How animals are given scientific names
Codes of nomenclature
There are three main Codes of
Nomenclature: the International Code of Zoological Nomenclature, covering
animals; the International Code of Botanical Nomenclature, covering
plants (including fungi); and the International Code of Nomenclature of
Bacteria. Although there are quite a few similarities between the codes,
there are also considerable differences and it is beyond the scope of this
handout to compare the Zoological Code with the other two in any detail.
The history of Zoological nomenclature
||Linnaeus published the 10th
edition of the Systema Naturae and in it consistently used his
system of binomial nomenclature. This system was adopted by other
naturalists but with no rules governing it so that by the middle of the
19th century there was confusion. The confusion was increased by the
proliferation of new species resulting from the growth of Science and the
voyages of exploration.
Hugh Strickland presented a
Code of nomenclature to the British Association for the Advancement of
Science (Charles Darwin was on its committee). It was translated and
circulated widely round the world. It was revised in succeeding years.
Douvillé Code, based on
the Stricklandian Code, adopted internationally by geologists and the
American Ornithologists Union.
The First International
Congress of Zoology in Paris adopted, in part, rules drawn up by Professor
discussed at the Second International Congress of Zoology in Moscow.
International Commission of
five zoologists appointed at the 3rd Congress in Leyden. Further members
A report by the
Commission was adopted by the 5th Congress in Berlin.
The report was published as
a Code in French, German and English. It was entitled Règles
internationales de la Nomenclature zoologique. It contained no
directives concerning types.
Amendments to Code at
Boston Congress including provisions for generic types.
Amendments to Code at
Monaco Congress including recommendations regarding types of species.
Amendments to Code at
Amendments to Code at Padua
Formal rules and
recommendations regarding type specimens adopted at the Paris Congress.
Publication of 1st
edition of the
International Code of Zoological Nomenclature
resulting from Congresses following the 2nd World War.
2nd edition of the International
Code of Zoological Nomenclature.
At the 17th Congress of
Zoology in Monaco, responsibility for future Codes was transferred from
the International Zoological Congresses to the International Union of
||Publication of 3rd edition of
International Code of Zoological Nomenclature.
||Publication of 4th edition of
International Code of Zoological Nomenclature
The hierarchy of ranks
Organisms are placed in hierarchies so
that one divide up the species into manageable chunks and so that one can see
the relationship of species and groups to one another. The full hierarchy of
ranks for animals is as follows (using a species of beetle as an example).
[FAM] Family: TenebrionIDAE
[FAM] Tribe: PlatynotINI
[FAM] Subtribe: Anomalipina
The Zoological Code recognises three
main types of names: family group names (FAM); genus group names
(GEN); and species group names (SP). The other ranks are not controlled by the code so at these ranks you can choose the names
you like (zoologists, with a few exceptions, try to coordinate as much as
possible so that there is a minimum of chaos).
names have the suffix -oidea; family names -idae; subfamily
names -inae, and tribal names -ini. The genus name is
always included with the species name to form the binomial. The subgenus to
which it belongs (if there is one) can be included in brackets after the genus
name and before the species name but inclusion of this name is not essential.
Notice that the author of the name can be included at the end of the name. If
the genus name is not the same as the one originally used by the author, then
the author’s name is enclosed in brackets. For instance, Camponotus
fulvopilosus (De Geer) was originally described by De Geer as Formica
When an author introduces a new
name at a particular rank within the family group, that name can be used at
other ranks within the family group as well. This is the Principle of
Coordination (see later). For instance, within the ants there are the names
Formicoidea, Formicidae, Formicinae and Formicini. All four of these names have
the same author, date and type genus; they only differ in the suffix used for
each rank. In practice, a name is rarely used at so many ranks. For instance,
within the subfamily Formicinae is the tribe Camponotini; this name is not use
at the subfamily rank because it was established later than the name Formicinae.
This same Principle of Coordination applies to genus-group names (e.g. a
subgenus name could later be used as a genus name) and species group names (e.g.
a species name might later be used as a subspecies name).
Each family group name has
a type genus, each genus group name has a type species, and
each species group name has a type specimen or type series. Types
are important because they are the reference points for each taxon. By comparing
the types you can make a decision about whether two taxa are the same or not. In
the late 19th century specimens were often labelled as types merely because they
were ‘typical’ of the species. However, in its modern meaning a type is not
necessary typical of the taxon it represents. A taxonomist might describe a new
species from a single specimen which s/he designates as a holotype. At a later
date more specimens of the species might be discovered and it might be found
that the type is in fact at the extreme of variation for that species and
therefore not typical. However, that specimen still remains the ultimate point
of reference for that name.
In family group and genus
group names, there are a number of different ways in which a type might be
designated and the differences between them are best illustrated by examples (of
ant genera). When Ettershank described the genus Nothidris he did
designate a type species so this is a type by original designation. When
Emery described the genus Chelaner he did not designate a type at the
time but did so at a later date. This is a type by subsequent designation.
When Santschi described the ant genus Oxyepoecus he did not designate a
type species. However, he only listed one species under the genus so this
species is regarded as the type species by monotypy.
The specimen or specimens used by
the author for the description accompanying a species group name is/are regarded
as the type specimen(s). The author usually labels the specimen as a type but
this is not always the case and one has to compare the label of the specimen
with the collection information accompanying the description to assess whether a
specimen is a type or not. There are a number of different terms used for type
specimens and some of these are listed below.
If the existing type of a species
is useless for distinguishing the species (making the name a nomen dubium),
an author can ask the Commission to allow him/her to designate a neotype
The different sorts of names for animals
General purpose names that are not proposed for zoological nomenclature. An
organism can have any number of vernacular names in any number of languages.
However, scientists of different nationalities need to be able to refer to the
same taxon using a single name so as to avoid ambiguity. This is one of the main
reasons why we have scientific names, governed by a code of rules.
Latin or latinized names for organisms. They can be derived from any language
but must be converted to a latin form using latin letters (but including the
letters "j", "k", "w" and "y"). A
species scientific name consists of two components (ie a binomen), the genus
name and the species name. A subspecies scientific name consists of three
components (ie a trinomen), the genus name, the species name and the subspecies
name. All other names above the species level (eg Families) consist of one name.
Available names (=
validly published names in Bot. code). When a name is proposed and it
meets the criteria of availability, it is added to the pool of names that are
available for use. The main criteria for availability are as follows.
The name must have been validly
published (see below) after 1757.
It must be spelled in latin
The Principle of binomial
nomenclature must have been used consistently in the publication.
It must be accompanied by
a description of the taxon or by a reference to a description of
the taxon. Names published before 1930 are more lenient on this point -
one of the following ‘indications’ is enough to replace the
description: in family group names, the genus name from which the family
name is formed (e.g. Formica for Formicidae) indicates what the
family looks like; in genus group names, referring to a species within
the genus is sufficient. Even an illustration or a reference to an
illustration is regarded as an adequate indication to what the taxon
looks like. After 1930 the Code does not allow these indications and in
addition it demands that a type species (see later) be proposed for each
new genus name.
Available names are either valid
Unavailable names. Scientific
names that do not fit the criteria of availability (see above). An unavailable
name is known as a Nomen nudum.
According to the latest (4th
edition) of the Code, an author should not displace a name that has been
regularly used as valid (by at least 10 authors in 25 publications during the
past 50 years covering at least 10 years) by an earlier synonym or homonym which
has not been used as valid since 1899.
The Principles of zoological nomenclature
There are six principles stated in the Code of
Zoological Nomenclature. Most of these have already been implied earlier in this
handout but they are all included here for completeness.
Principle of binomial nomenclature.
"The scientific name of a species, and not of a taxon of any other rank, is
a combination of two names (a binomen), the first being the generic name and the
second the specific name. The principle applies to the names of species, and the
fact that family-group and genus-group names are uninomial and subspecies names
trinomial is not inconsistent with the principle."
Principle of name-bearing types.
"The principle that each nominal taxon has, actually or potentially, its
name-bearing type that provides the objective standard of reference by which the
application of the name is determined."
Principle of priority.
"The principle that the valid name of a taxon is the oldest name applied to
it, provided that the name is not invalidated by any provision of the Code or by
any ruling by the Commission."
Principle of coordination.
"The principle that within the family group, or the genus group, or the
species group, a name established for a taxon at any rank in the group is deemed
to be simultaneously established with the same author and date for taxa based on
the same name-bearing type at other ranks in the group."
Principle of homonymy.
"The principle that an available name that is a junior homonym of another
available name must not be used as a valid name."
Principle of the first reviser.
"The principle that the relative precedence of two or more names or
nomenclatural acts published on the same date, or of different original
spellings of the same name, is determined by the first reviser."
The process of naming a new species
- Allocate the species to a particular genus eg.
- Give it a latinized species name eg capensis
that is not a homonym of some previous name.
- Describe the species from the type(s). After
1999, this species account must include information on the collection where
the type is or will be deposited.
- Publish these details. By printing multiple
identical copies of your paper and making them obtainable to those who are
interested, you are producing a valid publication. However, it is strongly
recommended in the Code that the work is published by conventional means and
that you do not publish by photocopying, microfiche or some other
ill-defined process. In other words it is best to publish new scientific
names or nomenclatural acts in books or scientific journals. Read-only cd's
are now (after 1999) also acceptable provided they are distributed widely
and deposited in at least 5 major publicly accessible libraries. The date of
publication, very important because of the Principle of Priority, is the
date on which the work is first distributed to the public, which does not
always correlate with the date given in the publication.
- After 1999, the new name in the publication
must have some wording after it to explicitly indicate that it is new e.g.