Mammalian

By their appearance, dolphins might look like fish, but they actually belong to the mammalian family.

“You know, there were societies set up to deliberately introduce stuff so that the Europeans felt more at home. Australia just like New Zealand has suffered enormously as a result. Australia unfortunately has the worst record internationally for mammalian extinction, and that is largely to do with the activities of feral cats and feral foxes.”

An article describing the discovery of the reptilian fossil with mammalian teeth is published this week in the journal Nature.

The genetic evidence comes from an unusually well-preserved polar bear jawbone with a canine tooth still attached to it — a rare find because most polar bear carcasses are consumed by scavengers or sink to the sea bottom. The DNA mapped from the jawbone is the earliest mammalian genome ever sequenced.

The single-imaging optic of the mammalian eye offers some distinct visual advantages. Such lenses can take in photons from a wide range of angles, increasing light sensitivity. They also have high spatial resolution, resolving incoming images in minute detail.