Myxobolus pseudowulii sp. n. (Myxozoa: Myxosporea), a new skin parasite of yellow catfish Tachysurus fulvidraco (Richardson) and redescription of Myxobolus voremkhai (Akhmerov, 1960)

Abstract

Two species of Myxobolus Bütschli, 1882 were found in yellow catfish Tachysurus fulvidraco (Richardson). A species of Myxobolus infecting the gills was morphologically identified as Myxobolus voremkhai (Akhmerov, 1960) and it was characterised here with additional morphological and molecular data. The other species of Myxobolus infecting the host's skin did not conform to any known myxosporean species. It is characterised by the presence of round, black or milky white plasmodia with black spots. Myxospores are pyriform in frontal view and lemon-shaped in lateral view, measuring 12.9-16.2 μm (14.6 ± 0.7 μm) in length, 8.1-10.8 μm (9.4 ± 0.5 μm) in width, and 6.1-8.1 μm (7.0 ± 0.4 μm) in thickness. Two ampullaceous polar capsules are slightly unequal in size, larger polar capsule 7.2-9.5 μm (7.9 ± 0.4 μm) long by 3.0-3.9 μm (3.5 ± 0.2 μm) wide, smaller capsule 6.9-8.0 μm (7.4 ± 0.3 μm) long by 2.9-3.9 μm (3.4 ± 0.2 μm) wide. Polar filaments are coiled with seven to nine turns. Histologically, the plasmodia develop in the stratum spongiosum of skin dermis, resulting in epithelial cell shedding and immunological cell infiltration. Given the morphological and molecular differences between this species and other species of Myxobolus, we proposed the name of Myxobolus pseudowulii sp. n. for this parasite from the skin of yellow catfish. Interestingly, some spores of the new species possess Henneguya-like caudal appendages. Phylogenetically, M. pseudowulii sp. n. and M. voremkhai infecting yellow catfish group together in one clade with other parasites of Siluriformes, indicating that parasites clustering according to the fish host order may be an important factor affecting the evolution of species within the Myxobolus clade.

Morphological and genetic analysis of Ceratomyxa saurida Zhao et al. 2015 and Ceratomyxa mai sp. nov. (Myxozoa: Ceratomyxidae) from the East China Sea

“…Studies of another speciose myxozoan group, the Myxobolidae, have shown that closely related myxobolids have closely related vertebrate host species [40–43]. While we recovered this pattern among ceratomyxids, with many clades of Ceratomyxa sharing common host orders (), we also found that closely related ceratomyxids infect different host orders, and some host orders are shared by parasites from multiple clades.…”

Myxozoan hidden diversity: the case of Myxobolus pseudodispar Gorbunova, 1936

“…Moreover, this myxozoan sequence was detected only once in A. brama (Baska 1987, Forró andEszterbauer 2016) and once in Scardinius erythrophthalmus. Most of other M. pseudodispar related clades studied in the present work have also a narrow host spectrum similarly as many other species of Myxobolus, e.g., M. bejeranoi Lövy, Smirnov, Brekhman, Ofek et Lotan, 2018 from hybrid tilapia of Oreochromis aureus (Steindachner) male × Oreochromis niloticus (Linnaeus) female, or M. pseudowulii Zhang, Zhai, Liu et Gu, 2017 from the yellow catfish Pylodictis olivaris (Rafinesque) (Zhang et al 2017, Lövy et al 2018. The Abramis clade is the exception of the narrow host spectrum with four hosts (Abramis brama, Blicca bjoerkna, Perca fluviatilis and Sabanejewia bulgarica) detected to be infected by this myxobolid.…”

Morphological and molecular studies on two myxosporean infections of cyprinid fishes: Thelohanellus pyriformis from tench and Thelohanellus cf. fuhrmanni from nase

“…are rather host specific parasites infecting mostly a single species ( Akhmerov, 1955 , 1960 ; Molnár, 1982 ; Shin et al, 2014 ). Moreover, recent studies prove that most species can be characterized by strict tissue and organ specificity ( Akhmerov, 1955 ; Molnár and Eszterbauer, 2015 ; Liu et al, 2016 ; Zhang et al, 2017 ). The synopsis on Thelohanellus by Zhang et al (2013) focused to designate only the host and organ from where the Thelohanellus species were first described.…”