Dr. Francisco J. Vega was Head of the Geology Department, Instituto de Geologia, UNAM, and Secretary of the Paleontological Society (South Central Section). His contributions deal with biostratigraphy and systematics of Cretaceous and Tertiary Crustacea and Mollusca. Torrey Nyborg received his MS degree from Kent State University. He works with decapod crustaceans and fossil mammal and bird tracks. Torrey is currently working towards his PhD from Loma Linda University. Dr. Maria del Carmen Perrilliat is a prominent specialist on Cretaceous and Tertiary Mollusca. She is currently the Elected President of the Mexican Paleontological Society (SOMEXPAL). Dr. Marisol Montellano-Ballesteros got her PhD from The University of California at Berkeley, and has been a key piece for the Mexican Vertebrate Paleontological Society. Her field of interest is Late Mesozoic and Late Cenozoic mammals. Dr. Sergio R. S. Cevallos-Ferriz received his MS and PhD from the University of Alberta, and was Head of the Department of Paleontology, Instituto de Geologia, UNAM. Dr. Cevallos-Ferriz is a well known specialist on Mesozoic and Cenozoic paleobotany. Dr. Sara A. Quiroz-Barroso got her MS and PhD from the UNAM and she has been Secretary of the Mexican Paleontological Society. She works with Paleozoic Mollusca from Mexico.