Transitional Fossils - The "Frogamander"

Transitional fossils are great. Darwin recognised their value when he lamented their scarcity:


“But as for this theory, innumerable transitional forms must have existed, why do we not find them embedded in countless numbers in the crust of the earth?” (Origin of species 1859).

Not surprisingly, creationists intentionally misuse this quote to claim such fossils do not exist and use Darwin as an argument from authority. Of course, only 4 years earlier, perhaps the most famous transitional fossil of all; Archaeopteryx lithographica was discovered, and the second specimen, now called the “London specimen” was discovered 3 years after the “Origin” was published. Their importance was not realised until later though, but every time a new transition is found, this prediction of Darwin’s is further confirmed. It also means creationists have to spend more and more time with their heads in the sand in denial, or spread lies about the nature of the fossil. Every now and then they concede that the fossil does display the characteristics of two related groups, but childishly claim that there are now two gaps that need to be filled – one before the transitional form and one after it. This truly is the stuff of desperation, and often these gaps are filled. Even worse for creationists though is the fact that we can predict where and in what age of rocks we will find transitional fossils of a particular lineage in – it’s called geographic distribution of lineages fundies!

Since Darwin commented on the rarity of transitional forms (150 years ago – take note fundies) hordes of transitional forms have been discovered. A small fraction of which are noted here. With every new transitional fossil, a further nail goes into the creationist coffin. Recently, a new one has been described that sorts out the evolution of frogs and salamanders. It had been suggested that frogs and salamanders evolved from a tetrapod group called the Temnospondyli. These are an ancient group that are found in early Permian rocks. This new specimen called Gerobatrachus hottoni has been dubbed a “frogamander” (pictured above) as it displays characteristics of frogs, salamanders and other Temnospondyls. Thanks to this fossil, we can also propose that frogs and salamanders diverged from each other some 240 and 275 million years ago.

More information can be found here.