Zoosyst. Evol. 99 (2) 2023, 391-397 | DOI 10.3897/zse.99.105770

> PENSUFT.

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BERLIN

First report of a histozoic Henneguya (Cnidaria, Endocnidozoa)
infecting a synbranchid potamodromous fish from South America:
Morphostructural and biological data

Patrick D. Mathews", Omar Mertins*, Luis L. Espinoza®, Julio C. Aguiar!, Tiago Milanin*

1 Department of Parasitology, Institute of Biosciences, Sado Paulo State University, 18618-689 Botucatu, Brazil
2 Laboratory of Nano Bio Materials, Department of Biophysics, Paulista Medical School, Federal University of Sao Paulo, 04023-062 Sao Paulo,

Brazil

3 Laboratory of Biology and Molecular Genetics, Faculty of Veterinary Medicine, Universidad Nacional Mayor de San Marcos, Lima 15021, Peru

4 Department of Basic Sciences, Faculty of Animal Science and Food Technology, University of Sdo Paulo, 13635-900, Pirassununga, Brazil

https://zoobank. org/7 D9E1775-A6FC-49D0-9B89-EBF51D3DC912

Corresponding author: Patrick D. Mathews (patrickmathews83@gmail.com)

Academic editor: Pavel Stoev # Received | May 2023 # Accepted 12 June 2023 @ Published 5 July 2023

Abstract

In this study, a Henneguya myxosporean species is described to infect an ecological, biological, and evolutionary important fish from
Amazon biome. The myxosporean was found in the skin of only one specimen of marbled swamp eel, Synbranchus marmoratus
caught in a small stream from Peruvian Amazon floodplain. Mature myxospores have ovoid shape from the valvular view, measuring
32.2 + 0.6 um (31.6—32.8) in total length, 21.5 + 0.3 um (21.2—21.8) in spore body length, 11.7 + 0.5 um (11.2—12.2) in width and
10.6 + 0.9 um (9.7-11.5) in thickness. Non-bifurcate caudal appendage, measuring 10.7 + 0.4 um (10.3—11.1) in length. Two polar
capsules elongated aubergine in shape, equal in size and measuring 4.9 + 0.2 um (4.7—5.1) in length and 3.1 + 0.5 um (2.6—3.6) in
width. Polar tubules coiled in 7—8 turns. This is the first report of a Henneguya species parasitizing a fish of the order Synbranchiformes

from Amazon basin and the first to describe this parasite infecting a potamodromous fish from South America.

Key Words

Henneguya, myxosporean, marbled swamp eel, skin, Peru

Introduction

Myxosporean are a biologically diverse group of micro-
scopic cnidarians of wide distribution around the world (At-
kinson et al. 2018). They mostly innocuous parasites with
complex life cycles that involve invertebrate and vertebrate
hosts (Okamura et al. 2015). Although, most myxosporean
species have fish hosts, they have radiated sporadically into
other groups of vertebrates, including amphibians, reptiles,
waterfowl and small mammals (Okamura et al. 2015).
Within myxosporean, Henneguya Thélohan, 1892 is one of
the most species rich genera with more than 250 species
described taxonomically (Eiras 2002; Rangel et al. 2023).
Although the Amazon basin is one of the main biodiversity

hotspots, the myxosporean fauna is poorly known. To date
only 19 Henneguya species have been reported in fish from
this geographic region with almost all reported data so far
coming from the Brazilian part of the Amazon basin (Eiras
and Adriano 2012; Mathews et al. 2016; Naldoni et al.
2018). In the Peruvian Amazon, despite a recording of over
650 fish species, there 1s a gap in the knowledge of myxo-
sporean diversity. Indeed, only three Henneguya species
have been described (Mathews et al. 2017, 2018, 2020).
The marbled swamp eel Synbranchus marmoratus Bloch,
1795 is considered a potential predator and it can be found
throughout flooded forests, small streams and associated
swamps subject to water level changes, between the rainy
season and the dry period (Heisler 1982; Favorito et al. 2005;

Copyright Mathews, P.D. et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use,
distribution, and reproduction in any medium, provided the original author and source are credited.

392 Mathews, P.D. et al

Junges et al. 2010). This species of fish is a protogynous di-
andric, meaning that females will change their sex and be-
come males (Allsop and West 2003). It is a potamodromous
species which is capable of switching from exclusive water
breathing to exclusive air breathing (Heisler 1982). Despite,
the ecological, biological, and evolutive importance of the
marbled swamp eel, little is known about its parasitic fauna,
particularly the ones concerning myxosporean parasites.
This study aims to contribute to the increase of knowl-
edge of diversity cnidarian myxosporean and their interac-
tion with fishes from Amazon biome. Thus, spore morphol-
ogy features using light, scanning and transmission electron
microscopy as well as other important biological characters
such as tissue tropism and host-specificity are provided.

Materials and methods

Six specimens of S. marmoratus (ranging from 18.1 to
21.6 cm in length) that died during transport were donat-
ed by local fishers for ornamental fishes in March 2018.
According to the fishers, these fish were caught in a small
stream near of the Village Oran (3°21'0"S, 72°31'0"W),
Omagua Region, Department of Loreto, Peru.
Morphometric analysis was performed following the
criteria outlined by Lom and Arthur (1989). Measure-
ments and photographs were taken from 30 randomly
selected formalin-fixed mature myxospores, using a com-
puter equipped with Axiovision 4.1 image capture soft-
ware coupled to an Axioplan 2 Zeiss microscope (Carl
Zeiss AG, Oberkochen, Germany). Spore length, thick-
ness, polar capsule length, width, and caudal appendage
length were measured and given in micrometers (um) and
expressed as a mean + standard deviation, followed by
the range in parentheses where appropriate. Permanent
slides containing mature myxospores stained with Giem-
sa were mounted and deposited in the cnidarian collection
of the Zoology Museum at the University of Sao Paulo —
MZUSP, Sao Paulo, Brazil (Hapantotype MZUSP 8733).
Histological analysis was performed on fresh tissue
fragments containing plasmodium. Infected tissue was
fixed in 10% buffered formalin solution, then dehydrated
with increasing series of ethanol, diaphanized, embedded
in paraffin, cut into serial sections 5 um thick using an HM
340E electron microtome (Thermo ScientificTM, Mas-
sachusetts, USA), and stained with haematoxylin/eosin.
A light microscope DM1000 (Leica, Washington, USA)
coupled to a computer and using the Leica Application
Suite software version 1.6.0 was used for image capture.
Surface ultrastructure observation was performed in
leaked myxospores from ruptured plasmodium using a
glass slide previously treated with poly-L-lysine. Samples
were processed as described in Mathews et al. (2022a).
Samples were visualized with a DSM 940 scanning elec-
tron microscope (Carl Zeiss, Hamburg, Germany) oper-
ating at 15 kV. For internal structural analyses, a whole
intact plasmodium was fixed in 2.5% glutaraldehyde with
0.1 M buffered cacodylate (pH 7.4) for 24 h and processed

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.. First cnidarian Henneguya from a potamodromous fish from South America

routinely according to standard transmission electron mi-
croscope methods. Samples were examined under a JEOL
1200 EX II transmission electron microscope at 60 kV and
micrographs were captured with a GATAN 791 camera.
For molecular diagnostic, extraction of genomic DNA
(gDNA) was performed in a single plasmodium dissected
from the skin and fixed in absolute ethanol. The gDNA
was extracted using a DNeasy Blood & Tissue Kit (Qia-
gen Inc., California, USA), in accordance with the man-
ufacturer’s instructions for animal tissue protocol. Poly-
merase chain reactions (PCRs) were conducted in a final
volume reaction of 25 wL, which comprised 10-50 ng
of extracted DNA, 0.2 pmol for each primer, 12.5 wL of
Dream Taq Green PCR Master Mix (Thermo Scientific)
and nuclease-free water. Partial 18S rDNA sequence was
amplified using routinely chosen primers paired as fol-
lows ERIB1 with ACTIr and Myxgen4F with ERIB10
(Barta et al. 1997, Kent et al. 2000, Hallett and Diamant
2001). PCRs were performed in an AG22331 Hamburg
Thermocycler (Eppendorf, Hamburg, Germany) and am-
plification thermal cycling consisted of 95 °C for 5 min,
followed by 35 cycles at 95 °C for 1 min, 58 °C for 1 min,
72 °C for 2 min, and then final elongation at 72 °C for
5 min. Amplification PCR products were electrophoresed
in 2.0% agarose gel in a Tris-Acetate EDTA buffer,
stained with Sybr Safe DNA gel stain (Invitrogen by Life
Technologies, Carlsbad, USA), and analyzed under a
Stratagene 2020E trans illuminator (Stratagene Califor-
nia, San Diego, USA). Band sizes of the amplicons was
estimated by comparison with the concurrently run mo-
lecular weight marker 1 Kb Plus DNA Ladder (Invitrogen
by Life Technologies). PCR products were purified using
USB ExoSap-IT (Thermo Fisher Scientific, Waltham,
USA) in accordance to the manufacturer’s instructions.
Purified PCR amplicons were sequenced using the same
PCR primers and performed with a BigDye Terminator
v3.1 cycle sequencing kit (Applied Biosystems Inc., Cal-
ifornia, USA) in an ABI 3730 DNA sequencing analyzer.

Results

Of six wild specimens of S. marmoratus, a single wild
specimens of S. marmoratus examined, was infected in
the skin by an unknown cnidarian myxosporean species.
Based on the phenotypic characters of the mature myxo-
spores, this species was assigned to the genus Henne-
guya. The fish presented five plasmodia distributed in the
body skin. The same were not found in any other organ.

Taxonomic summary

Phylum: Cnidaria Verrill, 1865.
Subphylum: Endocnidozoa Schuchert, 1996.
Class: Myxosporea Biitschli, 1881.

Order: Bivalvulida Shulman, 1959.

Family: Myxobolidae Thélohan, 1892.

Zoosyst. Evol. 99 (2) 2023, 391-397

Genus Henneguya Thélohan, 1892

Species. Henneguya sp. (We suggest that this isolate,
after determination by molecular phylogenetic data, be
named as (H. atingae) based on host species common
name in Peru.

Type host. Symbranchus marmoratus (Teleostei:
Symbranchidae).

Site of infection. Stratus corneum of epidermis layer
of the skin.

Type locality. Small stream, adjacent area of Oran
Village, Loreto Department, Peru (3°21'0"S, 72°31'0"W).

Description. Morphological observations by light mi-
croscopic showed mature myxospores have ovoid shape
from the valvular view, measuring 32.2 + 0.6 um (31.6—
32.8) in total length, 21.5 + 0.3 um (21.2—21.8) in spore
body length, 11.7 + 0.5 wm (11.2—12.2) in width and 10.6 +
0.9 um (9.7—-11.5) in thickness (Fig. 1a, c). Non-bifurcate
caudal appendage, measuring 10.7 + 0.4 um (10.3—11.1) in
length (Fig. 1a, c). Two polar capsules elongated aubergine
in shape, equal in size and measuring 4.9 + 0.2 um (4.7—

Figure 1. Henneguya sp. parasite from the skin of Synbranchus
marmoratus. a: formalin-fixed myxospores in valvular view
showing appendage caudal (large arrows) and two polar cap-
sules in the anterior pole of spore occupied only the anterior
third of the myxospore body (small blue arrows). b: mature
myxospores stained with Giemsa with noticeable binucleate
sporoplasm (double arrow) and polar capsules with aubergine
shape (large arrow). ¢: schematic illustration of mature myxo-
spore with polar tubule inside of polar capsule. Scale bars: 5 um.

393

5.1) in length and 3.1 + 0.5 um (2.6—3.6) in width (Fig. 1b,
c). Sporoplasm evidenced two nuclei in valvular view and
sutural line was noticeable in side view (Fig. 1b, c).
Surface topography analyses of mature myxospores
in valvular view revealed smooth valve cell with pres-
ence of mucous in a small area (Fig. 2a). In sutural view
myxospore evidence a conspicuous sutural line (Fig. 2c).
The density of caudal appendage 1s likely be identical to
that of its valve (Fig. 2b). Internal ultrastructural obser-
vations showed binucleated sporoplasm contained sev-

Figure 2. Surface topography by SEM of Henneguya sp. in-
fecting skin of Synbranchus marmoratus. a: mature myxo-
spore in valvular view showing smooth valve cell with
presence of mucous (white star) in a small area and caudal
appendage. Scale bar. | um. b: amplified area of the caudal
appendage evidencing density of caudal appendage likely to
be identical to that of its valve. Scale bar. 200 nm ¢: myxo-
spore evidence a conspicuous sutural line in sutural view.
Scale bar: 100 nm.

Figure 3. Internal ultrastructure by TEM of myxospore of Henneguya sp. infecting skin of Synbranchus marmoratus. a: sporoblast
in young developmental stage showing binucleated sporoplasm (n) contained several sporoplasmosomes (asterisk), valve-forming
materials (white arrow) and polar capsules (pc) with absence of polar tubule. b: polar capsule (pc) with capsular nuclei, polar tubule
internalized contained seven to eight coils (pt), sporoplasm binucleated (spl/n) and contained sporoplasmosomes (asterisk) at a more
advanced sporoblast developmental stage. c: Spores with sutural lines (small arrows), sporoplasm with numerous sporoplasmo-
somes (asterisk) and caudal appendage (large arrow). Scale bars: 2 um.

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Mathews, P.D. et al

Y ’ Ba pale val *
vl) gee pe eek Pi
+e ea
| as Big: Pca) cet ey
seer ; 7 = DF *
A. ere ‘, fe

Figure 4. Histological sections of the host-tissue infected of
Synbranchus marmoratus with Henneguya sp. a: Intact plasmo-
dium located in the stratus corneum of epidermis layer of the
skin. Scale bar. 50 um. b: mature myxospore in sutural view
with noticeable caudal appendage. Scale bar. 10 um.

Figure 5. Agarose gel showing 18S rDNA gene PCR amplifi-
cation of Henneguya sp. from skin infected of S. marmoratus.
Lane 1: DNA ladder marker, Lane 2: amplicon 1000 pb approx.
(ERIBI/ACTIr), Lane 3: amplicon 1100 pb approx. (Myx-
gen4F/ ERIB10), Lane 4: Negative Control.

eral sporoplasmosomes and valve-forming materials in
young sporoblast developmental myxospore stage (Fig.
3a). Polar capsule with polar tubule internalized and con-
tained seven to eight coils at a more advanced sporoblast
developmental stage (Fig. 3b). Caudal appendage and
conspicuous sutural line in mature spores. (Fig. 3c).

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.. First cnidarian Henneguya from a potamodromous fish from South America

Histologic evidenced tissue tropism of the myxospor-
ean under study, occurring in the stratus corneum of epi-
dermis layer of the skin (Figure 4). The parasites induced
no apparent tissue destruction, ulcerations, necrosis or
inflammatory response. For molecular procedures, par-
tial 18S rDNA gene was successfully amplified by PCR
(Fig. 5), however, sequencing failed.

Discussion

Despite the growing description of myxosporean infect-
ing South American fishes (Sousa et al. 2021; Adriano
and Oliveira 2022), the diversity of these ancient meta-
zoans in this neotropical realm remains largely unknown
(Okamura et al. 2018; Mathews et al. 2022b). In this con-
text, our study describes a histozoic myxosporean spe-
cies of Henneguya, infecting skin of the Amazonian pota-
modromous fish S. marmoratus. In the Amazon biome,
Henneguya encompasses 22 recognized species (Table
1), reported infecting Characiform, Perciform, Cichli-
form, Gymnotiform and Siluriform fishes (Mathews et
al. 2017, 2018; Adriano and Oliveira 2022; Rangel et al.
2023). However, to the best of our knowledge, this is the
first report of a Henneguya species parasitizing a fish of
the order Synbranchiformes from Amazon basin and the
first to describe this parasite infecting a potamodromous
fish from South America. Thus, our results contribute to
freshwater myxobolids taxonomy and to increasing our
knowledge of cnidarian myxosporean diversity.

The morphological data of the mature myxospore iso-
lated were first compared considering Henneguya species
previously described from Peruvian Amazon freshwater
fishes. Nevertheless, these differ from the new isolated in
myxospore body length (18.7 + 0.9 um in length for H.
multiradiatus, 14.3 + 0.1 um for H. loretoensis, 13.4 +
0.9 um for H. peruviensis and 21.5 + 0.3 um to the new
isolated), polar capsule length (9.1 + 0.1 um in H. multira-
diatus, 5.1 + 0.2 um in H. loretoensis, 3.3 + 0.2 um in H.
peruviensis and 4.9 + 0.2 um in the new isolated), number
of coils of the polar tubule (10-11 in H. multiradiatus, five
in H. loretoensis, four to five in H. peruviensis and seven
to eight in the new isolated) and in the length of the cau-
dal appendage (25.8 + 0.6 um in H. multiradiatus, 21.9 +
O.1um in H. loretoensis, 10.7 + 0.1 in H. peruviensis and
10.7 + 1.2 um in the new isolated). Compared with the
all other freshwater Henneguya species reported to infect
Amazonian fishes, the new isolated differed in at least one
characteristic (shape of spore, size of spore or polar cap-
sule, presence or absence or number of valve striations,
size of caudal appendage and number of polar tubules
turns), tissue and host preference as showed in the Table 1.

According to Molnar and Eszterbauer (2015), for fresh-
water histozoic myxosporean particularly for Henneguya
and Myxobolus species, the site of infection is considered
an important taxonomic key for identification due to high
organ and/or tissue specificity of these group of parasites.
Accordingly, differences are observed because plasmodia

Zoosyst. Evol. 99 (2) 2023, 391-397

395

Table 1. Comparative data of Henneguya sp. with other Henneguya species parasites of Amazon fish. Spore dimensions, infection
sites, and fish host are given. TL: total length; BL: body length; APCL: caudal appendage length; SW: spore width; ST: spore thick-
ness; PCL: polar capsule length; PCW: polar capsule width; NCT: number of coils of polar tubules, *: Peru. All measurements are
in um and/or means + SD. Source: Rangel et al. 2023, Eiras, 2002.

Species TL BL APCL SW ST PCL PCW NCT Site of Fish species
infection
*Henneguya sp. | 32.2+0.6 | 21.5+0.3 | 10.7+0.4 | 11.7+0.5 |10.6+0.9 skin Synbranchus
marmoratus
Henneguya 53.4+2.9 | 12.6+0.6 | 40.7 + 2.8 4-5 | gill filaments, Plagioscion
longisporoplasma fins squamosissimus
*Henneguya 44.5+0.6 | 18.7+0.9 | 25.8+0.6 Abdominal | Brochis multiradiatus
multiradiatus cavity serosa
*Henneguya 24.2+1.3 | 13.4+0.9 | 10.7+1.2 4-5 | Gill filaments | Hyphessobrycon
peruviensis loretoensis
*Henneguya 36.24+0.2 | 14.3+0.1 | 21.9+0.1 Gill filaments Corydoras
loretoensis leucomelas
Henneguya 43.8+41 |] 14+08 | 28.1+4.3] 6.1+0.7 ~ 3.4+0.5 |1.98+0.3) 3-4 | Gill filaments | Cichla monoculus
tucunarel
Henneguya 54.6+3.9 | 16.4+1.2 4-5 | Gill filaments Cichla pinima
tapajoensis
Henneguya 46.7+1.5 | 13.4+0.7 Fins Cichla monoculus
Jariensis
Henneguya 42.3+0.3 |12.8+ 0.42|29.5+0.73|} 86+0.3 - 74+0.1 | 2.6+0.1 | 5-7 |Gillfilaments| Cichla temensis
paraensis
Roma 0k =

Henneguya melini| 40.8 + 0.3 | 15.5 + 0.2

25.3+0.1 ] 4.7+0.1

48+0.5

1.7+0.3

5-6 | Gill filaments

Corydoras melini

Henneguya 41+1.5 3+0.3 3+0.3 4-6 | Gill flaments Aequidens
aequidens plagiozonatus
Henneguya 48.62 +0.5 | 28.53 + 0.3) 19.64 +0.4 | 7.25 + 0.31 |3.06 + 0.2|6.41 +0.2/1.84+0.1 Brain and Brachyhypopomus
torpedo spinal cord pinnicaudatus
Henneguya 4.9+0.2| 65+0.2 | 6.3+0.1 Gill arch Arapaima gigas
arapaima
Henneguya 17.7 7 10.7 3.6 2.5 eS 0.85 6-7 Lateral Gymnorhamphichthys
rondoni nerves rondoni
Henneguya 10-11 | Gill flaments Rhamdia quelen
rhamdia
Henneguya Kidney Schtzodon fasciatum
schtzodon
Henneguya Gut, gill, Leporinus friderici
friderici kidney and

liver
Henneguya 47.8 +0.71 }15.2 + 0.77] 32.64 1.11 5.0 +0.13/1.5+0.07} 8-9 | Gill flaments | Astyanax bimaculatus
astyanax
Henneguya 19.1 3.3 + 0.02] 1.5 + 0.04 Kidney Curimata inormata
curimata
Henneguya Testicle Moenkhausia
testicularis oligolepis
Henneguya 28.3 12.6 LA 4.8 - Su 1.8 6-7 | Gill flaments | Hoplias malabaricus
malabarica
Henneguya Seal 3-4 | Gill flaments | Acestrorhynchus
adherens falcatus
Henneguya 59.3+0.5 | 13.9+0.1 | 45.4+0.6 | 5.7 + 0.06 3.3 + 0.02|1.5 + 0.04 Gill lamellae | Crenlcichla lepldota
amazonica

of the new species were located in the skin, whereas H.
peruviensis and H. loretoensis plasmodia are found in the
gill filaments and H. multiradiatus plasmodia in the ab-
dominal cavity serosa. To our knowledge no Henneguya
species have been reported from the skin of a fish from
Amazon biome (Table 1). In the same vein, fish host rep-
resent an indispensable trait for accurately distinguishing
new freshwater histozoic Henneguya/Myxobolus species
since these parasites tend to cluster largely based on host
phylogenies (Carriero et al. 2013; Mathews et al. 2021;

Milanin et al. 2021). This is the first report of a Henneguya
Species parasitizing a synbranchid fish. Thus, considering
the fine-scale of the host-specificity, we consider our find-
ing to be important for this isolate as an unknown species.

Regarding molecular data, from South America of
the around hundred recognized species, large number
of species lack molecular data (Milanin et al. 2017).
Indeed, for much of the myxosporean described myxo-
spore morphology was used by ichthyopathologist re-
searchers for species discrimination, because myxo-

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396 Mathews, P.D. et al

spore 1S a unique structure possessing many characters
important for classification (Lom and Dykova 1992). In
our study, the partial 18S rDNA gene was successfully
amplified by PCR using general eukaryotic and specif-
ic primers to myxosporean parasites (Fig. 5). However,
after the amplification process, sequencing failed so it
was not possible to carry out phylogenetic analysis. In
addition, to the few samples with only five plasmodia
to perform morphological, ultrastructural, histological
and molecular analysis and limitations in accessing
new samples of the same region. Although, we were not
able to provide the phylogenetic data, the new isolate
was strongly characterized based on spore morphomet-
rically features as well as biological traits such as tis-
sue preference and host specificity both important tax-
onomic keys for classification of freshwater histozoic
myxobolids. Future molecular phylogenetic studies are
highly recommended, since this would permit stronger
taxonomic comparison.

Acknowledgements

The authors thank the Sao Paulo Research Founda-
tion, FAPESP, for Post-Doc fellowship awarded to P.D.
Mathews. The authors are grateful to A.H. Aguillera, P.A.
Cortez and Prof. R. Sinigaglia-Coimbra from the Elec-
tron Microscopy Center (CEME) at UNIFESP for sup-
porting the SEM and TEM analysis. The authors thank
Dr. Christopher George Berger from Occidental College,
Los Angeles for revision of the English language.

References

Adriano EA, Oliveira OMP (2022) Myxobolidae in Catalogo Tax-
ondmico da Fauna do Brasil. PNUD. http://fauna.jbrj.gov.br/fauna/
faunadobrasil/152860 [Accessed 18 Jan 2022]

Allsop DJ, West SA (2003) Constant relative age and size at sex
change for sequentially hermaphroditic fish. Journal of Evolu-
tionary Biology 16(5): 921-929. https://doi.org/10.1046/j.1420-
9101.2003.00590.x

Atkinson SD, Bartholomew JL, Lotan T (2018) Myxozoans: Ancient
metazoan parasites find a home in phylum Cnidaria. Zoology (Jena,
Germany) 129: 66-68. https://doi.org/10.1016/j.z001.2018.06.005

Barta JR, Martin DS, Liberator PA, Dashkevicz M, Anderson JW,
Feighner SD, Elbrecht A, Perkins-Barrow A, Jenkins MC, Danforth
D, Ruff MD, Profous-Juchelka H (1997) Phylogenetic relationships
among eight Eimeria species infecting domestic fowl inferred using
complete small subunit ribosomal DNA sequences. The Journal of
Parasitology 83(2): 262-271. https://doi.org/10.2307/3284453

Carriero MM, Adriano EA, Silva MRM, Ceccarelli PS, Maia AAM
(2013) Molecular phylogeny of the Myxobolus and Henneguya
genera with several new South American species. PLoS ONE 8:
e73713. https://doi.org/10.1371/journal.pone.0073713

Eiras JC (2002) Synopsis of the species of the genus Henneguya Thelo-
han, 1892 (Myxozoa: Myxosporea: Myxobolidae. Systematic Par-
asitology 52(1): 43-54. https://doi.org/10.1023/A:1015016312195

zse.pensoft.net

.. First cnidarian Henneguya from a potamodromous fish from South America

Eiras JC, Adriano EA (2012) Checklist of the species of the genus Hen-
neguya Thélohan, 1892 (Myxozoa, Myxosporea, Myxobolidae)
described between 2002 and 2012. Systematic Parasitology 83(2):
95-104. https://doi.org/10.1007/s11230-012-9374-7

Favorito SE, Zanata AM, Assump¢ao MI (2005) A new Synbranchus
(Teleostei: Synjbranchidae) from Ilha de Marajo, Para, Brazil, with
notes on its reproductive biology and larval development. Neo-
tropical Ichthyology 3: 319-328. https://doi.org/10.1590/S1679-
62252005000300001

Hallett SL, Diamant A (2001) Ultrastructure and small-subunit ribosom-
al DNA sequence of Henneguya lesteri n. sp. (Myxosporea), a par-
asite of sand whiting Sillago analis (Sillaginidae) from the coast of
Queensland, Australia. Diseases of Aquatic Organisms 46: 197-212.
https://do1.org/10.3354/da0046197

Heisler N (1982) Intracellular and extracellular acid-base regulation
in the tropical fresh-water teleost fish Synbranchus marmoratus
in response to the transition from water breathing to air breath-
ing. The Journal of Experimental Biology 99(1): 9-28. https://doi.
org/10.1242/jeb.99.1.9

Junges CM, Lajmanovich RC, Peltzer PM, Attademo AM, Basso A
(2010) Interactions between Synbranchus marmoratus (Teleostei:
Synbranchidae) and Hypsiboas pulchellus tadpoles (Amphibia: HyI-
idae): importance of lateral line in nocturnal predation and effects of
fenitrothion exposure. Chemosphere 81(10): 1233-1238. https://doi.
org/10.1016/j.chemosphere.2010.09.035

Kent ML, Khattra J, Hedrick RP, Devlin RH (2000) Tetracapsula re-
nicola n. sp. (Myxozoa: Saccosporidae); the PKX myxozoan: the
cause of proliferative kidney disease of salmonid fishes. The Journal
of Parasitology 86: 103-111. https://doi.org/10.1645/0022-3395(20
00)086[0103:TRNSMS]2.0.CO;2

Lom J, Arthur JR (1989) A guideline for the preparation of species de-
scriptions in Myxosporea. Journal of Fish Diseases 12(2): 151-156.
https://doi.org/10.1111/j.1365-2761.1989 tb00287.x

Lom J, Dykova I (1992) Myxosporidia (Phylum Myxozoa). In: Lom
J, Dykova I (Eds) Protozoan parasites of fishes. Developments in
aquaculture and fisheries sciences Elsevier, Amsterdam, 159-235.

Mathews PD, Maia AAM, Adriano EA (2016) Henneguya melini n.
sp. (Myxosporea: myxobolidae), a parasite of Corydoras melini
(Teleostei: siluriformes) in the Amazon region: morphological and
ultrastructural aspects. Parasitology Research 115(9): 3599-3604.
https://do1.org/10.1007/s00436-016-5125-z

Mathews PD, Naldoni J, Adriano EA (2017) Morphology and small
subunit rDNA- based phylogeny of a new Henneguya species, in-
fecting the ornamental fish Corydoras leucomelas from the Peru-
vian Amazon. Acta Tropica 176: 51-57. https://doi.org/10.1016/).
actatropica.2017.07.017

Mathews PD, Mertins O, Pereira JOL, Maia AAM, Adriano EA (2018)
Morphology and 18S rDNA sequencing of Henneguya peruviensis
n. sp. (Cnidaria: Myxosporea), a parasite of the Amazonian orna-
mental fish Hyphessobrycon loretoensis from Peru: A myxospor-
ean dispersal approach. Acta Tropica 187: 207-213. https://doi.
org/10.1016/j.actatropica.2018.08.012

Mathews PM, Mertins O, Milanin T, Espinoza LL, Alama-Bermejo G,
Audebert F, Morandini AC (2020) Taxonomy and 18S rDNA-based
phylogeny of Henneguya multiradiatus n. sp. (Cnidaria: Myxobo-
lidae) a parasite of Brochis multiradiatus from Peruvian Amazon.
Microbial Pathogenesis 147: 104372. https://doi.org/10.1016/j.mic-
path.2020.104372

Zoosyst. Evol. 99 (2) 2023, 391-397

Mathews PD, Bonillo C, Rabet, N, Lord C, Causse R, Keith P, Audebert F
(2021) Phylogenetic analysis and characterization of a new parasitic
cnidarian (Myxosporea: Myxobolidae) parasitizing skin of the giant
mottled eel from the Solomon Islands. Infection Genetics and Evolu-
tion 94: 104986. https://doi.org/10.1016/j.meegid.2021.104986

Mathews PD, Mertins O, Milanin T, Aguiar JC, Gonzales-Flores APP,
Tavares LER, Morandini AC (2022a) Ultrastructure, surface topog-
raphy, morphology and histological observations of a new parasitic
cnidarian of the marbled swamp eel from the world’s largest tropical
wetland area, Pantanal, Brazil. Tissue & Cell 79: 101909. https://do1.
org/10.1016/j.tice.2022.101909

Mathews PD, Mertins O, Flores-Gonzales APP, Espinoza LL, Aguiar
JC, Milanin T (2022b) Host—Parasite Interaction and Phylogenetic
of a new Cnidarian myxosporean (Endocnidozoa: Myxobolidae)
Infecting a valuative commercialized ornamental fish from Pan-
tanal wetland biome, Brazil. Pathogens (Basel, Switzerland) 11(10):
1119. https://doi.org/10.3390/pathogens11101119

Milanin T, Atkinson SD, Silva MR, Alves RG, Maia AA, Adriano EA
(2017) Occurrence of two novel actinospore types (Cnidaria: Myxo-
sporea) in Brazilian fish farms, and the creation of a novel actino-
spore collective group. Seisactinomyxon. Acta Parasitologica 62(1):
121-128. https://doi.org/10.1515/ap-2017-0014

Milanin T, Mathews PD, Morandini AC, Mertins O, Audebert F, Pereira
JOL, Maia AA M (2021) Morphostructural data and phylogenetic
relationships of a new cnidarian myxosporean infecting spleen of
an economic and ecological important bryconid fish from Brazil.
Microbial Pathogenesis 150: 104718. https://doi.org/10.1016/j.mic-
path.2020.104718

397

Molnar K, Eszterbauer E (2015) Specificity of Infection Sites in Verte-
brate Hosts. In: Okamura B, Gruhl A, Bartholomew JL (Eds) Myx-
ozoan Evolution, Ecology and Development. Springer, Switzerland,
295-313. https://doi.org/10.1007/978-3-319-14753-6_ 16

Naldoni J, Maia AAM, Correa LL, Da Silva MRM, Adriano EA (2018)
New myxosporeans parasitizing Phractocephalus hemioliopterus
from Brazil: Morphology, ultrastructure and SSU-rDNA sequenc-
ing. Diseases of Aquatic Organisms 128(1): 37-49. https://doi.
org/10.3354/dao003210

Okamura B, Gruhl A, Bartholomew JL (2015) An introduction to Myx-
ozoan evolution, ecology and development. In: Okamura B, Gruhl
A, Bartholomew JL (Eds) Myxozoan Evolution, Ecology and De-
velopment, Springer, Switzerland, 1—20. https://doi.org/10.3354/
dao03210

Okamura B, Hartigan A, Naldoni J (2018) Extensive uncharted biodi-
versity: The parasite dimension. Integrative and Comparative Biolo-
gy 58: 1132-1145. https://do1.org/10.1093/icb/icy039

Rangel LE, Santos MJ, Rocha S (2023) Synopsis of the species of
Henneguya Thélohan, 1892 (Cnidaria: Myxosporea: Myxobolidae)
described since 2012. Systematic Parasitology 100(3): 291-305.
https://doi.org/10.1007/s11230-023-10088-2

Sousa FB, Milanin T, Morandini AC, Espinoza LL, Flores-Gonzales
A, Gomes ALS, Matoso DA, Mathews PD (2021) Molecular di-
agnostic based on 18S rDNA and supplemental taxonomic data of
the cnidarian coelozoic Ceratomyxa (Cnidaria, Myxosporea) and
comments on the intraspecific morphological variation. Zoosys-
tematics and Evolution 97(2): 307-314. https://doi.org/10.3897/
zse.97.64769

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