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| Rhyacoglanis beninei Crispim-Rodrigues, Silva, Shibatta, Kuranaka & Oliveira, 2023 |
Abstract
In this study, a new species of Rhyacoglanis is described from the Jamanxim River basin, Tapajós River basin. The new species differs from congeners based on the combination of the following diagnostic characters: two oblique dark bands formed by an agglomerate of melanophores on the predorsal region; dorsal confluence between the dark subdorsal and subadipose bands in large juveniles and adults; ventral confluence between the dark subadipose and caudal peduncle bands; body without conspicuous dark brown spots; complete dark band on caudal peduncle; body with three dark bands; a thin dark caudal-fin band; pectoral-fin spine with anterior serrae distributed along the entire margin; the posterior tip of the post-cleithral process reaching vertical through the base of the dorsal-fin spine; and hypural 5 free of hypural 3 and 4 and pointed caudal-fin lobes. Additionally, our molecular phylogenetic results using ultraconserved elements (UCEs) corroborate the new species as Rhyacoglanis and sister to an undescribed species of Rhyacoglanis from the Xingu River basin. Moreover, as pointed out in previous studies, we confirm Cruciglanis as a sister group to Pseudopimelodus plus Rhyacoglanis.
Keywords: Amazon basin; Bumblebee catfishes; Phylogenomic; South America region; Pseudopimelodinae
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| Rhyacoglanis beninei, holotype, MZUSP 127014, 59.1 mm SL, from córrego Jussara, an affluent of Jamanxim River, Tapajós River basin. Scale bar = 10 mm. |
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| A. Habitat of Rhyacoglanis beninei in córrego Jussara; B. A rock where specimens of R. beninei were associated; C. Paratype of R. beninei just after capture. Photos: Gabriel S. Costa e Silva. |
Rhyacoglanis beninei, new species
Diagnosis. Rhyacoglanis beninei can be diagnosed from all congeners by two oblique dorsal dark brown bars on the predorsal region (Fig. 2) (vs. absent). Additionally, R. beninei is distinguished from some congeners by having a dorsal confluence between the dark subdorsal and subadipose bands in large juveniles and adults (> 28 mm SL) (vs. lack dorsal confluence in R. paranensis, R. annulatus, R. varii, and R. rapppydanielae); ventral confluence between the dark subadipose and caudal peduncle bands (vs. lack ventral confluence in R. annulatus, R. epiblepsis, R. paranensis, R. seminiger, and R. rapppydanielae); body without conspicuous dark brown spots (vs. conspicuous dark brown spots in R. epiblepsis and R. rapppydanielae); complete dark band on caudal peduncle (vs. caudal peduncle-band with a unpigmented central region in R. annulatus); body with three dark bands (vs. two dark bands in R. seminiger); a thin dark caudal-fin bands (vs. large caudal-fin bands in R. paranensis and R. epiblepsis); pectoral-fin spine with anterior serrae distributed along the entire margin (restricted to the proximal half in R. pulcher and R. seminiger); posterior tip of the post-cleithral process reaching vertical through the base of the dorsal-fin spine (vs. not reaching in R. epiblepsis and R. rapppydanielae); hypural 5 free of hypural 3 and 4 (vs. hypurals 4 and 5 fused in R. rapppydanielae); pointed caudal-fin lobes (vs. rounded lobes in R. epiblepsis).
Etymology. Rhyacoglanis beninei is named in honor of Ricardo Cardoso Benine, Professor at Universidade Estadual Paulista “Júlio de Mesquita Filho”, in recognition of his dedication and remarkable contributions to the knowledge of Neotropical freshwater fishes.
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| Pigmentation of oblique dark bars in the predorsal region of Rhyacoglanis beninei. A. MZUEL 23049, 29.6 mm SL; B. LBP 32145, 32.9 mm SL; C. LBP 32145, 37.3 mm SL; D. MZUEL 23049, 42.6 mm SL; E. LBP 32145, 50.2 mm SL. Scale bars = 10 mm. |
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| Variation pattern of dark body bands in Rhyacoglanis beninei. A. MZUEL 23049, 42.6 mm SL; B. LBP 32145, 29.8 mm SL; C. LBP 32163, 27.0 mm SL; D. LBP 32163, 42.9 mm SL. Scale bars = 10 mm. |
Jefferson Luan Crispim-Rodrigues, Gabriel de Souza da Costa e Silva, Oscar Akio Shibatta, Mariana Kuranaka and Claudio Oliveira. 2023. Description and Phylogenetic Position of A New Species of Rhyacoglanis (Siluriformes: Pseudopimelodidae) from the Jamanxim River Basin. Neotrop. ichthyol. 21(3); DOI: 10.1590/1982-0224-2023-0051
