Back in 2010, paleontologist James Crampton discovered a partial ichthyosaur skeleton. The fossil he discovered is that of an extinct dolphin-like reptile estimated to have lived during the Late Cretaceous era, just under 100 million years ago. Crampton made the discovery while working in North Canterbury, New Zealand.
After its discovery, the fossil was encased within a hard concretion and was taken from Coverham for storage and storage at GNS Science, and was kept there until 2021. During its time in storage, the fossil was identified as an ichthyosaur due to its signature hourglass-shaped vertebrae.
However, a new study is now shedding new light on the fossil, which is more complete than any other ichthyosaur skeleton in the country. Prior to Crampton’s discovery, the only ichthyosaur pieces found in New Zealand were fragments of jaws and vertebrae from different specimens.
Extinct dolphin-like reptiles remained largely misunderstood until now
The lack of well-preserved ichthyosaur specimens had previously made it very difficult for scientists in New Zealand to understand these dolphin-like reptiles. However, the new investigations into Crampton’s fossil promises to change this thanks to experts using medical CT scanners to image the bones that were previously too difficult to prepare.
All of the bones from the specimen were rendered in 3D to better understand the prehistoric animal’s morphology, using a technique known as virtual preparation. The fossils used in the new study included the base of the skull, parts of the animal’s shoulder, and front flippers, as well as the left pelvis.
This reconstructed skeleton is particularly special, as it is around 98 million years old, meaning it dates back to around 4 million years before the species became extinct. This makes this fossil one of the youngest semi-complete ichthyosaur skeletons known.
The ichthyosaur’s evolutionary links
From the physical characteristics studied through the scans, scientists were able to determine some of the ichthyosaur’s evolutionary links.
For instance, they successfully determined that the specimen is closely related to an Australian species known as the Platyperygius Australis as well as Cretaceous ichthyosaurs found in Europe.
Remarkably, the fossil of this prehistoric, dolphin-like reptile shows that it is unrelated to the Western Gondwana ichthyosaurs which inhabits modern-day South America. This surprised scientists given that 98 million years ago, South America and New Zealand were closer to each other than to Europe.
This would suggest that the species in New Zealand were separated from those in South America, implying regionalism amongst this species. This finding also contradicts ancestry patterns identified in younger fossils of other marine reptiles found in South America, New Zealand, and Antarctica, suggesting a relationship between animals in these regions.