Four Ancient Cockroach Species Found in Colorado

Researchers have recently discovered four ancient species of cockroach in the 49-million-year-old Green River Formation near Rifle, Colorado. The cockroaches belong to the genus Ectobius.

These cockroaches were earlier thought as Old World natives. The latest study argues that the invasive pests were present in North America much before they landed in Europe and Africa.

Previously, the cockroach species remains were found in Baltic amber, which is about 44 million years old.

Researchers aren't sure what factors led to the demise of the cockroach species in America. These species, however, thrived in Western Europe.

"About 65 years ago, several entomologists in the northeastern United States noted that four species of Ectobius were present in North America," said corresponding author Dr. Conrad Labandeira, according to a news release. "It was always assumed that these four newcomers were the first Ectobius species to have ever lived in North America. But the discovery in Colorado proves that their relatives were here nearly 50 million years ago."

The study is published in the journal Annals of the Entomological Society of America.

One of the newly discovered species, Ectobius kohlsi, is named after David Kohls who lives near Rifle, Colorado. Kohls' collection of 150,000 insects and 31,000 slabs of shale is kept in the Smithsonian's Department of Paleobiology, according to the news release.

Like Horse

According to the researchers, the history of the cockroach in America is quite similar to that of the spread of horses in the region. Horses first originated in the New World, but were wiped out after the Pleistocene ecological crisis. It was the Spanish explorers that re-introduced horses in America.