 The Californian population probably inhabited freshwater or saline lagoons or shallow lakes.A later species, "M. opsigonus", was found in the Clarendonian Juntura Formation at Juntura, Malheur County, Oregon.Whether the species "M. goliath" belongs into this genus or into "Palaelodus" is not quite certain; it surpasses all forms in the latter genus in size, but is generally similar.