Protocinctus is a genus of cinctan and, as of 2024, it is the oldest such recognized genus.[1] It is known from the Wuliuan age of the Mansilla Formation, Zaragoza, Spain.[2] It is represented by the single species Protocinctus mansillaensis.

Protocinctus
Temporal range: Miaolingian (Wuliuan), 506.5–504.5 Ma
Ventral view of a specimen of Protocinctus mansillaensis
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Echinodermata
Class: Cincta
Family: Sucocystidae
Genus: Protocinctus
Rahman & Zamora, 2009
Species:
P. mansillaensis
Binomial name
Protocinctus mansillaensis
Rahman & Zamora, 2009

Description

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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.[2]

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.[3]

References

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  1. ^ Zamora, Samuel; Wright, David F.; Nohejlová, Martina (2023). "Phylogenetic position of Bohemiacinctus gen. nov. (Echinodermata, Cincta) from the Cambrian of Bohemia: implications for macroevolution and the role of taxon sampling in palaeobiological systematics". Papers in Palaeontology. 9 (1): e1482. Bibcode:2023PPal....9E1482Z. doi:10.1002/spp2.1482. ISSN 2056-2802.
  2. ^ a b Rahman, Imran A; Zamora, Samuel (September 2009). "The oldest cinctan carpoid (stem-group Echinodermata), and the evolution of the water vascular system". Zoological Journal of the Linnean Society. 157 (2): 420–432. doi:10.1111/j.1096-3642.2008.00517.x.
  3. ^ Rahman, Imran A.; Zamora, Samuel; Falkingham, Peter L.; Phillips, Jeremy C. (2015-11-07). "Cambrian cinctan echinoderms shed light on feeding in the ancestral deuterostome". Proceedings of the Royal Society B: Biological Sciences. 282 (1818): 20151964. doi:10.1098/rspb.2015.1964. PMC 4650160. PMID 26511049.
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