Descriptive Study of the Species Eudiaptomus Vulgaris (Schmeil, 1896) Belong to Genus Eudiaptomus (Kiefer, 1932) , from the Al-Hussainiya River in the Holy Karbala Governorate

Abstract

After determining the date and location of sample collection, this study examined the external morphology of the species. Samples were collected from the Al-Hussainiya River, located north of Karbala Governorate. The genus Eudiaptomus vulgaris is widely distributed across various aquatic systems. Species identification was based on morphological characteristics of the body, including overall shape and specific diagnostic features such as the number and structure of antennae, the arrangement of spines on the basal segment of the antennule, the morphology of the fifth peduncle, and the structure of the caudal branches. This  study aims to represent one of the few detailed taxonomic studies on members of the order Calanoida in Iraq, contributing to the enrichment of biodiversity records for freshwater zooplankton. Moreover, the precise description of this species provides a valuable reference for future ecological assessments and water quality monitoring, as such organisms serve as important bio indicators in aquatic ecosystems. Due to the scarcity of detailed taxonomic research on species of the order Calanoida, this study highlights the importance of clarifying their taxonomic status. This was achieved by examining their external morphology, diagnosing and describing their structures, and providing illustrative drawings of their body parts.