binomial nomenclature In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

, a ''nomen dubium'' (

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application.

Zoology

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 A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

, isotype,

syntype In biological nomenclature, a syntype is any one of two or more biological types that is listed in a description of a taxon where no holotype was designated. Precise definitions of this and related terms for types have been established as part of ...

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). O ...

) is lost or destroyed. The zoological and botanical codes allow for a new type specimen, or

neotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

, to be chosen in this case. A name may also be considered a ''nomen dubium'' if its

name-bearing type Under the ''International Code of Zoological Nomenclature'' (''Code''), the name-bearing type is the biological type that determines the application of a name. Each animal taxon regulated by the ''Code'' at least potentially has a 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 The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the ...

'' allows a new type specimen, or

, 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 rt. 81the existing name-bearing type and designate a neotype.

For example, the crocodile-like archosaurian reptile ''Parasuchus hislopi'' Lydekker, 1885 was described based on a

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * Ros ...

(part of the snout), but this is no longer sufficient to distinguish ''

Parasuchus ''Parasuchus'' is an extinct genus of basal phytosaur known from the Late Triassic (late Carnian to early Norian stage) of Andhra Pradesh and Madhya Pradesh, India. At its most restricted definition, ''Parasuchus'' contains a single species, ' ...

'' 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. The International Commission on Zoological Nomenclature considered the case and agreed in 2003 to replace the original type specimen with the proposed neotype.

Bacteriology

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: *ambiguous names, ''nomina ambigua'', have been used with more than one meaning *names causing confusion, ''nomina confusa'', are based on a mixed culture *perplexing names, ''nomina perplexa'', confusingly similar names *perilous names, ''nomina periculosa'', names that may lead to accidents endangering life or health or with potential serious economic consequences

Botany

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 In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

'' is of more frequent use. Such names may be proposed for rejection.

References

{{Use dmy dates, date=October 2018 Zoological nomenclature Latin biological phrases

Zoology

Bacteriology

Botany

See also

References