Morphological and Ultrastructural Redescription of Philometra cyanopodi from Epinephelus chlorostigma and Variola louti in the Red Sea, Egypt

This study provides a detailed morphological and ultrastructural redescription of the nematode parasite Philometra cyanopodi Moravec and Justine, 2008, collected from the gonads of two serranid fish species, Epinephelus chlorostigma and Variola louti, in the Red Sea, Egypt. A total of ten fish (five of each species) were examined, revealing a 40% infection rate in both hosts. The parasites were characterized using light microscopy and scanning electron microscopy (SEM), revealing distinct morphological features, such as a small, filiform body, fine transverse striations, and specific cephalic and caudal structures. Comparative analysis with previously described specimens highlighted both similarities and notable differences in morphological measurements. This redescription confirms the presence of P. cyanopodi in new host species and geographical locations, expanding our understanding of its taxonomy, host-parasite relationships, and geographic distribution. The study underscores the importance of detailed taxonomic analyses for accurate species identification and provides insights into the host specificity and ecological interactions of this nematode parasite.