Amphiplaga brachyptera

Amphiplaga brachyptera Cope 1877

    Eocene

    Ypresian

    Kemmerer

    USA

    Length 10cm / 4"

    Amphiplaga is one of the rarer of the Green River fish fossils, making up some 1% of the total from Fossil Lake, its only known location. Amphiplaga belongs to the family Percopsidae within the order Percopsiformes.

    The Order Percopsiformes is a small order of North American freshwater fishes that includes three families: Amblyopsidae (cavefishes); Aphredoderidae (pirate perches); and Percopsidae (trout-perches).  

    Closely related to neither trout nor perch, trout-perches have characteristics of both the trout and perch families. They exhibit characters of the salmonids, such as an adipose fin, cycloid scales, and soft fin rays, as well as characters of the percids, such as dorsal and anal fin spines, and ctenoid scales.

    Trout-perch are generally silvery in appearance, often with a partially transparent appearance, and relatively large heads and eyes. They are small fish with weak fin spines, and an adipose fin similar to those of trouts. Amphiplaga grew to as much as 150 mm. long; the average length was 100 mm. They feed on insects and small crustaceans.

    Fossil percopsids are only known from North America, the current home of the extant genus Percopsis.