INTER AND INTRA SPECIES MORPHOLOGICAL AND MOLECULAR POLYMORPHY OF KHAWIA SPECIES

Abstract

The present study investigates interspecific and intraspecific variations (polymorphism) of Khawia spp. that infect cyprinid fishes in the Kurdistan Region of Iraq, using a combined taxonomic approach morphologically, the general features of the genetic constitution and ultrastructural morphological with SEM.

The study performed during September 2024 – August 2025, in both Greater Zab and Lesser Zab rivers the morphological and ultrastructure showed some variations scolex shapes and microtrichia. And some other features were studied, while the Molecular study on the 18S rRNA gene (approximately 600 bp) showed high homology (99.11 –100%) between Khawia armeniaca and K. sinenis (similar species). However, some minor nucleotide changes were found indicating intraspecific polymorphism (GC Content: 49.63%), (A: 170) Phylogenetic analysis confirmed that the samples sit in the monophyletic group Caryophyllaeidae.

These results highlight the limitations of using morphology alone due to surface variability (phenotypic plasticity) and demonstrate the importance of combining molecular and ultrastructural data in addition to the morphological characters for correct species identification. This study provides new insights into the diversity and genomic variation of Khawia in this region.