242 Evolution? The Fossils Say YES!
by the press because it had features of both frogs and salamanders (fig. 10.11). It had a long
tail and salamander-like body, but its head is short with a rounded snout like that of a frog.
It also had the large eyes and large eardrum found in frogs and not salamanders. Most
importantly, its teeth are attached to the jaw on tiny pedestals with a distinct base, a feature
that defines the modern frogs and amphibians as a natural group.
There are also fossil frogs from the Triassic such as Triadobatrachus. They looked a bit
more like living frogs but do not yet have the shortened trunk, reduced number of verte-
brae, long hipbones and extremely long jumping hind legs that living frogs do. In short, the
transition from a primitive amphibian to a modern frog has now been completely filled by
transitional fossils.
FIGURE 10.11. (A) The only specimen of Gerobatrachus hottoni. (Courtesy Diane Scott and Jason Anderson) (B) A
reconstruction of it in life. (Courtesy Nobumichi Tamura)
(A)
(B)