ABSTRACT

Three samples of the foraminiferan Ammonia parkinsoniana, from Baffin Bay and Laguna Madre, Texas, were analyzed to determine the effects of temperature and salinity on morphology. Salinity is the more important factor of the two. Specimens collected at a time of higher salinity (50 ppt) differ significantly (p < 0.01) from those collected at lower salinity (14 ppt) in having a larger proloculus and fewer chambers in whorls 1 and 2. They differ marginally significantly (p < 0.1) in having fewer total number of chambers and somewhat smaller umbo diameter. Multivariate statistical analyses also reveal a statistically significant relationship between environment and test morphology. The South Texas samples support the recognition of A. parkinsoniana as a distinct species and not an ecophenotypic variant of A. beccarii, because it is, by far, the dominant foraminiferal taxon regardless of salinity or temperature. All specimens appear to be megalospheric.