Morphometric Analysis of <i>Ammonia</i> Species Distributed along Chandipur Coast, Odisha, India

ABSTRACT The foraminifera genus Ammonia is widely distributed in shallow marine and estuarine environments, yet its taxonomy remains controversial due to significant morphological variability. This study applies a morphometric approach to distinguish three Ammonia species: Ammonia beccarii, Ammonia dentata, and Ammonia tepida, the most abundant species found along the Chandipur coast, Odisha, India. A total of 90 well-preserved specimens were analysed using biometric measurements and statistical analysis, using 28 morphological parameters, where the most influential parameters are greatest spiral diameter (gsd), umbilical diameter (du), proloculus diameter (prol.), and height (h). Cluster analysis puts all the species in different clusters, with one cluster containing overlapping morphometric ranges between Ammonia beccarii and Ammonia dentata. SIMPER analysis confirmed spiral diameter as the most significant parameter contributing to species differentiation, followed by umbilical diameter and height. Linear ‘r’ Pearson correlation analysis further highlighted intraspecific variability. The findings support the effectiveness of morphometric approaches in species delineation and highlight the potential role of test morphology variability in foraminiferal taxonomy. This study provides a quantitative framework for distinguishing morphologically different Ammonia species.