Incertae sedis

Incertae sedis (Latin for "of uncertain placement"), abbreviated "inc. sed.", is a term used to define a taxonomic group where its broader relationships are unknown or undefined.

Examples
The taxonomy for humans is usually recognized as follows:
 * Empire Neomura - along with all the living organisms, except eubacteria.
 * Domain Eukaryota - along with all other nucleated organisms.
 * Kingdom Animalia - along with all other animals
 * Phylum Chordata - along with all other vertebrates and the invertebrate chordates
 * Class Mammalia - along with all other mammals
 * Order Primates - along with all other primates
 * Superfamily Hominoidea - along with all other apes
 * Family Hominidae - along with all other great apes
 * Subfamily Homininae - along with gorillas and chimpanzees
 * Tribe Hominini - along with chimpanzees
 * Subtribe Hominina - along with Australopithecus and prehistoric humans
 * Genus Homo - along with Homo erectus and other prehistoric humans
 * Species H. sapiens - humans

If modern humans were newly discovered or considered to be a taxonomic enigma, they might be given the rank of incertae sedis. For example, if it were uncertain how Homo related to other members of the family Hominidae, a list of the great apes would look like this:


 * Kingdom Animalia
 * Phylum Chordata
 * Class Mammalia
 * Order Primates
 * Family Hominidae
 * Genus Homo incertae sedis
 * Subfamily Ponginae - orangutan
 * Subfamily Homininae - gorilla and chimpanzees

Likewise, if humans were known to be primates, but no other relationships were clear, a taxonomy of the primates would look like this:


 * Kingdom Animalia
 * Phylum Chordata
 * Class Mammalia
 * Order Primates
 * Genus Homo incertae sedis
 * Suborder Strepsirrhini - non-tarsier prosimians
 * Suborder Haplorrhini - tarsiers, monkeys and apes