Kudoa viseuensis, Monteiro & Da Silva & Sanches & Hamoy & Matos, 2019

Monteiro, Elideth Pacheco, Da Silva, Diehgo Tuloza, Sanches, Osimar, Hamoy, Igor & Matos, Edilson Rodrigues, 2019, Morphological and Molecular Characteristics of Kudoa viseuensis n. sp. (Myxosporea: Multivalvulida), Found in the Muscle of Batrachoides surinamensis (Teleostei: Batrachoididae) in the Brazilian Amazon Region, Acta Protozoologica 58 (1), pp. 7-16 : 9-13

Kudoa viseuensis n. sp.

ZooBank: lsid:zoobank.org:act: AF886D76-EC95- 4EA7-8F0D-DA2D4B956A60

Host: Batrachoides surinamensis (Bloch and Schnei- der, 1801).

Infection site: Pseudocysts in the somatic musculature.

Type locality: Brazil, state of Pará, municipality of Viseu (1°08’ S, 46°05’ W) .

Prevalence: 86% (52/60) of the examined hosts were infected.

Etymology: the specific name, viseuensis , refers to the municipality of Viseu, where the specimens were captured.

Type specimen: A glass slide with a 5 μm-thick his- tological section stained in Haematoxylin and Eosin , containing the spores of the new species was deposited in the Zoology Museum of the National Institute of Amazonian Research (INPA) in Manaus, Amazonas, Brazil, under catalog number CNIDARIA – INPA 038 .

Description of the spores: The spores of Kudoa viseuensis n. sp. were 7.2±0.2 μm in length and 5.2±0.2 μm in width ( Figure 3 ). In the apical view, the polar capsules were 1.8±0.2 μm in length and 1.3±0.1 μm in width. When observed laterally, the mean length was 2.7±0.2 μm and the width was 1.3±0.1 μm ( Table 1 ). Table 1 compares the dimensions of the spores and polar capsules (and the shape of the spores) of other Kudoa species with Kudoa viseuensis n. sp. ( Cnidaria: Myxozoa: Myxosporea: Multivalvulida : Kudoidae ). Kudoa viseuensis n. sp. was restricted to the skeletal musculature of the host, and was not found in any other organ of the host fish.

The morphological comparisons indicated that Kudoa viseuensis n. sp. is most similar to K. orbicularis ( Azevedo et al. 2016) in terms of the width of the spore and the polar capsule, although other dimensions are clearly distinct from those of this species, and other Kudos species, studies previously. These findings, to- gether with the molecular data (see below) lend support to the present description of the new species.

Phylogenetic analyses

A partial sequence of 1400 base pairs (bps) of the SSU rDNA gene was obtained from the spores of Kudoa viseuensis n. sp., found in the musculature of B. surinamensis . This sequence was deposited in GenBank under accession number MK256272 . The phylogenetic tree generated by Bayesian Inference defined a major clade, denominated clade A, composed of species of the genus Kudoa ( Figure 4 ), which is subdivided into two clades, denominated A1 and A2, with high support (posterior probabilities). Each of these clades was influenced strongly by the tissue tropism of the parasites, with Kudoa viseuensis n. sp. being included in subclade A2. Subclade A1 is composed of Kudoa species that parasitise the musculature, brain, and intestine of fish- es. Kudoa viseuensis n. sp. is included in subclade A2, which is basal to A1. Kudoa viseuensis n. sp. parasitizes the musculature of the marine fish B. surinamensis , and clusters with Kudoa orbicularis ( Azevedo et al. 2016) , a parasite of the musculature of the freshwater fish, Chaetobranchopsis orbicularis . In this arrangement, K. orbicularis is the sister species of Kudoa viseuensis n. sp., and the two species not only share the infection site, but are also found in the same geographic region.

The outgroup is composed of species of the genus Unicapsula Davis, 1924 , a member of the order Multivalvulida Schulman, 1959 , which infects the musculature of its hosts.

A new alignment was run for the pairwise comparison of key Kudoa species with Kudoa viseuensis n. sp. ( Table 2 ). The smallest pairwise genetic distance (p) found in this analysis between Kudoa viseuensis n. sp. and the other Kudoa species was 3.9% in the case of K. orbicularis ( KM192365 ), while the greatest distance was 4.9% for K. rosenbuschi ( AY623795 ).

Figures

Figure 3. Schematic drawing of a spore of Kudoa viseuensis n. sp. in apical view (right) and side view (left). Scale bar = 5 μm

Figure 4. Phylogenetic tree derived from Bayesian Inference (BI), based on the partial sequences of the SSU rDNA gene of Kudoa vi- seuensis n. sp. and closely-related myxosporans. The GenBank access numbers are shown next to the species names, and the numbers at each node are the BI posterior probabilities.The new species is highlighted in bold type. Abbreviations: Msl – muscle; Dtr – digestive tract; Nsy – nervous system.

Tables

Table 1. Morphometric measurements (μm) of the spores of Kudoa viseuensis n. sp., and closely-related species. The data area presented as means with their respective standard deviations (with the range of values within parentheses).

Species (Reference)	Host	Spore (µm)		Polar capsule (µm)				Spore form
		Width	Length	Width (L*)	Length (L*)	Width (A*)	Length (A*)
This study	Batrachoides surinamensis	5.2±0.2 (5.1–5.4)	7.2±0.2 (6.7–7.4)	1.3±0.1 (1.1–1.4)	2.7±0.2 (2.4–2.9)	1.3±0.1 (1.2–1.5)	1.8±0.2 (1.6–2.0)	Pseudo-square
K. orbicularis ( Azevedo et al. 2016)	Chaetobranchopsis orbicularis	5.1 (4.2–5.8)	4.3 (3.6–5.0)	ND	2.1 (1.7–2.6)	1.3 (0.9–1.7)	ND	Rounded quadrate
K. pleurogrammi ( Kasai et al. 2016)	Pleurogrammus monopterygius	8.6 (8.2–9.1)	6.3 (5.6–6.8)	ND	2.8 (2.7–2.8)	1.6 (1.4–2.0)	ND	Subquadrate
K. rayformis ( Shin et al. 2016)	Scomberomorus sierra	5.0 ± 0.3 (4.6–5.7)	5.4 ± 0.2 (5.0–5.7)	1.7 ± 0.2 (1.4–2.0)	2.3 ± 0.2 (1.9–2.6)	1.9 ± 0.2 (1.5–2.5)	1.9 ± 0.3 (1.5–2.6)	Subquadrate
K. islandica (Kristmundsson and Freeman, 2014)	Cyclopterus lumpus	7.4 (6.5–8.6)	4.8 (4.1–5.1)	ND	1.7 (1.4–1.9)	1.5 (1.2–1.8)	ND	Pseudo-square
K. paraquadricornis ( Burger and Adlard, 2010)	Caranx ignobilis	7.79±0.22 (7.3–8.2)	8.03± 0.24 (7.6–8.5)	1.57±0.09 (1.3–1.7)	4.17±0.21 (3.7–4.5)	1.7± 0.06 (1.5–1.8)	1.98± 0.05 (1.9–2.1)	Subquadrate
K. quadricornis ( Burger and Adlard, 2010)	Carangoides fulvoguttatus	7.84±0.28 (7.2–8.3)	8.38± 0.27 (7.9–9.0)	1.55± 0.1 (1.4–1.8)	4.26±0.2 (3.8–4.6)	1.67± 0.08 (1.5–1.8)	2.01± 0.08 (1.9–2.2)	Subquadrate
K. inornata ( Dyková et al. 2009)	Cynoscion nebulosus	5.9 (5.8–6.0)	5.4 (5.3–5.5)	ND	2.7	ND	ND	Pseudo-square
K. alliaria ( Whipps and Diggles, 2006)	Macruronus magellanicus	8.51 (7.84–9.25)	6.35 (5.84–6.86)	ND	2.60 (2.27–2.82)	1.61 (1.40–1.87)	ND	Pseudo-square
K. rosenbuschi ( Abollo et al. 2005)	Merluccius hubbsi	4.47 (4.2–4.8)	3.21 (2.8–3.6)	ND	ND	ND	ND	Pseudo-square
K. paniformis ( Hervio et al. 1997)	Merluccius productus	5.9 (5.0–6.5)	5.0 (4.5–6.0)	ND	2.0 (1.9–2.4)	1.6 (1.4–1.9)	ND	Pseudo-square

ND – Not available; L* – Lateral; A* – Apic