During our study of the zooplankton communities associated with shrimp-ponds in coastal lagoon systems from Sonora and Sinaloa, Mexico, specimens of the genus Acartia were obtained and identified. Among these, aproximately 150 specimens of A. bacorehuisensis, 30 males and 120 females were recognized, representing new northern (Laguna de la Cruz Bahía Kino, Sono ra) and southern (Escuinapa, Sinaloa) distribution limits. Specimens were collected at the surface (0-1 m depth) by means of a filtration device described by Nuñez- Pastén et al. (1992. Revista Ciencias del Mar, U.A.S. 12: 27-30). Additional data are provided here.