Frogs’ faces give clues to special secret of their evolutionary success

WASHINGTON - In a new study, scientists from the Friedrich Schiller University Jena (Germany) analyse why frogs are the champions of evolution.

“In terms of numbers frogs are superior to all the other amphibians, and even mammals”, said Professor Dr. Lennart Olsson.

“We are interested in how the frogs developed in such a great variety and which evolutionary new development is responsible for making frogs so particularly successful”, said Jennifer Schmidt from Olsson’s team.

The success apparently lies in their faces.

Certain forms of cartilage and bone structures in the region of the head of the tadpoles are among the frogs’ ‘innovations’ - these structures seen in the oral region enable the tadpoles to chip vegetarian food from the soil and from stones or to filter it from the water.

The team found that the gene FOXN3 plays a key role in the embryonal development of the heads of claw frogs.

“It is responsible for the normal development of cartilages, bones and muscles”, Jennifer Schmidt explained.

“Our analyses with microCT show that the larvae without an intact ‘FOXN3′-gene are developing normally up to a certain time. But then the development slows down,” said Schmidt.

“We were able to show that the ‘FOXN3′ most of all influences the development of the cartilages in the oral region and the gills”, Professor Olsson said.

These structures are now missing in other amphibians.

Schmidt concluded, “We are going to compare the embryonal development of the claw frogs with those of other amphibians.”

“It would be interesting to find out to what extent the genetic control of those new developments changed in the course of the evolution.”

The study appears in Journal of Anatomy. (ANI)