In binomial nomenclature, a nomen dubium (Latin for "doubtful name", plural nomina dubia) is a scientific name that is of unknown or doubtful application.
In binomial nomenclature, a nomen dubium (Latin for "doubtful name", plural nomina dubia) is a scientific name that is of unknown or doubtful application.
In case of a nomen dubium, it may be impossible to determine whether a specimen belongs to that group or not. This may happen if the original type series (i. e. holotype, isotype, syntype or paratype) is lost or destroyed. The zoological and botanical codes allow for a new type specimen, or neotype, to be chosen in this case.
A name may also be considered a nomen dubium if its name-bearing type is fragmentary or lacking important diagnostic features (this is often the case for species known only as fossils). To preserve stability of names, the International Code of Zoological Nomenclature allows a new type specimen, or neotype, to be chosen for a nomen dubium in this case.
75.5. Replacement of unidentifiable name-bearing type by a neotype. When an author considers that the taxonomic identity of a nominal species-group taxon cannot be determined from its existing name-bearing type (i.e. its name is a nomen dubium), and stability or universality are threatened thereby, the author may request the Commission to set aside under its plenary power [Art. 81] the existing name-bearing type and designate a neotype. [1]
For example, the crocodile-like archosaurian reptile Parasuchus hislopi Lydekker, 1885 was described based on a premaxillary rostrum (part of the snout), but this is no longer sufficient to distinguish Parasuchus from its close relatives. This made the name Parasuchus hislopi a nomen dubium. In 2001 a paleontologist proposed that a new type specimen, a complete skeleton, be designated. [2] The International Commission on Zoological Nomenclature considered the case and agreed in 2003 to replace the original type specimen with the proposed neotype. [3]
In bacteriological nomenclature, nomina dubia may be placed on the list of rejected names by the Judicial Commission. The meaning of these names is uncertain. Other categories of names that may be treated in this way (rule 56a) are: [4]
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In botanical nomenclature the phrase nomen dubium has no status, although it is informally used for names whose application has become confusing. In this regard, its synonym nomen ambiguum is of more frequent use. Such names may be proposed for rejection.
A holotype is a single physical example of an organism used when the species was formally described. It is either the single such physical example or one of several examples, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN, the definitions of types are similar in intent but not identical in terminology or underlying concept.
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.
In taxonomy, a nomen nudum is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published with an adequate description. This makes it a "bare" or "naked" name, which cannot be accepted as it stands. A largely equivalent but much less frequently used term is nomen tantum. Sometimes, "nomina nuda" is erroneously considered a synonym for the term "unavailable names". However, not all unavailable names are nomina nuda.
Paleorhinus is an extinct genus of widespread basal phytosaur known from the Late Triassic. The genus was named in 1904 based on the type species Paleorhinus bransoni, which is known from Wyoming and Texas in the United States. Another valid species, Paleorhinus angustifrons from Bavaria, Germany, is also commonly referred to the genus. Paleorhinus had a length of about 2.5 meters.
Parasuchus is an extinct genus of basal phytosaur known from the Late Triassic of Andhra Pradesh and Madhya Pradesh, India. At its most restricted definition, Parasuchus contains a single species, Parasuchus hislopi. Parasuchus hislopi is one of several species belonging to a basal grade of phytosaurs, typified by the genus Paleorhinus. Historically, Paleorhinus has been known from better-described fossils, and many species have been lumped into that genus. Parasuchus hislopi, despite being described earlier than Paleorhinus, was considered an undiagnostic chimera until new neotype fossils were described in the late 1970s. Parasuchus hislopi and the two unambiguously valid species of Paleorhinus are all closely related; some authors have historically described them all under the species Paleorhinus, while others place the two Paleorhinus species into Parasuchus according to the principle of priority.
Macropterygius is a genus of ichthyosaurs known from the Late Jurassic of England. Though many specimens have been referred to this genus from all over Europe, the type specimen of the only recognized species, M. trigonus, consists of just a single vertebra. Because this cannot be used to distinguish ichthyosaurs from one another, the genus and species are currently considered nomina dubia.
In biological classification, a species inquirenda is a species of doubtful identity requiring further investigation. The use of the term in English-language biological literature dates back to at least the early nineteenth century.
This is a list of terms and symbols used in scientific names for organisms, and in describing the names. For proper parts of the names themselves, see List of Latin and Greek words commonly used in systematic names. Note that many of the abbreviations are used with or without a stop.