multiplacophoran reconstruction
September 20, 2012

Ancient Mollusk Reconstructed Using New Technology

Brett Smith for - Your Universe Online

Using computer animation, CT scanning and 3-D printing technology, a team led by University of Texas at Austin paleontologist Jakob Vinther has reconstructed an ancient mollusk that inhabited the waters around modern day Ohio about 390 million years ago.

Until now, only a few partial fossils of the creature, known as a multiplacophoran, existed and the new model allows paleontologists to study the physiology of the specimen in greater detail, according to the team´s report in the upcoming issue of Paleontology.

To begin the process of bringing the ancient mollusk to life, Vinther used scanning technology to create a digital, three-dimensional model of the most complete fossil available – found in northern Ohio in 2001.

Vinther – along with help from computer animator Ryan Carney, a doctoral student at Brown University – digitally rearranged the fossil pieces that had been fragmented and drifted apart by the forces of time and nature. Vinther said his study is the first to use scanning and animation technology to reassemble a fossil that had been so poorly degraded, according to National Geographic.

Next, Vinther turned to Danish model maker Esben Horn, who owns the company 10 Tons in Copenhagen. Horn created a physical model using 3-D printing technology along with clay, resin and silicon as building materials. The two worked hard to not only recreate the most accurate structure, but also the most realistic textures. Finally, Horn used airbrushed acrylic paints to give the model a lifelike look based on the colors of modern chitons, a mollusk relative of the multiplacophoran.

“We can now demonstrate that multiplacophorans are distant relatives of the modern chitons, which did not evolve until later in Earth history,” said Vinther. “We can also show that they evolved a number of characteristics seen in some modern chitons convergently.”

In addition to recreating the mollusk´s structures, Vinther decided to scale up the size of the animal by about 12 times so he could see its many features in more detail.

"When you have a specimen that is that small, it's hard to get a feeling for its morphology," Vinther told National Geographic. "With this large model, you can touch it with your fingers, and that makes a big difference."

The final reconstruction showed how the mollusk´s interlocking plates that made up its turtle-like protective shell were arranged in two parallel rows. Previous models had shown it to appear more like a long worm, with 17 plates arranged along its spine.

The model also reveals that multiplacophorans were more heavily armored than their contemporaries, both of which live in shallow, predator-friendly waters. Hunters of the prehistoric mollusk would likely have included large, toothy fish and beaked cephalopods, like squid and octopuses, which had just come onto the scene.

Vinther said the study illustrated how computer scanning and printing can be invaluable tools for paleontologists.

“CT scanning is an extremely powerful technique for paleontologists,” said Vinther, “since we can look inside fossils without destroying them.”

Chitons, the modern day relatives of multiplacophorans, are marine mollusks they can live in both cold and warm water. They are unlike shelled bivalves, which have been able to adapt to brackish and fresh water.