Extant taxon

Neontology is a part of biology. In contrast to paleontology, it 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:

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 extant species ("Lazarus species"), or if previously-known extant species are reclassified as members of the taxon.

The term neontologist is used largely by paleontologists referring to nonpaleontologists. Stephen Jay Gould said of neontology:

All professions maintain their parochialisms, and I trust that nonpaleontological readers will forgive our major . We are paleontologists, so we need a name to contrast ourselves with all you folks who study modern organisms in human or ecological time. You therefore become neontologists. We do recognize the unbalanced and parochial nature of this dichotomous division

...
Wikipedia