Green River Diplomystus. An extinct genus of freshwater clupeomorph fish distantly related to modern-day extant herrings, alewives, and sardines. The various fossil beds of the Green River Formation span a 5-million-year period, dating to between 53.5 and 48.5 million years old.

Green River Diplomystus. An extinct genus of freshwater clupeomorph fish distantly related to modern-day extant herrings, alewives, and sardines. The various fossil beds of the Green River Formation span a 5-million-year period, dating to between 53.5 and 48.5 million years… Continue Reading