Juvenile Notogoneus osculus | Green River Formation | Wyoming
Notogoneus osculus
Eocene (51.98 Million Years Ago)
Private Quarry, Green River Formation, Wyoming, USA
Obtained from the collection of Dr. William Rieger
Specimen approx. size: 7.25"
Matrix approx. size: 12" x 10"
This piece has had minimal restoration.
Beaked Sandfish - Notogoneus osculus
Order Gonorynchiformes, Family Gonorynchidae
Notogoneus osculus was the final North American member of the Gonorynchidae family. There are 5 modern species within the family that inhabit tropical marine regions of the Indo-Pacific Oceans. Notogoneus did not have teeth; instead, it had a "beak" adapted for bottom feeding. This beaked mouth was well-suited for its bottom-feeding and scavenging lifestyle.
Fossils of Notogoneus found in Fossil Lake show two distinct size distributions:
- Fry (juveniles): range from 1"-2" in length.
- Adults: range from 10"-35" in length. The average size for an adult specimen is around 18".
Specimens of intermediate size are notably rare in Fossil Lake. This is thought to indicate that Notogoneus was a migratory species. It might have hatched in Fossil Lake, migrated to connecting streams or rivers for development, then returned as adults to spawn and perish in deep-water zones. The large adult fossils are found almost exclusively in the 18-inch layer.