Revisionary study of the armored catfish Corydoras paleatus (Jenyns, 1842) (Siluriformes: Callichthyidae) over 180 years after its discovery by Darwin, with description of a new species

Abstract

The taxon known as Corydoras paleatus carries one of the most complex taxonomic histories among Corydoradinae catfishes. A comprehensive review of specimens attributed to that species from several localities was carried out, allowing the clear recognition of C. paleatus and also of a new species previously misidentified as C. paleatus, described herein. Corydoras paleatus can be distinguished from its congeners by presenting the following unique combination of features: perpendicularly directed serrations along entire posterior margin of the pectoral spine; three large black blotches along midline of flank; hyaline or black pectoral fin; and transversal black bars on caudal-fin lobes. Corydoras paleatus is known from the lower rio Paraná basin, coastal rivers from Southern Brazil and Uruguay and rio Uruguai basin. The new species can be distinguished from its congeners by having the following unique combination of features: three large black blotches along midline of flank; three nasal pores; mesethmoid short; infraorbital 2 not in contact with compound pterotic; striated black spots from the snout tip to nuchal plate region; markedly rounded snout; and anterior portion of dorsal fin spotted. The new species is known from the upper rio Uruguai basin, from the rivers Canoas, do Peixe and Pelotas.O táxon conhecido como Corydoras paleatus carrega uma das histórias taxonômicas mais complexas dentre os bagres Corydoradinae. Uma revisão abrangente de espécimes atribuídos a essa espécie, de várias localidades, foi conduzida. A análise do material colhido permitiu o reconhecimento claro de C. paleatus e também de uma espécie nova, previamente identificada erroneamente como C. paleatus, aqui descrita. Corydoras paleatus pode ser distinguida de suas congêneres por possuir a seguinte combinação única de características: serrilhas perpendicularmente direcionadas ao longo de toda a margem posterior do acúleo peitoral; três manchas pretas grandes ao longo da linha mediana do flanco; nadadeira peitoral hialina ou preta; e barras transversais pretas nos lobos da nadadeira caudal. Corydoras paleatus é conhecida da bacia do baixo rio Paraná, rios costeiros do sul do Brasil e Uruguai, e bacia do rio Uruguai. A espécie nova pode ser distinguida de suas congêneres por possuir a seguinte combinação única de caracteres: três manchas pretas grandes ao longo da linha mediana do flanco; três poros nasais; mesetmóide curto; infraorbital 2 não contatando o pterótico composto; manchas pretas estriadas da ponta do focinho até a região da placa nucal; focinho marcadamente arredondado; e porção anterior da nadadeira dorsal com manchas. A espécie nova é conhecida da bacia do alto rio Uruguai, dos rios Canoas, do Peixe e Pelotas.

From the inside out: a new species of armoured catfish Corydoras with the description of poorly‐explored character sources (Teleostei, Siluriformes, Callichthyidae)

“…Even though lineage 6 has a similar general morphological pattern as lineage 9, the assignment of C . benattii to lineage 6 is less plausible as all species of that clade exhibit a distinctive colour pattern on the midline of the flank (Tencatt et al, ) not observed in the new species. Additionally, regarding general morphological and colour patterns, the two species most similar to C. benattii ( i.e ., C. loretoensis and C. osteocarus ) are among the members of lineage 9.…”

Two new species of Heptapterus (Siluriformes: Heptapteridae) from the Uruguay River basin, Brazil

“…Heptapterus carnatus is geographically restricted to the Araucaria forest plateau ecoregion in southern Brazil and to the upper portions of the Jacuí and Uruguay Rivers. Malabarba et al (2009) (Ferrer & Malabarba, 2011;Tencatt et al, 2016;Lucena et al, 2017;Reis, 2017), all endemic to this area. The description of H. carnatus adds one more species to list of fishes endemic to the Araucaria forest plateau ecoregion, highlighting the importance of aquatic conservation in this region.…”

“…() identified a high degree of fish endemism in this region, listing eight species as endemic, namely: Astyanax brachypterygium Bertaco and Malabarba 2001, Astyanax cremnobates Bertaco and Malabarba 2001, Bryconamericus patriciae da Silva 2004, Cnesterodon brevirostratus Rosa and Costa 1993, Eurycheilichthys pantherinus (Reis & Schaefer 1992), Jenynsia eirmostigma Ghedotti and Weitzman 1995, Pareiorhaphis eurycephalus Pereira and Reis 2002 and Pareiorhaphis vestigipinnis (Pereira & Reis, 1992). Additional species have since been described for the Araucaria forest plateau, such as Trichomycterus tropeiro Ferrer and Malabarba , Corydoras froehlichi Tencatt, Britto and Pavanelli , Astyanax taurorum Lucena, Zaluski & Lucena , Eurycheilichthys castaneus Reis , E. planus Reis , E. vacariensis Reis , E. coryphaenus Reis (Ferrer & Malabarba, 2011; Tencatt et al ., 2016; Lucena et al ., 2017; Reis, 2017), all endemic to this area. The description of H. carnatus adds one more species to list of fishes endemic to the Araucaria forest plateau ecoregion, highlighting the importance of aquatic conservation in this region.…”

Record of morphological deformities in Corydoras aff. longipinnis in two reservoirs under urban influence in Upper Iguaçu and Southern Coastal basins in Paraná State, Brazil

“…The fish were collected in 2002, using cast nets and trawl nets, fixed in formaldehyde 10% and conserved in alcohol 70 o GL. Species identification followed Tencatt et al (2016). Each individual was examined using a visual method to identify morphological abnormalities, following Flores-Lopes & Reuss-Strenzel (2011).…”