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Integrative Taxonomy of Urocleidoides spp. (Monogenoidea, Dactylogyridae) Parasites of Pseudanos trimaculatus (Characiformes: Anostomidae) from Eastern Amazon, Brazil

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João Neto at Federal University of Para
João Neto
Marcus V. Domingues
Marcus V. Domingues
Marcus V. Domingues
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Abstract and Figures

Two new species of Urocleidoides are described from the gills of Pseudanos trimaculatus (Characiformes: Anostomidae) from the coastal drainages of the Eastern Amazon, Brazil. Urocleidoides itabocaensisn. sp. is characterized by having a sclerotized, tubular, sigmoid male copulatory organ (MCO), a circular sclerotized tandem brim associated with the base of the MCO; an accessory piece articulated with the MCO, a V-shaped, divided into two subunits, distal subunit spoon-shaped; and a vaginal pore dextroventral with opening marginal. Urocleidoides omphalocleithrumn. sp. is characterized by presenting a C-shaped or sigmoid MCO; an accessory piece articulated with the MCO, L-shaped, divided into two subunits, distal subunit gutter-shaped; a vaginal pore dextroventral with opening marginal; and a ventral bar broadly V-shaped, with anteromedial projection. Molecular phylogenetic analysis based on partial 28S rDNA and COI mtDNA genes indicate that U. itabocaensisn. sp. and U. omphalocleithrumn. sp. are closely related and appear as a sister group to other Urocleidoides species (U. paradoxus, U. digitabulum and U. sinus) parasitizing anostomid fishes. This study represents the first record of monogenoids from the gills of P. trimaculatus for the Eastern Amazon.
Urocleidoides itabocaensis n. sp. - a. Holotype, whole-mount (ventral view); b-c. Male copulatory organ; d. Vaginal sclerite; e. Dorsal bar; f. Ventral bar; g. Hook pairs 4 and 6; h. Hook pairs 2 and 3; i. Hook pairs 1 and 7; j. Hook pair 5; k. Dorsal anchor; l. Ventral anchor. Scale bars: fig. a scale of 50µm; figs. b–l scale of 25µm.
Urocleidoides itabocaensis n. sp. - a. Holotype, whole-mount (ventral view); b-c. Male copulatory organ; d. Vaginal sclerite; e. Dorsal bar; f. Ventral bar; g. Hook pairs 4 and 6; h. Hook pairs 2 and 3; i. Hook pairs 1 and 7; j. Hook pair 5; k. Dorsal anchor; l. Ventral anchor. Scale bars: fig. a scale of 50µm; figs. b–l scale of 25µm.
… 
Urocleidoides omphalocleithrum n. sp. - a. Holotype, whole-mount (ventral view); b. Vaginal sclerite; c. Hook pairs 4 and 6; d. Hook pairs 2 and 3; e. Hook pairs 1 and 7; f. Hook pair 5; g. Male copulatory organ; h. Ventral bar; i. Dorsal bar; j. Dorsal anchor; k. Ventral anchor. Scale bars: figs. a. scale of 50µm; Fig. b–k scale of 25µm.
Urocleidoides omphalocleithrum n. sp. - a. Holotype, whole-mount (ventral view); b. Vaginal sclerite; c. Hook pairs 4 and 6; d. Hook pairs 2 and 3; e. Hook pairs 1 and 7; f. Hook pair 5; g. Male copulatory organ; h. Ventral bar; i. Dorsal bar; j. Dorsal anchor; k. Ventral anchor. Scale bars: figs. a. scale of 50µm; Fig. b–k scale of 25µm.
… 
Urocleidoides itabocaensisn. sp. - a. Copulatory complex; b. Haptor; Urocleidoides omphalocleithrumn. sp. - c. Copulatory complex; d. haptor. Scale figure: figs. a–d scale of 25µm.
Urocleidoides itabocaensisn. sp. - a. Copulatory complex; b. Haptor; Urocleidoides omphalocleithrumn. sp. - c. Copulatory complex; d. haptor. Scale figure: figs. a–d scale of 25µm.
… 
Molecular phylogeny estimated by Bayesian inference using partial sequences of the partial 28S rDNA (763 bp long) of dactylogyrids from the Neotropical region. Species newly sequenced for the present study are in bold. Species name precedes the GenBank sequence ID. Bootstrap support values and posterior probabilities are given between the branches (bootstrap values <60 and posterior probabilities <0.70 not reported). Branch length scale bar indicates the number of substitutions per site.
Molecular phylogeny estimated by Bayesian inference using partial sequences of the partial 28S rDNA (763 bp long) of dactylogyrids from the Neotropical region. Species newly sequenced for the present study are in bold. Species name precedes the GenBank sequence ID. Bootstrap support values and posterior probabilities are given between the branches (bootstrap values <60 and posterior probabilities <0.70 not reported). Branch length scale bar indicates the number of substitutions per site.
… 
Molecular phylogeny estimated by Bayesian inference using partial sequences of the partial COI mtDNA (347 bp long) of dactylogyrids from the Neotropical region. Species newly sequenced for the present study are in bold. Species name precedes the GenBank sequence ID. Bootstrap support values and posterior probabilities are given between the branches (bootstrap values <60 and posterior probabilities <0.70 not reported). Branch length scale bar indicates the number of substitutions per site.
Molecular phylogeny estimated by Bayesian inference using partial sequences of the partial COI mtDNA (347 bp long) of dactylogyrids from the Neotropical region. Species newly sequenced for the present study are in bold. Species name precedes the GenBank sequence ID. Bootstrap support values and posterior probabilities are given between the branches (bootstrap values <60 and posterior probabilities <0.70 not reported). Branch length scale bar indicates the number of substitutions per site.
… 
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Vol.: (0123456789)
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Syst Parasitol (2024) 101:35
https://doi.org/10.1007/s11230-024-10154-3
Integrative Taxonomy ofUrocleidoides spp. (Monogenoidea,
Dactylogyridae) Parasites ofPseudanos trimaculatus
(Characiformes: Anostomidae) fromEastern Amazon,
Brazil
JoãoF.Santos‑Neto· MarcusV.Domingues
Received: 18 November 2023 / Accepted: 16 February 2024 / Published online: 3 May 2024
© The Author(s), under exclusive licence to Springer Nature B.V. 2024
Abstract Two new species of Urocleidoides are
described from the gills of Pseudanos trimacula-
tus (Characiformes: Anostomidae) from the coastal
drainages of the Eastern Amazon, Brazil. Uro-
cleidoides itabocaensis n. sp. is characterized by
having a sclerotized, tubular, sigmoid male copula-
tory organ (MCO), a circular sclerotized tandem brim
associated with the base of the MCO; an accessory
piece articulated with the MCO, aV-shaped, divided
into two subunits, distal subunit spoon-shaped; and
a vaginal pore dextroventral with opening mar-
ginal. Urocleidoides omphalocleithrum n. sp. is
characterized by presenting a C-shaped or sigmoid
MCO; anaccessory piece articulated with the MCO,
L-shaped, divided into two subunits, distal subunit
gutter-shaped; a vaginal pore dextroventral with open-
ing marginal; and a ventral bar broadly V-shaped,
with anteromedial projection. Molecular phyloge-
netic analysis based on partial 28S rDNA and COI
mtDNA genes indicate that U. itabocaensis n. sp.
and U. omphalocleithrum n. sp. are closely related
and appear as a sister group to other Urocleidoides
species (U. paradoxus, U. digitabulum and U. sinus)
parasitizing anostomid fishes. This study represents
the first record of monogenoids from the gills of P.
trimaculatus for the Eastern Amazon.
Introduction
South America has the world’s most diverse freshwa-
ter fish fauna, with over 5,100 known species, with
the order Characiformes accounting for about 33%
of this diversity (Reis etal., 2016). Within this fish
order, the anostomids represent the second largest
family, with 151 valid species widely distributed in
South America (Garavello & Britski, 2003; Sidlaus-
kas & Vari, 2008; Nelson et al., 2016; Fricke et al.,
2023). However, despite this diversity, only 15%
of anostomid’s diversity was examined for monog-
enoids (Oliveira etal., 2020). Currently, 26 species
of monogenoids have been reported for anostomid
fishes: Demidospermus Suriano, 1983 (one species),
Jainus Mizelle, Kritsky & Crane, 1968 (three spe-
cies), Kritskyia Kohn, 1990 (one species), Rhinoxe-
nus Kritsky, Boeger & Thatcher, 1988 (three species),
Scleroductus Jara & Cone, 1989 (one species), Tere-
ancistrum Kritsky, Thatcher & Kayton, 1980 (three
species), Trinibaculum Kritsky, Thatcher & Kayton,
1980 (one species), and Urocleidoides Mizelle &
Price, 1964 (11 species) (Oliveira etal., 2020).
J.F.Santos-Neto· M.V.Domingues(*)
Laboratório de Sistemática e Coevolução, Instituto
de Estudos Costeiros, Universidade Federal doPará,
Tv. Leandro Ribeiro, s/n, bairro Aldeia, Bragança,
Pará68600-000, Brazil
e-mail: mvdomingues@ufpa.br
J.F.Santos-Neto· M.V.Domingues
Programa de Pós-Graduação em Biologia Ambiental,
Universidade Federal doPará, Bragança, Brazil
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Currently, the genus encompasses 57 species (Table 1), including parasites of fishes from Characiformes, Siluriformes, Gymnotiformes, and Cyprinodontiformes [4,[8][9][10][11]. Seven Urocleidoides species are still considered "incertae sedis" by Kritsky et al. [3] and Ferreira et al. [12], mainly due to the absence of vaginal sclerite, namely, U. advenai Mendoza-Franco & Reina, 2008; U. amazonensis Mizelle and Kritsky, 1969 α Species considered incertae sedis [3,12]. ...
... Our analyses of the LSU rDNA and COI mtDNA genes suggest that the current taxonomic classification of the genus Urocleidoides still needs revision, as the sequences analyzed were not shown to be monophyletic. This finding is consistent with previous studies by Oliveira et al. [27], Santos-Neto & Domingues [11,24], and Ebert et al. [9]. In the phylograms based on LSU rDNA data, Urocleidoides species parasitizing erythrinids were found in distinct and well-supported clades, showing a close relation with other monopisthocotylan dactilogyrids from Characiformes fishes. ...
... In the phylograms based on LSU rDNA data, Urocleidoides species parasitizing erythrinids were found in distinct and well-supported clades, showing a close relation with other monopisthocotylan dactilogyrids from Characiformes fishes. Notably, these species did not cluster with other Urocleidoides species that infect erythrinids (i.e., U. vanini and U. atilaiamarinoi), aligning with the results of Santos-Neto & Domingues [11] and Ebert et al. [9]. In contrast, the COI mtDNA analysis showed that U. vanini is closely related to U. triangulus and U. cuiabai (i.e., only in the COI mtDNA analysis), which clustered separately from the other sequences. ...
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... Two eyespots, granules ovate, few accessory granules dispersed in cephalic region. Pharynx subspherical, muscular, 14(11)(12)(13)(14)(15)(16)(17)(18)(19); n = 9) in diameter; short esophagus bifurcating into two intestinal caeca, confluent posterior to gonads. Gonads intercaecal, overlapping. ...
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  • Jun 2021
  • Parasitol Int
The present study describes three new species of monogenean parasites of characid fishes from the Upper Paraná River basin, Brazil: Characithecium paranapanemense n. sp. on Psalidodon paranae and Psalidodon bockmanni, Diaphorocleidus magnus n. sp. on Astyanax lacustris and Psalidodon fasciatus, and Diaphorocleidus neotropicalis n. sp. on Astyanax lacustris and P. bockmanni. An amendment for Diaphorocleidus is proposed, since additional characters observed in the new species required to extend the generic diagnostic features mainly to include: articulation process connecting the base of the MCO with accessory piece present or absent, and accessory piece with variable shapes (plate-like, pincer-shaped, wrench-shaped, sheath-shaped), divided or not into subunits. Characithecium paranapanemense n. sp. can be distinguished from other congeners by the morphology of its MCO and accessory piece. Diaphorocleidus magnus n. sp. differs from most of its congeners by the morphology of its accessory piece, the presence of articulation process connecting the base of the MCO with accessory piece, and the morphology of the sclerotized structures of the haptor. Diaphorocleidus neotropicalis n. sp. can be easily distinguished from its congeners by the morphology of the accessory piece, the sclerotized structures of the haptor and the morphology of the vagina. Molecular data of the new species (partial 28S rDNA and mitochondrial cytochrome oxidase I) were obtained and the first phylogenetic analysis based on 28S rDNA gene sequences for species of Characithecium and Diaphorocleidus are provided. Although Diaphorocleidus and Characithecium share some morphological similarities, phylogenetic analysis indicates that species of these two genera are not closely related.
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Trinigyrus spp. (Monogenea: Dactylogyridae) from Brazilian catfishes: new species, molecular data and new morphological contributions to the genus
Article
  • Jan 2020
This study describes two new species, Trinigyrus anthus n. sp. and Trinigyrus carvalhoi n. sp., from gills of Hypostomus spp. from the Upper Paraná River basin, Brazil. Trinigyrus peregrinus is redescribed based on examination of its holotype, paratypes and new material of specimens parasitizing Pterygoplichthys ambrosettii , also from the Upper Paraná River basin, Brazil. New morphological features were included in the diagnosis of the genus, such as the presence of a sclerotized border on the anchor base, and a weakly sclerotized fringe on the base of the male copulatory organ (MCO). Trinigyrus anthus n. sp. differs from other congeners by the shape of the MCO, presenting an enlarged base with sclerotized fringes resembling flower petals. Trinigyrus carvalhoi n. sp. and T. peregrinus are similar but can be differentiated from each other mainly by the sclerotization of the vagina (absent in the new species), and the morphology of the MCO (C-shaped versus one counterclockwise circle, respectively). For the first time, gene sequences of Trinigyrus spp. from Brazil were obtained (partial ribosomal 28S and mitochondrial cytochrome c oxidase I (mtCOI)). The genetic divergences among the new species and T. peregrinus varied from 2 to 3% (6‒18 pb) based on sequences of 28S ribosomal DNA (rDNA), and 6–7% (83‒92 pb) using mtCOI. Phylogenetic analyses based on partial 28S rDNA revealed that Trinigyrus , Heteropriapulus and Unilatus formed a monophyletic and well-supported clade of monogeneans from Neotropical freshwater loricariids, suggesting a closer relationship among these dactylogyrids and their hosts.
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