''Protocinctus'' is a genus of cinctan and, , it is the oldest such recognized genus. It is known from the Wuliuan age of the Mansilla Formation,

Zaragoza Zaragoza (), traditionally known in English as Saragossa ( ), is the capital city of the province of Zaragoza and of the autonomous communities of Spain, autonomous community of Aragon, Spain. It lies by the Ebro river and its tributaries, the ...

, Spain. It is represented by the single species ''Protocinctus mansillaensis''.

Description

The genus bears a combination of characters unique to cinctans, with an elongated oval-shaped theca with a single anterior left marginal feeding groove, and a posterior marginal frame open in posterior ventral view. Like other cinctans, they would have been active pharyngeal filter feeders. The animal would lay close to the sediment surface with the anterior region oriented downstream and generate an inhalant flow of water directing suspended food particles to the mouth.

References

Carboniferous echinoderms Homalozoa Prehistoric echinoderm genera {{Paleo-echinoderm-stub