U.S. palaeontologists claim to have discovered an extinct giant shark nursery in Panama.

A team from the Smithsonian’s and the University of Florida collected more than 400 fossil shark teeth from Panama’s 10-million-year-old Gatun Formation as part of its research to reveal the origins of this narrow landbridge that rose to connect North and South America 3 million years ago.

“The 28 teeth that we identified as C. megalodon were mostly from neonates and juveniles,” Catalina Pimiento, who led the team, said.

The palaeontologists used reference collections at the Smithsonian’s National Museum of Natural History and the Florida Museum of Natural History to characterise the teeth.

“Very little is known about the life cycle of this giant shark that ruled the oceans not so long ago. Now we think that the young spent their first years close to the coast among mangroves,” said team member Carlos Jaramillo.

The team discarded several other explanations for the concentration of small teeth at the site. Before their discovery in Panama, two other fossil beds have been proposed as paleo—shark nurseries: the Williamsburg Formation from the Paleocene and the Oligocene Chandler Bridge Formation, both in the US state of South Carolina.

The sandy soils of the Gatun Formation have been used for years to make cement. Soon these outcrops will be exhausted. Scientists continue to race against the clock to find out more about the ancient inhabitants of the region.

The findings have been published in the ‘PLoS ONE’ journal.