The freshwater fishes from the Costa Verde Fluminense region of southeastern Brazil

Dopazo, Manuela; Souto-Santos, Igor Cavalcanti de Araújo; Britto, Marcelo Ribeiro de; Moreira, Cristiano Rangel; Buckup, Paulo Andreas

doi:10.1590/1676-0611-BN-2022-1422

Abstract

The region between the Brazilian Shield and the Atlantic Ocean is characterized by the presence of numerous hydrographic basins isolated by mountainous terrain that flow directly into the ocean without forming wide coastal plains. However, knowledge about the diversity and distribution of freshwater fish in several coastal areas is still incipient. One of these areas is the Costa Verde Fluminense region, situated between the municipalities of Mangaratiba and Paraty in the Brazilian State of Rio de Janeiro. In order to eliminate the gap of knowledge about the freshwater fish fauna of this region, we prepared a list of the species, and dichotomous identification keys and illustrations of all species. We examined material from expeditions carried out between 1942 and 2019, deposited in the Ichthyological Collection of the Museu Nacional, Universidade Federal do Rio de Janeiro, Brazil. The material comes from 29 continental coastal rivers and four drainages on Ilha Grande island. We recognized 54 fish species belonging to 16 families and 9 orders. The order Siluriformes was the most diverse with 18 species, followed by Characiformes with 14 species, Cyprinodontiformes with 10 species, Cichliformes with four species, Gobiiformes with three species, Syngnathiformes with two species, and Gymnotiformes, Salmoniformes and Synbranchiformes with one species each. These records include two putative undescribed species and four introduced species. Phalloceros anisophallos was the most widely distributed species, recorded in 24 drainages. More than a half (52 %) of the native species occur exclusively in coastal streams, demonstrating the importance of the area for biogeographic and conservation studies.

Keywords:
Angra dos Reis; Mangaratiba; Paraty

Resumo

A região entre o Escudo Brasileiro e o Oceano Atlântico é caracterizada pela presença de inúmeras bacias hidrográficas isoladas por terrenos montanhosos que deságuam diretamente no oceano sem formar amplas planícies costeiras. No entanto, o conhecimento sobre a diversidade e distribuição de peixes de água doce em diversas áreas costeiras ainda é incipiente. Uma dessas áreas é a região da Costa Verde Fluminense, situada entre os municípios de Mangaratiba e Paraty no Estado do Rio de Janeiro. A fim de eliminar a lacuna de conhecimento sobre a ictiofauna de água doce desta região, elaboramos uma lista das espécies, chaves de identificação dicotômicas e ilustrações de todas as espécies. Examinamos material de expedições realizadas entre 1942 e 2019, depositado na Coleção Ictiológica do Museu Nacional da Universidade Federal do Rio de Janeiro, Brasil. O material é proveniente de 29 rios costeiros continentais e quatro drenagens da Ilha Grande. Reconhecemos 54 espécies de peixes pertencentes a 16 famílias e 9 ordens. A ordem Siluriformes foi a mais diversa com 18 espécies, seguida de Characiformes com 14 espécies, Cyprinodontiformes com 10 espécies, Cichliformes com quatro espécies, Gobiiformes com três espécies, Syngnathiformes com duas espécies e Gymnotiformes, Salmoniformes e Synbranchiformes com uma espécie cada. Esses registros incluem duas espécies presumidamente não descritas e quatro espécies introduzidas. Phalloceros anisophallos foi a espécie mais amplamente distribuída, registrada em 24 drenagens. Mais da metade (52 %) das espécies nativas ocorrem exclusivamente em córregos costeiros, demonstrando a importância da área para estudos biogeográficos e de conservação.

Palavras-chave
Angra dos Reis; Mangaratiba; Paraty

Introduction

The region between the Brazilian Shield and the Atlantic Ocean is characterized by the presence of numerous hydrographic basins isolated by mountainous terrain. These drainages flow directly into the ocean without forming wide coastal plains and harbor endemic fish populations (Buckup 2011BUCKUP, P.A. 2011. The Eastern Brazilian Shield. In: Albert, J., Reis, R.E. (Ed.) Historical biogeography of Neotropical freshwater fishes. Berkeley: University of California Press, p.203–210.). Most eastern Brazilian coastal basins are small and isolated drainages, characterized by relatively low fish diversity (when compared to the Paraná basin), and high level of endemism (Thomaz & Knowles 2018THOMAZ, A.T. & KNOWLES, L.L. 2018. Flowing into the unknown: Inferred paleodrainages for studying the icthyofauna of Brazilian coastal rivers. Neotrop. Ichthyol. 16(3):e180019. https://doi.org/10.1590/1982-0224-20180019
https://doi.org/10.1590/1982-0224-201800... ). One of these areas is the Costa Verde Fluminense region, situated between the municipalities of Mangaratiba and Paraty, which is home to one of the largest remnants of native Atlantic Forest in the Brazilian State of Rio de Janeiro. As for most eastern Brazilian coastal basins, the knowledge about the diversity and distribution of its freshwater fish fauna is still incipient.

The basins of the Costa Verde Fluminense are included in the Fluminense Ecoregion (FEOW352), limited to the north by the Paraíba do Sul (FEOW329) and to the south by Ribeira de Iguape (FEOW330) ecoregions (Abell et al. 2008ABELL, R., THIEME, M.L., REVENGA, C., BRYER, M., KOTTELAT, M., BOGUTSKAYA, N., COAD, B., MANDRAK, N., BALDERAS, S.C., BUSSING, W., STIASSNY, M.L.J., SKELTON, P., ALLEN, G.R., UNMACK, P., NASEKA, A., NG, R., SINDORF, N., ROBERTSON, J., ARMIJO, E., HIGGINS, J.V., HEIBEL, T.J., WIKRAMANAYAKE, E., OLSON, D., LÓPEZ, H.L., REIS, R.E., LUNDBERG, J.G., SABAJ, M.H.P. & PETRY, P. 2008. Freshwater Ecoregions of the World: A New Map of Biogeographic Units for Freshwater Biodiversity Conservation. BioScience. 58(5): 403–414. https://doi.org/10.1641/B580507
https://doi.org/10.1641/B580507... ). This ecoregion is occupied by one of the highest densities of urban occupation in the Atlantic Forest. Despite of the long history of human occupation of the Atlantic coast of Rio de Janeiro, the distribution of freshwater fishes is still poorly known. The first description of a fish species, Characidium japuhybense, from a locality situated in the Costa Verde region was published only in the middle of the 20^th Century (Travassos 1949TRAVASSOS, H. 1949. Notas ictiológicas. II. Characidium japuhybensis n. sp. (Actinopterygii, Ostariophysi). R. bras. Biol. 9(2):229-233.) based on material collected in the Japuíba basin, at Angra dos Reis, a few years earlier by George Myers, Paulo Miranda-Ribeiro and Haroldo Travassos. Additional species have been described in recent decades, totaling 11 species described from specimens collected in the Costa Verde region (Table 1), but no comprehensive study of fish composition is currently available (Guimarães et al. 2021GUIMARÃES, F.V., SOUZA, T.M., RODRIGUES, R.R. & SOUZA-LIMA, R. 2021. Composition and distribution of fishes from the Perequê-Açu river basin, Paraty, Rio de Janeiro, Southeastern Brazil. Biota Neotrop. 21(2):1–8. https://doi.org/10.1590/1676-0611-bn-2020-1096
https://doi.org/10.1590/1676-0611-bn-202... ).

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Table 1.
Freshwater fishes with type-locality located in river drainages of the Costa Verde Fluminense, southeastern Brazil.

Bizerril & Primo (2001BIZERRIL, C.R.S.F. & PRIMO, P.B.S. 2001. Peixes de águas interiores do Estado do Rio de Janeiro. Fundação de Estudos do Mar, Rio de Janeiro, p.417.) provided three lists of fish species from river drainages of Ilha Grande Bay, the largest area in the Costa Verde Fluminense region. Those lists are the most comprehensive ever published for Costa Verde Fluminense, but they are not associated with voucher specimens from museum collection. One of the lists was extracted from an unpublished master’s thesis by H. São-Thiago, and included 22 marine and freshwater species from the Parati-Mirim River. The second list (based on “field data” and three unpublished contributions by C. Coutinho, E. Caramaschi, and H. São-Thiago compiled fish diversity from 22 coastal basins, including again the Parati-Mirim. The third list, based on personal communication by R. Mazzoni, presented 18 species of fish that occur in the drainages of the Ilha Grande island.

Here we present a compilation of fish species from the Costa Verde Fluminense region based on voucher specimens deposited in a permanent ichthyological collection. In addition to the list of voucher specimens collected from 33 river basins, we provide identification keys for all species.

Material and Methods

Study area

The study area comprises the Costa Verde Fluminense region (Figure 1), in the municipalities of Mangaratiba, Angra dos Reis and Paraty, in the Brazilian State of Rio de Janeiro, and São José do Barreiro and Bananal in the Brazilian State of São Paulo. This region includes both continental and insular drainages of the Ilha Grande and Sepetiba Bays, between the rio Itinguçu (22°54'44.16"S, 43°52'47.97"W) in the east and the western border of the State of Rio de Janeiro where it meets the ocean (23°22'06"S, 44°43'27"W). Additionally, we included the small drainages of the Ilha Grande, the largest island inside the Ilha Grande Bay. The continental rivers drain the coastal lowlands and the slopes of the Serra do Mar, locally known as Serra da Bocaina (Francisco & Oliveira 2009FRANCISCO, C.N. & OLIVEIRA, C.A.V. 2009. Sustentabilidade hídrica da Região Hidrográfica da Baía da Ilha Grande, RJ. Anais XIV Simpósio Brasileiro de Sensoriamento Remoto. INPE, Natal, p.4707–4714.), while the headwaters of some of these rivers drain the main plateau of the Bocaina highlands. The sampled coastal rivers were numbered from east to west following the shoreline (Table 2).

Figure 1.
Sampled localities in the Costa Verde Fluminense (Rio de Janeiro) region. River drainages are numbered according to . Circles may represent more than one sample locality.

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Table 2.
River drainages sampled in the Costa Verde Fluminense region, numbered from east to west according to the position of their mouth () and coordinates of sampled localities. Drainages 30 to 33 are located on Ilha Grande island. Original geographic coordinates obtained with GPS at collection localities are provided, except for those indicated by an asterisk (*), which are estimated from topographic maps.

Specimens

For the purpose of inclusion in our list, species were considered as freshwater according to Reis et al. (2003REIS, R.E., KULLANDER, S.O., FERRARIS, C.J. (Ed.). 2003. Check list of the freshwater fishes of South and Central America. Edipucrs, Porto Alegre, p.742.). The list is based on examination of specimens collected between 1942 and 2019 (Supplementary file 1), and deposited at the Ichthyological Collection of the Museu Nacional (MNRJ), Universidade Federal do Rio de Janeiro, Brazil, which harbors the largest collection of freshwater fishes from the Costa Verde Fluminense region. Literature records of species from the region are included in the list and discussed as deemed appropriate, but only when associated with material deposited in a museum collection.

Species

Specimens were identified to the lowest taxonomic level possible using available literature (e.g., Buckup et al. 2014BUCKUP, P.A., BRITTO, M.R., SOUZA-LIMA, R., PASCOLI, J.C., VILLA-VERDE, L, FERRARO, G.A., SALGADO, F.L.K, GOMES, J.R. 2014. Guia de identificação das espécies de peixes da bacia do Rio das Pedras, município de Rio Claro, RJ. The Nature Conservancy, Rio de Janeiro, p.79.; Costa 2009COSTA, W.J.M. 2009. Peixes aploqueilóideos da Mata Atlântica brasileira: história, diversidade e conservação. Rio de Janeiro: Série Livros 34, Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, p.172.; Menezes et al. 2007MENEZES, N.A., WEITZMAN, S.H., OYAKAWA, O.T., LIMA, F.C.T., CASTRO, R.M.C. & WEITZMAN, M.J. 2007. Peixes de água doce da Mata Atlântica: lista preliminar das espécies e comentários sobre conservação de peixes de água doce neotropicais. Museu de Zoologia da Universidade de São Paulo, São Paulo, p.407.; Oyakawa et al. 2006OYAKAWA, O.T., AKAMA, A., MAUTARI, K.C. & NOLASCO, J.C. 2006. Peixes de riachos da Mata Atlântica. Editora Neotropica, São Paulo, p.201.) or by direct comparisons with type series or specimens identified by experts. DNA Barcoding methods (sensu Hebert et al. 2003aHEBERT, P.D.N., CYWINSKA, A., BALL, S.L., DEWAARD, J.R. 2003a. Biological identifications through DNA barcodes. Proc. R. Soc. B: Biol. Sci. 270(1512):313–321. https://doi.org/10.1098/rspb.2002.2218
https://doi.org/10.1098/rspb.2002.2218... ; Hebert et al. 2003bHEBERT, P.D.N., RATNASINGHAM, S., DEWAARD, J.R. 2003b. Barcoding animal life: cytochrome c oxidase subunit 1 divergences among closely related species. Proc. R. Soc. B: Biol. Sci. 270(1):596–599. http://doi.org/10.1098/rsbl.2003.0025
https://doi.org/http://doi.org/10.1098/r... ) were used for species confirmation of Characidae and Trichomycterus (data not shown). The taxonomic nomenclature follows Eschmeyer’s Catalog of Fishes (Fricke et al. 2022FRICKE, R., ESCHMEYER, W.N. & VAN DER LAAN, R. 2022. Eschmeyer’s catalog of fishes: genera, species, references. Available from: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. Electronic version (last access in 21/08/2022)
http://researcharchive.calacademy.org/re... ). The species are listed following the order of the classification proposed by Nelson et al. (2016NELSON, J.S., GRANDE, T.C., WILSON, M.V.H. 2016. Fishes of the world. John Wiley & Sons, Hoboken, p.707. https://doi.org/10.1002/9781119174844
https://doi.org/10.1002/9781119174844... ).

The identification keys are provided for the species that occur in the Costa Verde Fluminense region, including exotic species recorded to date. Exotic species are those with origins from any other continent. We first present a dichotomous key to identify fish orders. Orders that include a single family or single species, have their respective names given in parentheses. Separate keys are presented for families and genera which have more than one species present in the area.

The extinction risk of each species of fish was obtained from the Brazilian Red List and IUCN Red List of Threatened species (MMA 2014MMA [Ministério do Meio Ambiente]. 2014. Portaria Nº445, de 17 de dezembro de 2014. Lista nacional de espécies da fauna ameaçada de extinção – peixes e invertebrados. Diário Oficial da União, Brasília/DF, Seção 1, No. 98, 1–86. https://www.icmbio.gov.br/cepsul/images/stories/legislacao/Portaria/2014/p_mma_445_2014_lista_peixes_amea%C3%A7ados_extin%C3%A7%C3%A3o.pdf
https://www.icmbio.gov.br/cepsul/images/... ; MMA 2018MMA [Ministério do Meio Ambiente]. 2018. Portaria Nº444, de 26 de novembro de 2018. Estratégia Nacional para Conservação de Espécies Ameaçadas de Extinção. Diário Oficial da União, Brasília/DF, Seção 1, No. 228, 1–161. https://www.in.gov.br/materia/-/asset_publisher/Kujrw0TZC2Mb/content/id/52249904
https://www.in.gov.br/materia/-/asset_pu... ; ICMBIO 2018ICMBIO [Instituto Chico Mendes de Conservação da Biodiversidade]. 2018. Livro Vermelho da Fauna Brasileira Ameaçada de Extinção: Volume VI – Peixes. Brasília, p.1235.; IUCN 2021IUCN. 2021. The IUCN Red List of Threatened Species. Version 2021-1. Available from: http://www.iucnredlist.org (last access in 21/08/2022)
http://www.iucnredlist.org... ). The distribution map of the examined material (Supplementary file 1) was generated with QGIS software (http://qgis.org) following Calegari et al. (2016CALEGARI, B. B., DELAPIEVE, M.L., SOUZA, L.M. 2016. Tutorial para preparação de mapas de distribuição geográfica. Bol. Soc. Bras. Ictiologia. 118:15–30.), and using river traces obtained manually from Google Earth satellite images.

Results

The 13.692 examined fish specimens (857 lots) belong to 54 species, 16 families, 9 orders of freshwater fishes (Table 3). Siluriformes (Figure 2) was the most diverse order (18 species), followed by Characiformes (Figure 3, 14 species), Cyprinodontiformes (Figure 4 and Figure 5, 10 species), Cichliformes (Figure 6, four species), Gobiiformes (Figure 6, three species), Syngnathiformes (Figure 6, two species), and Gymnotiformes, Salmoniformes and Synbranchiformes (Figure 6, one species each). The most diverse family was Characidae (10 species), followed by Loricariidae (eight species), Poeciliidae (six species), Heptapteriade (five species), Trichomycteridae, Cichlidae and Rivuliidae (four species each), Crenuchidae (three species), Eleotridae and Syngnathidae (two species each), and Callichthyidae, Erythrinidae, Gobiidae, Gymnotidae, Salmonidae and Synbranchidae (one species each). Phalloceros anisophallos Lucinda 2008 was the most common species in Costa Verde (found in 24 drainages), followed by Awaous tajasica (Lichtenstein 1822) and Geophagus brasiliensis (Quoy & Gaimard 1824) (found in 15 drainages), and by Schizolecis guentheri (Miranda Ribeiro 1918) (found in 14 drainages). Some species were found only in a single drainage: Crenicichla lepidota Heckel 1840 in the Itinguçu drainage; Kryptolebias ocellatus (Hensel 1868) in the Muriqui drainage; Characidium grajahuense Travassos 1944 and Neoplecostomus microps (Steindachner 1877) in the Saco drainage (in the municipality of Mangaratiba); Atlantirivulus lazzarotoi (Costa 2007) in the Japuíba drainage; Listrura costai Villa-Verde, Lazzarotto & Lima 2012 in the Jurumirim drainage; Astyanax lacustris (Lütken 1875) the Bracuí drainage; Deuterodon sp., Psalidodon scabripinnis (Jenyns 1842), Hemipsilichthys nimius Pereira, Reis, Souza & Lazzarotto 2003, and Pareiorhina rudolphi (Miranda Ribeiro 1911) in the Perequê-Açu drainage; Characidium sp., Coptodon rendalli (Boulenger 1897) and Oreochromis niloticus (Linnaeus 1758) in the Parati-Mirim drainage; and Atlantirivulus simplicis (Costa 2004) in Saco do Mamanguá drainage. Two possibly undescribed species were found (Characidium sp. and Deuterodon sp.). Four non-native species were recorded in the region: Coptodon rendalli (Boulenger 1897), Oncorhynchus mykiss (Walbaum 1792), Oreochromis niloticus (Linnaeus 1758), and Poecilia reticulata Peters 1859.

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Table 3.
Freshwater fishes found in the Costa Verde Fluminense region. Drainages are numbered from east to west according to the position of their outlet into the sea (see and ). One asterisk (*) indicates non-native species. Two asterisks (**) indicate record based solely on Medeiros et al. (2022MEDEIROS, L.S., FERREIRA-ARAÚJO T., LAZZAROTTO H. & LIMA S.M.Q. 2022. Type locality, distribution and conservation of the threatened catfish Taunayia bifasciata (Eigenmann & Norris 1900) (Siluriformes: Heptapteridae) in the Atlantic Forest streams of Southeastern Brazil. Zootaxa. 5154(5):595–600. https://doi.org/10.11646/zootaxa.5154.5.8
https://doi.org/10.11646/zootaxa.5154.5.... ).

Figure 2.
Species of Siluriformes from Costa Verde Fluminense region, southeastern, Brazil. A. Listrura costai, MNRJ 31917, 31.3 mm SL. B. Trichogenes longipinnis, MNRJ 11722, 62.3 mm SL. C. Trichomycterus jacupiranga, MNRJ 43846, 28.3 mm SL. D. Trichomycterus potschi, MNRJ 52215, 45.1 mm SL. E. Scleromystax barbatus, MNRJ 46672, 58.2 mm SL. F. Ancistrus multispinis, MNRJ 38081, 64.0 mm SL. G. Hemipsilichthys nimius, MNRJ 50595, 79.7 mm SL. H. Kronichthys heylandi, MNRJ 43848, 36.8 mm SL. I. Neoplecostomus microps, MNRJ 51835, 75.9 mm SL. J. Neoplecostomus paraty, MNRJ 41727, 50.9 mm SL. K. Pareiorhina rudolphi, MNRJ 24917, 46.0 mm SL. L. Rineloricaria zawadzkii, MNRJ 17185, 106.7 mm SL. M. Schizolecis guentheri, MNRJ 38080, 36.7 mm SL. N. Acentronichthys leptos, MNRJ 17182, 68.08 mm SL. O. Pimelodella lateristriga, MNRJ 46676, 54.1 mm SL. P. Rhamdia quelen, MNRJ 30539, 65.5 mm SL. Q. Rhamdioglanis frenatus, MNRJ 17184, 86.50 mm SL. R. Taunayia bifasciata, UFRN 5592, 74.9 mm SL.

Figure 3.
Species of Characiformes from Costa Verde Fluminense region, southeastern, Brazil. A. Characidium grajahuense, MNRJ 20866, 70.7 mm SL. B. Characidium japuhybense, MNRJ 43512, 58.6 mm SL. C. Characidium sp., MNRJ 15447, 57.8 mm SL. D. Hoplias malabaricus, MNRJ 43893, 120.7 mm SL E. Astyanax keronolepis, MNRJ 43492, 87.7 mm SL. F. Astyanax lacustris, MNRJ 52222, 68.30 mm SL. G. Bryconamericus ornaticeps, MNRJ 17181, 52.7 mm SL. H. Deuterodon hastatus, MNRJ 51734, 25.1 mm SL. I. Deuterodon intermedius, MNRJ 22795, 76.2 mm SL. J. Deuterodon sp., MNRJ 51718, 74.2 mm SL. K. Hollandichthys multifasciatus, MNRJ 43242, 46.2 mm SL. L. Mimagoniates microlepis, MNRJ 46673, 48.98 mm SL. M. Oligosarcus hepsetus, MNRJ 43495, 131.3 mm SL. N. Psalidodon scabripinnis, MNRJ 50607, 72.4 mm SL.

Figure 4.
Females (left) and males (right) of species of Poeciliidae (Cyprinodontiformes) from Costa Verde Fluminense region, southeastern Brazil. A. Phalloceros anisophallos, MNRJ 43253, ♀ 34.8 mm SL, ♂ 26.0 mm SL. B. Phalloceros enneaktinos, MNRJ 43245, ♀ 24.9 mm SL, ♂ 22.9 mm SL. C. Phalloceros harpagos, MNRJ 43508, ♀ 36.2 mm SL, ♂ 19.5 mm SL. D. Phalloceros leptokeras, MNRJ 43505, ♀ 31.3 mm SL, MNRJ 4226, ♂ 21.2 mm SL. E. Poecilia reticulata, MNRJ 43892, ♀ 27.6 mm SL, ♂ 15.2 mm SL. F. Poecilia vivipara, MNRJ 43891, ♀ 45.1 mm SL, ♂ 31.2 mm SL.

Figure 5.
Females (left), males (right), and hermaphrodite (center) of species of Rivulidae (Cyprinodontiformes) from Costa Verde Fluminense region, southeastern Brazil. A. Atlantirivulus lazzarotoi, MNRJ 5997, ♀ 30.2 mm SL, ♂ 35.2 mm SL. B. Atlantirivulus simplicis, MNRJ 20249, ♀ 12.5 mm SL, ♂ 19.8 mm SL. C. Kryptolebias brasiliensis, MNRJ 26460, ♀ 20.8 mm SL, ♂ 25.2 mm SL. D. Kryptolebias ocellatus, MNRJ 11397, hermaphrodite, 48.9 mm SL.

Figure 6.
Fish species from Costa Verde Fluminense, southeastern Brazil. A. Gymnotiformes (Gymnotus pantherinus, MNRJ 28731, 88.5 mm SL). B. Salmoniformes (Oncorhynchus mykiss, MNRJ 22796, 181.8 mm SL). C. Gobiiformes (Dormitator maculatus, MNRJ 30631, 38.2 mm SL). D. Gobiiformes (Eleotris pisonis, MNRJ 22137, 99.02 mm SL). E. Gobiiformes (Awaous tajasica, MNRJ 43852, 79.6 mm SL). F. Cichliformes (Coptodon rendalli, MNRJ 11733, 159.1 mm SL). G. Cichliformes (Crenicichla lepidota, MNRJ 51738, 82.0 mm SL). H. Cichliformes (Oreochromis niloticus, MNRJ 11737, 157.5 mm SL). I. Cichliformes (Geophagus brasiliensis, MNRJ 46677, 31.8 mm SL). J. Synbranchiformes (Synbranchus marmoratus, MNRJ 30676, 219.0 mm SL). K. Syngnathiformes (Microphis lineatus, MNRJ 30930, 148.0 mm SL). L. Syngnathiformes (Pseudophallus brasiliensis, MNRJ 19178, 84.7 mm SL).

The ranking of species richness among the basins is as follows: Bracuí (25 species), Perequê-Açu (24 species), Mambucaba (23 species), Parati-Mirim (22 species), Japuíba (21 species), Jurumirim (19 species), Ariró (18 species), Caputera (13 species), Saco (Mangaratiba) and Ambrósio (11 species each), Jacuecanga (10 species), Sistema Lagunar do Sul e do Leste (eight species), Sahy, Muriqui, Andorinha and Toca do Boi (seven species each), Itinguçu and Pequeno (six species each), Saco (Angra dos Reis), São Roque and Barra Grande (five species each), Praia do Retiro (four species), Grataú, Praia Tarituba and Mateus Nunes (three species each), Saco do Mamanguá and Barra Pequena (two species each), and Praia Grande, Monsuaba, Floresta, Taquari, Praia Grande de Cajaíba and Lopes Mendes (one species each).

Identification keys

Identification Key to Orders

1.
a. Dorsal fin absent……….. 2

b. Dorsal fin present……….. 3
2.
a. Anal fin absent……SYNBRANCHIFORMES (Family Synbranchidae: Synbranchus marmoratus)

b. Anal fin present ……GYMNOTIFORMES (Family Gymnotidae: Gymnotus pantherinus)
3.
a. A single dorsal fin with rays……….. 4

b. Two dorsal fins with rays……GOBIIFORMES
4.
a. Sensory lateral line divided on the flank into two sections ……CICHLIFORMES (Family Cichlidae)

b. Sensory lateral line continuous, without division……….. 5
5.
a. Pelvic fin absent ……SYNGNATHIFORMES (Family Syngnathidae)

b. Pelvic fin present………..6
6.
a. Body covered with scales……….. 7

b. Body covered by skin or bone plates……SILURIFORMES
7.
a. Adipose fin usually present, except in Hoplias malabaricus ……….. 8

b. Adipose fin absent……CYPRINODONTIFORMES
8.
a. Opercular membrane with 4-5 branchiostegal rays……CHARACIFORMES

b. Opercular membrane with more than 10 branchiostegal rays ……SALMONIFORMES (Family Salmonidae: Oncorhynchus mykiss)

CHARACIFORMES

Identification Key to Families

1.
a. Posterior margin of caudal fin rounded Erythrinidae (Hoplias malabaricus)

b. Posterior margin of caudal fin emarginated or forked……….. 2
2.
a. Anal fin with less than 9 branched rays………..Crenuchidae

b. Anal fin with more than 15 branched rays………..Characidae

Family Characidae