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| Aequidens pirilampo R.C. Oliveira, Tencatt, Deprá, Britzke, C. Oliveira & Graça, 2024 |
Abstract
Morphological and molecular data support the description of a new Aequidens species from the upper rio Correntes, considered herein as endemic to the upper rio Paraguai basin in the Cerrado biome in Brazil. The new species is distinguished from all congeners, except from A. plagiozonatus by having anteriorly oblique dark brown flank bars vs. vertical flank bars, and is additionally distinguished from some congeners by showing a discontinuous lateral band and presence of a dark cheek spot. The new species differs from Aequidens plagiozonatus by having the profile of the dorsal part of head almost straight (in lateral view), with a conspicuous concavity at the interorbital, and by the longer length of upper and lower jaws. Furthermore, delimitation analyses based on mitochondrial data provide additional support for the validity of the species. Our study data also revealed the occurrence, and consequently the first record, of A. plagiozonatus in the upper rio Araguaia basin, which was most likely driven by headwater capture events.
Keywords: Cerrado biome; DNA barcode; Molecular data; Morphological data; Species delimitation
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| Aequidens pirilampo, living specimens photographed just after capture in the rio Comprido, rio Paraguai River basin, 17°32’04.8”S 54°25’36.6”W, uncatalogued. Photos by L. F. C. Tencatt. |
Aequidens pirilampo, new species
Diagnosis. Aequidens pirilampo is distinguished from all congeners, except A. plagiozonatus, by having anteriorly oblique dark brown flank bars (vs. vertical). The new species differs from A. plagiozonatus by having the dorsal head contour, from the tip of the snout to the vertical through the posterior margin of the eye, almost straight, except for a conspicuous concavity at the interorbital region (Fig. 2) (vs. dorsal head contour convex, with a subtle concavity at the interorbital region in occasional specimens), by having longer lower jaw (40.2–46.9% HL and 16.7–18.5% SL vs. 35.2–39.3% HL and 13.2–15.2% SL in A. plagiozonatus), and longer upper jaw, (12.2–15.1% SL vs. 9.3–12.1% SL in A. plagiozonatus). Additionally, A. pirilampo is distinguished from its congeners, except A. chimantanus Inger, 1956, A. diadema, A. epae, A. mauesanus Kullander, 1997, A. michaeli, A. patricki Kullander, 1984, A. plagiozonatus, A. potaroensis Eigenmann, 1912, and A. tubicen Kullander & Ferreira, 1991, by having a discontinuous lateral band in fixed specimens (vs. continuous). ...
Etymology. The specific epithet “pirilampo” means firefly in the popular Portuguese naming in the region the new species occurs. It is a bioluminescent Coleoptera very common in this region. These insects emit an intense green light, which alludes to the color pattern in life displayed by the new species. A noun in apposition.
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| Collecting sites of Aequidens pirilampo, showing (A) the ribeirão Comprido, its type-locality, (B) a stream with unknown name, and (C) the córrego de Cima, all tributaries of the rio Correntes in the border region of Mato Grosso and Mato Grosso do Sul states, Central Brazil. Photo (A) by LFCT, (B) by Heriberto Gimênes Jr., and (C) by Hans Evers. |
Rianne Caroline de Oliveira, Luiz Fernando Caserta Tencatt, Gabriel de Carvalho Deprá, Ricardo Britzke, Claudio Oliveira and Weferson Júnio da Graça. 2024. A New Species of Aequidens (Cichliformes: Cichlidae) from the rio Paraguai basin, Brazil. Neotrop. ichthyol. 22 (2); DOI: doi.org/10.1590/1982-0224-2023-0106
Resumo: Dados morfológicos e moleculares apoiam a descrição de uma nova espécie de Aequidens do alto rio Correntes, considerada aqui como uma espécie endêmica da bacia do alto rio Paraguai, no bioma Cerrado no Brasil. A nova espécie distingue-se de todas as congêneres, exceto de Aequidens plagiozonatus, por apresentar barras laterais marrom-escuras oblíquas em direção anterodorsal vs. barras verticais nos flancos. Além disso, distingue-se de algumas espécies por apresentar uma faixa lateral descontínua e pela presença de uma mancha escura na porção entre a órbita e a margem preopercular. A nova espécie difere de A. plagiozonatus por apresentar o perfil da parte dorsal da cabeça (em vista lateral) aproximadamente reta, com uma concavidade conspícua na porção interorbital, e pelo maior comprimento das maxilas superior e inferior. Além disso, análises de delimitação baseadas em dados mitocondriais oferecem evidência a favor da validade da espécie. Nossos dados também revelaram a ocorrência e, consequentemente, o primeiro registro de A. plagiozonatus na bacia do alto rio Araguaia, provavelmente devido a eventos de captura de cabeceiras.
Palavras chave: Bioma Cerrado; Dados moleculares; Dados morfológicos; Delimitação de espécies; DNA barcode
