Assorted Fossil Fish Plate | 100% Natural | Green River Formation | Wyoming

Plate approx. size: 34.5" x 41"

Diplomystus approx. size: 4.5"

Phareodus approx. size: 22.5"

Cockerellites approx. size: 5"

Notogoneous approx. size: 14"

This exceptional fossil plate features a Phareodus encaustus,  Notogoneous,  Cockerellites and Diplomystus showcasing a "Quad" effect. This rare occurrence provides a glimpse into a dynamic ecological event that has been frozen in time for millions of years.

Beaked Sandfish - Notogoneus osculus

Order Gonorynchiformes, Family Gonorynchidae

N. osculus was the last survivor of the Gonorynchiformes order in North America. There are 5 modern species in the Gonorynchidae family. They inhabit tropical marine regions of the Indo-Pacific Oceans.

Very young juveniles and large adults are the only N. osculus specimens found from Fossil Lake. This could indicate that N. osculus was a migratory species. Their lifecycle may have consisted of:

Hatching in Fossil Lake

Migrating to connecting streams to mature

Returning to Fossil Lake as an adult to spawn and die

N. osculus had a down-turned, sucker-like mouth. Its toothless mouth suggests that this was a bottom-feeding species. The highly salty water conditions at the bottom of Fossil Lake should have excluded most scavengers and bottom-feeders. Yet, N. osculus is found exclusively in deep-water deposits. This suggests that N. osculus spent most of its life outside of Fossil Lake in connecting rivers and streams.

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. dentatus spawned in open water.

This species' upturned mouth indicates it fed at the surface of Fossil Lake. D. dentatus specimens are commonly found with other fish stuck in their mouths, including other D. dentatus specimens.

Bony-Tongue Fish - 2 Species Identified: Phareodus encaustus & Phareodus testis

Order Osteoglossiformes, Family Osteoglossidae
Living members of the Osteoglossidae family:

• include 10 modern species
• live exclusively in tropical freshwaters
• found in South America, Africa, Asia, and Australia
• mouth-brooders (parents hold eggs and hatchlings in their mouths)

Phareodus fossils:

• adult specimens usually found alone, but juveniles known from mass mortalities
• indicates that Phareodus schooled as a juvenile and became solitary as an adult
• often preserved with smaller fish in their jaws and stomach, indicating they were predators
• rearward oriented fins on back and underside, adaptation for speed
• large, sharp teeth
• max known size of P. encaustus: 30 inches
• max known size of P. testis: 20 inches