Green River Fossil Fish Death Assemblage with Astephus Catfish

Description: There are numerous locations worldwide that are noted for wondrous preservation of bony fishes, and the Green River formation that covers some 25,000 square miles of SW Wyoming, western Colorado and eastern Utah is one of the premier examples. The formation is one of the largest lacustrine sedimentary accumulations in the world, and spans the period from 40 to 50 million years ago during the Eocene Epoch. During that time period there existed three different lakes of various extent and duration: Fossil Lake, Lake Gosiute, and Lake Uinta. While Fossil Lake gets most of the attention, there are fine examples from the other sites as well, such as this death assemblage from Lake Gosiute. The largest specimen is the Ictalurid catfish Astephus antiquus. It is quite complete. Along with Hypsidoris, they form the earliest examples of the Ictaluridae. Based upon mouth shape they both probably preyed upon smaller fish, crayfish and mollusks much like the members of the family do today. The Aspetphus is surrounded by a constellation of a dozen Clupeids known as Gosiutichthys. When first described in 1980 they were referred to as Knightia cf alta, but there were sufficient differences to erect the new genus Gosiutichthys. Like Knightia, they are sometimes found in vast rafts of examples which died in some massive fish kill. This specimen was collected some years ago on private land and has recently become available. This massive plate would make an excellent display item. There is one repaired crack which passes through the center of the piece, but the joining of the halves renders it almost invisible.