Researchers have found broken teeth in one of the largest carnivores on Earth.
No, it's not A T.Rex. It's not even a dinosaur. Instead, the tooth belongs to a rare and mysterious giant ichthyosaur— a carnivorous marine reptile that patrolled the world's oceans during the late Triassic period, about 205 million years ago.
According to a new study published April 28 in the Journal of Vertebrate Paleontology, although the crown part of the tooth is missing, the root of the tooth fossil is twice as wide as any other known ichthyosaur tooth.
The previous record holder for the largest tooth was a ichthyosaur nearly 50 feet (15 meters) long — which could make the owner of the newly described tooth one of the largest animals ever lived on land or at sea, the study authors said.
However, the researchers say that because scientists only have half a tooth to study, it is impossible to tell whether this ancient marine reptile is a true behemoth or just one of the many similar-sized sea monsters that ruled the Triassic seas.
Lead study author P. Martin Sander of the University of Bonn in Germany said in a statement: "It is difficult to say whether this tooth came from a large ichthyosaur with huge teeth or from a giant ichthyosaur with medium-sized teeth. ”
Heinz Furrer holds a ichthyosaur vertebrae. (Rossi Ross/University of Zurich)
Abyss Monsters
Ichthyosaurs, whose names translate to "fish lizards," appeared in the mid-Triassic period (about 252 million to 201 million years ago), and shortly after extinction at the end of the Permian, about 95 percent of life in Earth's oceans disappeared.
Aquatic reptiles do well for themselves in these ever-changing oceans. The study authors write that within about 5 million years of their first appearance, ichthyosaurs swelled to enormous sizes and dominated all of the world's oceans.
The largest known ichthyosaur is Shastasaurus sikanniensis, a whale-like creature that is 69 feet (21 m) long and may even be longer.
The artist reconstructed the Ichthyosaur. (Marcello Perillo/University of Bonn)
In contrast, according to the American Museum of Natural History, modern blue whales typically range in length from 80 to 100 feet (24 to 30 m), while the average length of the predator King T. rex is 40 feet (12 m).
According to the researchers, many large ichthyosaurs, including the massive Shastalong, appear to have become top predators without evolving teeth. Only one giant ichthyosaur known to be the 50-foot-long Himalayan dragon found in Tibet — had teeth in its mouth.
So when scientists found a large fossil of ichthyosaur teeth in the Kössen Formation in the Swiss Alps, a rock formation at 9,200 feet (2,800 m) on the Triassic seafloor, the team was a bit mysterious in their hands.
The root of the ichthyosaur's tooth is 60 mm wide. (Rossi Ross/University of Zurich)
In the new study, the researchers analyzed in detail fossil teeth found in the same alpine formation between 1976 and 1990, as well as some large ichthyosaur ribs and vertebrae. The team compared the skeleton samples with other more complete giant ichthyosaur fossils to estimate the size and variety of the new specimens.
The researchers say the fossil tooth is about 2.3 inches (60 mm) wide at the base and 4 inches (100 mm) tall from the root to the broken end of the crown, which is twice as wide as any known Himalayanosaurus tooth.
The unique pattern of dentin— the hard tissue that makes up much of the teeth of reptiles and mammals — proves that the teeth belong to ichthyosaurs, but the extraordinary size of the fossils is not suitable for any known species.
If the creature's body is much larger than that of a Himalayan dragon, as the teeth suggest, researchers may be looking for the largest ichthyosaur ever found.
Similarly, the ribs and vertebrae of the Corson group are some of the largest of its kind found in Europe, the researchers said. The teeth, ribs and vertebrae appear to belong to three different specimens of ichthyosaurs – all of which are huge.
"These late Triassic giant ichthyosaurs are clearly one of the largest animals ever made on our planet," the researchers wrote. ”
However, given that there are only a few bones left per specimen, it is not possible to reliably classify them as a specific species.
The team said the measurements of the bones may also be slightly skewed, as several fossils appear to have been flattened by the movement of tectonic plates that have carried the Alps out of the sea over hundreds of millions of years.
Currently, researchers have grouped the three specimens into the family Shastalonge — a family of giants that share the same family as Shastadosaurus, Shauronisone, and Himalayanosaurus. Whether the specimens dwarf other giant sea monsters is a question that cannot be answered without more fossil evidence.
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