A New Species of Neotenic Ambystoma (Amphibia, Caudata) Endemic to Laguna Alchichica, Puebla, Mexico by Ronald A. Brandon, Edward J. Maruska, and William T. Rumph, Bull. Southern California Acad. Sci. 80(3): 112- 125, 1981. Comparison of the neotenic population of Ambystoma that is endemic in Laguna Alchichica with the holotype of Ambystoma subsalsum Taylor 1943, and with A. tigrinum from several populations in Puebla, Tlaxcala, and Hidalgo reveals that the holotype is identifiable as A . tigrinum and is specifically different from the Laguna Alchichica neotenes. The population in Laguna Alchichica is described; this species differs from A. tigrinum in number of gill rakers, in morphology of the base of the dorsal body fin, in coloration, in number of vomerine teeth, in morphology of the vomerine tooth series, in apparently requiring saline waters, and in being neotenic.