividly recall first seeing the skeleton in 2016. While we recognized its rarity then, we didn’t anticipate its significant contribution to our understanding of the intricate faunal turnover during the Pliensbachian period,” stated Dr. Lomax.
“This era is critical for ichthyosaurs, as certain families disappeared while new ones emerged, making this new species potentially the ‘missing piece of the ichthyosaur puzzle.’
“It is more closely related to species from the Late Jurassic, and its discovery helps indicate that faunal turnover transpires much earlier than we previously thought.”
“This marks the first early Jurassic ichthyosaur genus to be described in this region in over a century.”
Skeleton and skull of Siphodracon goldencapensis. Image credit: Dean Lomax.
Named Siphodracon goldencapensis, this new ichthyosaur measures approximately 3 meters (10 feet) in length and likely preyed on fish and squid. Evidence of its last meal can also be observed in the remains.
According to Dr. Erin Maxwell, an ichthyosaur specialist at the State Museum of Natural History in Stuttgart: “This skeleton not only offers essential insights into the evolution of ichthyosaurs but also enhances our understanding of life in Britain’s Jurassic seas.”
“The limb bones and teeth appear malformed, suggesting the animal suffered significant injury or disease during its life, and indications show the skull may have been bitten by a large predator, possibly another larger ichthyosaur, leading to this individual’s death.”
“Life in the Mesozoic ocean was perilous.”
The researchers identified several traits in Siphodracon goldencapensis that have not been seen in any known ichthyosaur.
One of the most peculiar features is the lacrimal bone, which has a unique protruding structure around the nostril.
“Thousands of complete or nearly complete ichthyosaur skeletons exist from both pre- and post-Pliensbachian layers,” noted Judy Massare, a ichthyosaur expert from the State University of New York at Brockport.
“Although the overall ecosystem shows similarities, the two faunas differ significantly with no overlapping species.”
“Evidently, a substantial shift in species diversity took place at some point during the Pliensbachian period.”
“Siphodracon goldencapensis aids in pinpointing when this change happened, yet we still lack insight into the reasons.”
This work is detailed in a study published in this month’s edition of Paleontology Papers.
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Dean R. Lomax et al. 2025. A new species of ichthyosaur with an elongated snout reveals complex faunal alterations during the poorly sampled Early Jurassic (Pliensbachian) period. Paleontology Papers 11 (5): e70038; doi: 10.1002/spp2.70038
Source: www.sci.news
