The FishesSIO and DFL

Scientific Names - Genus and Species

Each species of living thing has a unique two-part name. That name is the official scientific name for a unique species. Because of its two parts, this name is also called a binomial name. The name must include both parts in order to designate a particular species. The binomial name is a recognized around the world, regardless of language. Unlike common names, there is only one name per species and there is no ambiguity.


Both parts of the two-part names are printed in italics. In hand-written or older manuscripts produced on a typewriter, underlining under each of the two words is equivalent. The name is always “latinized” although the roots of the name need not be in Latin.


Electrolux addisoni The newly discovered and named Ornate Sleeper Ray, Electrolux addisoni. The genus is named after it’s brilliant powers of electricity generation and it’s ability to sweep the ground. The species is named after the person who collected the holotype, Mark Addison. Photograph courtesy photographer Phil Heemstra.

Genus species Common name
Somniousus microcephalus Greenland Shark
Somniousus pacificus Pacific Sleeper Shark
Microstomus pacificus Dover Sole
Electrolux addisoni Ornate Sleeper Ray
Homo sapiens Humans

The genus part of the name is either an established or newly established phylogenetic group that may include one or more species, i.e you don’t get to decide the genus name unless you’re the one who discovers and first descrbes the new genus.


In the example, we refer to two kinds of the sleeper sharks – Somniosus pacificus, the Pacific Sleeper Shark and Somniosus microcephalus, the Greenland Shark. Sometimes it’s difficult to locate still valid yet older references about a particular organism because the scientific name has changed. As our understanding of phylogenetic relationships improve, there is an official process by which misnomers are corrected. It usually takes an expert to be familiar with all the archaic scientific names.


The species part of the name is selected by the person who first discovers and describes an organism. While the genus part of the name tends to be unique, species names may often be used with other genus names. For example, in plants, many herbs used for pharmaceutical purposes were name with the species officinalis, for example: Rosmarinus officinalis for rosemary, and Calendula officinalis, for a kind of marigold. Sometimes you may come across a reference to one or more species within a genus shown as Felis sp.or Felis spp.


More about Genus and Species:

  • Wikipedia: Genus
  • Wikipedia: Species
  • What’s a Greenland Shark?
  • What’s a Pacific Sleeper Shark? Link TBA
  • Electrolux addisoni