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| Pseudolithoxus kinja |
Abstract
The rapids-dwelling suckermouth catfish genus Pseudolithoxus was previously only known from the Guiana-Shield-draining Orinoco and Casiquiare river systems of Colombia and Venezuela, but new records have expanded this range considerably further into the Amazon basin of Brazil, and include occurrences from rivers draining the northern Brazilian Shield. These highly disjunct records are now placed in an evolutionary and phylogeographic context using a dated species tree constructed from mitochondrial (Cytb) and nuclear (RAG1) gene sequence data. Due to mito-nuclear discordance, we also delimit the putative species using statistical coalescent models and a range of additional metrics. We infer that at least two species of Pseudolithoxus are present in the Amazon basin: P. nicoi, previously only recorded from the río Casiquiare, but now also reported from the upper rio Negro, and a new species, which we describe herein from south-draining Guiana Shield and north-draining Brazilian Shield. Our data reject a simple model of Miocene vicariance in the group following uplift of the Uaupés Arch separating the Orinoco and Amazon systems, and instead suggest more complex dispersal scenarios through palaeo-connections in the Pliocene and also via the contemporary rio Negro and rio Madeira in the late Pleistocene.
Key words: aquatic, biodiversity, ichthyology, Neotropics, phylogeny, rio Negro, taxonomy
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| Figure 1. Pseudolithoxus kinja, holotype, 148.0 mm SL, INPA 3220; adult male in alcohol, rio Uatum~a, Amazonas, Brazil. |
Pseudolithoxus kinja sp. nov.
Bifi, de Oliveira, Rapp Py-Daniel & Collins
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ETYMOLOGY: ‘Kinja’, meaning the ‘true people’, is
how the Waimiri-Atroari indigenous people refer to themselves.
The Kinja people inhabit areas surrounding
the rio Uatum~a and part of the rio Negro in the states of
Amazonas and Roraima, Brazil. The ethnic term
‘Waimiri-Atroari’ was adopted in the beginning of the
20th century. The epithet ‘kinja’ pays homage to this
brave people who survived three attempts of genocide
in the last century, and survive and thrive today in their
protected area. Treated as a noun in apposition.
Rupert A. Collins, Alessandro G. Bifi, Renildo R. de Oliveira, Emanuell D. Ribeiro, Nathan K. Lujan, Lúcia H. Rapp Py-Daniel and Tomas Hrbek. 2018. Biogeography and Species Delimitation of the Rheophilic Suckermouth Catfish Genus Pseudolithoxus (Siluriformes: Loricariidae), with the Description of A New Species from the Brazilian Amazon. Systematics and Biodiversity. DOI: 10.1080/14772000.2018.1468362
