''Pentremites'' is an extinct
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
blastoid
Blastoids (class Blastoidea) are an extinct type of stemmed echinoderm, often referred to as sea buds. They first appear, along with many other echinoderm classes, in the Ordovician period, and reached their greatest diversity in the Mississi ...
echinoderm
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the s ...
belonging to the family
Pentremitidae.
[
]
Description
These stalked echinoderms averaged a height of about but occasionally ranged up to about 3 times that size. They, like other blastoids, superficially resemble their distant relatives, the crinoids or ''sea lilies'', having a near-identical, planktivorous
A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton. Planktivorous organisms encompass a range of some of the planet's smallest to largest multicellular animals in both the present day and i ...
lifestyle living on the sea floor attached by a stalk. As with all other blastoids, species of ''Pentremites'' trapped food floating in the currents by means of tentacle-like appendages.Museum of Victoria
/ref>
''Pentremites'' species lived in the early to middle Carboniferous, from 360.7 to 314.6 Ma. Its fossil
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 ...
s are known from North America.[
]
References
* ''Fossils'' (Smithsonian Handbooks) by David Ward (Page 190)
Blastozoa genera
Carboniferous echinoderms of North America
Fossils of Georgia (U.S. state)
Paleozoic life of Alberta
Paleozoic life of the Northwest Territories
Paleozoic life of Yukon
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