Corresponding author: Wilson J. E. M. Costa (
Academic editor: Nicolas Hubert
The Brazilian Cerrado highlands shelter the headwaters of the three largest South American hydrographic basins, where a great species diversity is concentrated, but some biological groups are still insufficiently known. The focal taxa of this study are trichomycterid catfishes of the
Studies on the Cerrado biota have quickly increased since the 1980s (
The great trichomycterine species diversity concentrated in mountain ranges of south-eastern Brazil is probably a consequence of the past Cenozoic scenario, characterised by intense re-arrangements of the hydrographic systems due to generalised uplift during the Neogene (
The main focus of this study is an undescribed species of
The primary objectives of this study are to perform a multigene phylogenetic analysis to test the phylogenetic positioning of the new taxon and to provide a formal description to it. The secondary objective is to conduct a dating analysis in order to establish if the estimated divergence timing for
Material used in this study included specimens previously deposited in ichthyological collections:
Measurements were made using landmarks proposed by
DNA was extracted from muscle tissues of the caudal peduncle, using DNeasy Blood & Tissue Kit (Qiagen), according to manufacturer’s protocol. Amplification of DNA fragments was made using polymerase chain reaction (
The new species and twelve species representing all lineages of
Alignment was conducted in Clustal W (
The concatenated dataset was additionally analysed using Bayesian Inference (
Terminal taxa were the same as above, but including additional outgroups: the trichomycterines
Osteological structures included in the description are those that have informative variability to diagnose species of the eastern South American trichomycterine clade (e.g.
The phylogenetic analyses generated identical trees, which corroborated the new taxon as sister to
Phylogenetic tree generated by Maximum Likelihood analysis for 13 species of
Geographical distribution of
Time-scaled maximum credibility tree obtained from the Bayesian analysis in Beast for 13 species of
All from Brazil: Minas Gerais State: Araxá Municipality: Rio Araguari subdrainage, Rio Paranaíba drainage, Rio Paraná basin.
Morphometric data of
Holotype | Paratypes (n = 10) | Mean | |
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Standard length (mm) | 53.6 | 43.3–64.0 | 53.5 |
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Body depth | 19.3 | 15.8–20.9 | 18.5 |
Caudal peduncle depth | 14.7 | 13.4–15.8 | 14.7 |
Body width | 11.7 | 10.4–13.2 | 12.3 |
Caudal peduncle width | 4.1 | 3.8–5.6 | 4.6 |
Pre-dorsal length | 64.2 | 63.2–67.5 | 65.3 |
Pre-pelvic length | 59.6 | 58.0–62.3 | 60.0 |
Dorsal-fin base length | 11.6 | 11.4–14.2 | 12.4 |
Anal-fin base length | 8.7 | 9.0–11.6 | 9.8 |
Caudal-fin length | 19.0 | 17.3–20.2 | 18.9 |
Pectoral-fin length | 15.0 | 12.3–14.6 | 13.3 |
Pelvic-fin length | 10.2 | 9.7–11.3 | 10.5 |
Head length | 20.2 | 19.4–21.6 | 20.1 |
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Head depth | 54.9 | 51.0–67.9 | 56.2 |
Head width | 83.4 | 82.8–95.7 | 87.7 |
Snout length | 47.2 | 42.4–48.7 | 45.9 |
Interorbital length | 30.2 | 25.4–33.5 | 29.4 |
Preorbital length | 11.6 | 9.4–13.6 | 11.5 |
Eye diameter | 11.1 | 9.2–11.1 | 10.2 |
Live holotype of
Live paratypes of
Dorsal and anal fins subtriangular, distal margin slightly convex; total dorsal-fin rays 10 or 11 (i–ii + II + 7), total anal-fin rays 9 (ii + II + 5); anal-fin origin at vertical through base of 5th branched dorsal-fin ray. Pectoral fin subtriangular in dorsal view, posterior margin slightly convex, first pectoral-fin ray terminating in long filament, reaching about 40–60% of pectoral-fin length in specimens above about 50 mm
Osteological features in
Hyomandibula long, with well-developed anterior outgrowth; middle portion of dorsal margin of hyomandibula slightly concave. Opercle slender, with moderately deep odontode patch with 12–16 odontodes transversely arranged. Opercular odontodes pointed, anterior odontodes narrow and straight, posterior odontodes slightly broader, slightly curved. Dorsal process of opercle short. Opercular articular facet for hyomandibula with prominent rounded extension, articular facet for preopercle well developed, rounded. Interopercular patch of odontodes long, about four fifths of hyomandibula length, with 26–31 odontodes. Interopercular odontodes pointed, arranged in irregular longitudinal rows. Preopercle slender, narrowing anteriorly.
Parurohyal robust, lateral process subtriangular, latero-posteriorly directed, tip pointed; parurohyal head well-developed, with prominent anterolateral paired process; middle foramen oval circular; posterior process long, slightly shorter or equal to distance between anterior margin of parurohyal and anterior insertion of posterior process. Branchiostegal rays 8. Vertebrae 35. Ribs 12 or 13. Dorsal-fin origin at vertical through centrum of 19th vertebra; anal-fin origin at vertical through centrum of 22nd or 23rd vertebra. Two dorsal hypural plates, corresponding to hypurals 4 + 5 and 3, respectively; single ventral hypural plate corresponding to hypurals 1 and 2, and parhypural.
The name
The phylogenetic analyses highly supported
Recent studies have shown a high concentration of closely related trichomycterine species in different South American regions, often exhibiting geographical distribution patters restricted to some neighbouring river drainages around mountain and high plateau areas (e.g.
The divergence timing between
We are grateful to Valter M. Azevedo-Santos, for discussion about fish distribution patterns in the upper Paraná basin and help during type material collection. The manuscript benefitted from reviews provided by Francisco Langeani and Paulo Brito. Thanks are also due to the Meio Ambiente team of the Companhia Brasileira de Metalurgia e Mineração, for allowing collections and use of specimens from the farms comprising the RPPN São Sebastião and Monte Alto, and to Aléssio Datovo and Michel Gianeti by the loan of specimens. This work was partly supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq; grant 304755/2020-6 to WJEMC), Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ; grant E-26/201.213/2021 to WJEMC, E-26/202.005/2020 to AMK, and E-26/202.327/2018 to JLM). This study was also supported by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Finance Code 001) through Programa de Pós-Graduação em: Biodiversidade e Biologia Evolutiva /
Tables S1, S2
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