Marsupites is an extinct genus of stalkless crinoids from the Santonian stage of the Late Cretaceous.Marsupites at Fossilworks.org
Biostratigraphic significance The International Commission on Stratigraphy (ICS) had provisionally assigned the extinction of Marsupites testudinarius as the defining biological marker for the start of the Campanian stage of the Late Cretaceous, 83.6 ± 0.2 million years ago, until a new final definition was eventually ratified in 2022, based instead primarily on magnetostratigraphy.
Distribution Fossils of the genus have been found in: Lipnik, PolandLach & Salamon, 2016 Haslam Formation, British Columbia, CanadaHaggart & Graham, 2018
References
Bibliography
Fossils (Smithsonian Handbooks) by David Ward (Page 173)