SURPRISING SEA HORSE: The world's smallest known sea horse was just one of the notable species discovered last year.
JOHN SEAR

Even as species around the globe are rapidly falling prey to extinction, and countless others are threatened, scientists are still turning up new species of plants and animals every year—thousands of them. From the longest insect to the smallest snake, a fascinating diversity of organisms has remained unknown until the past year.

In 2007—the last year for which data is available—18,516 new species were described, according to this year's "State of Observed Species" report, which was released last week.

"Most people do not realize just how incomplete our knowledge of Earth's species is," Quentin Wheeler, an entomologist and director of the International Institute of Species Exploration (IISE) at Arizona State University in Tempe, said in a statement. "We are surrounded by such an exuberance of species diversity that we too often take it for granted," he continued.

Each year an international committee of taxonomists—those who name and classify new species—gather at the IISE to discuss the newly named specimens and whittle them down to a top 10. This year's includes a naturally decaffeinated coffee plant as well as bacteria that thrive in hair spray. Read on for the full and fascinating list.

The release of the list commemorates the May 23, 1707, birth of Carolus Linnaeus, who designed the modern classification and naming systems.

Slide Show: 2008's Top 10 New Species