Henneguya calcarifer, Borkhanuddin & Cech & Molnár & Shaharom-Harrison, 2020

Borkhanuddin, Muhammad Hafiz, Cech, Gábor, Molnár, Kálmán & Shaharom-Harrison, Faizah, 2020, Henneguya (Cnidaria: Myxosporea: Myxobolidae) infections of cultured barramundi, Lates calcarifer (Perciformes: Latidae) in an estuarine wetlands system of Malaysia: description of Henneguya setiuensis n. sp., Henneguya voronini n. sp. and Henneguya calcarifer n. sp., Parasitology Research (85) 119 (1), pp. 85-96 : 90-91

Henneguya calcarifer n. sp.

Type host: barramundi, Lates calcarifer (Bloch 1790) .

Site of infection: Skeletal muscle.

Type locality: Setiu Wetlands , Terengganu, Malaysia .

Prevalence of infection: 2.8% (1/35).

Type material: Digital images of syntype spores were deposited in the parasitological collection of the Zoological Department, Hungarian Natural History Museum, Budapest, collection no. HNHM-71894. The 18S rDNA sequence was deposited in GenBank under accession number MH743109

Etymology: The species is named after the host.

Description of spores: Fig. 3 . Myxospores symmetric, with two equal caudal appendages, and equal-sized polar capsules. Spore wall 0.3–0.4 μm, smooth and composed of two equal valves. Apical end of spore body blunt, the caudal end tapers and extends into the caudal appendages, total length 34–45 μm. Spore length 9.4 ± 0.6 (8.3–10.0) μm, width 5.2 ± 0.3 (4.8–5.5) μm and thickness 3.8 ± 0.1 (3.7–4.0) μm. Two polar capsules pear shaped, blunt at the posterior end and taper anteriorly, length 3.4 ± 0.2 (3.1–3.7) μm and width 1.4 ± 0.2 (1.1–1.7) μm. Polar tubules coiled in 6 turns perpendicular to the long axis of the capsule. Sporoplasm binucleate with a small iodinophilous vacuole. Caudal appendages straight, tapering, length 30.9 ± 3.0 (28.0–35.0) μm, ~ 4 times longer than the spore body. Plasmodia spherical 300 × 400 μm.

Remarks: H. calcarifer n. sp. resembles morphologically and morphometrically both H. setiuensis n. sp. and H. voronini n. sp. (Table 2) but has different tissue site of development (muscles not gill). This is the first muscle-infecting Henneguya described from Lates calcarifer and is relatively distinct from the only other species from a Lates congener: H. ghaffari from muscle and gills of L. niloticus in Egypt (Table 2).

Molecular analysis: 1696 bp 18S rDNA were sequenced. A BLAST search indicated that the most similar species were other Henneguya species, but all <89%. Pairwise analysis showed H. calcarifer n. sp. was molecularly very similar (97.7% over 1696 bp) with H. voronini n. sp., described from the same fish (above).

Histology: Low intensity of parasite plasmodia in the host skeletal muscle meant no plasmodia were visible in histological sections.

Figures

Fig. 3 Henneguya calcarifer n. sp. (a–b) Line drawings of mature myxospores in frontal view showing polar capsules with coiled polar tubules. (c) Unstained, compressed plasmodium, densely packed with mature myxospores