The ICZN, the rules and how they result in name changes

Everyone loves a good noun

● Talking about things without giving them names is hard

● Naming things is a natural part of language, as is classification

Folk nomenclatures

● Collections of nouns for describing related things

● Still widely used: common names

● Precedence given to useful things

An aside

● This happens elsewhere! The Roof Bed of the Bath Stone was favoured by quarrymen for the strength it provided to the roof of mines

An aside

● This happens elsewhere! Blue Lias uses quarrymen's terms for limestone layers:

Best

First Quick

Brick

Gumption

An issue

● One thing can have many folk names

● Regional variations

● Spelling variations (particularly when transcribing oral traditions)

Zoological Nomenclature

Formalises this so that:

● One animal has one (correct) name

As we learnt more

Iris

Stinking Iris

Why we like Linnaeus

Iris foetidissima

Move from descriptions that would get ever longer to binominals

That seems simple...

… why do we need a Commission on animal names?

… why do they keep changing?

...hold on, what is a species?

An aside on species concepts

● Phenetic

● Biological/Reproductive

● Phylogenetic

● Ecological

● Cohesion

Classification

Implicit in a binominal name is a grouping of related species

Carex divulsa

Carex pendula

Cyperus papyrus

So names change

● When we learn something that causes our definition of a species to change

● When we learn something that means the grouping (higher classification) of a species to change (only at generic level)

● Or when someone did something wrong (almost always accidental, and understandable)

Rules about name changes: priority

Generally (one animal, one name):● If an animal has two names: the oldest wins

● If two animals have the same name: the first one to get it keeps it

● If the species name is an adjective, it describes the genus and if in a language that uses gender must agree in gender.

*Lepidopterists by convention ignore the last rule, and many people are keen for this to disappear.

Availability & Validity

● An available name has been correctly published (has a type specimen, adequate description, etc). If a name has not been correctly published it is considered not to exist in relation to priority.

● A valid name is the currently correct name.

An animal may have many available names, but only one is valid.

Change in species definition 1

Two species are found to be the same:● The older name is valid (senior synonym)● The younger name is a junior synonym

If both names were published in the same publication the choice of which to use goes to the 'First Reviser'.

Changes in species definition 2

A species is found to be two species● The original species still exists, the name still

applies● A new name is described with a new type

specimen

A note on types

There are two kinds:● Primary types (Holotypes, Lectotypes Neotypes, Syntypes)

● Secondary types (Paratypes, Paralectotypes)

Primary types define a species, secondary types show within species variation (in phasmids generally include opposite sex to primary type, eggs, nymphs, etc)

Genus changes

Sometimes a species needs to be moved to a different genus, this can cause name changes

● Every species must have a unique name, so if there is a species with the same specific epithet in that genus the name must change (junior homonym)

● If an adjective the name may need to change to reflect the gender of the new genus

Mistakes

The same species is described twice:● The second name becomes a junior synonym

A type specimen is lost/destroyed● A neotype must be designated

A species is inadequately described● It should be redescribed from the same primary types

Subspecies

When a species is split into subspecies● The subspecies containing the original type is

nominotypical and the subspecific epithet is the same as the specific epithet (Conocephalus hastatus hastatus)

● The other species is given a unique subspecific epithet (Conocephalus hastatus bodenheimeri)

Species group

So far we have discussed names in the species-group

Some notes on the Genus group

Genera should have a type species the process of creating a type species is called fixation

● Original designation: the author of the genus name sets the type species explicitly

● Subsequent designation: a later author sets the type species of an unfixed genus as First Reviser

● Indication: by original monotypy when a genus is originally described with a single species. By absolute tautonymy when a genus is described including a species with a specific epithet identical to the genus name (Conocephalus conocephalus)

Subgenera

Used to split genera into groups

● The subgenus containing the type-species of the genus is nominotypical and takes the name of the genus (analogous to subspecies)

The Family Group

Highest level controlled by ICZN:● Covers Superfamily down to Tribe● Names are based on a generic name● All carry the authorship of the first person to

use that genus name as the root of a name in the family group

Writing names

Conocephalus (conocephalus) hastatus hastatus (Charpentier, 1825)

Genus (subgenus) species subspecies Author, Date

● If the species is not in the original genus the name and date are placed in parentheses (coordinate)

● Only the genus and author is capitalised

● Family-group names are not italicised

So far...

These things can be done by anybody publishing a scientific paper following the International Code of Zoological Nomenclature

The Code describes how species should be described, types designates, and problems solved

Standards, Sense and Stability

Stability

The International Commission on Zoological Nomenclature has the plenary power to suspend the rules of nomenclature in the case where not doing so would lead to instability

● An older available name is discovered for a well-known species (reversal of precedence – name added to The Official List of Names and Works in Zoology)

● The type specimen of a species still exists but may be considered no longer adequate (Archaeopteryx lithographica)

● To suspend all priority for a group of organisms based on a List of Available Names (new – currently in progress for Rotifera)

Process

● Authors prepare a Case for the Commission which is published in the Bulletin of Zoological Nomenclature

● Others may comment via the BZN supporting (or otherwise) the Case or proposing alternative solutions

The Commission votes on the Case and issue an Opinion in the BZN.

Cases

● Generally relate to names or groups of names of animals

● May relate to publications – making names in some publications unavailable or making pre-1758 names available

Further Notes 1

● Special rules for ichnotaxa

● Botanists have a separate code (as do microbiologists and virologists)

● Also International Code of Nomenclature for Cultivated Plants (cultivar, Group, grex)

Further Notes 2

● There are a lot more rules – but hopefully you get the general idea

● A lot more has been written about nomenclature, taxonomy and classification

● The history of nomenclature is quite interesting