Scanning Electron Microscopy of Acanthocephala Isolated from Saurida tumbil in Minab City, Hormozgan Province, South Coast of Iran

The Synodontidae family is a group of marine fish that includes four genera and ۵۷ species and is distributed throughout all waters of the world. A total of ۱۵۰ lizardfish (Saurida tumbil) were randomly sampled from various fish markets in Minab city, Hormozgan province, Iran, from June ۲۰۲۲ to May ۲۰۲۳. The fish were dissected, and their digestive tracts were examined for acanthocephalans. Taxonomic identification of the parasites was based on morphological characteristics described using a light microscope and then confirmed by Scanning Electron Microscope (SEM) to clarify ambiguous details. To prepare the parasites for observation using SEM, some samples were placed in ۲.۵% glutaraldehyde diluted with ۰.۱ M sodium cacodylate buffer for ۲ to ۴ hours at ۴°C.  After primary fixation, washing was performed three times with ۰.۱ M sodium cacodylate buffer, each wash lasting ۱۵ minutes. For secondary fixation, ۱% osmium tetroxide was applied for two hours. Following a repeat of the washing steps, the dehydration stage was performed using ascending grades of alcohol, with each grade applied for ۱۵ minutes. Finally, the samples were dehydrated and dried in a desiccator. The prepared samples were mounted on copper stubs, then coated with a ۴ to ۷ nm thick layer of gold using a sputter machine to enable imaging. The images were acquired using a Leo scanning electron microscope. The collected specimens exhibited characteristics typical of the genus. Parasite indices of prevalence, intensity, and mean abundance were evaluated for each parasite species. The discovered samples were identified morphologically as Neoechinorhynchus spp. and Quadrigyrus spp. from ten Saurida tumbil. This is the first report of Neoechinorhynchus and Quadrigyrus parasitizing Saurida tumbil.

کلیدواژه ها:

Scanning Electron Microscopy ، Acanthocephalans ، Saurida tumbil ، Iran