Morphometeric criteria and partial sequence of the 18S rRNA gene of Ceratomyxa sultani n. sp. from the gallbladder of Upeneus margarethae in the Arabian Gulf, with a note on its seasonal prevalence

This paper describes a new coelozoic myxosporean parasite named Ceratomyxa sultani n. sp. isolated from the gallbladder of Upeneus margarethae sourced from the Arabian Gulf off Saudi Arabia. Of 104 U. margarethae specimens examined, 27 (26%) were infected, with the highest prevalence in winter and lowest in autumn. The pseudoplasmodia were disporous and irregularly elliptical in shape, with an average size of 22 × 17 μm. Mature spores were mostly elliptical with symmetrical valves and equal spherical polar capsules. Spores were 9 µm in length and 25 µm in thickness, while polar capsules were 4 µm wide with four filament coils. The paper further provides a morphological comparison with closely related Ceratomyxa spp. together with phylogenetic analysis based on the partial 18S rRNA sequence, which revealed that C. sultani n. sp. clustered within a robust clade of Ceratomyxa species from the Arabian Gulf and Red Sea or nearby geographic regions.