More than 30 years ago, Sankar Chatterjee, a Paul Whitfield Horn Professor of Geosciences and the curator of paleontology at the Museum of Texas Tech University, discovered a new plesiosaur in Antarctica.
This new plesiosaur was named Morturneria. Plesiosaurs were large aquatic reptiles from the Mesozoic era. Prior to the discovery of the Morturneria, other plesiosaurs had large teeth used for hunting large prey.
Chatterjee said this was not so in the case of the Morturneria, which have delicate teeth, interwoven so they form a trap when closed.
In 2013, F. Robin O’Keefe, a paleontologist from Marshall University, reached out to Chatterjee and asked to take another look, Bill Mueller, the assistant curator in the paleontology division at the Museum of Texas Tech said.
“He came in (and) he studied the species. Then he invited other people who have discovered same age plesiosaur from Chile, Argentina. Especially since Antarctica was in the southern hemisphere, if you find something from Chile or Argentina, they may show some resemblance,” Chatterjee said.
The team reached the same conclusion as Chatterjee. The Morturneria teeth were not used for chomping on large prey; instead, they were used as a trapping mechanism. These plesiosaurs would capture prey in their jaws then expel water before eating the trapped ocean life, Chatterjee said.
However, O’Keefe and his team took it a step further and employed a concept called convergent evolution to draw a tie between the Morturneria and a modern-day baleen whale. Convergent evolution is the focus of O’Keefe’s latest paper, on which Chatterjee is listed as a co-author.
“Convergent evolution is an old concept but the example is a new one. No one has done it before. He proposed a genealogy, and so that family tree was there and he was able to document that this is a very specialized group,” Chatterjee said. “No other plesiosaur came up with this lifestyle or design so it is a very special time.”
This parallel between whales and Morturneria has changed the way the scientific community thinks about convergent evolution, according to an article published by phys.org
“Now, 33 years later, Chatterjee and his team have made a new discovery about Morturneria, one that adds a whole new dimension to science's understanding of plesiosaurs – and larger than that, to the understanding of evolution itself,” according to the article, “Plesiosaur fossil found 33 years ago yields new evolution findings.”
This is another achievement in Chatterjee’s long career. He came to Texas Tech more than 30 years ago mainly for the opportunity to do field work in Antarctica, he said.
“It so happened that Texas Tech had a long tradition of Antarctic search. I'd never heard of Texas Tech or Lubbock,” he said.
Chatterjee’s fascination with Antarctica stemmed from his home in India. Millions of years ago Antarctica and India were connected on the supercontinent Pangea, so many specimens collected from India and Antarctica share similarities, he said.
Thirty-three years ago, Chatterjee, along with several Tech students, set off to the frozen tundra. They stayed on Seymore Island, which is on the peninsula, and were there for three months. Over the course of several years, Chatterjee recovered more than 800 fossilized specimens, including the Morturneria, Mueller said.
“He’s a world-renowned paleontologist. He’s collected 15 of the 16 (holotypes) that we have. We have various researchers who come to visit our collection. They come from all over the world," Mueller said.
A holotype is the first specimen discovered when uncovering a new species of dinosaur, Mueller said. Once it is discovered and the paper has been published, the holotype belongs to the museum for which the finder works, in this case, Tech.
In addition to the Morturneria, Chatterjee and his team made another, never before seen find.
“We found a beautiful bird. It's the ancestor of the swans and ducks you see today. The beauty is that the fossil is so beautifully preserved. I could tell, for the first time, that they could sing. This is the oldest singing bird. It's a miracle that the syrinx would be preserved,” he said.
Because of Chatterjee, many holotypes can be found at the Museum of Texas Tech, which showcases a long career here at Tech.
“It was one year, then five years, then 10. I didn’t realize I’ve spent 20, almost 30 years right here,” he said.