In scientific classification, a nomen dubium (Latin for "doubtful name", plural nomina dubia) is a scientific name that is valid but of unknown or doubtful application: that is, it may be impossible to determine whether a specimen belongs to that group or not. Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Latin is the language originally spoken in the region around Rome called Latium. ...

This may happen if the original type specimen, or holotype, is lost or destroyed. All codes of nomenclature allow for a new type specimen, or neotype, to be chosen in this case. Type specimens When a new species is discovered, more important than creating a new and unique name for the species is developing a reasonably detailed description. ... A holotype (sometimes simply type) is the single physical example or illustration of an organism that defines the characteristics of the whole species. ...

A name may also become a nomen dubium if its holotype] 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. The International Code of Zoological Nomenclature (ICZN) is a set of rules in zoology that have one fundamental aim: to provide the maximum universality and continuity in classifying all animals according to taxonomic judgment. ...

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. Texan paleontologist Sankar Chatterjee proposed that a new type specimen, a complete skeleton, be designated.^[2] The International Commission on Zoological Nomenclature considered the case and agreed to replace the original type specimen with the proposed neotype.^[3] Groups Crurotarsi     Crocodylia (crocodiles) Ornithodira     Pterosauria     Dinosauria        Aves (birds) Archosaurs (Greek for ruling reptiles) are a group of diapsid reptiles that first evolved from Archosauriform ancestors during the Olenekian (Lower Triassic). ... Richard Lydekker (1849 - April 16, 1915) was an English naturalist, geologist and writer of numerous books on natural history. ... The maxillae are the largest bones of the face, except for the mandible, and form, by their union, the whole of the upper jaw. ... A rostrum (Latin beak) is an anatomical structure resembling a birds beak, such as part of the carapace of a crustacean. ...

See also

• Nomen nudum, a name proposed with no description.

This page is a candidate for speedy deletion, because: it is patent nonsense. ...

References

1. ^  International Code of Zoological Nomenclature (4th edition, 1999)
2. ^  Case 3165, Bulletin of Zoological Nomenclature 58:1, 30 March 2001.
3. ^  Opinion 2045, Bulletin of Zoological Nomenclature 60:2, 30 June 2003.