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In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. Until such a description has been published, the taxon has no formal or official name, although a temporary, informal name is often used. A published scientific name may not fulfil the requirements of the Codes for various reasons. For example, if the taxon was not adequately described, its name is called a nomen nudum . It is possible for a taxon to be "undescribed" for an extensive period of time, even if unofficial descriptions are published.
An undescribed species may be referred to with the genus name, followed by "sp.", but this abbreviation is also used to label specimens or images that are too incomplete to be identified at the species level. In some cases, there is more than one undescribed species in a genus. In this case, these are often referred to by a number or letter. In the shark genus Pristiophorus , for example, there were, for some time, four undescribed species, informally named Pristiophorus sp. A, B, C and D. (In 2008, sp. A was described as Pristiophorus peroniensis and sp. B as P. delicatus .) When a formal description for species C or D is published, its temporary name will be replaced with a proper binomial name.
The discovery of undescribed taxa has accelerated dramatically with advances in molecular biology and the growing use of image-based identifications. DNA barcoding and similar molecular techniques have revealed many cryptic species – organisms that appear morphologically identical but are genetically distinct enough to represent different species. This has led to a significant increase in the recognition of undescribed taxa within what were previously thought to be single species. [1]
The scale of undescribed biodiversity is substantial. In marine environments alone, while there are over 246,000 formally described species, scientists estimate the total number of species ranges from several hundred thousand to multiple millions. The gap between discovery and formal description continues to widen, with estimates suggesting it takes between 13 and 21 years on average from initial discovery of a new species to its formal taxonomic description. This delay between discovery and formal description, often called the "taxonomic impediment", is exacerbated by a shortage of taxonomic experts and the time-intensive nature of preparing formal species descriptions. As a result, many clearly distinct species remain in an undescribed state for extended periods, known only by temporary names or identifiers. [1]
Modern molecular methods have introduced new ways of recognizing potential undescribed species through DNA analysis. Molecular Operational Taxonomic Units (MOTUs) are groups of organisms distinguished by DNA sequence similarity, often revealing diversity that exceeds known described species. For example, in some large-scale environmental DNA studies, the number of MOTUs can surpass described species by an order of magnitude. [1]
DNA barcoding, which uses standardized genetic markers to identify species, has become particularly important in recognizing undescribed taxa. When DNA sequences from specimens do not match any known species in reference databases, they may represent undescribed species. These are sometimes called "dark taxa" in molecular databases, as they lack formal taxonomic names. However, while molecular methods are powerful tools for discovering potential new species, they do not replace traditional taxonomic description. MOTUs and similar molecular groupings serve as important indicators of undescribed diversity, but formal species description typically requires additional evidence, including morphological analysis and ecological data. [1]
In bacteriology, a valid publication of a name requires the deposition of the bacteria in a Bacteriology Culture Collection. Species for which this is impossible cannot receive a valid binomial name; these species are classified as Candidatus. [2]
A provisional name for a species may consist of the number or of some other designation of a specimen in a herbarium or other collection. It may also consist of the genus name followed by such a specimen identifier or by a provisional specific epithet which is enclosed by quotation marks. In the latter case, the author citation may be replaced by the Latin term ineditus or ined., meaning "unpublished". As of 2013, many species of the flowering plant genus Polyscias can be found in the scientific literature under such a designation. [3] An enquoted name, however, is not necessarily unpublished. It may be an illegitimate name that has not yet been replaced by a correct name. For example, the name "Endressia" (sensu Whiffin) was published in 2007 for a genus in family Monimiaceae, but is an illegitimate homonym of Endressia J.Gay in family Apiaceae. In 2010, it was noted as illegitimate, but still used with quotation marks. [4] This name was replaced with Pendressia in 2018. [5]
Major biodiversity databases have developed various approaches to handle undescribed taxa while maintaining taxonomic rigor. The World Register of Marine Species (WoRMS) allows for five broad name status categories: Accepted, Unaccepted, Uncertain, Alternative representation, and Temporary. Within WoRMS, temporary names can be used both for higher-rank placeholder taxa that accommodate species of uncertain classification, and for unnamed species that have been clearly identified as distinct through taxonomic studies. [1]
The Global Biodiversity Information Facility (GBIF) and Ocean Biodiversity Information System (OBIS) incorporate undescribed taxa into their occurrence records using standardized fields in Darwin Core, a biodiversity data standard. These databases use specific fields like "taxonConceptID" and "identificationQualifier" to track specimens that represent potentially new species. [1]
Management of undescribed taxa in databases presents unique challenges. For example, when a specimen is identified as representing a new species, it may initially receive a temporary collection-based identifier. This same specimen might then be referenced in molecular databases like GenBank or BOLD (Barcode of Life Data System) with a different identifier, and appear in published literature with yet another temporary name. Biodiversity databases must track these various identifiers and maintain links between them until the species receives formal taxonomic description. [1]
To address these challenges, database managers increasingly recommend standardized formats for temporary names. These often incorporate institutional collection codes, specimen numbers, or other stable identifiers that can help track specimens and their associated data across different databases and publications. When species are formally described, their temporary identifiers can be retained in databases as alternative names, maintaining the connection between pre- and post-description records. [1]
In biology, taxonomy is the scientific study of naming, defining (circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a more inclusive group of higher rank, thus creating a taxonomic hierarchy. The principal ranks in modern use are domain, kingdom, phylum, class, order, family, genus, and species. The Swedish botanist Carl Linnaeus is regarded as the founder of the current system of taxonomy, as he developed a ranked system known as Linnaean taxonomy for categorizing organisms and binomial nomenclature for naming organisms.
In biology, a type is a particular specimen of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to anchor or centralizes the defining features of that particular taxon. In older usage, a type was a taxon rather than a specimen.
GastoniaCommerson ex Lamarck is a formerly accepted genus of plants in the ivy and ginseng family, Araliaceae. It had been known as an unnatural group, but was recognized as late as 2010, when its nine species were distributed to four different subgenera of the large genus Polyscias. Because the genus Gastonia is now obsolete, its species are herein referred to by their names in Polyscias.
The Monimiaceae is a family of flowering plants in the magnoliid order Laurales. It is closely related to the families Hernandiaceae and Lauraceae. It consists of shrubs, small trees, and a few lianas of the tropics and subtropics, mostly in the southern hemisphere. The largest center of diversity is New Guinea, with about 75 species. Lesser centres of diversity are Madagascar, Australia, and the neotropics. Africa has one species, Xymalos monospora, as does Southern Chile. Several species are distributed through Malesia and the southwest Pacific.
In prokaryote nomenclature, Candidatus is used to name prokaryotic taxa that are well characterized but yet-uncultured. Contemporary sequencing approaches, such as 16S ribosomal RNA sequencing or metagenomics, provide much information about the analyzed organisms and thus allow identification and characterization of individual species. However, the majority of prokaryotic species remain uncultivable and hence inaccessible for further characterization in in vitro study. The recent discoveries of a multitude of candidate taxa has led to candidate phyla radiation expanding the tree of life through the new insights in bacterial diversity.
Siparunaceae is a family of flowering plants in the magnoliid order Laurales. It consists of two genera of woody plants, with essential oils: Glossocalyx in West Africa and Siparuna in the neotropics. Glossocalyx is monospecific and Siparuna has about 74 known species.
The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently.
Cuphocarpus is an obsolete genus of flowering plants in the family Araliaceae. Mabberley (2008) treated it as a synonym of Polyscias, but other authors still recognized it at that time. In 2010, in a phylogenetic analysis of DNA sequences, it was shown that Cuphocarpus was biphyletic and embedded in the large genus Polyscias. In an accompanying paper, Polyscias was divided into 11 subgenera, with seven species left incertae sedis.
In biology, taxonomic rank is the relative or absolute level of a group of organisms in a hierarchy that reflects evolutionary relationships. Thus, the most inclusive clades have the highest ranks, whereas the least inclusive ones have the lowest ranks. Ranks can be either relative and be denoted by an indented taxonomy in which the level of indentation reflects the rank, or absolute, in which various terms, such as species, genus, family, order, class, phylum, kingdom, and domain designate rank. This page emphasizes absolute ranks and the rank-based codes require them. However, absolute ranks are not required in all nomenclatural systems for taxonomists; for instance, the PhyloCode, the code of phylogenetic nomenclature, does not require absolute ranks.
Nyctophilus is a genus of the vespertilionids or vesper bats. They are often termed Australian big-eared bats or long-eared bats, as the length of their ears often greatly exceeds that of the head. They are sometimes colloquially called “Monbats”.:This genus occurs in the New Guinean-Australian region.
The Chloroflexota are a phylum of bacteria containing isolates with a diversity of phenotypes, including members that are aerobic thermophiles, which use oxygen and grow well in high temperatures; anoxygenic phototrophs, which use light for photosynthesis ; and anaerobic halorespirers, which uses halogenated organics as electron acceptors.
A species is a population of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour, or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species are given a two-part name, called a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet. For example, Boa constrictor is one of the species of the genus Boa, with constrictor being the species' epithet.
A taxonomic database is a database created to hold information on biological taxa – for example groups of organisms organized by species name or other taxonomic identifier – for efficient data management and information retrieval. Taxonomic databases are routinely used for the automated construction of biological checklists such as floras and faunas, both for print publication and online; to underpin the operation of web-based species information systems; as a part of biological collection management ; as well as providing, in some cases, the taxon management component of broader science or biology information systems. They are also a fundamental contribution to the discipline of biodiversity informatics.
Open nomenclature is a vocabulary of partly informal terms and signs in which a taxonomist may express remarks about their own material. This is in contrast to synonymy lists, in which a taxonomist may express remarks on the work of others. Commonly such remarks take the form of abbreviated taxonomic expressions in biological classification.
DNA barcoding is a method of species identification using a short section of DNA from a specific gene or genes. The premise of DNA barcoding is that by comparison with a reference library of such DNA sections, an individual sequence can be used to uniquely identify an organism to species, just as a supermarket scanner uses the familiar black stripes of the UPC barcode to identify an item in its stock against its reference database. These "barcodes" are sometimes used in an effort to identify unknown species or parts of an organism, simply to catalog as many taxa as possible, or to compare with traditional taxonomy in an effort to determine species boundaries.
Nemadactylus is a genus of marine ray-finned fish, traditionally regarded as belonging to the family Cheilodactylidae, the members of which are commonly known as morwongs. They are found in the South Atlantic, Indian and South Pacific Oceans.
The Barcode of Life Data System is a web platform specifically devoted to DNA barcoding. It is a cloud-based data storage and analysis platform developed at the Centre for Biodiversity Genomics in Canada. It consists of four main modules, a data portal, an educational portal, a registry of BINs, and a data collection and analysis workbench which provides an online platform for analyzing DNA sequences. Since its launch in 2005, BOLD has been extended to provide a range of functionality including data organization, validation, visualization and publication. The most recent version of the system, version 4, launched in 2017, brings a set of improvements supporting data collection and analysis but also includes novel functionality improving data dissemination, citation, and annotation. Before November 16, 2020, BOLD already contained barcode sequences for 318,105 formally described species covering animals, plants, fungi, protists.
DNA barcoding is an alternative method to the traditional morphological taxonomic classification, and has frequently been used to identify species of aquatic macroinvertebrates. Many are crucial indicator organisms in the bioassessment of freshwater and marine ecosystems.
DNA barcoding of algae is commonly used for species identification and phylogenetic studies. Algae form a phylogenetically heterogeneous group, meaning that the application of a single universal barcode/marker for species delimitation is unfeasible, thus different markers/barcodes are applied for this aim in different algal groups.
Fungal DNA barcoding is the process of identifying species of the biological kingdom Fungi through the amplification and sequencing of specific DNA sequences and their comparison with sequences deposited in a DNA barcode database such as the ISHAM reference database, or the Barcode of Life Data System (BOLD). In this attempt, DNA barcoding relies on universal genes that are ideally present in all fungi with the same degree of sequence variation. The interspecific variation, i.e., the variation between species, in the chosen DNA barcode gene should exceed the intraspecific (within-species) variation.