Phareodus testis | Green River Formation | Wyoming

Phareodus testis
Eocene (51.98 Million Years Ago)
In Stone Fossils Private Quarry
Green River Formation, Wyoming, USA
100% natural, zero restoration 

Specimen approx. size: 6.25"

Matrix approx. size: 9" x 7"

In the ancient waters of Fossil Lake, a formidable predator roamed. The Phareodus testis, a smaller but equally fascinating cousin of Phareodus encaustus. Both species boasted striking features, including pointy teeth and an impressive pectoral fin.

*The Bony-Tongue Fish Family*

Phareodus encaustus and Phareodus testis belong to the order Osteoglossiformes and family Osteoglossidae. Today, this family comprises 10 modern species that thrive in tropical freshwater habitats across South America, Africa, Asia, and Australia. Interestingly, these fish are mouth-brooders, where parents carefully nurture eggs and hatchlings in their mouths.

*Fossil Discoveries*

Fossil records reveal that adult Phareodus specimens often went solo, whereas juveniles frequently gathered in large groups. This suggests that Phareodus fish schooled together during their youth before becoming solitary predators as adults. The presence of smaller fish in their jaws and stomachs confirms their predatory nature. Adaptations like rearward-oriented fins and large, sharp teeth enabled Phareodus to chase down prey with ease.

*Size Comparison*

While Phareodus encaustus reached an impressive 30 inches in length, its smaller counterpart, Phareodus testis, measured around 20 inches. Despite their size difference, both species played vital roles in their ancient ecosystem.