How to Write Scientific Names of Animals
Scientific names must be printed or written in certain ways to reduce misunderstandings
among scientists working in different countries, subdisciplines or time
periods. The many rules seem very picky to lay people, but as biologists
and zoologists, you must learn to write and use scientific names properly
and understand at least some of the jargon of biological nomenclature.
In ZO 150, points are deducted from lab practical answers, discussion
question answers, and genus reports if names are not printed or written
and used correctly. Refer to this short guide every time you come
across a scientific name in lecture notes or the text, and see how the
rules are applied in those examples until you learn to use them properly
yourself. Correct your notes, labels of drawings, etc. as necessary
when you do them, rather than allowing bad habits to develop.
Official, scientific names are designated for each taxon (the plural
is taxa) of animals, just as they are for all living organisms.
Taxonomic names are arranged into a hierarchy with an indefinite number
A taxon is a group of organisms defined by particular reproductive,
anatomical, or genetically determined similarities.
Each taxon is named. Names are almost always unique, but sometimes
the same name will be used inadvertently for both plant and animal orders,
or for two, very distantly related animal families.
The basic taxonomic levels are domain, kingdom, phylum, class,
order, family and species binomial (genus + specific epithet).
Intermediate levels are indicated by a wide variety of prefixes.
Scientific names for taxonomic levels above genus are always capitalized
but not italicized (nor underlined when handwritten).
Examples: subkingdom, subphylum, infraclass, superfamily.
Some hierarchies include a level between sub- or infra-family and genus,
The scientific name for a taxon of organisms is exactly the same in all
languages and places.
Example: the scientific order name of lemurs, monkeys, apes and humans,
Common names are not officially defined, and the common name of a single
species of animal may differ between languages, regions, or even ethnic
groups of people in a single community. Also, many animals in different
species may share the same common name.
Common names are generally not capitalized (except as required grammatically).
Scientific names are often "anglicized" by changing their endings to English
format. Anglicized names are treated as common names and should not
Examples: tiger shark, timber wolf, daisy, puffball fungus
Exception: parts of the common names for some animals are capitalized because
they are based on a place or person's name.
Examples: Chordata becomes chordates, Hominidae becomes hominids, Eukarya
In rare cases, the scientific name for genus and the common name for an
organism are the same.
When one of these identical-common-name-genus-name cases is intended to
apply to a particular genus, it should be capitalized and italicized.
Examples: Kirtland's warbler, Carolina wren
But when it is referring to a less specifically identified animal with
a body form that might belong to any of several particular genera, it should
be written lower case and not italicized
Example: animals with a hydra-like body form may be in any of these genera
Hydra, Chlorohydra or Pelmatohydra. When the particular
genus is not identified, the name should be written lower case and not
italicized -- hydra.
The term species (plural: species) in proper scientific usage means
a defined taxon of organisms within a particular genus.
A species includes all individuals, and only those individuals, that
are capable of interbreeding.
For a particular species name to be valid, it must be assigned in a refereed
More exactly, there should be at least a small probability that the genes
of any two individuals belonging to the same species can eventually, over
many generations, be mingled in the genome of a single, common descendant,
and that this will happen without human intervention or disturbance of
normal environments or habitats. In other words, there should be
no geographical, anatomical or other absolute physical barriers that completely
isolate any group of individuals from all other such groups of the same
Further, the offspring of any two individuals in a species (assuming they
are of opposite sexes, or hermaphroditic), must be fertile and capable
of interbreeding with other members of that species.
Special problems in defining species arise for animals which reproduce
exclusively by parthenogenesis or simpler, asexual means, so that their
ability to interbreed cannot be tested.
There are no absolute standards for the amount of genetic or morphological
difference that must exist between two individuals to put them in separate
species. Nevertheless, nearly all animal species are defined by their
morphology. Interbreeding limits have been fully tested in only a
tiny percentage of named species.
The meaning of the name must also be documented by one or more type
specimens of the species that are given to a recognized museum for curation.
The type specimens must be made available to any credentialed scientist
who wishes to verify or enhance the original description, or compare the
original type specimens with other specimens of the same or related species.
The article in which the name is assigned must include a sufficient description
of the organism to which it applies, and be published in one of a short
list of accepted languages.
The name of a species must always have two parts: a genus (plural:
genera) name, and a specific epithet.
Example: Our specific epithet "sapiens" should never be written by itself,
but always as Homo sapiens or H. sapiens.
The genus name must be unique, that is, never applied to any other
type of organism.
The specific epithet does not have to be unique, and many species have
the same or similar specific epithets.
Examples: Anolis carolinensis , Gastrophryne carolinensis, Terrapene
carolina, Lissodendoryx carolinensis, Polymesoda caroliniana.
Notice in the examples that the ending of the epithet is changed to agree
with the gender of the genus name.
The genus name is always capitalized and italicized (or underlined
The specific epithet is not capitalized, even when it is based on
an otherwise capitalized place name.
Example: correct - Homo. INCORRECT - homo or Homo
The same is also true for epithets based on people's names
Examples: epithets based on "Carolina" above.
(However, plant names based on people or places are capitalized
The full species name may, but does not have to, include subspecies or
variety names following the specific epithet. When used for animals,
these additional names must also be italicized (or underlined) and not
Example: Hyla andersoni, named after a Mr. or Ms. Anderson
The genus name may be abbreviated to its first letter after it has been
printed in full earlier in the same document. The capital letter
abbreviating the genus is still italicized.
However, if another species name with a genus name that starts with "h"
is used in the same document, both genus names must be written in full
wherever they occur.
Example: After using Homo sapiens in a document, one may refer to
it throughout the rest of the document as H. sapiens.
Example If Hirudo medicinalis is mentioned together with Homo
sapiens, neither Homo nor Hirudo should be abbreviated
when they occur again in the same document.
The species binomial, when used properly and in a scientific publication,
should have with it the last name(s) of the describing author(s).
The describing author(s) is (are) the scientist (or scientists)
who assigns a name for the first time, and meets the other requirements
for establishing the official name for that kind of animal.
The earliest version of rules for establishing species names was
proposed by Karl Linne', a Swedish naturalist in the 18th century, who
then proceeded to publish official descriptions of hundreds, perhaps even
thousands, of species.
Linne' latinized his name to Carolus Linnaeus. Linnaeus, sometimes
abbreviated L., is given as describing author with many of the most common
species of plants and animals, including ours, Homo sapiens Linnaeus.
Notice that the describing author's name is capitalized but not italicized.
When the describing author's name is printed inside parentheses, it
means that the original description of the species was assigned to a different
genus than the one in which it is now classified.
Genera are continually being revised (taxonomically reorganized), and often
broken up into more narrowly defined, new genera which must be given new
Example: Chironomus plumosus (L.). Linnaeus originally described
this midge fly species as a member of Tipula , a genus which has
subsequently been broken up into many new genera belonging to several different
families of flies.
Maintained by Sam Mozley, email@example.com
Last modified on May 21, 2002