A freshwater shrimp, an island-dwelling lizard and a pupfish from Arizona have been declared extinct, while nearly 21,000 species are at risk of dying out, an updated "Red List" showed.

According to the update, 20,934 species are currently listed as "threatened with extinction", compared with 20,219 last October.

IUCN's Red List Manager Craig Hilton-Taylor pointed out to AFP that the rise of more than 700 species in this category was explained by increased pressure on a number of them. It was also due to species moving down from the more serious "endangered" category, as well as new species being added to the assessment list.

Tuesday's updates focused especially on the decline among conifers, a category of cone-bearing trees and shrubs that includes the world's oldest and largest organisms, such as the Bristlecone Pine that can live to be almost 5,000 years old and the Coast Redwood which can reach a height of 110 metres (360 feet).

Tuesday's report also provided the Red List's first-ever global assessment of freshwater shrimps, lamenting that a full 28 percent of the carideans vital to freshwater ecosystems are threatened with extinction.

One such species, the Macrobrachium leptodactylus, was declared extinct after it fell "victim of habitat degradation and urban development," it said.

(Source: AFP)