Ancient dolphins in the Lowcountry- a moment of science

A Moment of Science

Meet Ankylorhiza tiedemani.

Today its skeleton resides in the Mace Brown Museum of Natural History, but 24 million years ago this ancient dolphin ruled the waters that covered the Lowcountry. 

Paleontologist Dr. Robert Boessenecker has been studying it and other ancient dolphins and whales for a while at the College of Charleston. “We have multiple lines of evidence that Ankylorhiza was an apex predator like a modern-day killer whale- only a bit smaller.”

Slightly smaller than a killer whale, but at 16 feet long it was giant compared to its bottlenose brethren- and possibly more ferocious as well. 

Skull of Ankylorhiza tiedemani on display at the Mace Brown Museum of Natural History at the College of Charleston

“It’s got these bizarre tusks on the chin that stick straight forward and they’re very worn down. And we think… that if it had its mouth closed, those teeth would still be sticking out and it could’ve rammed large prey just by swimming snout first into them. There is precedent for behavior in today’s dolphins and whales.”

Paleontologists like Boessenecker make these conclusions by studying fossils, finding unique characteristics by comparing and contrasting bone structures with even older ancestors and their current-day counterparts.

Take flippers for example.

Both Ankylorhiza and modern whales have locked elbows, but Ankylorhiza bones are longer, unlike modern dolphins with lots of short, blocky finger bones. These details may seem trivial but they’re important puzzle pieces for paleontologists to place where and when the specimen lies on the evolutionary chain. To make matters more difficult, scientists often must make do with just fragments of skull and bone- leading to erroneous assumptions as the millions-year-old puzzle kit is missing most of its pieces. 

Ankylorhiza fell prey to this upon its discovery in the 19th century, “It was based on a partial skull that included just the tip of the snout. That original fossil, known as Squaladon tiedemani was a bit of a paleontological mystery for many many years.” 

Dr. Robert Boessenecker poses with the nearly complete Ankylorhiza tiedemani skeleton

Questions remained until the 1990s, when a nearly intact skeleton was found during the building of a housing development near Summerville.

“What this new skeleton told us is that this species does not in the genus Squaladon.” 

With more bones to work with, more evolutionary puzzle pieces were discovered, including bone size and teeth structure. “Most of the teeth are single-rooted- which brings us to the new genus name: Ankylorhiza, which means fused roots in Greek.”

Boessenecker recently discovered more details with Ankylorhiza, further understanding that while there was a split in the evolution of modern-day whales and dolphins 35 million years ago, both saw similar patterns independent of each other on how they became strong swimmers over millennia.

By studying small details, placing puzzle pieces together, to view evolution at work. 

Storm Team 2 Meteorologist David Dickson

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