Triactinomyxon, Štolc, 1890

Suhaimi, Nadhirah Syafiqah, Bogl, Sellyei, arka, Cech, abor, Sz, Csaba, ekely & Borkhanuddin, Muhammad Hafiz, 2024, First record and description of actinospore stages (raabeia, triactinomyxon, and aurantiactinomyxon types) of fish parasitic myxozoans from Malaysia, International Journal for Parasitology: Parasites and Wildlife 24, pp. 100964-100964 : 100964-

3.1.2. Triactinomyxon type nov ( Fig. 5A–D )

Description: Spore possesses a spore body, style and three caudal processes. Spore body cylindrical and elongated, 27.9 ± 3.1 (21.7–33.0) μm long and 8.9 ± 0.7 (7.4–10.5) μm wide. Style short, 29.8 ± 3.9

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data.SBL: spore body length, SBW: spore body width, CPL:caudal processes length, CPW:caudal processes width, PCL:polar capsule length, PCW:polar capsule width,

SCn: number of secondary cells.

(22.4–38.6) μm long and 9.5 ± 1.1 (8.0–12.1) μm wide. Total length of spore, 57.6 ± 4.1 (51.2–67.8) μm. Caudal processes short, with blunt tips and equal in length, 29.9 ± 3.2 (24.6–35.1) μm long and 9.7 ± 0.9 (8.2–11.0) μm wide at the base. Largest span of caudal processes, 59.3 ± 3.6 (52.3–66.7) μm. Valve cell nuclei located at the base of caudal processes. Three pyriform polar capsules, equal in size and protruding from the anterior end, 3.4 ± 0.4 (2.8–4.0) μm long and 2.2 ± 0.2 (1.7–2.6) μm wide. Polar filament turns not visible well. Sporoplasm containing 8 secondary cells ( Fig. 5D ). Measurements were obtained from 25 ethanol-fixed actinospores.

Host: Species of the genus Branchiodrilus Michaelsen, 1900 .

Site of infection: The intestinal epithelium. The studied worm showed a massive infection, with pansporocysts at various stages of development observed in the intestinal epithelium ( Fig. 5E and F ).

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Prevalence: 0.59% (4 infected in 682 oligochaetes examined).

Locality: Tasik Telabak, Hulu Besut, Terengganu.

Type material: Series of phototypes was deposited in the parasitological collection of the Zoological Department, Hungarian Natural History Museum, Budapest, Coll. No. HNHM-PAR-20895 .

Remarks: Morphometric measurements of the triactinomyxon type were compared with previously published 19 descriptions of triactinomyxon possessing 8 secondary cells ( Table 4). The morphology and morphometrics of the present triactinomyxon type are inconsistent with any previously described triactinomyxon types. The spores exhibit short caudal processes and a style length that may be indicative of specific differences from the previously described triactinomyxon types. Thus, the present triactinomyxon type appears to be novel. Throughout this study, several attempts at molecular analyses were conducted; however, we were unable to yield specific band sizes although using several primer combinations. First, primers the same as those used for the raabeia type were tested but did not work with this sample. Subsequently, semi-nested and nested PCRs were performed with different primer combinations, but these attempts were also unsuccessful. This is probably due to errors in sample fixation that hindered the extraction of high-quality genomic DNA.

Figures

Fig. 5. Triactinomyxon type nov. A) Schematic drawing of mature actinospore. B) Freshly released triactinomyxon from Branchiodrilus sp. C) Triactinomyxon spore fixed in 90% ethanol. D) Higher magnification of spore body showing 8 secondary cells. E) Heavily infected Branchiodrilus sp. with pansporocysts at various stages of development in the intestinal epithelium. F) Higher magnification showing pansporocysts of triactinomyxon type in the intestinal epithelium. Scale bars represent 20 μm, except D) 10 μm and E) 100 μm.