It is known that there are more than 5 million species on earth, of which humans know only a tiny part. The mollusks are one of the larger groups of animals. Only are exceeded in number by arthropods where insects are included. The number of living species of mollusks is estimated (somewhat risky in my opinion) between 80,000 and 150,000 besides getting to know some 35,000 fossil species. Taxonomy describes, classifies and gives an order to all living beings taking the "species" as the basic unit for the classification.
Most people have limited knowledge of the natural world and relate primarily with the species that influence their own lives. Beyond the range of common animals and plants it is usual that the names we give to the huge variety of beings end up soon. Biologists, however faced with the task of identifying, studying, and exchange information of the vast diversity of organisms. It is therefore reasonable to assume that these scientifics must have a uniform system that can give names to all these beings in order to group them together in a logical way. To develop this system is immensely complicated. The first problem appears with the basic unit of classification: the ''species''. It is already complicated dealing with this term. What is a species?. In latin means type, so in the simplest sense, the species are different types of organisms. In 1940 Ernst Mayr, Harvard University, gave a more rigorous definition: species are groups of natural populations that are actually or potentially reproducing with each other and have become isolated from other groups. The definition of Mayr agrees with common sense: if members of a species freely exchange genes with other members could no longer retain those unique characteristics that identify them as different types of organisms.
According to the binomial system of nomenclature developed by the Swedish naturalist Carlos Linnaeus in the eighteenth century and still in use, the scientific name of a being is comprised of two parts: the name of genus plus a specific epithet (adjective or modifier) The name of the genus always is written firstly, for example Cepaea, and the epithet after, for example nemoralis. Cepaea may be used only when one refers to the group members that constitute the whole genus, such as: Cepaea, Conus, Cypraea, Lymnaea ....... That designation is usually followed by a parenthesis which contains the name of the author that identified the species for the first time and the year of the identification, for example Cepaea nemoralis (Linné, 1758). As Linnaeus (or Linneo) was the one who designed the system and because he was the first to put it into practice, it´s natural that many of the species you see out there are just named by Linnaeus. Indeed, the scientific names are given in italics because of their Latin origin.
A specific epithet alone is meaningless because different species in different genus may have the same epithet. For example, the epithet reticulata refers to a reticulated pattern of the shell common in a lot of species of mollusks, as Diodora reticulata, Distorsio reticulata, Colubraria reticulata or Oliva reticulata. The epithet alone therefore doesn´t provide useful information.
Whoever describing a genus or species for the first time can have the privilege of giving his own name, but often receives the name of a friend or colleague. For example, the Andalusian snail Iberus cobosi referred to the malacologist A. Cobos, despite he was not its author.
The binomial nomenclature is a necessary tool to ensure a clear and unambiguous communication between people that handle these, whether or not biologists. When using different languages communication problems would be insurmountable without a system of universally recognized and accepted nomenclature.
The taxonomy of organisms is a hierarchical system which consists of groups within groups. In this system each group is called taxon and the level assigned to it is called category. At the time of Linnaeus 3 categories were accepted: species, genus and kingdom. Carlos Linneo and other taxonomists added other categories: families, orders, classes, and filum division. The naturalists recognized 3 kingdoms: plants, animals and minerals. Now we know that there are 5 kingdoms which are: Monera, Protista, Fungi (mushrooms), plant and animal. The key category in the hierarchical classification is the species.
Carlos Linneo ranked organisms according to their morphological characteristics. This classification system was called Linnaean system which is also the current system. Initially organisms were classified like labels each of which should go into his box so that when all these boxes were complete we would be able to understand the diversity of life. This system worked only if the species were static and immutable. However, when accepting that species evolve such classification seems inadequate.
That is why a systematic phylogenetic currently prevails. The phylogeny is the branch of biology that studies the evolution (history) of the species which is recognized in the genetic information of their cells. So now two species are not forthcoming in its systematic because its shapes are similar since it is necessary to verify their genetic kinship. Thanks to advances in genetic and biochemical techniques studies have been able to identify the similarities and differences between enzymes, proteins, hormones, routes and reactions in important structural molecules of cells in species that were considered close in their classification until now, obtaining surprising results that have sometimes even advised that they are very separate species in the evolution. Therefore, describing a new species without making the appropriate biochemical or genetic study is inconceivable nowadays and, of course, shells have been left as an exclusive tool of classification. That does not mean that we do not continue using the shell as an source of identification, sometimes indispensable.