Range expansion of the non-native Megalamphodus eques (Characiformes: Acestrorhamphidae) to the Laguna dos Patos system, southern Brazil

ABSTRACT

The non-native species Megalamphodus eques (Steindachner, 1882) (Characiformes: Acestrorhamphidae) was detected in the Laguna dos Patos system, southern Brazil, based on specimens collected in the Gravataí River basin-one of the five rivers flowing into the Jacuí River Delta, Rio Grande do Sul State. Megalamphodus eques is native to the Amazonas, Paraguay, lower Paraná, and Uruguay River basins. Possible invasion pathways are briefly discussed, including artificial connections between drainage basins and anthropogenic introduction, as the species is widely cultivated and valued in the ornamental fish trade.

KEYWORDS:
Aquarism; Megalamphodinae; Neotropical freshwater fish; Species introduction

Megalamphodus Eigenmann, 1915 was recently revali dated from Hyphessobrycon Durbin, 1908 according to the new classification for Characidae proposed by Melo et al. (2024). Those authors also proposed a new family to house most of the taxa belonging to Stethaprioninae (sensu Mirande 2019), named Acestrorhamphidae, and resurrected Megalamphodus into a new subfamily, Megalamphodinae, comprising 12 valid species of small characins distributed in the Amazon, Negro, Orinoco, Araguaia, Paraguay, Uruguay, lower Paraná and São Francisco River basins and Guyana and Suriname river basins (Bertaco et al. 2016, Melo et al. 2024, Fricke et al. 2025). The bright colors of its species have made them highly appreciated in hobby aquarism (Weitzman and Palmer 1997a). According to Melo et al. (2024: fig. 5), Megalamphodus is a monophyletic genus, and can be diagnosed by the presence of a conspicuous black blotch on the dorsal fin.

Megalamphodus eques (Steindachner, 1882), former Hyphessobrycon eques, popularly known as tetra-serpae, tetra-sangue, tetra mato-grosso, and mato-grosso (Froese and Pauly 2024), was described based on syntypes from Villa Bella (before Vila Bela da Imperatriz, currently municipality of Parintins) in the state of Amazonas, and the Amazon River in the municipality of Óbidos in the state of Pará, Brazil (Weitzman and Palmer 1997a, 1997b, Lima et al. in Toledo-Piza et al. 2024). It is naturally distributed in the Amazonas, Paraguay, and lower Paraná river basins, as well as the lower Uruguay River basin (Bertaco et al. 2016, Fricke et al. 2025), and is thought to have been introduced in the upper Paraná River basin (Dagosta et al. 2024), the São Francisco River (ZUEC-PIS 14676 - Universidade Estadual de Campinas, Departamento de Zoologia, Museu de Diversidade Biológica) and rivers of eastern Brazil, such as Ribeira de Iguape, Paraíba do Sul and Doce (Oyakawa and Menezes 2011, Sarmento-Soares et al. 2017, Magalhães et al. 2019).

Freshwater fish of the state of Rio Grande do Sul are distributed among three main drainages: the Uruguay River basin, the Laguna dos Patos system, and the Tramandaí River system (Bertaco et al. 2016). Although these river drainages have been extensively sampled for over 30 years (Bertaco et al. 2016), there has been no record of M. eques in the Laguna dos Patos system, only in the lower Uruguay River basin. Herein we report the first record of the non-native species M. eques for the Gravataí River basin, Laguna dos Patos system.

Fish were collected on the left bank of the Gravataí River, Laguna dos Patos system, municipality of Gravataí, state of Rio Grande do Sul, Brazil, in February, April, and November 2024 (Fig. 1). Voucher specimens are deposited in the fish collection of Museu de Ciências Naturais (MCN - see Material examined bellow), Secretaria Estadual de Meio Ambiente e Infraestrutura, Rio Grande do Sul, Brazil. The fish were collected using a seine (10 m long x 1.2 m wide, 5-mm mesh size) and then euthanized with clove oil, fixed in situ with 4% formaldehyde, and preserved in 70% ethanol. The collecting permit was issued by the Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio, number 14092-1). Fish collection was carried out in accordance with ethical regulations regarding animal experimentation following the CONCEA (2023).

Figure 1
Map of state of Rio Grande do Sul, Brazil with the record points of Megalamphodus eques in the lower Uruguay River basin (blue dots) and the new record in the Gravataí River basin (red dot), Laguna dos Patos system, South Brazil.

Searches for records of the species were performed on speciesLink (https://specieslink.net) and the National Database of Invasive Exotic Species (https://bd.institutohorus.org.br), as well as in fish collections not available in these databases, such as MCN and Universidade Federal do Rio Grande do Sul, Porto Alegre (UFRGS). The geographic distribution map was created using shape and raster files from the databases of the Agência Nacional de Águas (ANA) and Instituto Brasileiro de Geografia e Estatística (IBGE), and QGIS software version 3.34.10.

The collected individuals possess the diagnostic cha racters proposed by Weitzman and Palmer (1997a, 1997b), as follow: number of maxillary teeth (1-4; tri- or tetracuspidate); incomplete lateral line (5-7 perforated scales); total number of scales in the lateral line series (30-34); one black, narrow and vertically-elongate humeral spot; 25-28 branched anal-fin rays; dorsal fin with black spot on posterior half, which may extend across the entire fin; and bony hooks present on rays of anal and pelvic fins of males. The fins are intensely red in life (Fig. 2), and sometimes the body is conspicuously reddish.

Figures 2-3
(2) Specimen of Megalamphodus eques captured in the Gravataí River basin, Laguna dos Patos system, South Brazil (MCN 20410, 31.2 mm SL). (3) Habitat of Megalamphodus eques in the Gravataí River basin, Gravataí, Laguna dos Patos system, Rio Grande do Sul State, Brazil. Photo: Gilson F. Rey.

The habitat of the collection sites comprised a subs trate with silt and leaf litter, dark water without current, little floating (Eichhornia sp.) and emergent vegetation, and a depth of up to 0.8 m (Fig. 3). The Gravataí River at these sites has dense riparian vegetation has a width ranging from 30 and 40 m wide.

Material examined: MCN 20410, 1 specimen, 31.2 mm standard length (SL), 29°59’01”S 50°56’04”W, 26 Feb 2024, M.A. Azevedo, J.P. Krahe, G.F. Rey; MCN 20411, 2 specimens, 26.1-29.5 mm SL, MCN 20413, 13 specimens, 25.3-29.2 mm SL, 22 Nov 2024, 29°59’00”S 50°56’03”W, 12 Apr 2024, V.A. Bertaco, M.A. Azevedo, G.F. Rey.

Megalamphodus eques is found, within the state of Rio Grande do Sul, in the Ibicuí River basin and a few watercourses on the banks of the Uruguay River in the western region of the state, the lower portion of the Uruguay River basin (data from SpeciesLink and from lots stored at the MCN and UFRGS collections; Fig. 1).

The ichthyofaunas of the drainages of the Uruguay River and Laguna dos Patos have historically been isolated from each other and are distinct, with 275 and 200 species, respectively, of which just 86 are shared between both basins (Bertaco et al. 2016). However, since the 1980s, at least eight fish species native of the Uruguay River basin have been registered as invasive in the Laguna dos Patos system, the most recent record being the palometa, Serrasalmus maculatus Kner, 1858 (Bertaco et al. 2022, 2023, Bertaco and Azevedo 2023). It has been suggested that the artificial interconnections of river basins (dams, channels, and water pumps promoted by agricultural practices) found in the southwestern region of Rio Grande do Sul have facilitated the transposition of species (Bertaco et al. 2022).

Ichthyological surveys performed in the Gravataí River basin are scarce, represented only by Ferrer et al. (2015), in the conservation unit Refúgio da Vida Silvestre Banhado dos Pachecos, and Bertaco and Azevedo (2016) in the Área de Proteção Ambiental do Banhado Grande. Thus, the basin’s ichthyofauna is incompletely inventoried, with only about 80 species recorded (Bertaco and Azevedo 2016).

Megalamphodus eques is recognized as an exotic species in the Gravataí River basin. The Convention on Biological Diversity (CBD 2005, Decision VI-23) defines “Invasive exo tic species” as an exotic species whose introduction and/or dispersion threatens biological diversity. However, the introduction of a species will not always result in biological invasion, as introduced populations may not be successful in the new environment, remaining dormant or even becoming extinct (Espínola and Júlio Junior 2007). We prefer the term “non-native species” to refer any species introduced outside its natural distribution area, regardless of introduction phase or its effects on the environment, in order to simplify understanding (Vitule and Prodocimo 2012, Iannone et al. 2020, Garcia et al. 2021).

This history of fish species invasions into the Laguna dos Patos system from the Uruguay River basin suggests that introductions occurred through artificial connections in the west of Rio Grande do Sul. However, a single locality of occurrence of M. eques far beyond the basin boundaries suggests that the species did not disperse as the palometa and other species cited by Bertaco et al. (2022), and probably was intentionally introduced from aquariums, since the species is widely cultivated and appreciated in ornamental aquaculture throughout the world (Furlan-Murari et al. 2022). Ornamental aquaculture, together with the ornamental fish industry, have been responsible for introducing a great diversity of aquatic organisms originating from different drainage basins and zoogeographic regions (Latini et al. 2016, Luduvice and Brito 2023, Dechoum et al. 2024).

Megalamphodus eques has a significant role in the Brazilian and global aquarium fish trade due to its intense red body coloration, adaptability, easy handling, and stress resistance (Park et al. 2014, Berchielli-Morais et al. 2015, Çelik and Cirik 2019, Santana et al. 2019, Furlan-Murari et al. 2022). Some Brazilian studies have shown that escape from ornamental aquaculture ponds is one of the main ways by which non-native fish are introduced into drainage basins (e.g., Magalhães et al. 2019, Luduvice and Brito 2023). Thus, it is possible that the presence of M. eques in the Gravataí River occurred due to the intentional release or escape of individuals from aquariums or even as fauna that are together of species used in fish farming. In this case, the specimens established in the Gravataí River would not necessarily have originated from native populations of the Uruguay River basin. However, other non-native species might possibly be recorded in the near future in the Laguna dos Patos due to the floods of September and November 2023, and the catastrophic flooding that occurred in south Brazil during April and May 2024, particularly in Delta do Rio Jacuí, either due to temporary communication between basins in flooded areas, or due to the breaking of barriers and escape of species used in aquaculture and fish farming.

Megalaphodus eques is a habitat generalist in its natural distribution, inhabiting rivers, streams and flooded areas, typically forming small schools near aquatic vegetation (Casatti et al. 2003). For example, it is a common species in the Pantanal floodplain, upper Paraguay River basin, and generally occurs in areas with macrophytes (Carvalho et al. 2022). It is a typical species of backwater areas and is normally associated with aquatic vegetation (Casatti et al. 2003), as also observed at the collection sites on the Gravataí River.

Santana et al. (2019) studied the biology of the species in the Pantanal (Paraguay River basin) and found it to have a long reproductive period, partial spawning, a higher proportion of females and low estimated size at first maturation. Species with these characteristics are typically classified as r-strategists (sensu Pianka 1970) and, according to Duyck et al. (2007), these species may be favored in non-competitive environments. Although they are present in many different species and environments, it cannot be ruled out that, under certain conditions, these characteristics contribute to the success of species in invaded environments.

Fish farming, aquaculture activities, and intentional release to promote recreational fishing are recognized as the main causes of the introduction of exotic fish species into natural environments (Vitule et al. 2009, Latini et al. 2016, Casimiro et al. 2018) and, consequently, the loss of native biodiversity in the Neotropics (Magalhães et al. 2021, Nabout et al. 2024). To reduce or prevent new introductions of exotic species, and enhance the value of native fish species, environmental education actions aimed at the general community, clarifying the negative impacts of these introductions on the native fauna of a river basin, should be encouraged by government agencies (Latini et al. 2016). Aquariophily and fish trade have been identified as the main routes of introduction of M. eques into the upper Paraná River basin (Garcia et al. 2018, Dagosta et al. 2024) Northeast Atlantic Forest hydrographic ecoregion (Luduvice and Brito 2023), and French Guiana (Brosse et al. 2021) to mention ones.

A search of the National Database of Invasive Exotic Species revealed 38 records of Hyphessobrycon eques (currently Megalamphodus eques), all located in the Southeast (states of Espírito Santo, Minas Gerais, São Paulo, and Rio de Janeiro) and South (state of Paraná) regions of Brazil. A risk assessment conducted by the Hórus Institute (https://www.institutohorus.org.br) classified the species as having a high invasion risk and advised against its use. According to the institute, the main routes and vectors of introduction are escapes from aquarium shops and domestic or public aquaria; however, as discussed above, other pathways may also be involved.

In this context, intensified efforts to study the ichthyofauna of the Gravataí River basin will enhance knowledge of its diversity-critical for developing effective environmental policies to protect both the basin and its fish fauna.

ACKNOWLEDGMENTS

We are grateful to Gilson F. Rey, João C.P. Dotto, João P. Krahe, and Leandro H. Krüg (Fundação Estadual de Proteção Ambiental) for assistance on field work, and to Patrick Colombo (MCN) for assistance with Fig. 1.

LITERATURE CITED

• Berchielli-Morais FA, Fernandes JBK, Sipaúba-Tavares LH (2015) Diets supplemented with microalgal biomass: effects on growth, survival and colouration of ornamental fish Hyphessobrycon eques (Steindachner 1882). Aquaculture Research 47(10): 3061-3069. https://doi.org/10.1111/are.12756
  » https://doi.org/10.1111/are.12756
• Bertaco VA, Azevedo MA (2016) Peixes. In: Cardoso SL, Paloski NL, Bencke GA (Orgs) Flora e fauna do rio Gravataí e ambientes associados: guia ilustrado físico e biótico da bacia hidrográfica do sistema Gravataí. Creare Comunicação, Gravataí, 82-98.
• Bertaco VA, Azevedo MA (2023) Non-native freshwater fish from drainages of the Rio Grande do Sul State, Brazil. Papéis Avulsos de Zoologia 63: e202363003. https://doi.org/10.11606/1807-0205/2023.63.003
  » https://doi.org/10.11606/1807-0205/2023.63.003
• Bertaco VA, Azevedo MA, Malabarba LR (2023) Peixes de água doce não nativos e os impactos sobre a ictiofauna do Rio Grande do Sul, Brasil. Bio Diverso 3(1): 1-80.
• Bertaco VA, Becker FG, Azevedo MA, Ferrer J, Behr ER, de Moraes TR, et al. (2022) The record and threats of the invasion of palometa Serrasalmus maculatus (Characiformes: Serrasalmidae) in the Patos Lagoon drainage, Southern Brazil. Journal of Fish Biology 101(4): 1098-1103. https://doi.org/10.1111/jfb.15169
  » https://doi.org/10.1111/jfb.15169
• Bertaco VA, Ferrer J, Carvalho FR, Malabarba LR (2016) Inventory of the freshwater fishes from a densely collected area in South America - a case study of the current knowledge of Neotropical fish diversity. Zootaxa 4138(3): 401-440. https://doi.org/10.11646/zootaxa.4138.3.1
  » https://doi.org/10.11646/zootaxa.4138.3.1
• Brosse S, Baglan A, Covain R, Lalagüe H, Le Bail PY, Vigouroux R, Quartarollo G (2021) Aquarium trade and fish farms as a source of non-native freshwater fish introductions in French Guiana. Annales de Limnologie - International Journal of Limnology 57: 4. https://doi.org/10.1051/limn/2021002
  » https://doi.org/10.1051/limn/2021002
• Carvalho FR, Gimenes-Junior H, Rech R (2022) Characidae. In: Heriberto Gimênes-Junior H, Rech R (Orgs) Guia ilustrado dos peixes do Pantanal e entorno. Instituto de Meio Ambiente de Mato Grosso do Sul, Campo Grande, 106-179.
• Casatti L, Mendes HF, Ferreira KM (2003) Aquatic macrophytes as feeding site for small fishes in the Rosana Reservoir, Paranapanema River, Southeastern Brazil. Brazilian Journal of Biology 63(2): 213-222. https://doi.org/10.1590/S1519-69842003000200006
  » https://doi.org/10.1590/S1519-69842003000200006
• Casimiro ACR, Garcia DAZ, Vidotto-Magnoni AP, Britton JR, Agostinho AA, Almeida FS, Orsi ML (2018) Escapes of non-native fish from flooded aquaculture facilities: the case of Paranapanema River, southern Brazil. Zoologia 35: e14638. https://doi.org/10.3897/zoologia.35.e14638
  » https://doi.org/10.3897/zoologia.35.e14638
• CBD (2005) Convention on Biological Diversity. In: Handbook of the convention on biological diversity including its Cartagena protocol on biosafety. Secretariat of the Convention on Biological Diversity, Montreal, 3^rded.
• Çelik P, Cirik Ş (2019) Embryonic and larval development of serpae tetra Hyphessobrycon eques (Steindachner, 1882). Aquaculture Research 51(1): 1-15. https://doi.org/10.1111/are.14375
  » https://doi.org/10.1111/are.14375
• CONCEA (2023) Resolução Normativa CONCEA n^o 59. Ministério da Ciência, Tecnologia e Inovações, Conselho Nacional de Controle de Experimentação Animal, Brasília, https://antigo.mctic.gov.br/mctic/opencms/legislacao/outros_atos/resolucoes/Resolucao_Normativa_Concea_n_59_de_02052023.html
  » https://antigo.mctic.gov.br/mctic/opencms/legislacao/outros_atos/resolucoes/Resolucao_Normativa_Concea_n_59_de_02052023.html
• Dagosta FCP, Monção MS, Nagamatsu BA, Pavanelli CS, Carvalho FR, Lima FCT, et al. (2024) Fishes of the upper rio Paraná basin: diversity, biogeography and conservation. Neotropical Ichthyology 22(1): e230066. https://doi.org/10.1590/1982-0224-2023-0066
  » https://doi.org/10.1590/1982-0224-2023-0066
• Dechoum MS, Junqueira AOR, Orsi ML, Ziller SR, Pivello VR, Zenni RD, et al. (2024) Sumário para tomadores de decisão do relatório temático sobre espécies exóticas invasoras, biodiversidade e serviços ecossistêmicos. Plataforma Brasileira de Biodiversidade e Serviços Ecossistêmicos, Editora Cubo, São Carlos, 21 pp. https://doi.org/10.4322/978-65-00-87239-2
  » https://doi.org/10.4322/978-65-00-87239-2
• Duyck P-F, David P, Quilici S (2007) Can more K-selected species be better invaders? A case study of fruit flies in La Réunion. Diversity and Distributions 13(5): 535-543. https://doi.org/10.1111/j.1472-4642.2007.00360.x
  » https://doi.org/10.1111/j.1472-4642.2007.00360.x
• Espínola LA, Júlio Junior HF (2007) Espécies invasoras: conceitos, modelos e atributos. Interciencia 32(9): 580-585.
• Ferrer J, Azevedo MA, Giora J, Cavalheiro LW, Wingert JM, Aguiar AR, et al. (2015) Refúgio de Vida Silvestre Banhado dos Pachecos: um verdadeiro abrigo para a ictiofauna relictual de mata paludosa na região metropolitana de Porto Alegre, RS, Brasil. Boletim Sociedade Brasileira de Ictiologia 114: 8-15.
• Fricke R, Eschmeyer WN, Van der Laan R (2025) Eschmeyer’s catalog of fishes: genera, species, references. California Academy of Science, San Francisco. https://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp
  » https://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp
• Froese R, Pauly D (2024) FishBase. World Wide Web electronic publication, https://www.fishbase.org
  » https://www.fishbase.org
• Furlan-Murari PJ, Lima ECS, Souza FP, Urrea-Rojas AM, Amaral FAN, Silva RM, et al. (2022) Systematic literature review of Hyphessobrycon eques: a support for the improvement of captive breeding. Semina: Ciências Agrárias 43(4): 1605-1628. https://doi.org/10.5433/1679-0359.2022v43n4p1605
  » https://doi.org/10.5433/1679-0359.2022v43n4p1605
• Garcia DAZ, Britton JR, Vidotto-Magnoni AP, Orsi ML (2018) Introductions of non-native fishes into a heavily modified river: rates, patterns and management issues in the Paranapanema River (Upper Paraná ecoregion, Brazil). Biological Invasions 20(5): 1229-1241. https://doi.org/10.1007/s10530-017-1623-x
  » https://doi.org/10.1007/s10530-017-1623-x
• Garcia DAZ, Pelicice FM, Brito MFB, Orsi ML, Magalhães ALB (2021) Peixes não-nativos em riachos no Brasil: estado da arte, lacunas de conhecimento e perspectivas. Oecologia Australis 25(2): 565-587. https://doi.org/10.4257/oeco.2021.2502.21
  » https://doi.org/10.4257/oeco.2021.2502.21
• Iannone BV, Carnevale S, Main MB, Hill JE, McConnell JB, Johnson SA, et al. (2020) Invasive species terminology: standardizing for stakeholder education. The Journal of Extension 58(3): 27. https://doi.org/10.34068/joe.58.03.27
  » https://doi.org/10.34068/joe.58.03.27
• Latini AO, Oporto LT, Lima-Júnior DP, Resende DC, Latini RO (2016) Peixes. In: Latini AO, Resende DC (Eds) Espécies exóticas invasoras de águas continentais no Brasil. Ministério do Meio Ambiente, Brasília, 295-581.
• Lima FCT, Marinho MM F, Carvalho FR (2024) In: Toledo-Piza M, Baena EG, Dagosta FCP, Menezes NA, Ândrade M, Benine RC, et al. Checklist of the species of the Order Characiformes (Teleostei: Ostariophysi). Neotropical Ichthyology 22(1): e230086. https://doi.org/10.1590/1982-0224-2023-0086
  » https://doi.org/10.1590/1982-0224-2023-0086
• Luduvice JSV, Brito MFG (2023) Ornamental aquaculture as a pathway for the introduction of non-native fish in coastal drainage of northeastern Brazil. Acta Limnologica Brasiliensia 35: e9. https://doi.org/10.1590/S2179-975X3722
  » https://doi.org/10.1590/S2179-975X3722
• Magalhães ALB, Bezerra LAV, Daga VS, Pelicice FM, Vitule JRS, Brito MFG (2021) Biotic differentiation in headwater creeks after the massive introduction of non-native freshwater aquarium fish in the Paraíba do Sul River basin, Brazil. Neotropical Ichthyology 19(3): e200147. https://doi.org/10.1590/1982-0224-2020-0147
  » https://doi.org/10.1590/1982-0224-2020-0147
• Magalhães ALB, Brito MFG, Sarrouh B (2019) An inconvenient routine: introduction, establishment and spread of new non-native fishes in the Paraíba do Sul River basin, state of Minas Gerais, Brazil. Neotropical Biology and Conservation 14(3): 329-338. https://doi.org/10.3897/neotropical.14.e38058
  » https://doi.org/10.3897/neotropical.14.e38058
• Melo BF, Ota RP, Benine RC, Carvalho FR, Lima FCT, Mattox GMT, et al. (2024) Phylogenomics of Characidae, a hyper-diverse Neotropical freshwater fish lineage, with a phylogenetic classification including four families (Teleostei: Characiformes). Zoological Journal of the Linnean Society 202(1): zlae101. https://doi.org/10.1093/zoolinnean/zlae101
  » https://doi.org/10.1093/zoolinnean/zlae101
• Mirande JM (2019) Morphology, molecules and the phylogeny of Characidae (Teleostei, Characiformes). Cladistics 35(3): 282-300. https://doi.org/10.1111/cla.12345
  » https://doi.org/10.1111/cla.12345
• Nabout JC, Pinto FE, Rabelo PVS, de Carvalho RA, Teresa FB (2024) Human impacts and larger geographic area explain the highest number of non-native species of freshwater fishes into Brazilian protected area. Aquatic Conservation: Marine and Freshwater Ecosystems 34(12): e70026. https://onlinelibrary.wiley.com/doi/10.1002/aqc.70026
  » https://onlinelibrary.wiley.com/doi/10.1002/aqc.70026
• Oyakawa OT, Menezes NA (2011) Checklist dos peixes de água doce do Estado de São Paulo, Brasil. Biota Neotropica 11(1a): 1-13.
• Park JM, Kim NR, Han KH, Han JH, Son MH, Cho JK (2014) Spawning behavior, egg development, larvae and juvenile morphology of Hyphessobrycon eques (Pisces: Characidae). Characidae fishes. Development & Reproduction 18(4): 241-249. https://doi.org/10.12717/DR.2014.18.4.241
  » https://doi.org/10.12717/DR.2014.18.4.241
• Pianka ER (1970) On r- and K-Selection. The American Naturalist 104(940): 592-597. http://www.jstor.org/stable/2459020
  » http://www.jstor.org/stable/2459020
• Santana SC, Kondato KK, Súarez YR (2019) Reproductive biology of Hyphessobrycon eques (Characiformes: Characidae) in Southern Pantanal, Brazil. Brazilian Journal of Biology 79(1): 70-79. https://doi.org/10.1590/1519-6984.176273
  » https://doi.org/10.1590/1519-6984.176273
• Sarmento-Soares LM, Martins-Pinheiro RF, Rodrigues LN (2017) Peixes do rio Doce segundo as coleções. Boletim Sociedade Brasileira de Ictiologia 123: 9-25.
• Vitule JRS, Freire CA, Simberloff D (2009) Introduction of non-native freshwater fish can certainly be bad. Fish and Fisheries 10(1): 98-108. https://doi.org/10.1111/j.1467-2979.2008.00312.x
  » https://doi.org/10.1111/j.1467-2979.2008.00312.x
• Vitule JRS, Prodocimo V (2012) Introdução de espécies não nativas e invasões biológicas. Estudos em Biologia, Ambiente e Diversidade 34(83): 225-237. https://doi.org/10.7213/estud.biol.7335
  » https://doi.org/10.7213/estud.biol.7335
• Weitzman SH, Palmer L (1997a) The common serpa tetra of aquarists identified as Hyphessobrycon eques (Steindachner, 1882). Tropical Fish Hobbyist 45(9): 140-150.
• Weitzman SH, Palmer L (1997b) A new species of Hyphessobrycon (Teleostei: Characidae) from the Neblina region of Venezuela and Brazil, with comments on the putative ‘rosy tetra clade’. Ichthyological Exploration of Freshwaters 7(3): 209-242.

ADDITIONAL NOTES

• ZooBank register
  https://zoobank.org/43A7E290-703E-4452-A12B-F7644AC593EB
• Data Availability
  Datasets generated or analyzed in this study are available from the corresponding author on reasonable request.
• Funding
  This study did not receive research funding.
• How to cite this article
  Bertaco VA, Azevedo MA, Carvalho FR (2025) Range expansion of the non-native Megalamphodus eques (Characiformes: Acestrorhamphidae) to the Laguna dos Patos system, southern Brazil. Zoologia 42: e25019. https://doi.org/10.1590/S1984-4689.v42.e25019
• Published by
  Sociedade Brasileira de Zoologia at Scientific Electronic Library Online - https://www.scielo.br/zool

Edited by

• Editorial responsibility
  Luiz A.W. Peixoto

Data availability

Datasets generated or analyzed in this study are available from the corresponding author on reasonable request.

Data citations

Fricke R, Eschmeyer WN, Van der Laan R (2025) Eschmeyer’s catalog of fishes: genera, species, references. California Academy of Science, San Francisco. https://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp

Froese R, Pauly D (2024) FishBase. World Wide Web electronic publication, https://www.fishbase.org

Publication Dates

• Publication in this collection
  10 Oct 2025
• Date of issue
  2025

History

• Received
  11 Mar 2025
• Accepted
  05 June 2025