Filozoa

For an explanation of very similar terms, see Holozoa.

Filozoans
Orange elephant ear sponge, Agelas clathrodes, in foreground. Two corals in the background: a sea fan, Iciligorgia schrammi, and a sea rod, Plexaurella nutans.
Scientific classification
(unranked):	Holozoa
(unranked):	Filozoa Shalchian-Tabrizi et al., 2008
Subgroups
Filasterea Choanoflagellatea Metazoa

The Filozoa are a monophyletic grouping within the Opisthokonta. They include animals and their nearest unicellular relatives (those organisms which are more closely related to animals than to fungi or Mesomycetozoa).

Three groups are currently assigned to the clade Filozoa:

• Group Filasterea - recently erected to house the genera Ministeria and Capsaspora
• Group Choanoflagellatea - collared flagellates
• Kingdom Animalia or Metazoa - the animals proper

Etymology

From Latin filum meaning "thread" and Greek zōion meaning "animal".

Cladogram

The most up to date cladogram is

Opisthokonta	Holomycota Fungi Discicristoidea Nucleariida Fonticulida Holozoa Teretosporea Mesomycetozoa Corallochytrium Filozoa Filasterea Choanoflagellatea Animalia

Characteristics

The ancestral opisthokont cell is assumed to have possessed slender filose (thread-like) projections or 'tentacles'. In some opisthokonts (Mesomycetozoa and Corallochytrium) these were lost. They are retained in Filozoa, where they are simple and non-tapering, with a rigid core of actin bundles (contrasting with the flexible, tapering and branched filopodia of nucleariids and the branched rhizoids and hyphae of fungi). In choanoflagellates and in the most primitive animals, namely sponges, they aggregate into a filter-feeding collar around the cilium or flagellum; this is thought to be an inheritance from their most recent common filozoan ancestor.