Phareodus testis

Phareodus testis? Cope 1877

    Eocene

    Ypresian

    Kemmerer

    USA

    Length 43cm / 17"

    not sure about testis

    Phareodus (derived from phare = to have and odus = tooth) belongs to the osteoglossids. The genus includes at least four species, P testis and P. encaustus of North America, P. muelleri of Europe, and P. queenslandicus of Australia. Today they are represented by the Arawana. Arawana are found in tropical and semitropical fresh waters of South America, central Africa, Southeast Asia, and northern Australia.

    Phareodus was more common in Fossil Lake and rarely occurs in Lake Gosiute and Lake Uinta.

    P. testis was a freshwater fish with an oval outline, a small head, and a slightly pointed snout. Its dorsal and anal fins were situated posteriorly, with the anal fin being larger. Its caudal fin was slightly forked. It had small pelvic fins but long, narrow pectoral fins.

    P. encaustus is readily distinguished by its longer pectoral fin and large pointed teeth. The jaws of Phareodus testis are smaller with fewer teeth than Phareodus encaustus. The gill plate cover is slightly larger in Phareodus testis

    Maximum size for Phareodus testis was about 15 inches while P. testis averaged between 6" and 8".

    The Phareodus played an important role in the ecosystem of the ancient lake. This genus was an omnivorous feeder that kept the bottom near the shore free of half dead organisms as well as occasionally feeding on live fish. Spines of Mioplosus and Priscacara are often found in the stomachs of Phareodus.

    The pectoral appendages are modified fins that are usually equal in size to one third of the fish's total length. It appears that the fish used these appendages while in shallow water environments for rummaging purposes.