Page 11 - Amphibian

Wide, flat ANCIENT FROG
skull, like This 20-million-year-old fossil frog, Discoglossus, is from the
modern Miocene period and was found in Germany. It is
frogs structurally similar to its close relative from the late
Jurassic period, Eodiscoglossus, which was found in
Spain. The modern living species of Discoglossus
show that they have remained almost unchanged
over the last 150 million years.

Outline
of plump
body

Short
tail

MORE MODERN FROG
Well-preserved fossil frog skeletons, like Rana pueyoi
from the Miocene of Spain, are much like some modern
European frogs that belong to the same genus, Rana
(pp. 42–43). Fossil frogs like this help experts to date
when modern frog groups first appeared. They also
show how little some groups have changed in the
SLIM EVIDENCE 25 million years since the early Miocene period.
This fossil sandwich Fleshy,
(above and left) is the long
only known specimen hind leg
of Triadobatrachus,
which was found in
France dating from
the Triassic period,
about 210 million
years ago. It has a
wide, flat, froglike
skull, but it also
contains more
vertebrae than
modern frogs do, as
well as a bony tail and
short hind legs.

Long tail
of fossil
salamander is
like that of
modern
hellbender

RELATIVE FROM ABROAD
This fossil salamander, whose Latin name is
Cryptobranchus scheuchzeri, was found in
Switzerland and is about eight million years old. It
is a close relative of the hellbender, Cryptobranchus
alleganiensis, the only living member now living in
the southeastern US. Fossils like this provide
evidence that some amphibians, like these
ARROW-HEADED AMPHIBIAN hellbenders (pp. 48–49), once had a much wider
Short, stout leg This odd-looking amphibian, found distribution and that landmasses that are now
supporting in Texas, is Diplocaulus (24 in, 60 cm separate were once joined. Unfortunately, the
heavy body long), a member of an extinct group fossil record is poor and their origins and
that lived in Permian ponds. relationship remain a mystery.