AskDefine | Define infauna

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  1. A fauna, the life sites of whose members are within the dominant medium of their environment, e.g. burrowing bivalves that filter-feed from within seafloor sediments.

Derived terms


Extensive Definition

Fauna is all of the animal life of any particular region or time. The corresponding term for plants is flora.
Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna".
Paleontologists sometimes refer to a sequence of faunal stages, which is a series of rocks all containing similar fossils.
The name comes from Fauna, a Roman fertility and earth goddess, the Roman god Faunus, and the related forest spirits called Fauns. All three words are cognates of the name of the Greek god Pan, and panis is the Greek equivalent of fauna. Fauna is also the word for a book that catalogues the animals in such a manner. The term was first used by Linnaeus in the title of his 1747 work Fauna Suecica.

Subdivisions of fauna


Epifauna are animals that live upon the surface of sediments or soils.


Infauna are aquatic animals that live within the bottom substratum rather than on its surface. Bacteria and microalgae may also live in the interstices of bottom sediments. On average, infaunal animals become progressively rarer with increasing water depth and distance from shore, whereas bacteria show more constancy in abundance, tending toward one billion cells per milliliter of interstitial seawater. (Infauna are benthos that live buried in underwater mud.)


Macrofauna are benthic or soil organisms which are at least one millimeter in length.


Megafauna are large animals of any particular region or time. For example, Australian megafauna.


Meiofauna are small benthic invertebrates that live in both marine and fresh water environments. The term Meiofauna loosely defines a group of organisms by their size, larger than microfauna but smaller than macrofauna, rather than a taxonomic grouping. In practice these are organisms that can pass through a 1 mm mesh but will be retained by a 45 μm mesh, but the exact dimensions will vary from researcher to researcher. Whether an organism will pass through a 1 mm mesh will also depend upon whether it is alive or dead at the time of sorting.


Mesofauna are macroscopic soil invertebrates such as arthropods, earthworms, and nematodes.


Microfauna are microscopic or very small animals (usually including protozoans and very small animals such as rotifers).


Other terms include avifauna, which means "bird fauna" and piscifauna (or ichthyofauna), which means "fish fauna".

Fauna treatises

Classic faunas

infauna in Breton: Fauna
infauna in Catalan: Fauna
infauna in Czech: Fauna
infauna in Danish: Fauna
infauna in German: Fauna
infauna in Estonian: Loomastik
infauna in Modern Greek (1453-): Πανίδα
infauna in Spanish: Fauna
infauna in Esperanto: Faŭno
infauna in French: Faune (biologie)
infauna in Croatian: Fauna (životinje)
infauna in Indonesian: Fauna
infauna in Italian: Fauna
infauna in Hebrew: פאונה
infauna in Luxembourgish: Déierewelt
infauna in Malay (macrolanguage): Fauna
infauna in Dutch: Fauna (dierenleven)
infauna in Japanese: 動物相
infauna in Norwegian: Fauna
infauna in Occitan (post 1500): Fauna (biologia)
infauna in Polish: Fauna
infauna in Portuguese: Fauna
infauna in Romanian: Faună
infauna in Simple English: Animalia
infauna in Slovak: Fauna
infauna in Swedish: Fauna
infauna in Turkish: Fauna
infauna in Chinese: 動物相
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