Eccentrotheca is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of sclerite-bearing marine organism known from Cambrian

Cambrian

The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...

 deposits. Its sclerite

Sclerite

A sclerite is a hardened body part. The term is used in various branches of biology for various structures including hardened portions of sponges, but it is most commonly used for the hardened portions of arthropod exoskeletons....

 form rings that are stacked to produce a widening-upwards conical scleritome

Scleritome

The fossilized scleritome of [[Wiwaxia]] corrugata|thumbA scleritome is a skeleton made of isolated elements, like the scales of organisms such as the halwaxiids, the teeth in a radula,, spicules in a sponge skeleton, or the elements in a conodont apparatus. The term was coined by the...

. Individual plates have been homologized with the valves of brachiopod

Brachiopod

Brachiopods are a phylum of marine animals that have hard "valves" on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection...

s, and a relationship with the phoronid

Phoronid

Phoronids are a phylum of marine animals that filter-feed with a lophophore , and build upright tubes of chitin to support and protect their soft bodies. They live in all the oceans and seas including the Arctic Ocean but excluding the Antarctic Ocean, and between the intertidal zone and about...

s is also likely at a stem-group level. Its pointed end terminated in a stub that probably fastened it to a hard sea floor; its open end has been interpreted as a filter-feeding aperture.