Nomen dubium
Encyclopedia
In zoological nomenclature
, a nomen dubium (Latin
for "doubtful name", plural nomina dubia) is a scientific name that is of unknown or doubtful application. Note that in the ICBN and ICNB the phrase "nomen dubium" has no status (although it, and its synonym nomen ambiguum are in use for names whose application has become confusing; these names may be rejected or conserved with a new type).
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 and paratypes) is lost or destroyed. The ICZN 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.
For example, the crocodile
-like archosaur
ian reptile Parasuchus hislopi Lydekker
, 1885 was described based on a premaxilla
ry 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. Texan paleontologist Sankar Chatterjee 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.
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...
, a nomen dubium (Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "doubtful name", plural nomina dubia) is a scientific name that is of unknown or doubtful application. Note that in the ICBN and ICNB the phrase "nomen dubium" has no status (although it, and its synonym nomen ambiguum are in use for names whose application has become confusing; these names may be rejected or conserved with a new type).
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 and paratypes) is lost or destroyed. The ICZN 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
Name-bearing type
Under the International Code of Zoological Nomenclature , the name-bearing type is the biological type that determines the application of a name. Each taxon regulated by the Code at least potentially has a name-bearing type. The name-bearing type can be either a type genus , type species , or 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
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...
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.
For example, the crocodile
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
-like archosaur
Archosaur
Archosaurs are a group of diapsid amniotes whose living representatives consist of modern birds and crocodilians. This group also includes all extinct non-avian dinosaurs, many extinct crocodilian relatives, and pterosaurs. Archosauria, the archosaur clade, is a crown group that includes the most...
ian reptile Parasuchus hislopi Lydekker
Richard Lydekker
Richard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.-Biography:...
, 1885 was described based on a premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
ry rostrum
Rostrum (anatomy)
The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....
(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. Texan paleontologist Sankar Chatterjee proposed that a new type specimen, a complete skeleton, be designated. The International Commission on Zoological Nomenclature
International Commission on Zoological Nomenclature
The International Commission on Zoological Nomenclature is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 28 members from 20 countries, mainly practicing zoological taxonomists...
considered the case and agreed in 2003 to replace the original type specimen with the proposed neotype.
See also
- species inquirendaSpecies inquirendaIn 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....
, a species of doubtful identity requiring further investigation - nomen nudumNomen nudumThe phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
, a name proposed with no description (or illustration) - nomen oblitumNomen oblitumA nomen oblitum is a technical term, used in zoological nomenclature, for a particular kind of disused scientific name....
, a forgotten name