Two new species of Anacanthorus (Monogenoidea, Dactylogyridae) parasitizing serrasalmid fish in Brazil

Duas novas espécies de Anacanthorus (Monogenoidea, Dactylogyridae) parasitando peixes serrasalmideos no Brasil

Abstract

During studies on fish parasites, two new species of Anacanthorus were found parasitizing serrasalmid fishes, Anacanthorus simpliciphallus sp. n. from the hybrid Piaractus mesopotamicus x Piaractus brachypomus and Anacanthorus brandtii sp. n. from Serrasalmus brandtii. Anacanthorus simpliciphallus sp. n. resembles Anacanthorus reginae in the morphology of the male copulatory organ (MCO) and accessory piece but differs from A. reginae in terms of the smaller size of the accessory piece, which corresponds approximately half the size of the MCO and by the presence of a conspicuous metraterm, with a membranous terminal region. Anacanthorus brandtii sp. n. differs from Anacanthorus scapanus by the expansion of the accessory piece, from Anacanthorus jegui by the ratio MCO (male copulatory organ) /AP (accessory piece) and by the expansion of hook shank, from Anacanthorus sciponophallus and A. reginae by the ratio MCO/AP. Anacanthorus brandtii sp. n. can be distinguished from A. reginae and A. simpliciphallus sp.n. by the size of hooks which is similar in A. reginae and A. simpliciphallus sp. n. and dissimilar in A. brandtii sp. n. The two new species also differ from each other by the expansion of shank.

Keywords:
Anacanthorus spp.; Dactylogyridae; Neotropical Region; Serrasalmidae

Resumo

Durante estudos em parasitos de peixes, duas novas espécies de Anacanthorus foram encontradas parasitando peixes serrasalmideos, Anacanthorus simpliciphallus sp. n. do híbrido Piaractus mesopotamicus x Piaractus brachypomus e Anacanthorus brandtii sp. n. de Serrasalmus brandtii. Anacanthorus simpliciphallus sp. n. assemelha-se a Anacanthorus reginae na morfologia do órgão copulatório masculino (OCM) e peça acessória (PA), mas difere de A. reginae pelo tamanho menor da peça acessória, que corresponde a aproximadamente metade do tamanho do OCM e pela presença de um metraterma conspícuo, com uma região terminal membranosa. Anacanthorus brandtii sp. n. difere de Anacanthorus scapanus pela expansão da peça acessória, de Anacanthorus jegui pela proporção OCM / PA e pela expansão da haste do gancho, e de Anacanthorus sciponophallus e A. reginae pela proporção OCM / PA. Anacanthorus brandtii sp. n. pode ser distinguido de A. reginae e A. simpliciphallus sp. n. pelo tamanho dos ganchos que é similar em A. reginae e A. simpliciphallus sp. n. e dissimilar em A. brandtii sp. n. As duas espécies novas também diferem entre si pela expansão da haste do gancho.

Palavras-chave:
Anacanthorus spp.; Dactylogyridae; Região Neotropical; Serrasalmidae

Introduction

Serrasalmidae, understood by fish known as piranhas and pacus, is a diverse family of freshwater fishes belonging to the order Characiformes, that is endemic throughout tropical and subtropical South America. Piaractus mesopotamicus (Holmberg, 1887) and Piaractus brachypomus (Cuvier, 1818), popularly known in Brazil as pacu and pirapitinga, respectively, are species characteristic of tropical waters and restricted to South America (Froese & Pauly, 2023). Crossing the female of P. mesopotamicus with the male of P. brachypomus results in the hybrid known as “patinga”, which has been gaining much ground in the Brazilian fish market (Ribeiro et al., 2016).

Serrasalmus brandtii Lutken, 1875 popularly known as white piranha and “pirambeba” is an endemic species of São Francisco River Basin (Britski et al., 1988; Jegú, 2003) and has a carnivorous feeding habit, being primarily piscivorous and secondarily insectivorous (opportunistic) (Pompeu & Godinho, 2003). The specimens generally inhabit lentic environments and are abundant in the Três Marias reservoir (Braga, 1975).

Dactylogyridae represents one of the most species-rich groups among helminths parasites of fishes (Boeger & Vianna, 2006; Cohen et al., 2013). Among all the genera of dactylogyrids, Anacanthorus Mizelle & Price, 1965 stand out as being highly diverse in species, distributed in a large number of host species among Neotropical freshwater fish (Cohen et al., 2013). Currently, this genus has 92 nominal species, among which 41 species (Table 1) parasitize Serrassalmidae fish, the most common host group for Anacanthorus spp. (Moreira et al., 2019). So far, species of Piaractus Eigenmann have been found to be parasitized by six species of Monogenoidea, among which Anacanthorus is the parasite genus most represented in this host genus: Anacanthorus penilabiatus Boeger, Husak & Martins, 1995; Anacanthorus spathulatus Kritsky, Thatcher & Kayton 1979; Anacanthorus toledoensis Leão, São Clemente & Cohen, 2015; Mymarothecium ianwhittingtoni Leão, São Clemente & Cohen, 2015; Mymarothecium viatorum Boeger, Piasecki & Sobecka, 2002; Notozothecium janauachensis Belmont-Jégu, Domingues, & Martins, 2004. These parasites have been recorded in Brazil and Peru (Kritsky et al., 1979; Boeger et al., 1995; Pamplona-Basilio et al., 2001; Martins et al., 2002; Cohen & Kohn, 2005, 2009; Lizama et al., 2007; Dinis-Vásquez et al., 2014; Leão et al., 2015, 2017; Oliveira & Tavares-Dias, 2016; Jerônimo et al., 2020; Moreira et al., 2019). During studies with fish parasites, a new species of Anacanthorus was found parasitizing the gills of a hybrid fish (P. mesopotamicus x P. brachypomus) that are commercialized in marketplace located in São Luís Island, Maranhão, Brazil, and another one in the endemic S. brandtii from São Francisco River and are described herein.

Table 1
Anacanthorus spp. parasites of Serrasalmidae from Neotropical Region. Scientific names of hosts are given according to accepted names in Froese & Pauly (2023).

MONOGENOIDEA	HOSTS	LOCALITIES	REFERENCES
Anacanthorus amazonicus Van Every & Kritsky, 1992	Pristobrycon striolatus, Serrasalmus rhombeus, Serrasalmus altispinis, Serrasalmus sp.	Bolívia, Brazil	Van Every & Kritsky (1992)
Anacanthorus anacanthorus Mizelle & Price, 1965	Pygocentrus nattereri	Brazil*	Mizelle & Price (1965)
Anacanthorus beleophallus Kritsky, Boeger & Van Every, 1992	Pristobrycon eigenmanni	Brazil	Kritsky et al. (1992)
Anacanthorus brazilensis Mizelle & Price, 1965	P. nattereri	Brazil*	Mizelle & Price (1965)
Anacanthorus camposbacae Morey, Aliano & Grandez, 2019	Myloplus schomburgkii	Peru	Morey et al. (2019)
Anacanthorus carmenrosae Morey, Aliano & Grandez, 2019	M. schomburgkii	Peru	Morey et al. (2019)
Anacanthorus catoprioni Kritsky, Boeger & Van Every, 1992	Catoprion mento	Brazil	Kritsky et al. (1992)
Anacanthorus cinctus Van Every & Kritsky, 1992	P. striolatus, S. altispinis	Brazil	Van Every & Kritsky (1992)
Anacanthorus cladophallus Van Every & Kritsky, 1992	S. altispinis, S. spilopleura	Brazil	Van Every & Kritsky (1992)
Anacanthorus crytocaulus Van Every & Kritsky, 1992	S. altispinis, P. striolatus	Brazil	Van Every & Kritsky (1992)
Anacanthorus gravihamulatus Van Every & Kritsky, 1992	S. altispinis, S. rhombeus, P. eigenmanni, Serrasalmus sp.	Bolívia, Brazil	Van Every & Kritsky (1992)
Anacanthorus hoplophallus Kritsky, Boeger & Van Every, 1992	Myloplus rubripinnus	Brazil	Kritsky et al. (1992)
Anacanthorus jegui Van Every & Kritsky, 1992	Metynnis lippincottianus, P. eigenmanni, Pristobrycon sp., S. rhombeus, S. altispinis, Serrasalmus spilopleura, Serrasalmus sp.	Bolívia, Brazil	Van Every & Kritsky (1992)
Anacanthorus lasiophallus Van Every & Kritsky, 1992	P. striolatus	Brazil	Van Every & Kritsky (1992)
Anacanthorus lepyrophallus Kritsky, Boeger & Van Every, 1992	S. elongatus, S.altispinis, S. maculatus, S. marginatus, Serrasalmus sp.	Brazil	Kritsky et al. (1992)
Anacanthorus maltai Boeger and Kritsky, 1988	P. nattereri	Brazil	Boeger & Kritsky (1988)
Anacanthorus mastigophallus Kritsky, Boeger & Van Every, 1992	P. eigenmanni	Brazil	Kritsky et al. (1992)
Anacanthorus mesocondylus Van Every & Kritsky, 1992	S. spilopleura, Serrasalmus sp., P. eigenmanni, Pristobrycon sp.,	Brazil	Van Every & Kritsky (1992)
Anacanthorus myleusi Moreira, Carneiro, Ruz & Luque, 2019	M. schomburgkii	Brazil	Moreira et al. (2019)
Anacanthorus neotropicalis Mizelle & Price, 1965	P. nattereri	Brazil*	Mizelle & Price (1965)
Anacanthorus palamophallus Kritsky, Boeger & Van Every, 1992	P. eigenmanni	Brazil	Kritsky et al. (1992)
Anacanthorus paraspathulatus Kritsky, Boeger & Van Every, 1992	Mylossoma duriventris, M. aureum	Brazil	Kritsky et al. (1992)
Anacanthorus paraxaniophallus Moreira, Carneiro, Ruz & Luque, 2019	Serrasalmus maculatus, S. marginatus	Brazil	Moreira et al. (2019)
Anacanthorus pedanophallus Kritsky, Boeger & Van Every, 1992	M. rubripinnis	Brazil	Kritsky et al. (1992)
Anacanthorus penilabiatus Boeger, Husak & Martins, 1995	Colossoma macropomum, C. macropomum x Piaractus mesopotamicus, Piaractus brachypomus, P. mesopotamicus, P. brachypomus x P. mesopotamicus	Brazil	Boeger et al. (1995), Pamplona-Basilio et al. (2001), Martins et al. (2002), Lizama et al. (2007), Cohen & Kohn (2009), Leão et al. (2017), Jerônimo et al. (2020)
Anacanthorus periphallus Kritsky, Boeger & Van Every, 1992	S. altispinis, Serrasalmus sp.	Brazil	Kritsky et al. (1992)
Anacanthorus prodigiosus Van Every &Kritsky, 1992	S. elongatus, S. altispinis, S. rhombeus, Serrasalmus sp.	Brazil	Van Every & Kritsky (1992)
Anacanthorus ramosissimus Van Every & Kritsky, 1992	Serrasalmus elongatus	Brazil	Van Every & Kritsky (1992)
Anacanthorus reginae Boeger & Kritsky, 1988	P. nattereri	Brazil, Peru	Boeger & Kritsky (1988), Iannacone & Luque (1993)
Anacanthorus rondonensis Boeger & Kritsky, 1988	P. nattereri, S. rhombeus	Brazil, Bolívia	Boeger & Kritsky (1988), Córdova & Pariselle (2007)
Anacanthorus scapanus Van Every & Kritsky, 1992	S. spilopleura	Brazil	Van Every & Kritsky (1992)
Anacanthorus sciponophallus Van Every & Kritsky, 1992	S. altispinis, S. elongatus, S. maculatus, S.rhombeus, S. spilopleura, Serrasalmus sp.	Bolívia, Brazil	Van Every & Kritsky (1992), Córdova & Pariselle (2007)
Anacanthorus serrasalmi Van Every & Kritsky, 1992	S. altispinis, S. elongatus, S. rhombeus, Serrasalmus sp. Pristobrycon sp.,	Brazil	Van Every & Kritsky (1992)
Anacanthorus spathulatus Kritsky, Thatcher & Kayton, 1979	C. macropomum, C. macropomum x P. brachypomus, P. brachypomus, P. mesopotamicus	Brazil, Peru, Venezuela	Kritsky et al. (1979), Aragot et al. (2002), Fischer et al. (2003) , Centeno et al. (2004), Lizama et al. (2007), Morais et al. (2009), Godoi et al. (2012), Santos et al. (2013), Soberon et al. (2014), Dias & Tavares-Dias (2015), Oliveira & Tavares-Dias (2016), Silva et al. (2022)
Anacanthorus spinatus Kritsky, Boeger & Van Every, 1992	M. rubripinnus	Brazil	Kritsky et al. (1992)
Anacanthorus stachophallus Kritsky, Boeger & Van Every, 1992	P. nattereri	Brazil, Peru	Kritsky et al. (1992), Iannacone & Luque, 1993
Anacanthorus stagmophallus Kritsky, Boeger & Van Every, 1992	M.rubripinnis	Brazil	Kritsky et al. (1992)
Anacanthorus strongylophallus Kritsky, Boeger & Van Every, 1992	M. lippincottianus	Brazil	Kritsky et al. (1992)
Anacanthorus thatcheri Boeger & Kritsky, 1988	P. nattereri	Brazil, Peru	Boeger & Kritsky (1988), Iannacone & Luque (1993)
Anacanthorus toledeoensis Leão, São Clemente & Cohen, 2015	P. mesopotamicus	Brazil	Leão et al. (2015)
Anacanthorus xaniophallus Kritsky, Boeger & Van Every, 1992	P. eigenmanni, Pristobrycon sp.	Brazil	Kritsky et al. (1992)

• ^*
  Host obtained from Steinhart Aquarium, San Francisco, California

Material and Methods

One hybrid specimen of P. mesopotamicus x P. brachypomus purchased from a fish market on São Luís Island, State of Maranhão, which had been brought to the market from a fish farm established in the municipality of Matinhas (3º05'13.5"S, 45º02'56"W) and 168 specimens of S. brandtii captured by local fishers in Três Marias Reservoir (18º12'59"S, 45º17'34"W), Upper São Francisco River, Minas Gerais State, Brazil and sent to the “Centro Integrado de Recursos Pesqueiros e Aquicultura (CIRPA)” of the “Companhia de Desenvolvimento dos Vales do São Francisco e Parnaíba (CODEVASF)” were examined for Monogenoidea. The gills were removed and placed in vials containing hot water (~65ºC) and were shaken. Absolute ethanol was added to reach a concentration of 70%. Monogenoids were picked from the sediment and from the gill arches with the aid of a stereoscopic microscope. Some specimens were mounted in Hoyer’s medium to study of the sclerotized parts and others were stained with Gomori’s trichrome and mounted in Canada balsam (Humason, 1979; Boeger & Vianna, 2006). The specimens were observed using an Olympus BX 41 microscope with phase contrast and Zeiss Axioskop 2 Plus microscope with differential interference contrast, both equipped with a camera lucida for drawings. All measurements are presented in micrometers, and the range is followed by the mean in parentheses and the number of specimens measured. Identification of the authors and nomenclatural acts for the taxon was in accordance with the guidelines provided in Article 50.1 and recommendation 50A of the International Code of Zoological Nomenclature (ICZN), which specifically pertains to authorship identity. The holotype and paratypes for each parasite species were deposited in the Helminthological Collection of the Oswaldo Cruz Institute (CHIOC), Rio de Janeiro, Brazil.

Results

TAXONOMY

Class Monogenoidea Bychowsky, 1937

Subclass Polyonchoinea Bychowsky, 1937

Order Dactylogyridea Bychowsky, 1937

Family Dactylogyridae Bychowsky, 1933

Subfamília Anacanthorinae Mizelle & Price, 1965

Anacanthorus Mizelle & Price, 1965

Anacanthorus simpliciphallusSilva, Cohen, Costa & Justo sp. n. (Figure 1a-d; Figure 2a-c).

Figure 1
a-d: Anacanthorus simpliciphallus sp. n. parasite of hibrid Piaractus mesopotamicus x Piaractus brachypomus. (a): Total view, ventral (composite) (b): MCO (c) Hook (d) Hook 4A; e-h: Anacanthorus brandtii sp. n. parasite of Serrasalmus brandtii: (e): MCO (f) Hook pairs 1,5 (g) Hook pairs 2,4,6,7 (h) Hook 4A. Scale bars: (a) 100 µm (b, e) 20 µm (c, f, g) 10 µm (d, h) 5 µm.

Figure 2
Light photomicrographs of Anacanthorus simpliciphallus sp. n. parasite of hybrid Piaractus mesopotamicus x Piaractus brachypomus. (a): Total view, ventral (b) Copulatory complex (c) Haptor. Scale bars. (a) 100 µm, (b) 30 µm; (c) 30 µm.

Type host: Hybrid Piaractus mesopotamicus x Piaractus brachypomus (Characiformes, Serrasalmidae)

Site in host: Gill lamellae

Type-locality: Marketplace on São Luis Island, Maranhão state, host specimen obtained from a fish farm established in the municipality of Matinhas (3º05'13.5"S, 45º02'56" W).

Parasitological indexes: Total number of hosts: 1; total number of parasites: 7

Type-material: Holotype CHIOC 40268 a; Paratypes CHIOC 40268 b-g.

Etymology: The species name is from Latin (simplex=simples + phallus=penis) and refers to the morphology of the male copulatory organ.

DESCRIPTION: (Based on seven specimens: six mounted in Hoyer’s medium and one mounted in Gomori’s trichrome). Body elongated, fusiform, 262–550 (422, n= 5) long including the haptor, by 88–145 (123, n= 5) wide at the level of germarium. Two terminal, and two bilateral well developed cephalic lobes; three bilateral pairs of head organs. Two pairs of eyes equidistant, anterior pair smaller than posterior pair, slightly closer together than posterior pair; pairs slightly close to each other; accessory granules sparse in the cephalic region. Pharynx subspherical, 20 and 27 (n= 2) in diameter; long oesophagus. Two intestinal ceca confluent posterior to the gonads, lacking diverticula. Gonads overlapping; testis dorsal to germarium, 60–100 (86; n= 4) long, vas deferens looping intestinal caeca, single prostatic reservoir pyriform. Copulatory complex comprising male copulatory organ (MCO) and accessory piece (AP). MCO tubular, heavily sclerotized, J-shaped, with slightly sclerotized walls, base with smooth margin, 65–83 (73; n= 7) long. Accessory piece with a terminal flap, non articulated to MCO base, 37–45 (41; n= 7). Ratio MCO/AP 1:0.48-1:0.58 (1:0.55, n=7). Germarium 35 and 40 (n= 2) long by 40 and 45 (n= 2) wide. Metraterm conspicuous, with membranous terminal region. Genital pore and eggs not observed. Peduncle short. Haptor armed with 7 pairs of hooks (4 ventral, 3 dorsal), 2 pairs (1 dorsal, 1 ventral) of 4A's, 60–135 (93, n= 5) wide. Hooks similar in shape and size, each with truncate slightly depressed thumb, curved shaft, short point, shank proximal expansion 0.3 shank length, 20–24 (21; n= 20) long; filamentous hook (FH loop) delicate, extending as far as half of the shank. Similar 4A hooks, 9–12 (10; n= 10). Vitellaria dense, dispersed throughout the trunk, absent in the region of reproductive organs and copulatory complex.

Remarks:Anacanthorus simpliciphallus sp. n. differs from all congeneric species mainly in terms of the morphology of the accessory piece. The new species resembles Anacanthorus reginae Boeger & Kritsky, 1988, in the morphology of the male copulatory organ (J-shaped) and in that the accessory piece is not articulated to the MCO base and has a terminal flap. Both species differs mainly with regard to the ratio between MCO and accessory piece [practically the same size (MCO 57–76; accessory piece 42–67) in A. reginae x accessory piece 50% the size (MCO 65–83; accessory piece 37–45) in Anacanthorus simpliciphallus sp. n. and with regard to the size of hooks (23–34 (28) in A. reginae and 20–24 (21) in the new species). Moreover, the new species can be differentiated from A. reginae in that it has a metraterm conspicuous, with a membranous terminal region.

Anacanthorus brandtiiSantos-Clapp, Cohen, Justo & Brasil-Sato sp. n (Figure 1e-h; Figure 3a-c).

Figure 3
Light photomicrographs of Anacanthorus brandtii sp. n. parasite of Serrasalmus brandtii. (a): Total view, ventral (b) Copulatory complex (c) Haptor. Scale bars. (a) 100 µm, (b) 30 µm; (c) 20 µm.

Type host: Serrasalmus brandtii Lütken, 1875 (Characiformes, Serrasalmidae)

Site in host: Gill lamellae

Type-locality: Três Marias Reservoir (18º12'59" S, 45º17'34" W), Upper São Francisco River, Minas Gerais State.

Parasitological indexes: Total number of hosts: 145; total number of parasites: 142

Type-material: Holotype CHIOC 40263 a; Paratypes CHIOC 40263 b; 40264; 40265; 40266 a,b; 40267 a, b.

Etymology: The new species is named after the specific epithet of the host, Serrasalmus brandtii

DESCRIPTION: (Based on 30 specimens mounted in Hoyer’s medium). Body elongated, fusiform, 295–595 (433, n= 12) long including the haptor, by 100–165 (130, n= 12) wide at the level of germarium. Two terminal, and two bilateral cephalic lobes; three bilateral pairs of head organs. Two pairs of eyes, anterior pair smaller than posterior pair, slightly closer together than posterior pair; accessory granules distributed in the cephalic region. Pharynx subspherical, long oesophagus. Intestinal ceca lacking diverticula. Gonads overlapping; testis dorsal to germarium, 70–130 (84; n=6) long, vas deferens looping intestinal caeca, prostatic reservoir not observed. Copulatory complex comprising male copulatory organ (MCO) and accessory piece. MCO as a J-shaped tube, with slightly sclerotized walls, expanded base with smooth margin, 60–78 (70; n=13) long. Accessory piece with a midlength expansion extended to distal region, non articulated to MCO base, 38–45 (41; n= 13). Ratio MCO/AP 1:0.58–1:0,63 (1:0.6, n=13) Germarium, metraterm, genital pore and eggs not observed. Peduncle inconspicuous. Haptor armed with 7 pairs (4 ventral, 3 dorsal) of hooks, 2 pairs (1 dorsal, 1 ventral) of 4A's, 68–120 (94, n=12) wide. Hooks similar in shape, each with truncate slightly depressed thumb, curved shaft, short point, pairs 1,5, 20–24 (22, n=13) long, proximal expansion 0.4 shank length, pairs 2–4,6,7, 28–32 (30, n=13) long, proximal expansion 0.6 shank length; Filamentous hook (FH loop) delicate, extending until up to half of the shank. Similar 4A hooks, 10–15 (12; n=6). Vitellaria dense, dispersed throughout the trunk, absent in the region of reproductive organs and copulatory complex.

Remarks: Anacanthorus brandtii sp. n. is closely related to species previously described from Serrasalmus spp. as Anacanthorus scapanus, Anacanthorus jegui, Anacanthorus sciponophallus, A. reginae and A. simpliciphallus sp. n. by the morphology of copulatory complex. The new species differs from A. scapanus by the expansion of the accessory piece (subterminal in A. scapanus vs midlength expansion in the A. brandtii sp. n.), from A. jegui by the ratio MCO/AP (MCO 48 and AP 39 in A. jegui and MCO 70 vs AP 41 in the new species) and by the expansion of hook shank (0.3 and 0.4 in A. jegui vs 0.4 and 0.6 in A. brandtii sp. n.). The new species can be differentiated from A. sciponophallus and A. reginae by the ratio MCO/AP (MCO 76–82 and AP 74–79 in A. sciponophallus from different hosts, MCO 67 and AP 59 in A. reginae vs MCO 70 and AP 41 in the new species). The new species can also be distinguished from A. reginae and A. simpliciphallus sp. n. by the size of hooks which is similar in A. reginae and A. simpliciphallus sp. n. vs dissimilar in A. brandtii sp. n. The two new species also differ by the expansion of shank (0.3 in A. simpliciphallus sp. n. vs 0.4 and 0.6 in A. brandtii sp. n.).

Discussion

The new species are allocated in Anacanthorus because they possess a bilobed haptor with 7 pairs of hooks and 2 pairs of reduced hooks (4A’s), lacking anchors and bars, have tandem or slightly overlapping gonads, post-ovarian testis, modified (thickened or sclerotized) distal uterine wall or metraterm and vagina is absent (Kritsky et al., 1979, 1992).

Anacanthorus species are exclusively parasites of Neotropical characiforms, and so far, 19 species have been reported from Bryconidae, 8 from Erythrinidae, 21 from Triportheidae, and 44 from Serrasalmidae. Kritsky & Thatcher (1974) described Anacanthorus colombianus Kritsky & Thatcher, 1974 from Salminus affins Steindachner, 1880 and also reported its presence in Oreochromis mossambicus (Peters, 1852), a cichlid fish within the order Cichliformes. According to these authors, this latter occurrence was apparently accidental. Given the absence of further records in this order, it is considered that Anacanthorus spp. is specific to characiform fishes. Species of this genus have been found in five countries in the Neotropical Region (Brazil, Bolivia, Colombia, Peru, and Venezuela), and Brazil stands out as the country with the largest number of occurrences (156) (Boeger et al., 2023).

The sclerotized structures such as the copulatory complex and hooks of Anacanthorus species appear to have a high specificity in terms of morphology with regard to the host family level (Santos et al., 2019). Anacanthorus species that parasitize members of the family Serrasalmidae present the characteristic of a J-shaped MCO, an accessory piece that is not articulated to the MCO, hooks with truncated thumb and a shank with proximal dilation (Boeger & Kritsky, 1988; Kritsky et al., 1992; Van Every & Kritsky, 1992). The finding of two new species of Anacanthorus in serrasalmid hosts presenting morphological characteristics similar to those previously described on these hosts (Table 1) confirms that the lineages of the parasites from serrasalmid hosts shared those features.

Acknowledgements

This work was supported by “Coordenação de Aperfeiçoamento Técnico de Pessoal de Nível Superior/CAPES” (finance cod 001, Process: 88887.707472/2022-00. “Programa CAPES: PDPG Emergencial de Consolidação Estratégica dos Programas de Pós-Graduação (PPGs) Stricto sensu acadêmicos com notas 3 e 4”) and “Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão” (grant number UNIVERSAL-01148/18-, grant number BD-01172/20). The authors acknowledge Dr. Yoshimi Sato, leader of CIRPA/CODEVASF, Três Marias, Minas Gerais to the Agreements CEMIG-GT/CODEVASF and Universidade Federal do Rio de Janeiro / IBAMA, Minas Gerais for providing logistical ad material support during the collection of Serrasalmus brandtii.

• How to cite: Silva ALS, Cohen SC, Santos-Clapp MD, Brasil-Sato MC, Costa AP, Justo MCN. Two new species of Anacanthorus (Monogenoidea, Dactylogyridae) parasitizing serrasalmid fish in Brazil. Braz J Vet Parasitol 2024; 33(1): e017623. https://doi.org/10.1590/S1984-29612024007

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Publication Dates

• Publication in this collection
  08 Jan 2024
• Date of issue
  2024

History

• Received
  27 Oct 2023
• Accepted
  06 Dec 2023