In December 1995, in the Guanacaste Conservation Area, the first inventory of opisthobranch mollusks of the Pacific Coast of Costa Rica began. Taking advantage of the interest, availability, and knowledge of Drs. Jesús Ortea and Angel Valdés of the University of Oviedo, Spain, a group of marine mollusks researches from INBio was trained in collection, preservation, fixation, and identification techniques of the different groups of sea slugs.

In 1998, Dr. Terrence Gosliner of the California Academy of Sciences joined the inventory and helped with the training of INBio's personnel. Today, curators and parataxonomists from INBio continue collecting and inventorying this beautiful and colorful group of marine invertebrates, advised by Dr. Valdés (currently at the Museum of Los Angeles) and Dr. Gosliner. The inventory is financed by the Netherlands Government and has been carried out thanks to the joint work of the National Institute of Biodiversity and the Osa, Tempisque and Guanacaste Conservation Areas.

This inventory is the first grand-scale biological inventory in Costa Rica, and represents the most concerted collecting effort that has ever been carried out in Latin America.(January, 2000)