Aurantiactinomyxon, Janiszewska, 1957

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-

3.1.3. Aurantiactinomyxon type nov ( Fig. 6A–E )

Descriptions: Spore body subspherical, 8.8 ± 0.7 (7.6–10.1) μm in diameter. Caudal processes equal in size, elongated, tapering to pointed ends in apical view, and extending in a downward curve from spore body in side view, 36.7 ± 2.7 (30.7–43.8) μm long and 4.9 ± 0.6 (3.9–6.2) μm wide at the base of caudal processes. Valve cell nuclei not visible. Elongated pyriform polar capsules prominently protrude from the apex of spore body in both side view and apical view. Polar capsules

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in side view, 3.6 ± 0.3 (3.0–4.3) μm long and 1.3 ± 0.2 (1.1–1.9) μm wide; polar capsules in apical view, 2.0 ± 0.3 (1.5–2.5) μm in diameter. Polar filament turns not visible. Number of secondary cells not determined. Measurements were obtained from 25 ethanol-fixed actinospores.

Host: Species of the genus Bothrioneurum ˇStolc, 1886.

Site of infection: The intestinal epithelium. The studied worm displayed a severe infection, with pansporocysts at different developmental stages observed in the intestinal epithelium ( Fig. 6F ). In some parts of the worm, six to seven out of eight actinospores can be seen in the pansporocysts ( Fig. 6G ).

Prevalence: 2.7% (2 infected in 75 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-20896 .

Remarks: Morphometric measurements of the aurantiactinomyxon type were compared with 64 previously published descriptions of aurantiactinomyxon from freshwater and marine water ( Table 5). The morphology and morphometrics of the present aurantiactinomyxon type are inconsistent with any previously described aurantiactinomyxon types. The closest resemblance is found with aurantiactinomyxon type 11 ( El-Mansy et al., 1998b) although the present aurantiactinomyxon possess a larger spore body and caudal processes, while type 11 has shorter polar capsules. The spore body of the present aurantiactinomyxon closely resembles that of aurantiactinomyxon type 1 ( Milanin et al., 2018), and its polar capsule diameter is similar to aurantiactinomyxon type 1 described by Hallett et al. (1997), while other morphological features do not resemble to any known aurantiactinomyxon types. The spores exhibit prominently elongated pyriform polar capsules, which could be the distinguishing feature of this spore type compared to previously described aurantiactinomyxon types. Therefore, the present aurantiactinomyxon type appears to be novel. During this study, several attempts at molecular analyses were made using various primers to obtain specific band sizes but were unsuccessful. 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 PCR were performed with different primer combinations, but

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these attempts were also unsuccessful. This failure is probably due to errors in sample fixation that impeded the extraction of high-quality genomic DNA.

Figures

Fig. 6. Aurantiactinomyxon type nov. A) Schematic drawing of apical view. B) The side view of mature actinospores. C) Fixed (90% ethanol) aurantiactinomyxon spore in the apical view. D) Fixed (90% ethanol) aurantiactinomyxon spore in the side view. E) Higher magnification of fresh spore body showing three elongated polar capsules. F) Heavily infected Bothrioneurum sp. with pansporocysts at various stages of development in the intestinal epithelium. G) Pansporocyst showing six to seven of eight actinospores (arrowhead). In some spores, polar capsules can be seen (arrow). Scale bars represent 20 μm except E) 10 μm and F) 100 μm.