A nearly metre-long front flipper from a giant Jurassic ichthyosaur preserves unusually detailed soft-tissue anatomy, including a fleshy tip and a serrated trailing edge. In a 2025 study, researchers proposed that these features may have helped the animal swim more quietly while hunting in dim water. The fossil provides evidence for a possible adaptation—not direct proof of how the animal behaved—and it is not the first ichthyosaur fossil with preserved soft tissue.
What did the giant ichthyosaur flipper fossil reveal?
The specimen is an isolated front flipper attributed to Temnodontosaurus, a large marine reptile that lived during the Jurassic. The 2025 paper describes skin ornamentations and a prolonged fleshy tip. A University of Manchester account of the study also reports a scalloped or serrated trailing edge and mineralized, rod-like structures the researchers call “chondroderms.”
Those are anatomical observations. The proposal that they reduced swimming noise is a functional interpretation based on the flipper’s structure and modeling, not something the fossil directly records. Lead researcher Johan Lindgren said the flipper’s wing-like shape, lack of bones at its distal end and serrated trailing edge together indicate that the animal had evolved ways to minimize sound while swimming.
What was found, and how large was it?
The fossil consists of part and counterpart preserving almost the entire front flipper, although its top portion is missing. No other remains were found with it. The University of Manchester account places the animal at about 183 million years ago, estimates that it exceeded 10 metres in length, and describes the flipper as one metre long. These are approximate figures reported for this specimen, not population-wide measurements.
Recommended Free Tools
#1 Best Overall
- Meet Levy the Eurhinosaurus, a 7.3-inch PNSO Prehistoric Animal Models marine reptile model with a 64-page manual, A3 Sci-Art poster, and QR codes linking to online knowledge and drawing videos (internet required).
- PNSO reconstructs this Early Jurassic European ichthyosaur from an animal estimated at about 6 meters long, with a streamlined body, dorsal fin, four flippers, and broad tail fin.
- The swordlike upper jaw extends well beyond the lower jaw and makes up roughly 75 percent of the head length, creating Eurhinosaurus' defining profile.
- Large eyes, paddle-shaped limbs, a tall dorsal fin, crescent tail, and dark-and-cream hand painting capture the specialized form of this prehistoric marine reptile.
- Solid PVC combines with the 64-page manual, A3 Sci-Art poster, and QR codes linking to online educational videos (internet required) to create a display-and-learning set for ages 15+ and adult collectors.
Georg Göltz, a fossil collector, found the specimen in a temporary road-cutting exposure at Dotternhausen, Germany, and brought it to paleontologist Sven Sachs’s attention, according to the university account. The researchers speculated that a larger ichthyosaur might have torn off the flipper, but the isolated fossil does not establish how it became separated.
How might a flipper help an ichthyosaur swim quietly?
The researchers used the flipper’s shape and trailing-edge structures to investigate how it may have moved through water. The University of Manchester report says the team used synchrotron X-ray microtomography, time-of-flight secondary-ion mass spectrometry, infrared microspectroscopy and computational fluid-dynamics modeling. Their interpretation is that the fleshy, serrated edge may have helped limit sound as water moved around the flipper.
Rank #2
- Cast Replica Deinonychus Dinosaur Claw - 4 inches long
- Bonus Genuine Fossil Spinosaurus Dinosaur Tooth
- Claw Made In USA
If the flipper did reduce swimming noise, that could have helped a large predator approach prey without alerting it. The study links that possibility to hunting in low light. But neither stealth nor a particular hunting event is preserved in the fossil: both are inferences about what the anatomy may have enabled.
Was this the first ichthyosaur fossil with soft tissue?
No. The 2025 find is notable for preserving detailed soft-tissue anatomy in a large ichthyosaur’s flipper, but soft tissue had been reported in ichthyosaurs before. A 2018 study of Stenopterygius described preserved skin layers, blubber, pigment-bearing cells and molecular remnants. The authors used those findings to discuss body insulation and coloration. A 2022 review surveyed the wider record of ichthyosaur soft-tissue evidence.
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Rank #3
- The allosaurus was a large, theropod predator that lived roughly 156 to 130 million years ago and may have grown up to 39 feet (12 m) long
- Cast of the large toe ungual from the towering bipedal carnivorous dinosaur of the Jurassic
- The original claw was unearthed in the Morrison formation at the Cleveland-Lloyd Quarry in central Utah
- Detailed cast replica. 7 inches. Museum quality resin cast made in the USA
| Study | Preserved evidence | Research question |
|---|---|---|
| 2018 Stenopterygius study | Skin layers, blubber, pigment-bearing cells and molecular remnants | Body covering, possible insulation and coloration |
| 2025 Temnodontosaurus study | Flipper skin ornamentations, a fleshy distal tip and trailing-edge structures | Flipper anatomy and a possible role in reducing swimming noise |
The two discoveries address different parts of ichthyosaur biology; the later flipper fossil does not replace or invalidate the earlier evidence.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What does the find change about prehistoric predators?
Ichthyosaurs were extinct marine reptiles, not dinosaurs. This specimen adds detailed evidence about the construction of a large ichthyosaur’s flipper and supports a testable proposal about how that shape may have affected swimming. It does not preserve a whole animal, a complete set of soft organs or a witnessed attack. The evidence supports a more specific discussion of possible hunting adaptations—not the claim that one fossil changes everything known about prehistoric predators.
Quick Recap
Best Value
- Utahraptor was a large theropod dinosaur that lived during the Early Cretaceous period, known for its sharp claws and hunting abilities
- This replica is based on a real Utahraptor fossil discovered in Utah, accurately capturing the shape and detail of the original claw
- The Utahraptor’s curved claw was used for gripping and slashing, making it a key tool for hunting prey
- Cast in durable resin, this 5.5-inch replica offers museum-quality detail and texture
- Made in the USA, this fossil reproduction is perfect for collectors, educators, and dinosaur enthusiasts
Rank #4
- Large 5 inch T-REX Tooth Cast Replica in Brown Burlap Bag
- Genuine Fossil Spinosaurus Tooth Fragment in Blue Velvet Bag
- Each tooth fragment is unique; size may differ slightly
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
