Friday, March 9, 2018

[Ichthyology • 2018] Pseudacanthicus majorOne of the Largest Known Loricariidae (Hypostominae: Ancistrini), A Species from rio Tocantins Basin, Brazil

Pseudacanthicus major  Chamon & Costa e Silva, 2018


The genus Pseudacanthicus currently comprises the following six species distributed in the Amazon and Tocantins basins, and coastal drainages from Guyana to French Guyana: P. serratus, P. fordii, P. histrix, P. spinosus, P. leopardus, P. pitanga, and P. pirarara. Herein we describe Pseudacanthicus major, from rio Tocantins basin, one of the largest loricariid species known. The new species is distinguished from its congeners by the following combination of characters: having body color pattern with dark brown background without spots or blotches and dorsal and caudal fins with transversal white bands; anterior process of compound pterotic with no contacting with the posterior margin of the orbit and by the absence of a conspicuous crest on the posterior edge of parieto-supraocciptal. Other osteological characteristics are further used to diagnose P. major from others congeners. A discussion on gigantism and miniaturization in freshwater fish, ornamental fisheries activities, threats and conservation of the new species are also provided.

Keywords: Pisces, Amazon Basin, fish trade, Gigantism, Neotropical, taxonomy, conservation

FIGURE 2. Color in life of Pseudacanthicus major, specimen collected and released during monitoring for route of migratory fish. Image by Wesley Zago (CESTE, Consórcio Estreito Energia Usina Hidrelétrica Estreito)

 Pseudacanthicus major, new species

 Etymology. The specific epithet major, derives from Latin meaning greater than, larger than, in allusion to the large size of the specimens in comparison with others species of the genus. An adjective. 

Remarks. Pseudacanthicus major is known and marketed in ornamental fish trade, like others species of the genus. Pseudacanthicus major is recognized in the L number system employed by aquarists as L186 (Schraml & Schaefer, 2004; Stawikowski et al., 2004; Werner et al., 2005). There is no suggestion that the species is consumed as food source by the colonies of fishermen (pers. obs.)  

Carine C. Chamon and Thiago Costa e Silva. 2018. Pseudacanthicus major: Description of One of the Largest Known Loricariidae (Hypostominae: Ancistrini), A Species from rio Tocantins Basin, Brazil. Zootaxa. 4387(3); 499–510. DOI:  10.11646/zootaxa.4387.3.5

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