CHANGES IN COLONIAL DEVELOPMENT, INTRASPECIFIC HETEROCHRONY, MORPHOLOGICAL INTEGRATION, AND CHARACTER HERITABILITIES IN TWO POPULATIONS OF THE BRYOZOAN SPECIES BATOSTOMA JAMESI FROM THE KOPE FORMATION (UPPER ORDOVICIAN, CINCINNATIAN)

Abstract

Abstract Populations of the Upper Ordovician trepostome bryozoan Batostoma jamesi were collected from two different paleoenvironmental settings in the Kope Formation of southeastern Indiana. Within each colony and population, morphologic changes were analyzed during colony growth, or astogeny. Morphological measurements of zooecia, mesozooecia, and acanthostyles display similar patterns of change during colony growth in both populations but magnitudes are generally larger in the high diversity population. Canonical variates analyses provided multivariate confirmation of univariate character differences found within each population. Statistically significant multivariate morphological differences between growth stages persist even if assignments of colonies to populations are ignored. Results suggest different potentials for altering growth trajectories in different environments with early growth stage flexibility in colonies from lower diversity settings and later-stage flexibility in colonies from higher...