''Antedon'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of free-swimming, stemless

crinoids Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which ar ...

. The genus first appeared in the

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

in the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

period.

Characteristics

Members of this genus have no stems but have five pairs of feathery arms arising from a central concave disc. There are a number of

cirri Giovanni Battista Cirri (1 October 1724 – 11 June 1808) was an Italian cellist and composer in the 18th century. Biography Cirri was born in Forlì in the Emilia-Romagna Region of Italy. He had his first musical training with his brother ...

or unbranched appendages on a low, cone-shaped dorsal ossicle, a bone-like structure in the centre of the disc. The mouth and the ambulacral grooves are also on the upper surface. Clawed cirri on the lower surface provide temporary attachment to the substrate. There is great variability in the morphological features in Antedonids found in different habitats and the main distinguishing feature among the

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

is the number of cirri.

Species

The following species are recognised in the World Register of Marine Species: *'' Antedon arabica'' AH Clark & AM Clark *'' Antedon bifida'' (Pennant, 1777) *'' Antedon duebeni'' Böhlsche, 1866 *'' Antedon mediterranea'' (Lamarck, 1816) *'' Antedon nuttingi'' (AH Clark, 1936) *'' Antedon parviflora'' (AH Clark, 1912) *'' Antedon petasus'' (Düben & Koren, 1846)

References

{{Taxonbar, from=Q2852647 Antedonidae