Answer: Coelacanth

Taxons are a group of organisms that share characteristics; these groups can be as specific as individual species or as broad as biological classes, orders, and families. In paleontology, a “Lazarus taxon”—a name that gives a nod to the biblical tale of Lazarus coming back from the dead—is a taxon that vanished from the fossil record only to reappear later. The same term is used in conservation biology and ecology to refer to species or populations believed to be extinct, but that have been rediscovered in the wild.

Sometimes, a Lazarus taxon isn’t particularly impressive (the Giant Palouse earthworm was thought to be extinct in the 1980s, for example, but was then observed decades later in the wild), but other times, taxons will vanish for hundreds, thousands, or even millions of years only to be found again. The most notable case of such a long period is that of the coelacanth, a rare type of fish. The earliest examples of coelacanths come from the fossil record, dating back at least 66 million years. The fish were believed to be completely extinct by the end of the Cretaceous period and a century ago a scientist would tell you that the chances of finding one were probably about as good as the chances of running into a pterodactyl.

Yet in 1938, a species of coelacanth was found off the east coast of South Africa and, since then, a second extant species has been discovered in Indonesia—largely unchanged and existing in its present state as a living fossil.