DAO 113:25-32 (2015)  -  DOI: https://doi.org/10.3354/dao02821

Ortholinea saudii sp. nov. (Myxosporea: Ortholineidae) in the kidney of the marine fish Siganus rivulatus (Teleostei) from the Red Sea, Saudi Arabia

Abdel-Azeem S. Abdel-Baki1,2,*, Hatem Soliman3,4, Mona Saleh3, Saleh Al-Quraishy1, Mansour El-Matbouli3

1Zoology Department, College of Science, King Saud University, PO Box 12455, Riyadh 11451, Saudi Arabia
2Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
3Clinical Division of Fish Medicine, University of Veterinary Medicine, Vienna, Austria
4Fish Medicine and Managements, Faculty of Veterinary Medicine, University of Assiut, 71515 Assiut, Egypt
*Corresponding author:

ABSTRACT: Myxozoans, a diverse group of microscopic obligate endoparasites, can cause diseases in a number of economically important fish, including the marbled spinefoot Siganus rivulatus. To date, only 1 myxozoan, Zschokkella helmii, has been reported to infect S. rivulatus. Here we describe another myxozoan detected in S. rivulatus. Investigations of 40 marbled spinefoot fish caught from the Red Sea coast, Jeddah, Saudi Arabia, revealed clusters of parasitic spores in the kidney. Light microscope examination of the native spores revealed sub-spherical, mature spores with smooth shell valves. The 2 polar capsules were equal in size, and the polar filament was perpendicular to the longitudinal axis of the polar capsules. Histopathological examinations of the infected kidneys demonstrated the presence of both spores and developmental stages in the lumen of the renal tubules without any pathological effect. Electron microscopy investigations showed maturing spores composed of 2 valvogenic cells, each with a prominent nucleus. The valvogenic cells enclosed 2 polar capsules containing 3 filament coils as well as a binucleated sporoplasm cell filling the space between and beneath the 2 polar capsules. BLAST search analysis of the amplified sequence from the detected parasite indicated a high percent of identity to the 18S rDNA genes of different myxosporean species. Phylogenetic analysis placed the detected parasite within a clade of Ortholinea sp. (AL-2006). Based on the results of the light and electron microscopy, histopathological, and molecular investigations, the detected parasite was identified as a myxosporean parasite belonging to the genus Ortholinea and designated as O. saudii sp. nov.

KEY WORDS: Marine fish · Red Sea fish · Myxospores · Endoparasites · Marbled spinefoot

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Cite this article as: Abdel-Baki AAS, Soliman H, Saleh M, Al-Quraishy S, El-Matbouli M (2015) Ortholinea saudii sp. nov. (Myxosporea: Ortholineidae) in the kidney of the marine fish Siganus rivulatus (Teleostei) from the Red Sea, Saudi Arabia. Dis Aquat Org 113:25-32. https://doi.org/10.3354/dao02821

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