ACKNOWLEDGMENTS
We thank V. Contreras for his comments on PVSJ 567; M. Ezcurra and A. Haro for critical reading of this paper; Earthwatch Institute, CICITCA, and Instituto y Museo de Ciencias Naturales for funding fieldwork. We are indebted to the field crew and Earthwatch volunteers of 1994. We especially thank the reviewers (A. Arcucci and D. Dilkes) for their comments and observations, and the editor R. Irmis.
Handling editor: Randall Irmis