Species, Variety, Breed — Is There a Difference?
Species Names.
As people explored new continents, the number of species began to increase dramatically. Something had to be done about this diversity. There was no single approach to solving the problem. At the beginning of the 18th century, every scientist named newly discovered species and renamed long-known ones in their own way. Such confusion suited no one, and the Swedish naturalist Carl Linnaeus proposed to bring order in the following way. First of all, he defined the species, which became the main unit of classification for animals and plants. Linnaeus proposed grouping related species into genera.
To ensure uniformity, the scientist proposed assigning scientific names to species consisting of two Latin words, the first of which means the genus to which the animal belongs, and the second — the species in the strict sense of the word. For example, one of the popular aquarium fish bears the scientific name Barbus nigrofasciatus (black ruby barb). This means that in the genus Barbus there is a species nigrofasciatus. The word Barbus translates as “barbel”. Such a scientific name is used by all authors who want readers to easily understand which particular barb is being discussed and not confuse it with other species of fish.
Please note that the first word in a scientific name is always written with a capital letter, and the second – always with a lowercase letter. This applies even to cases where a species is named in someone’s honor. For example, Axelrod’s rainbowfish (Melanotaenia herbertaxelrodi) immortalized the name of Herbert Axelrod, a well-known American aquarist, author, and publisher of books dedicated to pets.
Linnaeus published his proposals in the book “Systema Naturae” (“System of Nature”), published in 1758. In it, the naturalist also provided the first scientific names of animals and plants known to him, including 418 species of fish. Over the years, ichthyologists have described many other species.
In addition to scientific names, common names also exist. Naturally, they arose only in those languages spoken by people living in the habitats of a particular species. Thus, the freshwater fish Esox lucius is called pike in English, Hecht in German, and shchuka in Russian. Some aquarium inhabitants have common names in the languages of ethnic groups that frequently encounter them in nature, such as “piranha”, “arowana”, “pacu”. These words migrated into European languages. However, most tropical fish had no common names by the time of their first description; they were coined by aquarists. These include the guppy, named after Bishop Guppy, and the mollie, which immortalized the name of the French minister Moullinet (embroidery threads share the same name). Common names also include “swordtail”, “angelfish”, “jewel cichlid” due to the fact that any animal and plant names that are not scientific are considered common. Very often, the common name of a rare animal is written with a capital letter. This is incorrect, as no one would write “Domestic Cow”, and the fact that a species is currently little known does not change the situation. Believe me, from a grammatical point of view, there is no difference between the phrases “domestic cow” and “three-lined rainbowfish”.
The right to assign a scientific name to a species belongs to the scientist who first describes that species. To ensure that information about the author is not lost, their surname and the year of publication of the article are indicated after the scientific name of the fish. Following the species and subspecies name comes the name of the author who described it and, separated by a comma, a number – the year of the original description. If the surname of the original describer and the year are in parentheses, it means that, according to the original description, the specified species was previously described as belonging to another genus. Example: Pterophyllum scalare (Lichtenstein, 1823). Pterophyllum (genus) scalare (species) (Lichtenstein – name of the original describer, 1823 – year of description) – in parentheses because originally, in 1823, Lichtenstein classified these fish, familiar to every aquarist today, in the genus Zeus and in the literature of those years they were mentioned as Zeus scalaris Lichtenstein, 1823.
Scientific names of subspecies consist of three words: the subspecies name is added to the species designation. For example, the splendid rainbowfish consists of four subspecies: Melanotaenia splendida splendida, Melanotaenia splendida inornata, Melanotaenia splendida tatei, Melanotaenia splendida australis. Pay attention to the first name in this list. It indicates the nominotypical subspecies — Melanotaenia splendida splendida. Thus, when referring to the splendid rainbowfish as a species as a whole, the name Melanotaenia splendida is used, and when speaking of its nominotypical subspecies, the term Melanotaenia splendida splendida is used. The subspecies name in this case duplicates the species name.
Aquarists often get ahead of ichthyologists by bringing in fish that do not yet have a scientific description. What is done in such cases? Usually, animals are given temporary designations, and it should be remembered that these designations have nothing to do with scientific names, they are not subject to special nomenclature rules, and therefore should not be taken too seriously. Some of them will later be described as independent units, while other names will be forgotten because they were assigned, for example, to varieties of the same species. To distinguish such names from scientific ones, the abbreviation sp. (from the Latin word species – “species”) is inserted into them, signaling that an unnamed fish is being discussed. For example, Lake Malawi is home to many species that have not yet received scientific descriptions, so when exporting them for the aquarium trade, names like Pseudotropheus sp. aggressive; P. sp. elongatus ornatus; P. sp. elongatus reef4; P. sp. variable are used. Temporary designations for subspecies are accompanied by the abbreviation ssp. (from subspecies).
Let me briefly remind beginner hobbyists about the designations adopted for scientific descriptions of fish that follow the genus name:
sp. or spec. – the species has not yet been determined;
sp. aff. – allied or similar species; usually used to designate a new, yet undetermined species of fish, but morphologically very similar to one of those already described;
cf. – most likely this is the species whose name follows these two letters;
ssp. – subspecies;
var. – local or geographical variation for which there is no separate scientific name;
hybride – hybrid;
intergrade – mixed population of two subspecies.
Thus, Symphysodon aequifasciatus axelrodi is a fish belonging to the genus Symphysodon, species aequifasciatus, and subspecies axelrodi. And Pseudotropheus sp. “Elongatus Boadzuiu” translates as a fish from the genus Pseudotropheus, of a yet undetermined species, but belonging to the “elongatus” group, a local form from Boadzulu Island.
Latin names are not difficult to read because in this language, unlike English and French, all letters correspond to simple sounds. To verify this, remember your geometry lessons: a—[a], b—[b], c—[ts/k], d—[d]… There are only a few letter combinations that produce a new sound, for example: ph—[f], ch—[kh], ae—[e], oe—[o]. The letter h after t, r, k is ignored in pronunciation. Most problems arise with the Latin letter c: in some cases before i and y it is read as [ts], and in others — as [k]:
System of Nature.
However, simply being able to distinguish species and assign names to them is not enough; it is important not to get confused by them. People have always marveled at the diversity of wildlife. To date, over one and a half million species of animals are known, and perhaps at least another million remain without a scientific description. At the same time, one is struck by the similarity of individuals that are clearly not closely related and even inhabit different continents.
In reality, it is much more important to trace speciation in nature. As you recall, Linnaeus proposed grouping closely related species into genera. Similar genera, in turn, he grouped into larger units — orders and classes. Thus, the natural system of living nature was formed, the description of which the naturalist presented in the book “Systema Naturae”. Later, the concept of family was introduced between the categories of genus and order, and intermediate units, such as subfamilies, superfamilies, suborders, etc., were proposed for the convenience of grouping by similar traits.
The hierarchy of taxa in which the black ruby barb is included looks like this: Order Cypriniformes ⇒ Family Cyprinidae ⇒ Genus Barbus ⇒ Species nigrofasciatus.
Species, genera, families, orders, and other classification units are generally called taxa. They also have scientific Latin names, each of which has a specific ending. For example, all order names end in – iformes, and family names in – idae. The root of the word is usually taken from the generic name of the oldest known genus in the corresponding group. For example, the genus Barbus is part of the carp family (Cyprinidae), which gets its name from the genus Cyprinus, described by Linnaeus.
The branch of biology that deals with the study of a species and its position relative to other species is called systematics. In turn, its branch dedicated to investigating and refining the hierarchy of all species is called taxonomy, and the rules for assigning scientific names and dealing with them — nomenclature. These terms are worth remembering if you want to engage in a dialogue with other aquarists about hundreds of different fish species.
In the system proposed by Linnaeus, the names themselves suggest how certain taxa are positioned relative to others. It should be mentioned that most of them contain several lower-ranking taxa, while some include only one. For example, the carp family includes hundreds of genera, while the genus Cyprinus contains ⇒ one species ⇒ common carp (Cyprinus carpio). Taxa containing only a single unit in their composition are called monotypic.
What are Aquarium Fishes? Fish Anatomy and External Structure.
Fish Taxonomy. Biological Nomenclature. 
