QUANTITATIVE ASSESSMENT OF SHELL MORPHOMETRY, ARCHITECTURE AND SPIRE INDEX VARIATION IN BABYLONIA SPIRATA FROM THE COASTAL WATERS OF PAKISTAN

This study presents a demorphometric and shell architectural analysis of Babylonia spirata collected from the coastal waters of Pakistan. A total of 146 specimens were evaluated to morphometric variations included total length, body length, width, height, spire length, apex, four whorls, and weight. Descriptive statistics revealed consistent proportions in shell size, with mean total length (30.91 ± 8.047 mm) closely aligned with body length (30.51 ± 8.05 mm). High variability in width (22.89 ± 5.490 mm) and height (19.44 ± 4.89 mm) suggests differences in shell growth, while spire mean length (19.70 ± 9.41 mm) shows significant variation in shell elongation. Regression slopes (b-values) indicated positive isometric to allometric growth across most pairwise comparisons. ANOVA confirmed significant relationships (p < 0.001) between total length and width, height, and weight. Shell morphology and architecture assessed using the Spire Index (SI = 0.64) and width-to-length ratio (WLR = 0.75) classified the shell as low-spired and broad, suggesting a globular morphology. Correlation analysis showed strong positive associations between shell weight, water content, and sediment retention. The shell morphometric variability reflects age, environmental influences, and genetic diversity that contribute to understanding species-specific growth and shell morphology in B. spirata, relevant for ecological, taxonomic, and evolutionary assessments.