An international team of scientists has created a lifelike reconstruction of a multiplacophoran, an ancient mollusk that lived about 390 million years ago.
This is a reconstruction of a 390 million year-old multiplacophoran (Jakob Vinther / University of Texas at Austin)
The fossil of this oval-shaped sea creature was discovered about 10 years ago in Ohio by a private collector.
Working with the delicate specimen partially covered by rock, the team used a micro CT scan – a noninvasive technology similar to medical CAT scanning – to create a 3D view of the fossil. The CT scan yielded an animated view of the original placement of the creature’s dense spines and shells, which had splayed out and decayed prior to fossilization. The results appear in a paper published online in the journal Palaeontology.
The CT scan also produced a 3D cast of the specimen in its reconstructed shape. Working with the cast, the animation and information on living relatives of the multiplacophorans, the team was able to create a multicolored, textured model in clay, resin and silicone showing how the creature looked millions of years ago, when it crawled on a single, suction-like foot over shells and rocky surfaces in ancient oceans.
The model helps address a debate about how multiplacophorans relate to chitons, another more widely known plated mollusk that lives on seashores and is commonly eaten in the Caribbean. By dating the origin of modern chitons, the scientists could demonstrate that multiplacophorans are stem group chitons.
“We can now demonstrate that multiplacophorans are distant relatives of the modern chitons, which did not evolve until later in Earth history,” said Dr Jakob Vinther, a postdoctoral researcher at the University of Texas at Austin’s Jackson School of Geosciences and lead author on the study. “We can also show that they evolved a number of characteristics seen in some modern chitons convergently.”
The CT scan was integral to the project, allowing the scientists to see below the surface of the fossil.
“CT scanning is an extremely powerful technique for paleontologists, since we can look inside fossils without destroying them,” Dr Vinther concluded.
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Bibliographic information: Vinther J. et al. 2012. The origin of multiplacophorans – convergent evolution in Aculiferan mollusks. Palaeontology, volume 55, issue 5, pages 1007–1019; doi: 10.1111/j.1475-4983.2012.01180.x
