Scientific Names
Official, scientific names are assigned to
each taxon
of organisms.
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A taxon (plural, taxa)
is a group of organisms that are, to some degree or level, anatomically
and (presumably) genetically similar.
-
Ideally, by modern standards, a taxon should be monophyletic, that is,
include the most recent common ancestor of all its members, as well as
all
descendants of that common ancestor. This is not true for many,
familiar
taxa, including Turbellaria and Crustacea.
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The standard of monophyly has caused much disruption in the use of
names
by zoologists, both in teaching and research.
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Taxa are arranged in a hierarchy of successively smaller and more
narrowly
defined groups.
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Examples of names of levels of taxa in this hierarchy are phylum,
order,
family, and species.
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Scientific names for higher taxonomic levels sometimes vary according
to
schools of thought.
-
When a scientist argues for a new name or newly recognized grouping,
some
of her or his colleagues will accept it and others will not.
-
But after a few decades of debate, biologists usually come to agreement
on the names that are used for higher taxa.
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Scientific names for taxonomic levels above genus are capitalized but
not
italicized
-
and not underlined when handwritten
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for example, Gastrotricha, Coleoptera, Gyraulidae
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Scientific names are said to be "anglicized" when the endings are
changed
to English format.
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Anglicized names should not be capitalized.
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For example, the phylum name Gastrotricha becomes "gastrotrich" when
anglicized,
Gyraulidae becomes "gyraulid," and Coleoptera becomes "coleopteran."
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Anglicized names are treated the same as common names (see below).
Species Names
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The term species means a taxon of organisms whose members are capable
of
interbreeding,
-
at least occasionally in nature
-
without human intervention or disturbance.
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The scientific name for a species of organism is the same in all
languages
and places.
- The name of a species (plural: species)
must always include both:
-
a genus (plural: genera)
name,
-
which is unique (never used for any other kind of organism outside this
genus),
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and a specific epithet.
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The specific epithet for the common stream crayfish, "bartoni," should
never be used alone, but always as Cambarus bartoni.
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The specific epithet does not have to be unique.
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Many species have the epithet "carolinensis," for example, Acroneuria
carolinensis (Banks).
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The epithet is treated like an adjective that modifies the genus name,
which itself is treated as a noun.
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Notice that the epithet "carolinensis" above is not capitalized, even
though
it is based on a capitalized place name.
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The same is true for specific epithets based on people's names (at
least
in zoology), such as Hydroporus blanchardi Sherman.
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The name "(Banks)" after the species name above is the describing
author.
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His name is in parentheses because he described and named the species
under
a different genus name, perhaps "Perla carolinensis."
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Later, someone changed the species into a new genus, but the epithet
and
describing author's name were retained.
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The author's name is supposed to be attached to the species name in
every
scientific publication the first time it is used, in the text or a
table,
but this rule is often ignored in non-taxonomic articles.
-
This does not apply to the genus author's name, which needs only to be
given in papers dealing mainly with taxonomy or systematics.
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The genus name is always capitalized AND italicized (or underlined, if
hand-written).
-
Helobdella or Helobdella,
not
helobdella or Helobdella
or
helobdella
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The full species name may, but does not have to, include subspecies or
variety epithets following the specific epithet.
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For example, Crangonyx richmondensis richmondensis Ellis
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These additional epithets are also italicized but not capitalized.
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The name after the subspecies name ("Ellis") is the describing author
of
the subspecies.
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Like the species author's name (which is not required if the subspecies
author is different), it should be capitalized but not italicized or
underlined.
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The genus name may be abbreviated to its first letter after it has been
given in full the first time it occurs in a document.
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After first using the full species name Skistodiaptomus reighardi (Marsh),
authors may refer to it as S. reighardi.
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However, if another species is named whose genus name starts with
"S",
the whole genus names should be used if there is any chance of
confusion.
-
For example if Spongilla lacustris (L.) is listed in the same
article
as
Skistodiaptomus reighardi, the author would have to
write out
both Spongilla and
Skistodiaptomus
in full every time they
occurred.
Describing a New Species, or Defining an
Existing
Species
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The rules and requirements for official species descriptions include:
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placing reference, "type" specimens in recognized museums or other
systematic
collections,
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publishing a full morphological description of adult life stages in a
refereed
scientific journal, in one of a few, widely used or classical languages.
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review and approval of the article before it is published by a panel of
peer scientists.
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The scientist (or scientists) who first does this, and thereby selects
the official name for the species, is called the describing author.
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That scientist's name follows the species name in taxonomic
publications.
-
for example, Chironomus plumosus (Linnaeus)
- Linnaeus's name is put in parentheses because he originally
described this
small midge under a different genus name, "Tipula plumosa Linnaeus"
-
Notice that, when the species was moved to a new genus, the ending of
the
specific epithet had to change to match the gender of the new genus
name, because
the epithet is treated like an adjective in Latin and must agreed with
the modified noun in gender.
- Some years after Linnaeus originally described Tipula
plumosa ,
Meigen split the very large genus Tipula into several new
families
and genera, including Chironomus.
- Linnaeus still gets credit as the describer of the species,
but now his
name is shown in parentheses.
- If the genus name has not changed since the species was
described, the
author's name is not put in parentheses.
-
For example, Sperchonopsis ecphyma Prasad and
Cook
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The earliest version of these rules was proposed by Karl Linne'.
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He was a Swedish naturalist in the late 18th century.
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He published the first official descriptions of thousands of species,
all
in Latin or Greek.
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He "latinized" his name to Carolus Linnaeus.
-
You will see the name Linnaeus, often abbreviated "L." because he was
so
well known, after many of the world's most common species of plants and
animals, including ours,
Homo sapiens L.
Common Names
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Common names are not officially defined.
-
The common name of the same animal may differ between languages,
regions,
or even within a single community.
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Field biologists have standardized at least the English common names of
some groups (e.g., fish, birds) for use in specialists' publications,
but
other scientists outside those societies are not obligated to follow
their
recommendations.
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Common names are generally not capitalized (except as required
grammatically).
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For example, mayfly, snail, flatworm, hellgrammite, crayfish, etc.
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However, ornithologists have determined that common names of birds are
standardized and should be capitalized in ornithological publicatons.
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In rare cases, the scientific name and common name for a genus are the
same.
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An example is "hydra."
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When the name is intended to apply to a particular genus of hydras, it
should be capitalized and italicized.
- When hydra is meant to refer to an unidentified animal with a
hydra-like
body form (possiblyHydra,
Chlorohydra,
Pelmatohydra,
etc.), it is written lower case and not italicized.
Maintained by Sam Mozley, s_mozley@ncsu.edu
Last modified on April 21, 2004