Neontology is a part of biology that, in contrast to paleontology, studies and deals with living (or, more generally, recent) organisms. It is the study of extant taxa (singular: extant taxon): taxa (such as species, genera and families) with members still alive, as opposed to (all) being extinct. For example:
- The Indian elephant (Elephas maximus) is an extant species, and the woolly mammoth (Mammuthus primigenius) is an extinct species.
- The moose (Alces alces) is an extant species, and the Irish elk (Megaloceros giganteus) is an extinct species.
- In the group of molluscs known as the cephalopods, as of 1987 there were approximately 600 extant species and 7,500 extinct species.
A taxon can be classified as extinct if it is broadly agreed or certified that no members of the group are still alive. Conversely, an extinct taxon can be reclassified as extant if there are new discoveries of living species ("Lazarus species"), or if previously known extant species are reclassified as members of the taxon.