Bivalvia - Pholadomyida - Megadesmidae
Full reference: J. D. Dana. 1847. Descriptions of fossil shells of the collections of the exploring expedition under the command of Charles Wilkes, USN, obtained in Australia, from the lower layers of the coal formation in Illawarra, and from a deposit probably of nearly the same age at Harper's Hill, Valley of the Hunter. American Journal of Science and Arts, Second Series 4:151-160
Parent taxon: Megadesmidae according to N. J. Morris et al. 1991
Sister taxa: Astartila, Astartilinae, Cowperesia, Huabiella, Megadesmus, Ochotomya, Plesiocyprellinae, Unklesbyella
Subtaxa: Pyramus concentricus, Pyramus igori, Pyramus laevis, Pyramus myiformis, Pyramus myriformis, Pyramus nelliae, Pyramus permianus, Pyramus planus, Pyramus primigenius, Pyramus silicius, Pyramus simmetricus
Type: Pyramus myiformis
Ecology: facultatively mobile infaunal suspension feeder