100% Natural Cockerellites liops, Knightia eocaena, and Diplomystus dentatus | Green River Formation | Wyoming
Beautiful multiple fish plate with three different specimens all occurring naturally on the same plate. Found in our private quarry in the prestigious 18" layer. This beautiful specimen is 100% natural, no restoration with great preservation.
We take great pride in the preparation of our fossils. We use the best microscopes and preparation tools available. This specimen is 100% natural with zero restoration.
Plate dimensions: approx. 15"×11"×.25"
Cockerelliteis is approx. 4.5" long
Diplomystus is approx. 5" long
Knightia is approx. 4" long
Order Perciformes
Family Moronidae
A diverse assemblage of fossil fish species, including C. liops, P. serrata, H. hypsacantha, and undescribed species of Priscacara and Hypsiprisca, have been discovered in the fossil record.
C. liops Specimens
Fossil evidence suggests that C. liops exhibited a gregarious behavior, with specimens found both as isolated individuals and in mass mortality assemblages. This indicates that C. liops likely traveled in schools throughout its life cycle.
Morphological Characteristics
- Maximum size: 6 inches
- Body shape: Similar to that of modern members of the family Centrarchidae (sunfish family), suggesting a possible convergent evolutionary relationship.
Paleoecological Implications
The presence of C. liops and other fossil fish species in the Moronidae family provides valuable insights into the paleoecology of ancient aquatic ecosystems. The discovery of mass mortality assemblages and the inferred schooling behavior of C. liops offer a glimpse into the complex interactions and dynamics of ancient fish populations.
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.
Knightia is an extinct genus of clupeid bony fish that lived in the freshwater lakes and rivers of North America and Asia during the Eocene epoch. The genus was erected by David Starr Jordan in 1907, in honor of the late University of Wyoming professor Wilbur Clinton Knight, "an indefatigable student of the paleontology of the Rocky Mountains." It is the official state fossil of Wyoming, and the most commonly excavated fossil fish in the world.
Knightia belongs to the same taxonomic family as herring and sardines, and resembled the former closely enough that both Knightia alta and Knightia eocaena were originally described as species of true herring in the genus Clupea.
As with modern-day clupeids, Knightia spp. likely fed on algae and diatoms, as well as insects and occasionally smaller fish.
Anatomy
In Knightia fish, rows of dorsal and ventral scutes run from the back of the head to the medial fins. They had heavy scales and small conical teeth. Their size varied by species: Knightia eocaena was the longest, growing up to 25 cm (10 in), though most specimens are no larger than 15 cm. K. alta was shorter and relatively wider, with specimens averaging between 6 and 10 cm.
Predators
A small schooling fish, Knightia made an abundant food source for larger Eocene predators. The Green River Formation has yielded many fossils of larger fish species preying on Knightia; specimens of Diplomystus, Lepisosteus, Amphiplaga, Mioplosus, Phareodus, Amia, and Astephus have all been found with Knightia in either their jaws or stomachs.