- PHOTO TAKEN 11JAN06 - A Hourglass Treefrog (Hyla ebraccata) rests on a trunk at La Selva biological station in Sarapiqui, 80 miles (129 km) north of San Jose, Costa Rica January 11, 2006. The Selva is one of the world's most important sites for tropical ecosystem research. [La Selva has about 73% of its area under primary tropical rain forest. Each year, more than 250 scientists from some 25 countries and international students come to La Selva to study tropical ecology. Species diversity include more than, 330 species of trees, and 43 species of birds. Picture taken January 11.]