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Extant is the opposite of the word extinct. It may refer to:
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Lycopodiopsida is a class of herbaceous vascular plants known as lycopods, lycophytes or other terms including the component lyco-. Members of the class are called clubmosses, firmosses and quillworts. They have dichotomously branching stems bearing simple leaves called microphylls and reproduce by means of spores borne in sporangia on the sides of the stems at the bases of the leaves. Although living species are small, during the Carboniferous, extinct tree-like forms formed huge forests that dominated the landscape and contributed to coal deposits.
The lycophytes, when broadly circumscribed, are a vascular plant (tracheophyte) subgroup of the kingdom Plantae. They are sometimes placed in a division Lycopodiophyta or Lycophyta or in a subdivision Lycopodiophytina. They are one of the oldest lineages of extant (living) vascular plants; the group contains extinct plants that have been dated from the Silurian. Lycophytes were some of the dominating plant species of the Carboniferous period, and included tree-like species, although extant lycophytes are relatively small plants.
A living fossil is an extant taxon that closely resembles organisms otherwise known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossils commonly are of species-poor lineages, but they need not be.
Equisetales is an order of subclass Equisetidae with only one living family, Equisetaceae, containing the genus Equisetum (horsetails).
In paleontology, a Lazarus taxon is a taxon that disappears for one or more periods from the fossil record, only to appear again later. Likewise in conservation biology and ecology, it can refer to species or populations that were thought to be extinct, and are rediscovered. The term Lazarus taxon was coined by Karl W. Flessa & David Jablonski in 1983 and was then expanded by Jablonski in 1986. Wignall and Benton defined Lazarus taxa as, 'At times of biotic crisis many taxa go extinct, but others only temporarily disappeared from the fossil record, often for intervals measured in millions of years, before reappearing unchanged'. Earlier work also supports the concept though without using the name Lazarus taxon, like work by Christopher R. C. Paul.
In phylogenetics, the crown group or crown assemblage is a collection of species, composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. It is thus a way of defining a clade, a group consisting of a species and all its extant or extinct descendants. For example, Neornithes (birds) can be defined as a crown group, as all modern birds, the most recent common ancestor of all modern birds, and all descendants of the most recent common ancestor are included within it.
Neontology is a part of biology that, in contrast to paleontology, deals with living organisms. It is the study of extant taxa : taxa with members still alive, as opposed to (all) being extinct. For example:
A sister group or sister taxon is a phylogenetic term denoting the closest relative(s) of another given unit in an evolutionary tree.
Nemestrinoidea is a small, monophyletic superfamily of flies, whose relationship to the other Brachycera is uncertain; they are sometimes grouped with the Tabanomorpha rather than the Asilomorpha. They are presently considered to be the sister taxon to the Asiloidea. The group contains two very small extant families, the Acroceridae and Nemestrinidae, both of which occur worldwide but contain only small numbers of rare species. One extinct family, Rhagionemestriidae, is also included in Nemestrinoidea.
Palaeoaldrovanda splendens is a form taxon of uncertain identity.
Phylogenetic bracketing is a method of inference used in biological sciences. It is to infer the likelihood of unknown traits in organisms based on their position in a phylogenetic tree. One of the main applications of phylogenetic bracketing is on extinct organisms, known only from fossils, going all the way back to the last universal common ancestor (LUCA). The method is often used for understanding traits that do not fossilize well, such as soft tissue anatomy, physiology and behaviour. By considering the closest and second-closest well-known organisms, traits can be asserted with a fair degree of certainty, though the method is extremely sensitive to problems from convergent evolution.
The euphyllophytes are a clade of plants within the tracheophytes. The group may be treated as an unranked clade, a division under the name Euphyllophyta or a subdivision under the name Euphyllophytina. The euphyllophytes are characterized by the possession of true leaves ("megaphylls"), and comprise one of two major lineages of extant vascular plants. As shown in the cladogram below, the euphyllophytes have a sister relationship to the lycopodiophytes or lycopsids. Unlike the lycopodiophytes, which consist of relatively few presently living or extant taxa, the euphyllophytes comprise the vast majority of vascular plant lineages that have evolved since both groups shared a common ancestor more than 400 million years ago. The euphyllophytes consist of two lineages, the spermatophytes or seed plants such as flowering plants (angiosperms) and gymnosperms, and the Polypodiophytes or ferns, as well as a number of extinct fossil groups.
Enhydrocyon is an extinct genus of bone crushing canid which inhabited North America during the Oligocene and Early Miocene, 30.8—20.4 Ma, existing for approximately 11 million years .
Terlinguachelys fischbecki is an extinct sea turtle that existed during the Late Cretaceous period some 80 million years ago. It is the sole species in the genus Terlinguachelys and is classified in the family Protostegidae along with other extinct marine turtles.
The spermatophytes, also known as phanerogams or phaenogams, comprise those plants that produce seeds, hence the alternative name seed plants. They are a subset of the embryophytes or land plants. The term phanerogams or phanerogamae is derived from the Greek φανερός, phanerós meaning "visible", in contrast to the cryptogamae from Greek κρυπτός kryptós = "hidden" together with the suffix γαμέω, gameo, "to marry". These terms distinguished those plants with hidden sexual organs (cryptogamae) from those with visible sexual organs (phanerogamae).
Annularia is a form taxon, applied to fossil foliage belonging to extinct plants of the genus Calamites in the order Equisetales.
Cetancodontamorpha is a total clade of artiodactyls defined, according to Spaulding et al., as Whippomorpha "plus all extinct taxa more closely related to extant members of Whippomorpha than to any other living species". Attempts have been made to rename the clade Whippomorpha to Cetancodonta, but the former maintains precedent.
Discinida is an order of brachiopods comprising the extant superfamily Discinoidea, and the extinct superfamilies Botsfordioidea (early—mid-Cambrian) and Acrotheloidea. It represents a sister taxon to the Lingulids, and is possibly paraphyletic with respect to the Acrotretoids.—or the acrotretids are paraphyletic with respect to it. The group displays a broad range of shell structures, some of which incorporate substantial organic or silicified components.
Anomotherium is an extinct genus of manatee that lived in the shallow seas of what is now northern Germany. Its closest relative is Miosiren. Fossils of the genus have been found in the Bohlen and Doberg Formations of Germany.
Submyotodon is a genus of vespertilionid bats, published as a new taxon in 2003 to describe a Miocene fossil species. Extant species and subspecies previously included in Myotis were later transferred to this genus.