Incertae sedis (Latin for "of uncertain placement") or problematica are terms used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty at specific taxonomic levels is indicated by incertae familiae (of uncertain family), incerti subordinis (of uncertain suborder), incerti ordinis (of uncertain order) and similar terms.
When formally naming a taxon, uncertainty about its taxonomic classification can be problematic. The International Code of Nomenclature for algae, fungi, and plants, stipulates that "species and subdivisions of genera must be assigned to genera, and infraspecific taxa must be assigned to species, because their names are combinations", but ranks higher than the genus may be assigned incertae sedis.
This excerpt from a 2007 scientific paper about crustaceans of the Kuril-Kamchatka Trench and the Japan Trench describes typical circumstances through which this category is applied in discussing:
...the removal of many genera from new and existing families into a state of incertae sedis. Their reduced status was attributed largely to poor or inadequate descriptions but it was accepted that some of the vagueness in the analysis was due to insufficient character states. It is also evident that a proportion of the characters used in the analysis, or their given states for particular taxa, were inappropriate or invalid. Additional complexity, and factors that have misled earlier authorities, are intrusion by extensive homoplasies, apparent character state reversals and convergent evolution.
If a formal phylogenetic analysis is conducted that does not include a certain taxon, the authors might choose to label the taxon incertae sedis instead of guessing its placement. This is particularly common when molecular phylogenies are generated, since tissue for many rare organisms is hard to obtain. It is also a common scenario when fossil taxa are included, since many fossils are defined based on partial information. For example, if the phylogeny was constructed using soft tissue and vertebrae as principal characters and the taxon in question is only known from a single tooth, it would be necessary to label it incertae sedis.
If conflicting results exist or if there is not a consensus among researchers as to how a taxon relates to other organisms, it may be listed as incertae sedis until the conflict is resolved.
In botany, a name is not validly published if it is not accepted by the author in the same publication.Article 36.1 In zoology, a name proposed conditionally may be available under certain conditions.Articles 11 and 15 For uncertainties at lower levels, the system of open nomenclature suggests that question marks be used to denote a questionable assignment. For example, if a new species was given the specific epithet album by Anton and attributed with uncertainty to Agenus, it could be denoted "Agenus? album Anton (?Anton)"; the "(?Anton)" indicates the author that assigned the question mark. So if Anton described Agenus album, and Bruno called the assignment into doubt, this could be denoted "Agenus? album (Anton) (?Bruno)", with the parentheses around Anton because the original assignment (to Agenus) was modified (to Agenus?) by Bruno.
Acontiinae is a subfamily of moth family Noctuidae.Acritarch
Acritarchs are organic microfossils, known from approximately 1.8 billion years ago to the present. Their diversity reflects major ecological events such as the appearance of predation and the Cambrian explosion.Bathyspondylus
Bathyspondylus is an extinct genus of plesiosaur. It was first described in 1982 from a specimen originally found in 1774, now housed at the Devizes Museum. Because it is known only from its fossil vertebrae (and so few of those have been recovered), paleontologists are not entirely sure of the taxonomy of Bathyspondylus; the family it belongs to is not currently known.The type, and only known, species of Bathyspondylus is Bathyspondylus swindoniensis, which was described from the same material as its genus.Castorimorpha
Castorimorpha is the suborder of rodents containing the beavers, the pocket gophers, and the kangaroo rats and kangaroo mice.Corvida
The "Corvida" were one of two "parvorders" contained within the suborder Passeri, as proposed in the Sibley-Ahlquist taxonomy, the other being Passerida. Standard taxonomic practice would place them at the rank of infraorder.
More recent research suggests that this is not a distinct clade—a group of closest relatives and nothing else—but an evolutionary grade instead. As such, it is abandoned in modern treatments, being replaced by a number of superfamilies that are considered rather basal among the Passeri.
It was presumed that cooperative breeding—present in many or most members of the Maluridae, Meliphagidae, Artamidae and Corvidae, among others—is a common apomorphy of this group. But as evidenced by the updated phylogeny, this trait is rather the result of parallel evolution, perhaps because the early Passeri had to compete against many ecologically similar birds (see near passerine).Grass skippers
Grass skippers or banded skippers are butterflies of the subfamily Hesperiinae, part of the skipper family, Hesperiidae. The subfamily was established by Pierre André Latreille in 1809.Grypania
Grypania is an early, tube-shaped fossil from the Proterozoic eon. The organism, with a size over one centimeter and consistent form, could have been a giant bacterium, a bacterial colony, or a eukaryotic alga. The oldest probable Grypania fossils date to about 2300 million years ago (redated from the previous 1870 million) and the youngest extended into the Ediacaran period. This implies that the time range of this taxon extended for 1200 million years.Hypocreales
The Hypocreales are an order of fungi within the class Sordariomycetes. In 2008, it was estimated that it contained some 237 genera, and 2647 species in seven families. Since then, a considerable number of further taxa have been identified, including an additional family, the Stachybotryaceae.Species of Hypocreales are usually recognized by their brightly colored, perithecial ascomata, or spore-producing structures. These are often yellow, orange or red.Leurospondylus
Leurospondylus is a genus of plesiosaur whose family is currently disputed, but is suggested to be Plesiosauridae.List of Ascomycota genera incertae sedis
This is a list of genera in the Ascomycota phylum of fungi with uncertain taxonomic placement (incertae sedis). These genera have not yet been assigned to any class, order, or family. The list is based on the 2007 Outline of Ascomycota as well as updates made in the literature since then. Certain genera (marked as tentative) have a tentative placement in the Ascomycota, and have been placed here provisionally pending further study.List of Dothideomycetes taxa incertae sedis
The following 14 families and 183 genera within the Dothideomycetes class of fungi have an unclear taxonomic placement (incertae sedis), according to the 2007 Outline of Ascomycota. A question mark preceding the genus name means that the placement of that genus within this order is uncertain.List of Pinus species
Pinus, the pines, is a genus of approximately 111 extant tree and shrub species. The genus is currently split into two subgenera: subgenus Pinus (hard pines), and subgenus Strobus (soft pines). Each of the subgenera have several sections within based on chloroplast DNA sequencing. Older classifications split the genus into three subgenera – subgenus Pinus, subgenus Strobus, and subgenus Ducampopinus (pinyon, bristlecone and lacebark pines) – based on cone, seed and leaf characteristics. DNA phylogeny has shown that species formerly in subgenus Ducampopinus are members of subgenus Strobus, so Ducampopinus is no longer used.
The species of subgenus Ducampopinus were regarded as intermediate between the other two subgenera. In the modern classification, they are placed into subgenus Strobus, yet they did not fit entirely well in either so they were classified in a third subgenus. In 1888 the Californian botanist John Gill Lemmon placed them in subgenus Pinus. In general, this classification emphasized cone, cone scale, seed, and leaf fascicle and sheath morphology, and species in each subsection were usually recognizable by their general appearance. Pines with one fibrovascular bundle per leaf, (the former subgenera Strobus and Ducampopinus) were known as haploxylon pines, while pines with two fibrovascular bundles per leaf, (subgenus Pinus) were called diploxylon pines. Diploxylon pines tend to have harder timber and a larger amount of resin than the haploxylon pines.
Several features are used to distinguish the subgenera, sections, and subsections of pines: the number of leaves (needles) per fascicle, whether the fascicle sheaths are deciduous or persistent, the number of fibrovascular bundles per needle, the position of the resin ducts in the needles, the presence or shape of the seed wings, and the position of the umbo and presence of a prickle on the scales of the seed cones.Octopodiformes
Octopodiformes is a superorder of the subclass Coleoidea, comprising the octopuses and the vampire squid. All members of Octopodiformes have eight arms.Olethreutinae
Olethreutinae is a subfamily of moth in the family Tortricidae.Pseudoepicoccum cocos
Pseudoepicoccum cocos is an ascomycete fungus that is a plant pathogen infecting coconut palms.Riboviria
Riboviria is the only realm of viruses circumscribed as of March 2019. It contains all RNA viruses and viroids. As such, it takes the first part of its name, ribo- from ribonucleic acid, or RNA.Sordariomycetes
Sordariomycetes is a class of fungi in the subdivision Pezizomycotina (Ascomycota), consisting of 28 orders, 90 families, 1344 genera. Sordariomycetes is from the Latin sordes (filth) because some species grow in animal feces, though growth habits vary widely across the class.
Sordariomycetes generally produce their asci in perithecial fruiting bodies.
Sordariomycetes are also known as Pyrenomycetes, from the Greek πυρἠν - 'the stone of a fruit' - because of the usually somewhat tough texture of their tissue.Sordariomycetes possess great variability in morphology, growth form, and habitat. Most have perithecial (flask-shaped) fruiting bodies, but ascomata can be less frequently cleistothecial (like in the genera Anixiella, Apodus, Boothiella, Thielavia, Zopfiella),. Fruiting bodies may be solitary or gregarious, superficial, or immersed within stromata or tissues of the substrates and can be light to bright or black. Members of this group can grow in soil, dung, leaf litter, and decaying wood as decomposers, as well as being fungal parasites, and insect, human, and plant pathogens.Thermoanaerobacterales
The Thermoanaerobacterales is a polyphyletic order of bacteria placed within the polyphyletic class Clostridia, and encompassing four families: the Thermoanaerobacteraceae, the Thermodesulfobiaceae, the Thermoanaerobacterales Family III. Incertae Sedis, and the Thermoanaerobacterales Family IV. Incertae Sedis, and various unplaced genera. This order is noted for the species' abilities to survive in extreme environments without oxygen and of relatively elevated temperatures for a living being (up to 80-90°C). An example organism in this order is Thermoanaerobacter ethanolicus.Tortricinae
The Tortricinae are the nominate subfamily of tortrix moths. Commonly referred to as leafrollers, as the larvae build shelters by folding or rolling leaves of the food plant, the tortricinae include several notable pests as well species used as biological control agents against invasive weeds.