The majority of frog and toad species reproduce via external fertilization: males bathe extruded eggs with sperm as they grip females’ bodies to encourage them to mate. However, a few species employ internal fertilization. Some of these amphibious innovators give birth to fully formed froglets.
Researchers have discovered a new frog species that fertilizes eggs internally, with females birthing tadpoles that will later metamorphose into frogs. Scientists working on the Indonesian island of Sulawesi described the unique reproductive strategy of a new fanged frog species; it is called Limnonectes larvaepartus.
With the study, the scientists observed live tadpoles in the oviducts of females while preparing specimens for study. Furthermore, on one occasion, the researchers observed a gravid female extrude tadpoles in-hand when she was captured.
In the paper, the researchers write: “In total, we have either observed tadpoles in the oviducts or direct-birth of tadpoles on 19 occasions.”
While the scientists found evidence to suggest that the frogs were letting tadpoles metamorphose in the oviducts before birthing froglets, the researchers concluded that it was more likely that they were giving birth to tadpoles that would undergo metamorphoses outside their mother’s body. They found free-living tadpoles during their collecting, and never collected a gravid female with froglets inside her oviducts
The research has been declared in the journal PLOS ONE The research reporte is headed “A Novel Reproductive Mode in Frogs: A New Species of Fanged Frog with Internal Fertilization and Birth of Tadpoles.”
