07392 - Top Rare 2.03 Inch Micraster (Heart Urchin) Upper Cretaceous Dyrosaurus phosphaticus pyrite is sometimes found in

pyrite is sometimes found in association with small quantities of gold

anoxic substrates without oxygen

Sister taxa: Cimolichthys

while the edges of the stone have been left in its raw state

Specimen without preparation or cleaning

07392 - Top Rare 2.03 Inch Micraster (Heart Urchin) Upper Cretaceous Dyrosaurus phosphaticus pyrite is sometimes found inWell preserved specimen. Micraster, Agassiz 1836 (heart urchin) Echinoidea Spatangoida Micrasteridae PaleoDB taxon number: 33430 Parent taxon: Micrasteridae according to A. G. Fischer 1966 See also Djabarov 1964 and Sepkoski 2002 Sister taxa: Brissopneustes, Cyclasterinae, Isopneustes, Ovulaster Subtaxa: Micraster (Gibbaster), Micraster (Micraster), Micraster (Plesiaster), Micraster acutus, Micraster americanus, Micraster carinatus, Micraster