A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are related. The species description also contains photographs or other illustrations of the type material and explains in which museums the holotype (and other types such as paratypes) have been deposited. The publication in which the species is described gives the new species a formal scientific name. Today, some 1.9 million species have been discovered and named and some 8.7 million may actually exist on Earth.
It is customary for scientists to introduce all relevant new findings and research in a scientific paper, which is scrutinised by other scientists (peer review) and, if accepted, published in a scientific journal of the appropriate discipline; this applies to the discovery and naming of a new species or other taxon. In many cases the scientific community will not formally accept the existence of a new species until a species description has been published, even when it may seem obvious that the species is indeed new.
History of species descriptions
Early biologists often published entire volumes or multiple-volume works of descriptions in an attempt to catalog all known species. These catalogs typically featured extensive descriptions of each species and were often illustrated upon reprinting.
The first of these large catalogs was Aristotle's History of Animals, published around 343 B.C. Aristotle included descriptions of creatures, mostly fish and invertebrates, in his homeland, and several mythological creatures rumored to live in far-away lands, such as the manticore.
In 77 A.D. Pliny the Elder dedicated several volumes of his Natural History to the description of all life forms he knew to exist. He appears to have read Aristotle's work, since he writes about many of the same far-away mythological creatures.
Toward the end of the 12th century, Konungs skuggsjá, an Old Norse philosophical didactic work, featured several descriptions of the whales, seals, and monsters of the Icelandic seas. These descriptions were brief and often erroneous, and a description of the mermaid and a rare island-like sea monster called Hafgufu was included. The author was hesitant to mention the beast (known today to be fictitious) for fear of its size, but felt it was important enough to be included in his descriptions.
As the catalog of known species was increasing rapidly, it became impractical to maintain a single work documenting every species. Publishing a paper documenting a single species was much faster and could be done by scientists with less broadened scopes of study. For example, a scientist who discovered a new species of insect would not need to understand plants, or frogs, or even insects which did not resemble the species; he would only need to understand closely related insects.
Modern species descriptions
Formal species descriptions today follow strict guidelines set forth by the Codes of nomenclature. Very detailed formal descriptions are made by scientists, who usually study the organism closely for a considerable time. These descriptions must specify the distinction between the new taxon and other taxa, and provide a name for it.
Rates of species description
According to the RetroSOS report, the following numbers of species have been described each year since 2000.
Year Total number of species descriptions New insect species described 2000 17,045 8,241 2001 17,003 7,775 2002 16,990 8,723 2003 17,357 8,844 2004 17,381 9,127 2005 16,424 8,485 2006 17,659 8,994 2007 18,689 9,651 2008 18,531 9,020 2009 19,232 9,738
- Mora, C. et al. (August 23, 2011). "How Many Species Are There on Earth and in the Ocean?". PLoS Biology.
- Aristotle (343 B.C.). History of Animals.
- Pliny the Elder (77). Natural History.
- Konungs skuggsjá. (Norwegian)
- Linnaeus, C. (1735). Systema Naturae.
- Quentin Wheeler; Sara Pennak (January 18, 2012). Retro SOS 2000-2009: A Decade of Species Discovery in Review (Report). International Institute for Species Exploration, Arizona State University. http://species.asu.edu/SOS. Retrieved April 25, 2013.
- Winston, Judith E. 1999. Describing Species: Practical Taxonomic Procedure For Biologists. Columbia University Press. ISBN 0-231-06824-7