TSN ID Chart- Pseudoplatystoma

thebiggerthebetter

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Thanks to Dr. H. H. Ng for bringing this up to our attention.

Useful and interesting info that goes to show what @wednesday13 has been telling us a while - we may get hybrids where we think we get genuine species... and more:

Molecular identification of intergenus crosses involving catfish hybrids: risks for aquaculture production

Diogo T. Hashimoto1 , Fernanda D. Prado2 , Fausto Foresti3 and Fábio Porto-Foresti2

http://www.scielo.br/pdf/ni/v14n2/1982-0224-ni-14-02-e150139.pdf

Monitoring of the interspecific hybrid production and trade is essential for the appropriate management of these animals in fish farms. The identification of catfish hybrids by morphological analysis is unreliable, particularly of juveniles and post-F1 individuals. Therefore, in the present study, we used five molecular markers (four nuclear genes and one mitochondrial gene) to detect hybrids in the trade of pimelodid juvenile fish from different stocks purchased of five seed producers in Brazil.

Samples commercialized as pintado (pure species Pseudoplatystoma corruscans) from three fish farms were genetically identified as hybrid cachapinta (♀ P. reticulatum x ♂ P. corruscans).

In the stocks purchased as cachandiá (hybrid between ♀ P. reticulatum x ♂ Leiarius marmoratus) and cachapira (hybrid between ♀ P. reticulatum x ♂ Phractocephalus hemioliopterus), we suggested the occurrence of intergenus crosses involving the hybrid cachapinta, which was used instead of the pure species P. reticulatum.

The problems involving the hybrid cachapinta production were discussed in the present study, especially because these animals have caused genetic contamination and threatened the genetic integrity of natural and cultivated populations.

In order to improve the surveillance of the production and provide criteria for the correct management of catfish hybrids, genetic markers has become an excellent alternative to the morphological identification, including juveniles or post-F1 generations.
 
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thebiggerthebetter

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http://www.planetcatfish.com/forum/viewtopic.php?f=14&t=44357#p301740

do Prado, FD, R Fernandez-Cebrián, DT Hashimoto, JA Senhorini, F Foresti, P Martinez & F Porto-Foresti, 2016. Hybridization and genetic introgression patterns between two South American catfish along their sympatric distribution range. Hydrobiologia doi:10.1007/s10750-016-3010-5

Abstract

The presence of introgressive hybridization in the wild, especially that resulting from human interference, can have negative impacts on biodiversity. Genetic tools provide essential information for species and hybrid identification, facilitating the conservation of natural resources. Here, we tested a set of markers to precisely elucidate introgressive hybridization between Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum, two South American catfishes. New microsatellites showed high interspecific genetic divergence, and simulated data demonstrated the high power of STRUCTURE and NEWHYBRIDS for hybrid identification and classification, especially when all 11 nuclear markers were used. The investigation of real populations suggested that natural hybridization is rare. Otherwise, different hybridization scenarios were observed in two wild populations: one involving advanced backcrosses and the other involving high admixture. Our data represent the first detailed evaluation of genetic introgression between these species in Parana and Paraguay Basins and suggest that genetic contamination is occurring through F1 hybrids from aquaculture facilities. The results also provide a useful set of markers for monitoring escapees to aid in the conservation of the wild population and sustainable aquaculture. Additionally, species genotypic data are freely available to be used in the future as “parental species reference” in Bayesian methods assignments.
 

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Notice he has no eyes thoughts? Subspecies?
 

thebiggerthebetter

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There are TSN born like that, especially on the farms. Looks like a typical TSN farm cull which is pretty much all we get in the trade.

Taxonomists do not agree on the number of TSN species but I am not aware of any subspecies in that genus. Lacking eyes doesn't make any fish a subspecies.
 
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