Page 183 - 《水产学报》2025年第12期

张金叶，等 水产学报, 2025, 49(12): 129414

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Plate I The gill tissue of infected C. auratus and the mature myxospores of T. xiushanensis n. sp.
1. the gills of heavily infected C. auratus, the region in white dashed line displays erosions, and the region in yellow dashed line displays pallor and vas-
cular congestion; 2. the partial marginal gill tissue with myxoplasmodia, black arrows represent the myxoplasmodia; 3. mature myxospore of T. xiushan-
ensis n. sp. in frontal view, white arrowhead represents the transparent membrane sheath; 4. mature myxospore of T. xiushanensis n. sp. in sutural view. 5-
6. mature myxospore of T. xiushanensis n. sp. in frontal view and insutural view under the scanning electron microscope, respectively, white arrow rep-
resents the suture. 7. schematic illustrations of T. xiushanensis n. sp. in frontal view and sutural view, respectively.
turns, were aligned parallel to the longitudinal axis T. wuhanensis (JQ690370), 91.62% with T. kitauei
of the polar capsule (Plate I-3, 7, Tab. 1). The (MN227353), and 90.32% with T. hovorkai
aspect ratios for myxospore and polar capsule were Achmerov, 1960 (DQ231155).
1.00∶0.55 and 1.00∶0.83, respectively. Addition- Phylogenetic analysis using ML and BI meth-
ally, the ratio of myxospore length to polar capsule ods yield similar results, thus they were incorpor-
length was 1.00∶0.41, and the ratio of spore width ated into a single tree based on the BI tree (Fig. 1).
to polar capsule width was 1.00∶0.66. In the phylogenetic trees, the vast majority of Thel-
2.2 Molecular and phylogenetic characteristics ohanellus species were clustered into two evolution-
ary sub-branches, with sub-branch A species mainly
In the present study, two sequences, both 1 938
lacking membranous sheath whereas sub-branch B
nt, were obtained from two isolated cysts in the tips
species mainly possessing it. The present species
of the gill filaments from two individual C. auratus.
(PQ607809 and PQ607808) fell into sub-branch B,
Both were deposited in GenBank (accession num-
and firstly clustered with Neoactinomyxum sp. NEO-
ber: PQ607808 and PQ607809, respectively).
7 (KY784594), then with T. wangi (KY784592) and
Sequence alignment revealed 100% mutual between
Thelohanellus sp. (MK412938) is sister to a, and the
the two equally long sequences, and a maximum
bootstrap support values both of BI/ML were
similarity of 99.95% with an actinosporean Neoac-
100/100 (Fig. 1).
tinomyxum sp. NEO-7 SSU rDNA (KY784594).
2.3 Histopathology
Similarities to other Thelohanellus species ranged
below 94%, including 93.73% with Thelohanellus In general, H.E stains demonstrated that
wangi Yuan et al., 2015 (KY784592), 92.19% with numerous mature and immature myxoplasmodia,

中国水产学会主办 sponsored by China Society of Fisheries https://www.china-fishery.cn
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