Research Training Program

Matthew Friedman
University of Rochester
Rochester, NY

James Tyler, Ph.D.
Dave Johnson, Ph.D.
Supervising Scientists
Department of Systematic Biology
Division of Fishes

"My project is an illustration of the rewarding and sometimes frustrating nature of paleontological research."

A putative lampridiform fish from the Oligocene of Peru

The order Lampridiformes is a unique group of modern fishes with a wide range of body plans. Members of this order range from elongated forms such as the silvery and ribbon-like oarfish, whose bizarre appearance and large size are thought to have led to myths of sea serpents, to deep-bodied fishes like the appropriately named moonfish or opah, whose profile is nearly circular. Despite the radical differences in outward appearance between members of this order, all are united by four unique features. Of these characters, three relate to the specialized jaws of the group; the bones of the upper jaw are unusually shaped and arranged, allowing the mouth to be protruded. This architecture allows one particularly odd fish of this order, the deep-water Stylephorus chordatus, to increase the volume of its oral cavity by a factor of nearly 40 merely by opening its mouth. The fossil skull that is the focus of this study is from northwestern Peru, and dates to the Oligocene Epoch (38-23 million years ago). In order to examine the features of the fossil, many different techniques have been used to "peer through" the hard rock that encases the specimen: computer tomography (better known as CT or "CAT" scans), acid baths to dissolve carbonates, and mechanical removal of the surrounding rock with a diamond-tipped drill. Although preparation of the fossil failed to reveal any of the diagnostic features in question, the bones of the front of the skull are consistent with the strange form of the upper jaw that is so characteristic of this order. Furthermore, many parts of the fossil, such as a large crest with an ornamental ridge and the plate-like bones that cover the gills, are very similar to equivalent structures in specimens of modern lampridiforms that were examined. In order to prove that the tentative placement of the fossil within the Lampridiformes is warranted, new CT data will be obtained that will allow the obscured portions of the skull to be examined in more detail, and come to a definitive conclusion about its taxonomic position.

This research was supported by a grant from the National Science Foundation Research Experiences for Undergraduates program, Award Number DBI-9820303.

Letter of Gratitude