The morphological and molecular characterization of Myxobolus khaliji n. sp. (Myxozoa: Myxosporea) from the double bar seabream Acanthopagrus bifasciatus (Forsskål, 1775) in the Arabian Gulf, Saudi Arabia

Abstract

Myxobolus khaliji n. sp., a new myxosporean, is described from the intestinal wall of the double bar seabream Acanthopagrus bifasciatus, collected from the Arabian Gulf off the coast of Saudi Arabia. It is characterized by the presence of ellipsoidal or round plasmodia of 2-4 mm in diameter. Mature spores were subspherical to elliptical in the frontal view, with a slightly pointed anterior end and a bluntly rounded posterior end, and measured 8.1 ± 0.4 (7.2-9.5) μm long, 6.3 ± 0.6 (5.1-7.4) μm wide, and 9.2 ± 0.7 (8.3-10.2) thick. Spore valves are relatively thin, sometimes with a prominent thick caudal appendage. Two equal elliptical polar capsules were situated in the plane of the suture line at the anterior end of the spores and occupied above half of the spore length. Polar capsules measured 5.5 ± 0.7 (4.1-6.1) μm long and 3.2 ± 0.2 (2.1-4.2) μm wide. Polar filaments, wound in three to four coils, were situated perpendicularly to the longitudinal axis of the polar capsules. Combining the morphological characteristics, host specificity and geographical distribution, tissue tropism, and the molecular analysis of the partial sequence of the SSU ribosomal DNA gene, it was concluded that M. khaliji n. sp. was distinct from all previously described Myxobolus species. Phylogenetic analysis placed the present Myxobolus species in a marine Henneguya clade, which is a sister group of marine Myxobolus species. This is the first Myxobolus species with Henneguya-like spores from the marine environment to be found in the Saudi Arabian coasts of the Arabian Gulf.

Supplemental description and molecular characterization of Myxobolus miyarii Kudo, 1919 (Myxosporea: Myxobolidae) infecting intestine of Amur catfish (Silurus asotus)

“…The reported species in the present work were highlighted in bold and species with spores of blunted anterior end underlined challenges the traditional taxonomy (Bahri 2008;Liu et al 2010Liu et al , 2014Zhang et al 2014) and suppression of Henneguya was also suggested (Kent et al 2001). In the present study, caudal appendages were firstly reported for some of spores of M.miyairii which is the ninth reported Myxobolus species with tailed spores after M. bizerti, M. mulleri, M. heterosporus, M. turpisrotundus, M. musseliusae, M. tsangwuensis, M. oralis, and M. khaliji (Bahri 2008;Liu et al 2010Liu et al , 2013Liu et al , 2014Zhang et al 2014). Interesting, two types of tailed spores (single tail or bifurcated tail) were firstly observed from most of plasmodia of M. miyairii which make it distinguished from the definition of Henneguya.…”

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

“…In conclusion, the few studies that have been performed on myxosporean parasites in the fish of the Arabian Gulf have not yet been able to take full account of the diversity of fish in this environment. The results of this study, along with the previous work of our team (Mansour et al, 2014, Mansour et al, 2015a, Mansour et al, 2015b, Zhang et al, 2014, Abdel-Baki et al, 2015, Abdel-Baki et al, 2017, Al-Qahtani et al, 2015) provides an initial indication of the potential importance of the Arabian Gulf as a source of new information on this field of science.…”

“…Until recently, little attention has been paid to the myxosporean parasites of these Arabian Gulf fish, and thus very little is known about these parasites. Most of the previous studies that have done on Arabian Gulf fish have concentrated mainly on the helminthes (Kardousha, 2016), and although sporadic work has been carried out on myxosporean parasites (Kardousha and El-Tantawy, 2002, Mansour et al, 2014, Mansour et al, 2015a, Mansour et al, 2015b, Zhang et al, 2014, Abdel-Baki et al, 2015, Abdel-Baki et al, 2017, Al-Qahtani et al, 2015), there is clearly a need for more extensive work to get a better idea of the species infecting fish in the Arabian Gulf in general and those off Saudi Arabia in particular. Here we present a minor contribution to this assemblage of work by describing a new species of Ceratomyxa from the gallbladder of Upeneus based on the morphometric criteria of its spores and the partial sequence of the 18S rRNA gene.…”

Morphological, ultrastructural, and molecular description of Unicapsula fatimae n. sp. (Myxosporea: Trilosporidae) of whitespotted rabbitfish (Siganus canaliculatus) in Omani waters

“…Although the majority of species belonging to this genus has been detected from the musculature (Miller and Adlard 2013 ; Tomochi et al 2014 ), some have been detected from other organs such as the gills (Diebakate et al 1999 ), kidney (Sarkar 1999 ), and urinary bladder (Naidjenova and Zaika 1970 ). Although marine parasitological investigations in the Arabian Peninsula region dates back to the 1980s, the myxozoan parasite fauna received only most recent attention, resulting in several new species being recorded from various marine hosts, caught off the coasts of the Kingdom of Saudi Arabia (Red Sea and Arabian Gulf) (Zhang et al 2014 ; Mansour et al 2014 , 2015a , 2015b ). The present study describes a new species of Unicapsula using morphological, ultrastructural, histological, and molecular characterization, infecting the esophagus and stomach endothelium of S. canaliculatus .…”