MORPHOMETRIC ANALYSIS OF THE MONTASTRAEA CAVERNOSA COMPLEX IN THE MIOCENE TO RECENT OF THE WESTERN CARIBBEAN

In previous work, species in the Montastraea cavernosa species complex have been differentiated by number of septa, corallite size, and costa thickness, however preliminary work using geometric morphometrics has shown an increase in the number of species. This study uses geometric morphometrics to distinguish species in the Montastraea cavernosa complex, based on collections consisting of 112 colonies that were originally identified using the number of septa as Montastraea canalis, M. cavernosa, M. endothecata, and M. cylindrica. Fossil specimens, dating from the late Miocene to early Pleistocene, were collected from Panama and Costa Rica and analyzed in addition to modern samples from Belize. Data points were taken from a 21 point landmark scheme, after which Bookstein shape coordinates, one-way ANOVA, and canonical variates analysis were performed to assess the data and distinguish species. A total of five species were distinguished. Of the five, two are long ranging (greater than 10Ma) and two are extant. Comparisons with previous work show a decrease in complex diversity through time, in response to closure of the Central American Isthmus and the onset of northern hemisphere glaciations.