Morphological and molecular characterisation of Myxobolus pronini n. sp. (Myxozoa: Myxobolidae) from the abdominal cavity and visceral serous membranes of the gibel carp Carassius auratus gibelio (Bloch) in Russia and China

Abstract

BackgroundMyxozoa is a well-known economically and ecologically important group of metazoan parasites, phylogenetically related to Cnidaria. High diversity of myxosporeans has been recorded in Russia and China; however, most of the species were solely morphologically characterised. Here, we identified a new gibel carp-infecting Myxobolus species and morphologically and molecularly compared the Russian and Chinese isolates of this new myxosporean.Results Myxobolus pronini n. sp. was found free in the abdominal cavity of Carassius auratus gibelio (Bloch, 1782) in Lake Baikal watershed, Russia, and embedded in the visceral serous membranes of the same fish species in Lake Taibai, Hubei province, China. The morphometric data of the plasmodia and mature spores exhibited some differences between the Russian and Chinese isolates, but SSU rDNA sequences indicated that these two geographical isolates are conspecific. The mature spores from the two locations are obovate in frontal view, with wider anterior than posterior end and lemon-shaped in sutural view. Spores of the Russian isolate were 14.3–16.2 (mean 15.1 ± 0.2) μm long, 9.6–10.8 (10.1 ± 0.1) μm wide and 6.4–7.4 (6.7 ± 0.15) μm thick; those of the Chinese isolate were 13.8–15.6 (14.7 ± 0.24) μm long, 9.6–13.3 (9.6 ± 0.65) μm wide and 6.2–7.2 (6.6 ± 0.16) μm thick. The newly-generated rDNA sequences (including SSU rDNA, ITS and LSU rDNA) from the two isolates represented some variations within the intraspecific range. Homology search by BLAST showed that the newly obtained rDNA sequences do not match any sequences available on GenBank. Phylogenetic analysis based on the aligned partial SSU rDNA sequences indicated that this novel species clustered with several gibel carp-infecting Myxobolus spp. with round anterior end of spores. Additionally, phylogenetic analysis based on all obtained ITS sequences showed that distinct genetic geographical differentiation occurred for this new parasite.Conclusions Myxobolus pronini n. sp. is described by integrating morphological, ecological and molecular evidence. Two geographical isolates of this species showed some morphological and genetic differences but within the intraspecific range of variation.

Henneguya ovata n. sp. (Myxosporea: Bivalvulida), causing severe enteric henneguyosis of net-cage-cultured ovate pompano, Trachinotus ovatus in China

“…However, the spore shape of most of freshwater congeneric species, especially Siluriform-infecting species was lanceolate or spermatozoa-like. Our previous analysis of phylogenetic relationships of cyprinid-infecting myxobolids produced similar results (Liu et al, 2016). However, several Henneguya species infecting freshwater Perciformes possess freshwater species-typical spore shape, e.g.…”

Biodiversity and host-parasite cophylogeny of Sphaerospora (sensu stricto) (Cnidaria: Myxozoa)

“…The lack of tissue-tropism diversity in sphaerosporids led us to investigate other patterns such as geography, which was not found to mirror the phylogenetic tree of this group (Fig. 3 ) though important for the clustering of other myxozoans, especially at the species level [ 54 , 81 – 83 ]. Host habitat and host order clearly reflect sphaerosporid clustering, similar to other myxozoan clades (e.g.…”

Morphological plasticity in Myxobolus Bütschli, 1882: a taxonomic dilemma case and renaming of a parasite species of the common carp

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