Chili peppers’ evolutionary origins have Colorado flavor, new study shows

Scientists previously thought chili peppers evolved in South America 15 million years ago. But their roots may go back 50 million years – including in North America. That's according to researchers from the University of Colorado Boulder, whose findings were published in the journal New Phytologist.

The researchers compared chili fossils from Colombia to plant fossils from the Green River Formation in northwestern Colorado. The fossils’ calyx teeth – the little spikes on the end of the stem that hold on to the pepper – had the same unique shape. Researcher Rocío Deanna and student Abel Campos spotted the similarities while surveying fossils at the CU Boulder Museum of Natural History.

"They have a history here, they have a little story," said Stacey Smith, a study author and associate professor of evolutionary biology at CU Boulder. "So, it reminds me that Colorado didn't always used to be this dry and forced us to turn on humidifiers – that it used to be pretty lush, pretty tropical."

Smith says they can't be sure of the exact shape or color of the ancient chili that was collected from Colorado. But they believe it was smaller than a modern version – and possibly quite spicy.

This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNR in Nevada, the O'Connor Center for the Rocky Mountain West in Montana, KUNC in Colorado, KUNM in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting.