Phylum: Echinodermata Klein 1754
Class: Rhombifera Zittel 1879
Order: incertae sedis
Family: Pleurocystitidae Neumayr 1889
Species: Pleurocystites squamosus
Author Citation Billings, 1874
Sub Period: None
International Age: Sandbian - Katian
Acquired by: Purchase/Trade
Length: 5 cm
Width: 1.6 cm
Brechin, Carden Quarry
Synonym: Pleurocystites robustus Billings, 1854.
Alternative spelling: Pleurocystis.
Taxonomy from fossilworks.org.
Diagnosis (Sprinkle et al., 1985): “Theca rounded-triangular, nearly symmetrical; 3 rhombs elliptical, dichopores occupying less than 40% of sutures; periproct occupying 70% of lower side, about 680-700 periproctals, no rectal lobe, anal pyramid away from margin; ornament composed of medium growth lines and few ridges radiating to the plate sides and corners; brachioles having large groove extending up aboral side, cover plates fairly large; proximal stem slowly tapering and moderately ridged.”
ID determined by oilshale.
Billings, E. (1874). Paleozoic Fossils, v. II, pt. I. Canada Geological Survey 1-144
Parsley, R. L. (1970). Revision of the North American Pleurocystitidae (Rhombifera-Cystoidea). Bulletins of American Paleontology 58:135-213.
Sprinkle, J., Henry, L., Zimmer, F., Kelley, L., & Whiteley, J. (1985). New Pleurocystites from the Bromide Formation of Oklahoma. Journal of Paleontology, 59(6), 1476-1480.
Brower, J. (1996). Growth and Functional Morphology of Pleurocystites Squamosus Billings, An Ordovician Rhombiferan Echinoderm. The Paleontological Society Special Publications, 8, 48-48. doi:10.1017/S2475262200000502
Paton, T. (2017). Paleo Pompeii; Genesis and Preservation of an Upper Ordovician Mounded Hardground with a Diverse Encrusting Community. Master-thesis, University of Cincinnaty.
Paton, T. and Brett, C. E. (2019). Revised stratigraphy of the middle Simcoe Group (Ordovician, upper Sandbian-Katian) in its type area: An integrated approach. Canadian Journal of Earth Sciences 57(1).