''Cephalodiscus planitectus'' is a
sessile
Sessility, or sessile, may refer to:
* Sessility (motility), organisms which are not able to move about
* Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant
* Sessility (medicine), tumors and polyps that ...
hemichordate
Hemichordata is a phylum which consists of triploblastic, enterocoelomate, and bilaterally symmetrical marine deuterostome animals, generally considered the sister group of the echinoderms. They appear in the Lower or Middle Cambrian and include ...
belonging to the order
Cephalodiscida.
Distribution
It is found at a depth of 100–300 metres off the island of
Jōgashima
is an island in the municipality of Miura, Kanagawa Prefecture, Japan, off the southernmost and western tip of Miura Peninsula, facing Sagami Bay.
It is home to the Jōgashima Lighthouse, the fourth oldest western style lighthouse to be built ...
,
Sagami Bay
lies south of Kanagawa Prefecture in Honshu, central Japan, contained within the scope of the Miura Peninsula, in Kanagawa, to the east, the Izu Peninsula, in Shizuoka Prefecture, to the west, and the Shōnan coastline to the north, while the ...
, Japan.
Anatomy
There are three pairs of arms with tentacles.
Phylogenetics
''Cephalodiscus planitectus'' is the most divergent of all ''
Cephalodiscus
''Cephalodiscus'' is a genus of hemichordates in the monotypic family Cephalodiscidae of the order Cephalodiscida.
Description
Unlike ''Rhabdopleura'', ''Cephalodiscus'' species do not form large colonies and are only pseudocolonial. ''Cephalod ...
'' species, with Miyamoto, Nishikawa and Namikawa (2020) suggesting that it constitutes a
sister group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and t ...
to all existing ''Cephalodiscus'' species.
References
planitectus
Animals described in 2020
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