31. May, 2017

Watch my heart beat: a new wonder discovered in the Amazone

The Amazone basin has an incredible diversity of animal species many of which are not yet catalogued by biologists. Glassfrogs, belonging  to the  amphibian family of  Centrolenidae -which consists of about 12 genera-  are one example. They are nocturnal animals that reside most oftheir time in the treetops of the forests. Glass frogs are small transparent creatures that will fit on a matchbox. A group of biologists from Ecuador and  US discovered a new species of the glassfrog genus Hyalinobatrachium which consists of around 40 different speciesThe new species was found in three localities in the Amazonian lowlands of Ecuador and was baptised Hyalinba-trachium yaku (Yaku Glassfrog.) The specific epithet yaku is the Kichwa word for water. Water, in the form of streams, is fundamental for the reproductive biology of all glassfrogs. Water pollution through oil and mining activities represents one of the biggest threats for Amazonian amphibians, as well as for numerous other water-dependent species.

The Yaku glass frog. Top row: adult male in dorsal and ventral view. Bottom row: adult male seen from front and the side*

The glassfrog eggs are usually deposited on the leaves of trees or shrubs hanging over the running water of mountain streams, creeks, and small rivers. All species of the glassfrog genus have a completely transparent ventral peritoneum, which means that the belly organs are fully visible in ventral view. But Yaku differs from related glassfrogs by having small, middorsal, dark green spots on the head and dorsum (picture, upper row left), and a transparent pericardium which also exposes its beating heart (picture, upper row right). Males attend egg clutches located on the underside of leaves overhanging streams.  Their reproductive behavior is also unusual, with males calling from the underside of leaves and providing parental care to egg clutches. Its transparent underside body  probably gives it a clever evolutionary advantage. The silhoutte of a Yaku frog  clutched upside down to the underside of a leave will be very difficult to spot by aerial predators that fly over the bushes.