After a 49-million-year hiatus, a cockroach reappears in North America

Jan 06, 2014
After a 49-million-year hiatus, a cockroach reappears in North America
This is a 44-million-year-old Ectobius cockroach (Ectobius balticus) from northern Europe. Credit: D. S. Shcherbakov

The cockroach in the genus Ectobius is a major textbook example of an invasive organism, and it is the most common cockroach inhabiting a large region from northernmost Europe to southernmost Africa.

Ectobius has a long fossil history in Europe, occurring in Baltic amber that is about 44 million years old, and its lineage was believed to have been exclusively from the Old World. However, a shocking new discovery has uprooted that view. In fact, it now appears that Ectobius may have originated in the New World.

Four ancient Ectobius species were recently discovered in the 49-million-year-old Green River Formation near Rifle, Colorado in deposits that are about five million years older than the Baltic amber. However, these cockroaches soon became extinct in North America. The cause for the extinction of Ectobius in North America in the dim past is unknown, but it evidently survived in the Old World, and western Europe in particular.

"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. "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."

After a 49-million-year hiatus, a cockroach reappears in North America
This is a 49-million-year-old Eocene Ectobius cockroach (Ectobius kohlsi) from Colorado. Credit: Peter Vršanský

In many ways the history of Ectobius mirrors that of the biogeographic history of the horse. Horses occurred in the New World and became extinct during the late Pleistocene ecological crisis. Horses, attached to human habitation, were subsequently introduced to North America by early Spanish explorers about 11,000 years after their demise.

The newly discovered species of Ectobius, specifically Ectobius kohlsi, are described in the January 2014 issue of Annals of the Entomological Society of America in an article called "Native Ectobius (Blattaria: Ectobiidae) From the Early Eocene Green River Formation of Colorado and Its Reintroduction to North America 49 Million Years Later."

After a 49-million-year hiatus, a cockroach reappears in North America
A modern Ectobius cockroach (Ectobius vittiventris) from northern Europe. Credit: Amada44, CC-BY-3.0

This particular species is named after David Kohls, who lives near Rifle, Colorado and has been an indefatigable collector of fossil insects and plants from the nearby Green River Formation. His collection of approximately 150,000 insects from 31,000 slabs of shale now constitutes the Kohls Green River Fossil Insect Collection, which is housed in the Smithsonian's Department of Paleobiology.

Explore further: Colossal new predatory dino terrorized early tyrannosaurs

More information: Annals of the Entomological Society of America DOI: 10.1603/AN13042

Related Stories

Newly discovered raptor lived alongside T. rex

Dec 19, 2013

(Phys.org) —It's been a big year for the University of Alberta's Phil Currie, even by his standards as one of the world's top dinosaur hunters. He's lead instructor on Dino 101. This summer, he had a museum named after him. ...

Alligator relatives slipped across ancient seaways

Mar 04, 2013

The uplift of the Isthmus of Panama 2.6 million years ago formed a land-bridge that has long thought to be the crucial step in the interchange of animals between the Americas, including armadillos and giant ...

New info on an elusive green cicada

Sep 12, 2013

For nearly 80 years, the North American cicada Okanagana viridis has received little attention in scientific literature, but a new article in the Annals of the Entomological Society of America provides the fi ...

Reconstructing the New World monkey family tree

Jan 03, 2014

When monkeys landed in South America 37 or more million years ago, the long-isolated continent already teemed with a menagerie of 30-foot snakes, giant armadillos and strange, hoofed mammals. Over time, the ...

Recommended for you

And now the Acropolis is crumbling...

16 hours ago

Just when Greece thought it had come through the worst of the crisis it was hit by a new blow Wednesday—the Acropolis is crumbling.

How dinosaur arms turned into bird wings

Sep 30, 2014

Although we now appreciate that birds evolved from a branch of the dinosaur family tree, a crucial adaptation for flight has continued to puzzle evolutionary biologists. During the millions of years that elapsed, wrists went ...

User comments : 0