So you’d think, reading this:
“This terrestrial fish spends all of its adult life living on the rocks in the splash zone, hopping around defending its territory, feeding and courting mates. They offer a unique opportunity to discover in a living animal how the transition from water to the land has taken place,” says Dr Ord, of the UNSW School of Biological, Earth and Environmental Sciences.
First, they studied the camouflage patterns of five different populations of the fish and found that in each case, the fish was camouflaged to match the rocks. They then made plasticine models and put them on the rocks, then more visibly on sand. Sure enough, birds, lizards and crabs attacked the models placed on sand more often. And, as it happened, the blenny camouflage patterns that protected them against a background of rocks resembled those of fully sea-dwelling fish and fish that spend some time on land (all of which also presumably camouflage themselves against rocks).
“These species provide an evolutionary snapshot of each stage of the land invasion by fish,” says Dr Ord. The similarities in colour between these species and the land-dwelling fish suggest the ancestors of the land-dwelling fish already had a colouration that matched the rocky shoreline before they moved out of the water, which would have made it easier for them to survive in their new habitat.
Hold it, we haven’t demonstrated very much here at all. The big sea-to-land problems do not involve camouflage, but adjustment to air breathing. The researchers acknowledge that, re the blenny: “It remains on land all its adult life but has to stay moist to be able to breathe through its gills and skin.”
In short, the blenny, dependent on tidal pools to breathe, never became a terrestrial species of the sort whose origin we are seeking. Never in its entire history so far did it do that.
The blenny is in reality an example of how an essentially aquatic creature can adapt to spending most of its time on land, as long as it can breathe in water. A piece in the puzzle yes, but not the one we are looking for: That would be a creature in the act of moving from life in the water to life on land, which is currently transitioning from gills to lungs. Doubtless such creatures have existed; the blenny, as it happens, isn’t one of them.
In today’s media environment, when seeking information about origins, we find big problems shoved under the carpet while pretending that a minor, interesting find helps answer questions. Camouflage was never a big part of the water-to-land puzzle.
See also: Land-based fish helps researchers assess how animals moved to land – and stayed there
Lobbing a grenade into the tetrapod evolution picture
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