Open Nomenclature in Biological Classification
In the precise world of biological classification, taxonomists often encounter specimens that do not fit neatly into established categories. To communicate these nuances, they use open nomenclature—a vocabulary of partly informal terms and signs used to express remarks about their own material. Unlike synonymy lists, which focus on the work of other researchers, open nomenclature allows a scientist to provide critical context regarding the identity and certainty of a specific taxon.
Because these expressions are often abbreviated, they serve as a shorthand for complex taxonomic judgments. However, this flexibility comes with a trade-off: there are no strict conventions regarding which expressions to use or where to place them within a Latin name. This lack of standardization can sometimes lead to difficulties in interpretation.
[ไม่มีภาพประกอบ]Key Facts
- Definition: A system of informal terms used by taxonomists to describe their own specimens.
- Regulatory Status: The International Code of Zoological Nomenclature (ICZN) does not provide rules for open nomenclature, leaving its meaning to the interpretation of the author.
- Purpose: To indicate uncertainty, affinity, or the status of a specimen when a definitive identification is not possible.
- Distinction: It differs from synonymy lists, which are used to comment on the work of others.
Common Shorthand and Their Meanings
Taxonomists employ specific Latin-based abbreviations to signal the level of confidence they have in a specimen's classification. These terms help other researchers understand whether a specimen is potentially new to science or simply difficult to identify.
Indicating New or Uncertain Species
- Sp. (pl. spp.): Short for "species." This indicates a potentially new species without specifying its affinity. It suggests that identification is incomplete, evidence is insufficient to allocate the specimen to a known taxon, or there is not yet enough confidence to assign it to a new taxon.
- Sp. aff. or aff.: Short for species affinis. This indicates that a potentially new and undescribed species has an affinity to (is closely related to), but is not identical to, the named species.
- Cf. or ?: Cf. is short for the Latin confer ("compare with"), while a question mark or inc. (species incerta) signifies varying degrees of uncertainty. In modern usage, "cf." typically indicates a higher level of uncertainty than a question mark.
Verification of Material
Some terms describe the physical evidence the taxonomist used to reach their conclusion:
- V.: Short for vidimus ("we have seen"). This confirms the author personally inspected the original type specimens.
- Non v.: Short for non vidimus ("we have not seen"). This indicates the original specimen was not observed, a common occurrence with materials like certain fungal spores.
Comparison of Taxonomic Terms
Beyond open nomenclature, several other Latin terms are used to describe the status of names and taxa within biological classification.
| Term | Meaning |
|---|---|
| Candidatus | A candidate taxon proposed from metagenomics or incomplete information. |
| Incertae sedis | A taxon whose position in the classification is uncertain. |
| Nomen dubium | A name of unknown or doubtful application. |
| Nomen novum | A new name, often replacing an unacceptable name (e.g., a junior synonym). |
| Nomen nudum | An invalid name, usually lacking an adequate published description. |
| Species inquirenda | A species that requires further investigation. |
Frequently Asked Questions
How does open nomenclature differ from synonymy lists?
Open nomenclature is used by taxonomists to make remarks about their own material and specimens, whereas synonymy lists are used to express remarks on the work of other taxonomists.
Does the ICZN regulate the use of open nomenclature?
No, the International Code of Zoological Nomenclature (ICZN) makes no reference to open nomenclature, meaning its use and interpretation are left entirely to the individual taxonomist.
What is the difference between "sp." and "sp. aff."?
"Sp." indicates a potentially new species without mentioning its relationship to others. "Sp. aff." specifically indicates that the specimen is related to (has an affinity with) a known species but is not identical to it.
What does "v." mean in a taxonomic description?
The abbreviation "v." stands for vidimus, meaning "we have seen." It signifies that the author has personally examined the original type specimens to base their statements on first-hand experience.
What is a nomen nudum?
A nomen nudum is a name that appears to be a taxon name in the correct binomial form but is considered invalid because it was not published with an adequate description.