Phareodus testis Fish Fossil from Green River Formation

Phareodus testis

Order Osteoglossiformes, Family Osteoglossidae;

Geological Time: Eocene

Size (25.4 mm = 1 inch): 180 mm in length on a 250 mm by 165 mm matrix

Fossil Site : Green River Formation, Fossil Lake, Kemmerer, Wyoming

Code: WFF66

Price: $295.00 - sold

Description: This 50 million year old, Eocene-Era fossil fish comes from one of the world's famous Laggerstatten, the Green River Formation in Wyoming. A small portion of the fish fossils from Green River exhibits such fine preservation. The significant extent of soft-tissue preservation that makes the site famous is evident in this specimen.

The genus Phareodus is uncommon in the Green River formation and is readily distinguished by the long pectoral fin (here prominantly splayed) and large pointed teeth. There are two spcies:encaustus and testis, of which testis is the more rare. Phareodus sports teeth that are testiment to the fish’s carnivorous habit. In fact, the genus name means "to have tooth". A member of family Osteoglossidae (bony-tongues), it has extant cousins found in Central-South America and Southeast Asia, known as the Arrowana and Arapaima. The genus is known from the Eocene deposits of North America and Australia.

About the Green River Formation: Class Actinopterygii, the ray-finned bony fishes, comprise almost half of all known species of vertebrates, some 20,000 extant species. 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, west Colorado and east 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 the Eocene, based on the fossil record, the region was sub-tropical to temperate. Some 60 vertebrate taxa have been described from the formation, including crocodiles, boa constrictors, and birds, as well as abundant invertebrates and plants. The unusually excellent preservation of the Green River fish fossils is usually attributed to a combination of two factors: 1) a cold period during the Eocene that would have caused dead fish to sink faster due to a less inflated swim bladder; and 2) the great depth of the lakes and the consequent anoxic conditions that would have often prevented scavengers from disturbing the carcasses.

Fossils Purchase Information

click to enlarge

Fossil Mall Navigation:
l Home l Fossils for Sale Map l Museum and Rare Fossils l How to Buy Fossils l

Navigate by Fossil Category:
l Trilobites
l Ammonites l Fish Fossils l Invertebrate Fossils l
l Crinoids and Echinoderms l Insect Fossils l Dinosaur and Reptile Fossils l
l Cambrian Explosion Fossils l Plant Fossils l Stromatolites l
l Vertebrate Fossils l Fossil Amber l Trace & Ichnofossils l

l Fossils and Paleotological Science Information l