Sea pen
| Sea pen Temporal range: | |
|---|---|
| "Pennatulida" from Ernst Haeckel's Kunstformen der Natur, 1904 | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Subphylum: | Anthozoa |
| Class: | Octocorallia |
| Superfamily: | Pennatuloidea Ehrenberg, 1834 |
| Families | |
|
see text | |
Sea pens are marine cnidarians belonging to the superfamily Pennatuloidea, which are colony-forming benthic filter feeders within the order Scleralcyonacea. There are 14 families within the order and 35 extant genera, and it is estimated as of 2011 that, of 450 described species, around 200 are valid.
Sea pens have a cosmopolitan distribution, being found in tropical and temperate waters worldwide, from intertidal shallow waters to deep seas of more than 6,100 m (20,000 ft).
The earliest accepted sea pen fossils are known from the Cambrian-aged Burgess Shale (Thaumaptilon). Similar fossils from the Ediacaran may show the dawn of sea pens. Precisely what these early fossils are, however, is not decided.