The present study aimed to conduct a scientific morphological identification of freshwater bivalve molluscs (Class: Bivalvia) distributed across the aquatic environments of Karbala Province, Iraq. Field specimens were randomly collected from various aquatic habitats including rivers, streams, and ponds across selected sites in the province over the period from December 19, 2025 to March 10, 2026. A total of 75 individuals were examined. Morphological and anatomical characteristics were adopted as the primary criteria for taxonomic classification, supplemented by validated taxonomic keys. The results revealed notable species diversity, with four species recorded and morphologically distinguished based on shell characteristics including length, width, height, umbo shape and position, external shell margins, growth lines, internal surface features, and muscle scar patterns. The identified species were: Pseudodontopsis euphraticus (Bourguignat, 1852), Unio tigridis Bourguignat, 1852, Corbicula fluminea (O.F. Müller, 1774), and Corbicula fluminalis (O.F. Müller, 1774). The findings confirm that Karbala Province represents a suitable freshwater habitat for bivalve species diversity and underscore the ecological importance of these organisms in aquatic ecosystem functioning.
Ali Abdul Razzaq Nouh Al-Khurasani* (Fri,) studied this question.