The species, which scientists have named Diplomoceras maximum, lived about 68 million years ago in waters near present-day Antarctica.
D. maximum was a large squid-like creature - its shell was over 1.5 meters in height. He was an ammonite and part of the now extinct group of tentacled cephalopods. D. maximum died out at the same time as the dinosaurs, presumably for the same reason - due to the collision of the Earth with an asteroid, which formed the impact crater Chikshulub.
What made Diplomoceras especially stand out wasthe unique shape of its shell. The top is curved both back and forth to resemble a paper clip. In this new work, scientists have discovered something else remarkable about the ancient creature - its lifespan.
A sketched reconstruction of a typical Antarctic marine environment from the Cretaceous period, including the ammonite Diplomoceras in the form of a paper clip. Credit: James Mckay (jamesmckay.info).
A couple of researchers examined the shell of the specimen,which was previously discovered by other researchers. As part of their work, they investigated its chemical composition. Scientists have discovered repeating isotope signatures. The researchers speculate that the signatures were formed from methane that enters the water every year from the seabed. Methane left a trail annually covering the D. maximum shell. By adding up the number of methane ridges on the shell, the researchers were able to calculate its age. They found that D. maximum survived to about 200 years.
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