“The evolution of a group of muscled frogs scattered throughout Asia is telling geologists about the sequence of events that led to the rise of the Himalayas and the Tibetan plateau starting more than 55 million years ago,” according to a recent Science Daily post and a paper in PNAS.
Science Daily writes:
According to the researchers’ genetic reconstruction, the tribe Paini arose in what is now Indochina and spread into Western China about 27 million years ago, diverging into two groups: Nanorana, now consisting primarily of high-elevation species up to 4,700 meters, in Western China; and Quasipaa, consisting of mostly low-elevation species in Indochina and South China.
As the Tibetan plateau was pushed higher, it became separated from the Himalayas, isolating populations in these regions some 19 million years ago. Those restricted to the Himalayas are now considered the Paa subgenus. The Nanorana subgenus isolated in Tibet began to diversify again about 9 million years ago, consistent with the period during which the Tibetan plateau rose above 3,000 meters. These new Nanorana species became well adapted to the cold, arid, low-oxygen conditions of Tibet, and as a result, some organs degenerated, Papenfuss said. For example, some frogs today have no or reduced structures in the ear, including the external tympanum, which transmits sound to the inner ear, and the columella in the middle ear.
The researchers found that in Indochina and South China, on the other hand, the Quasipaa frogs were split by the uplift of the Truong Son Mountain Range on the Laos-Vietnam border, along what is called the Ailao Shan-Red River shear zone. This uplift and the opening of the South China Sea probably occurred as the Indian landmass pushed Indochina southeastward, isolating the frogs of Indochina (now subgenus Eripaa) from those of South China (Quasipaa).
Hopefully additional studies such as this one will allow us to use genetics of various organizations to understand the history of the planet Earth and the living beings evolving in it.