Newly discovered frog species has a visible heart © Jamie Culebras/Ross Maynard

Newly discovered frog species has a visible heart

The tiny Hyalinobatrachium yaku belongs to the family of frogs called Centrolenidae, or glass frogs.

We’ve all heard the expression ‘wearing your heart on your sleeve’, but few of us can pull off that trick with the aplomb of a newly discovered species of frog. The tiny amphibian’s heart is clearly visible at all times, thanks to the translucent skin on its chest.


The frog, which measures just  two centimetres in length, has been named Hyalinobatrachium yaku, and it has just been described for the first time in a paper published in the journal ZooKeys by a team of scientists led by Juan M Guayasamin from Ecuador’s Universidad San Francisco de Quito. It falls into a family of frogs called Centrolenidae, or ‘glass frogs’, all of which have translucent skin on their abdomen that renders their liver, stomach and intestines visible. In H. yaku, however, this translucence extends to the chest area, putting the frog’s heart on view.

All known Centrolenidae species are native to Central and South America, and H. yaku is no different, with three populations discovered in Ecuador. As these three populations are quite widely dispersed, lying some 110km from each other, it’s believed the frog may make its home across a much wider swathe of Ecuador and neighbouring Peru.

Intriguingly, the three populations of H. yaku so far discovered exhibit varying behavioural characteristics. In two areas, they have been found only on the underside of leaves hanging a metre or so above shallow, slow-moving streams. However, in the third area, the frogs were located on the leaves of small shrubs and ferns lying more than 30m from the nearest water source.

This extract came from issue 310 of BBC Focus magazine – for the latest science news and discoveries subscribe here.


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