By Andrew McCarthy

The glass frog (Hyalinobatrachium dianae) was rediscovered in 2015 in the Caribbean foothills of Costa Rica.  

The last time this species of glass frog was found in the country was back in the 1970s.

The frog belongs to the amphibian family Centrolenidae. With its 149 species, this family is found from southern Mexico, through Central America, into the northern half of South America, and along the Atlantic Forest of southeastern Brazil and the extreme northeastern margin of Argentina.

In 2015, a research by a group of scientists led by Dr. Brian Kubicki of the Costa Rican Amphibian Research Center rediscovered the extraordinary amphibian and named Diane’s bare-hearted glass frog.

The species name honors Dr. Kubicki’s mother Janet Diane Kubicki, who always encouraged Brian’s lifelong interest in natural history, especially fish and amphibians.  

Additionally, the name alludes to the Roman goddess of the hunt, wild animals and woodlands, Diana, who was believed to have a preference for dwelling in sacred forests on high mountains.

The tiny frog lives in the tropical wet forests and pre-montane rain-forests of the Caribbean foothills of Costa Rica, at elevations between 400–800 meters.

It is distinguished from other glass frogs due to its unique combination of morphological characteristics, calling and genetic distance.

Diane’s bare-hearted glass frog is small, about 2.7-2.9 cm long. It is lime green in color and has a transparent belly.

If the glass frog is discovered, its fragile bones and some red veins are visible through a transparent belly. The yellow hands are also translucent, and the pale green skin with pale yellow dots matches leaf perches. To better disappear, the frog’s body is flat. The fingers and toes have enlarged, adhesive disks that help with climbing. 

The diet of this frog is not well understood, but it probably feeds on small insects.

The frog is nocturnal and it has been observed to inhabit mature secondary and primary humid forests with varying topography. 

This species has not been encountered in high densities.

Males of this species call at night from sites among the forest understory. They call from the underside of the vegetation, but being that some other congeners can at times be observed calling from the upper leaf surface. Males may occasionally call from the upper leaf surfaces as well.

With the addition of Diane’s bare-hearted glass frog, Costa Rica is known to have 14 glass frog species inhabiting its territory. 

Nearly 50% of glass frog species evaluated by the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species are threatened with extinction Many glass frog species have small ranges and are threatened by ongoing habitat fragmentation, climate change, introduction of exotic species, chain extinctions, as well as other threats, according to the U.S.-based national conservation organization, Defenders of Wildlife.

---------------
How can we protect the Costa Rican glass frogs? We would like to know your thoughts on this story. Send your comments to news@amcostarica.com