Mioplosus approx: 11.25"
Knightia approx: 4" each
Diplomustus approx: 3.5"
- Family Latidae - M. labracoides
- are characterized by 2 dorsal fins and a forked tail
- known to reach 20 inches
- juveniles commonly found in mass mortalities and adults found alone, indicating M. labracoides traveled in schools as a juvenile and became solitary as an adult
- juvenile and adult specimens often found preserved with smaller fish in the jaw or stomach
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 eocaena & Knightia alta
Order Clupeiformes, Family Clupeidae
The Clupeidae family has an estimated 50 modern freshwater species. Clupeidae species can lay as many as 200,000 eggs at once, allowing species to multiply quickly. Modern species are also prone to mass die offs.
K. eocaena is:
- The most common fish found from Fossil Lake.
- The most commonly found articulated vertebrate fossil in the world.
- The Wyoming state fossil.
Both K. eocaena and K. alta are frequently discovered in mass mortality plates, some containing up to 100 fish per square meter. This suggests that, like their modern relatives, the Knightia species were sensitive to environmental changes.
K. eocaena specimens of all sizes are found in mass mortality plates, indicating this species schooled as both a juvenile and adult. The average adult size of K. eocaena specimens is about 6 inches, though specimens as large as 10 inches have been found.