_Z1LUMRQ.webp)
Günther’s marsupial frog, Gastrotheca guentheri, is a mid-sized Andean treefrog that holds a singular distinction among living amphibians: it is the only known frog with true teeth in both the upper and lower jaw. It is found in the Andean regions of Colombia and Ecuador, where it lives among the vegetation of tropical moist forest.
Identification
Males measure 68–78 mm in snout-vent length, while females reach 70–82 mm, making this one of the larger members of its genus; the facts box carries the full range. Like other marsupial frogs, females carry a dorsal brood pouch, but the feature that sets this species apart is hidden in the mouth: lower-jaw teeth, a structure that had been absent from frogs for more than 200 million years before re-evolving in this lineage, a case biologists have cited as a challenge to Dollo’s law, the idea that lost evolutionary traits cannot return.
Habitat and range
The species occupies tropical moist forest in the Cordillera Occidental and the Colombian Massif in Colombia, and the Cordillera Occidental in Ecuador. It is nocturnal, sheltering by day in vegetation and especially in arboreal bromeliads perched above the forest floor, and becoming active after dark.
Behaviour and breeding
As in other members of the genus Gastrotheca, females of this species carry their developing eggs in a pouch of skin on their back rather than leaving them in water or on leaves, a strategy that gives the young greater protection through early development than the exposed clutches laid by many other treefrogs. Beyond this general pattern of marsupial brooding shared across the genus, little has been published on the courtship, call or clutch size specific to G. guentheri.
Conservation
The species’ facts box carries its current IUCN Red List category, Data Deficient. Despite that listing, the species is thought to be declining, with habitat loss, climate change and the amphibian disease chytridiomycosis all cited as likely pressures. It has not been confirmed in Ecuador since a sighting in 1996, and the state of its Colombian populations is unknown for lack of recent surveys, so local or even complete extinction cannot be ruled out.
Similar species
Günther’s marsupial frog belongs to Gastrotheca, a genus of marsupial frogs found across Central and South America, most told apart from one another by size, skin texture and the structure of the brood pouch rather than by a single obvious field mark. Within its own range, its dentition is the clearest diagnostic: no other Andean frog sharing its forest habitat carries functional teeth in the lower jaw.