Johann Friedrich Gmelin in the context of "Entomologist"

Systema Naturae (originally in Latin written Systema Naturæ with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomenclature, was partially developed by the Bauhin brothers, Gaspard and Johann, Linnaeus was the first to use it consistently throughout his book. The first edition was published in 1735. The full title of the 10th edition (1758), which was the most important one, was Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, which appeared in English in 1806 with the title: "A General System of Nature, Through the Three Grand Kingdoms of Animals, Vegetables, and Minerals, Systematically Divided Into their Several Classes, Orders, Genera, Species, and Varieties, with their Habitations, Manners, Economy, Structure and Peculiarities".

The tenth edition of this book (1758), published in Stockholm, is considered the starting point of zoological nomenclature. In 1766–1768 Linnaeus published the much enhanced 12th edition, the last under his authorship. Another again enhanced work in the same style titled "Systema Naturae" was published by Johann Friedrich Gmelin between 1788 and 1793. Since at least the early 20th century, zoologists have commonly recognized this as the last edition belonging to this series.

The Mammalia in the 10th edition of Systema Naturae forms one of six classes of animals in Carl Linnaeus's tenth reformed edition written in Latin.The following explanations are based on William Turton's translations who rearranged and corrected earlier editions published by Johann Friedrich Gmelin, Johan Christian Fabricius and Carl Ludwig Willdenow:

Linnaeus divided the mammals based on the number, situation, and structure of their teeth; mammals have the following characteristics: