Which one of the following is not a living fossil?

Explanation

The earliest known bird fossil is that of archaeopteryx, two species of which have been found from rocks of Jurassic period of earth's history. The fossil shows that archaeopteryx, was about the size of a crow with skull similar to that of present day birds. It had bony teeth in the jaw socket unlike modem birds which do not have teeth. Jaws extended into a beak and there was a long tail. Each wing had three claws. With the exception of feathers these birds showed resemblance to the dinosaurs (giant reptiles of the past). Many fossils of birds from later eras of earth history have also been found that had teeth. The above evidence suggests that birds evolved from reptilian ancestors. The archaeopteryx and others had characteristic of both reptiles and birds and therefore form a connecting link between the two distinct groups.