This link has a fossil photo of Amphiplaga brachyptera.
The fossil is 11.2 cm. (4.4 inches) in length. It was found in the Green River Formation at Fossil Lake in Wyoming. This fossil dates to the Wasatchian stage (55.4 - 50.3 million years ago) of the Eocene.
Amphiplaga brachyptera was a fish of the Eocene. The systematic paleontology of it is:
Actinopterygii Cope 1882
Neopterygii Regan 1923
Teleostei Muller 1846
Paracanthopterygii Greenwood et al. 1996
Perciformes Bleeker 1859
Percopsidae Regan 1911
Amphiplaga Cope 1877
Amphiplaga brachyptera Cope 1877
Alison M. Murray and Mark V.H. Wilson wrote an article titled Contributions of fossils to the phylogenetic relationships of the percopsiform fishes (Teleostei: Paracanthopterygii): order restored. It was published in 1999. The abstract and the introduction are on this link.
Terry R. Finger wrote an article titled A COMPARISON OF FISH COMMUNITY STRUCTURE AMONG SEVERAL PALEOENVIRONMENTS OF EOCENE FOSSIL LAKE, WYOMING: A PRELIMINARY REPORT. The text is on this link.
Andrea B. Ward and Elizabeth L. Brainerd wrote an article titled Evolution of axial patterning in elongate fishes. It was published in 2007 in the Biological Journal of the Linnean Society, 90, 97-116. The complete text is on this link.