1.5" Diplomystus dentatus | Green River Formation | Wyoming

Diplomystus dentatus Eocene (51.98 Million Years Ago) In Stone Fossils Private QuarryGreen River Formation, Wyoming, USA   Plate approx. size: 2.5" x 2" Diplomystus approx. size: 1.5"   Diplomystus is an extinct genus of freshwater clupeomorph fish distantly related to modern-day extant herrings, alewives, and sardines. The genus was first named and described by Edward Drinker Cope in 1877.   Ray-finned Fish - Diplomystus dentatus Order Ellimmichthyiformes, Family Paraclupeidae The last known species of the Ellimmichthyiformes order went extinct sometime in the middle Eocene. D. dentatus is a primitive relative of the modern-day herring. The genus Diplomystus is also known from fossil deposits in China. D. dentatus is the 2nd most common fossil fish found from Fossil Lake. Specimens ranging from embryonic size (about 0.7 inches) to full-grown adults (about 26 inches) are common. Smaller-sized specimens are more commonly found in mid-lake than near-shore deposits. This suggests that D.