Did 189 gecko species migrate to Australia together?

Lizards have a widespread distribution, having conquered much of the earth, but certain groups of lizards are localized to a single continent. Here I illustrate an example from geckos.

Carphodactylidae includes 28 species of geckos, all of which inhabit Australia. Species include the long-necked Northern leaf-tailed gecko (Orraya occultus)

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and the smooth knob-tailed gecko (Nephrurus laevissimus).

Pale_Knob-tailed_Gecko_(Nephrurus_laevissimus)_(8656883171)

Then there is Diplodactylidae, a family of 126 species of geckos that live in Australia, New Zealand and New Caledonia, an island east of Australia. This group includes the crested gecko (Correlophus ciliatus)

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and the Northern spiny-tailed gecko (Strophurus ciliaris).

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Finally, a group known as Pygopodidae, the 35 species of legless geckos, is found in Australia and New Guinea. Below is the hooded scaly-foot (Pygopus nigriceps).

pygopus_nigriceps

These anatomically disparate gecko species have something in common besides all living in or very near Australia: they are all more genetically similar to each other than they are to other lizards or even to other geckos. Below is a molecular phylogeny by Pyron et al. [1] containing 4161 species of lizards and using up to 12896 letters of DNA for comparison. What you should notice is that the Australian geckos, Carphodactylidae, Diplodactylidae and Pygopodidae, are all clustered together at the top of the phylogeny to the exclusion of all other geckos (Eublepharidae, Sphaerodactylidae, Phyllodactylidae, Gekkonidae).

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In the context of evolutionary theory, this has a very simple explanation: an ancestral gecko species invaded Australia and diversified into the many Australian geckos that survive today. An alternative creationist hypothesis posits that 189 species of gecko (along with any extinct forms) all walked/slithered across Asia and crossed some portion of the Indian ocean together. This hypothesis suggests that it is simply a coincidence that they are all genetically more similar to each other than they are to other geckos.

Questions for Creationists

If these geckos were on Noah’s ark, how would they know to head to Australia together? Did they swim across the ocean together? Why did they not head elsewhere in the world? Why are they more genetically similar to each other than to other geckos?

References

1. Pyron, R. A., Burbrink, F. T., & Wiens, J. J. (2013). A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes. BMC evolutionary biology13(1), 93.

Photo Credit

Orraya occultus, Nephrurus laevissimus, Correlophus ciliatus, Strophurus ciliaris

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