An artist's impression of Ichthyosaurus somertensis [Illustration by Joschua Knüppe]
Paleontologist Sven Sachs was studying another ancient sea dragon in Hannover's Lower Saxony State Museum when a large fossil caught his eye. This fossil was first discovered about 20 years ago, but it hasn't received much academic attention since. However, it turns out to be quite an important find, being the largest known specimen of its species.
Sachs thus reached out to Dean Lomax, an Ichthyosaurus expert. Ichthyosaurus is a genus of ichthyosaurs, which are large and ancient sea reptiles from the late Triassic and early Jurassic. Together, Sachs and Lomax figured out that the specimen belonged to a newly-named species called Ichthyosaurus somersetensis.
That, of course, is not all the researchers found out. Their study reveals many other details about the specimen, including the fact that it was pregnant when it died. The embryo has also been preserved, though not in its entirety. Still, the discovery is a significant one, providing scientists with a lot of new information about this remarkable species.
The fossil [Photo by Dean Lomax]
"It amazes me that specimens such as this [the biggest] can still be 'rediscovered' in museum collections,” says Lomax. “You don't necessarily have to go out in the field to make a new discovery. This specimen provides new insights into the size range of the species, but also records only the third example of an Ichthyosaurus known with an embryo. That's special."
This is the second Ichthyosaurus that Lomax and his colleague Judy Massare declared this year, bringing the genus's known members to seven. Also, as only the third Ichthyosaurus specimen discovered with an embryo, it can contribute to a body of knowledge that's still in its relative infancy.
As Sachs and Lomax conducted their studies on the large sea dragon, they realized that the museum had given it a tail from another species. It made the fossil look more complete, but it of course wasn't accurate. However, the museum didn't intend to produce a fake specimen, but merely wanted to make a better display. If anything, this serves as a reminder for other researchers to be wary of situations like this, which can lead to false findings.
Still, even without the tail, the researchers found that the specimen was about three meters long. This proves that this specimen is indeed the largest known individual of its kind.
The skull of the Ichthyosaurus somertensis specimen [Photo by Dean Lomax]
The specimen's embryo, of course, is another interesting finding. It's incomplete, and the only parts left are part of the backbone, ribs, a forefin, and some other bones. The remaining backbone is just short of seven centimeters long. Since the embryo's bones had not ossified yet, it was therefore still developing.
This specimen already has a lot going for it, but it has more. It also has good geographical or geological records, which most other Ichthyosaurus specimens lack. As such, it can help researchers date other Ichthyosaurus specimens and fill in other missing information.
According to Sachs, there may still be undiscovered species with specimens just sitting in museums. This kind of discovery, apparently, is quite common among paleontologists. Perhaps there are more sea dragon species just sitting in museum displays, waiting for a scientist's curious eye.
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