Bringing the eyes along

Vertebrates lumbered ashore in the Devonian period, perhaps 400 million years ago, using modified swim bladders as lungs. The creatures that crossed this Rubicon interface were probably part of the clade that includes the Dipnoan order, and some of these dipnoans are still with us. Although this order is not the oldest order of fish, it is ancient and has changed little since the Devonian period. Today, the extant dipnoans are represented by the lungfish, with three distinct genera on three of the remnants of Gondwana, including South America, Africa, and Australia. The most primitive representative of these three groups is the Australian species Neoceratodus forsteri (cover image), an animal has changed little over the last 100 million years, thus providing a window to primitive tetrapod vision.

Although N forsteri has been observed walking across land, much like a seal, it is unable to aestivate, or caulk itself in a mucous lined mud case during drought as its fellow genera in Africa and South America can. This primitive trait suggests it is closer to the last common ancestor that led to …