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| Phenacorhamdia suia Silva, Ochoa & Castro, 2022 Photographed by Dario Faustino-Fuster. |
Heptapteridae is a diverse group of catfishes composed of 231 valid species endemic to the Neotropical region, recognized in two subfamilies: Rhamdiinae and Heptapterinae. Phenacorhamdia is a Heptapterinae member and currently has 13 valid species broadly distributed throughout the main river basins of South America. Here we described a new species of Phenacorhamdia from the Xingu River basin. Morphological data were obtained from 30 specimens under 23 morphometric measures and 6 meristic counts. The new species differs from congeners based on the exclusive combination of the following diagnostic characters: atypical mottled colored body and all fins with interradial membranes mottled pigmented; multicuspid teeth; maxillary barbel reaching pectoral-fin origin; lacking a short extension of the first pectoral-fin ray; caudal fin lobes extremely elongated and pointed; and 43−45 total vertebrae.
Keywords: Amazon River basin, Brazilian Shield, Catfishes, Taxonomy.
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| Phenacorhamdia suia, MNRJ 24850, holotype, 81.8 mm SL, Brazil, Mato Grosso State, São Félix do Araguaia, upper Xingu River basin. Photographed by Dario Faustino-Fuster. |
Phenacorhamdia suia, new species
Diagnosis. Phenacorhamdia suia differs from all congeners by having an atypical mottled colored body (Figs. 1−2) (vs. uniformly counter-shaded, without mottled pattern; with a longitudinal dark brown stripe along the dorsal half of the body in P. unifasciata), and by having all fins with interradial membranes pigmented and mottled (vs. fins with interradial membranes hyaline). Additionally, P. suia differs from all congeners, except P. taphorni by having multicuspid teeth (vs. conical teeth) (Fig. 3). The new species differs from some of its congeners by maxillary barbel reaching pectoral-fin origin (vs. maxillary barbel reaching the end of adpressed pectoral fin in P. anisura, P. boliviana, P. nigrolineata, and P. tenebrosa; reaching half the length of pectoral fin in P. tenuis; surpassing pectoral fin in P. provenzanoi and P. taphorni; reachingpelvic-fin origin in P. macarenensis); lacking a short extension of the first pectoral-fin ray (vs. present in P. anisura, P. macarenensis, P. nigrolineata, P. provenzanoi, and P. taphorni), by caudal fin deeply forked with extremely elogated and pointed lobes (vs. moderately pointed in P. hoehnei; rounded in P. somnians); and by having 43−45 total vertebrae (vs. 39 in P. taphorni; 41 in P. hoehnei; 41−42 in P. tenebrosa;46−47 P. unifasciata; 47−48 in P. provenzanoi; 53−55 in P. tenuis).
Etymology. The specific name “suia” refers to the Suias indigenous people who, since the 90’s, have stood out in the fight to protect the Suiá-Missu River environment and for recovery of their traditional lands outside the limits of Xingu park. A noun in apposition.
Gabriel S. C. Silva, Luz E. Ochoa and Íthalo S. Castro. 2022. New Species of Phenacorhamdia (Siluriformes: Heptapteridae) from the Xingu River Basin. Neotrop Ichthyol. 20(2); e210143. DOI: 10.1590/1982-0224-2021-0143
Resumo: Heptapteridae é um grupo diverso de bagres neotropicais composto por 231 espécies válidas, endêmicas da região Neotropical, divididas em duas subfamílias: Rhamdiinae e Heptapterinae. Phenacorhamdia é um membro de Heptapterinae e atualmente possui 13 espécies válidas amplamente distribuídas pelos principais rios da América do Sul. Aqui nós descrevemos uma nova espécie de Phenacorhamdia da bacia do rio Xingu. Dados morfológicos foram obtidos de 30 espécimes, 23 medidas morfométricas e seis contagens merísticas. A nova espécie é diferenciada de suas congêneres com base na seguinte combinação de características: um atípico corpo manchado com as membranas interradiais de todas as nadadeiras manchadas; dentes multicuspidados; barbilhão maxilar atingindo a origem da nadadeira peitoral; ausência de uma curta extensão do primeiro raio da nadadeira peitoral; lóbulos da nadadeira caudal extremamente alongados e pontiagudos, e 43−45 vértebras.
Palavras-chave: Bacia do rio Amazonas; Bagres; Escudo Brasileiro; Taxonomia
