Australasian Science: Australia's authority on science since 1938

Legless on Land

By Stephen Luntz

In another blow to proponents of Intelligent Design, clues have been found to the evolution of one of the world’s oddest fish, the Pacific leaping blenny (Alticus arnoldorum).

The full text of this article can be purchased from Informit.

“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 Terry Ord of the UNSW School of Biological, Earth and Environmental Sciences.

The fish appears uniquely unsuited to the ecological niche it occupies since it must move on land without legs and can never afford to dry out as it breathes through moisture on its gills. Its method of motion is to curve its tail around and press hard against the ground, causing it to spring into the air.

Ord says that leaping blennies have colonised rocky locations on islands across the Pacific, and even on Mauritius. “All environments are a complex mix of niches, and these are not necessarily saturated by one species,” he says. “Had there been some lizard or crustacean filling this niche perhaps the blenny would not have been able to grab it.”

The blenny is well-camouflaged, its green and brown markings blending into the rocks. To test the value of this attire Ord made carefully coloured plasticine blenny models and placed them on rocks and nearby white sand.

“After several days we collected the models and recorded how often birds, lizards and crabs had attacked them from the...

The full text of this article can be purchased from Informit.