EFEMexico City

The National Autonomous University of Mexico, or UNAM, has a wide-ranging collection of more than 1,500 crustacean speciess, biologist Fernando Alvarez Noguera told Efe.

"When something dies and falls to the sea floor, a good portion decomposes, thanks to crustaceans. They are the submarine vultures that recycle organic matter," Alvarez said.

At the base of the major marine food chain are plankton, which eat algae and are themselves eaten by fish.

Alvarez, who is a member of the UNAM Biology Institute, works with the National Crustacean Collection made up of some 1,500 specimens, some of them gathered in the 19th century by agencies that preceded the institute.

More than 30,000 jars preserve everything from rare specimens, such as the crab spider (Thomisidae), to the most common crabs, shrimp, prawns and blue crabs.

Crustaceans, in general, are characterized by a calcareous shell and articulated legs.

Most crustaceans, like shrimp and prawns, live in the ocean, but some of these animals, like the acocil (Cambarellus), have adapted to fresh water, and others, like the cochinilla (Oniscidea), can be found in humid ground under stones in any garden.

Scientific reports say that Mexico is home to 10-12 percent of the estimated 70,000 crustacean species in the world, or between 7,000 and 9,000 varieties, of which 1,500 have been identified.

Mexico has some 10,000 specific areas where crustaceans are present, with about 8,000 at the bottom of the sea and 2,000 on continental areas, Alvarez said.

"We have a pretty good idea of what is out there, not to settle on what we have achieved so far, but to encourage us to wonder what we still have to learn," the 56-year-old biologist said.

The scientific study of crustaceans in Mexico began in 1938-1939 with the arrival of Spaniard Enrique Rioja at the Biology Institute, Alvarez said.

"Before him, there was nothing," he said.

The institute's collection includes animals from marine coastal areas and lakes, some specimens that are edible and others that are not, Alvarez said.