This trip focused on sampling the pencil catfish Trichomycterus aereolatus from the Maipo drainage and adjacent areas of central Chile. This trip is a follow-up based on phylogeographic results obtained from our initial work in this system. Participants on this Dr. Jerry Johnson, BYU undergraduate student Benjamin Groves, Alfonso Flores and a graduate student from the University of Concepción, Carlos Muñoz. This trip was funded through Brigham Young University, but is part of a larger project supported by the U.S. National Science Foundation (OISE 0530267). The molecular genetics data collection for this project is being conducted primarily by Ben Groves as part of his undergraduate ORCA project (funded in 2008).