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| Author(s): |
João Paulo Capretz Batista da Silva
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) |
| Defense date: | 2010-01-22 |
| Examining board members: |
Marcelo Rodrigues de Carvalho;
Jose Lima de Figueiredo;
Ulisses Leite Gomes
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| Advisor: | Marcelo Rodrigues de Carvalho |
| Abstract | |
The family Potamotrygonidae is a monophyletic group of rays exclusive of freshwater environment, occurring on the majority of South American neotropical rivers. It also presents an extremely confuse taxonomic situation due to its highly diverse disc coloration, the absence of a greater number of diagnostic characters to identify its members and the confusion on the literature involving its nominal species. The coloration pattern, used as the main character on the identification of species is not adequate to separate similar species since an enormous quantity of intermediate patterns exists. Potamotrygom orbignyi (Castelnau, 1855), and species with similar reticulate color patterns were submitted to an accurate taxonomical analysis, since the limits of P. orbignyi and the taxonomic status of the probable related nominal species were uncertain. In this way, with the intention to solve part of the taxonomic problematic inside the family Potamotrygonidae, Potamotrygon orbignyi (Castelnau, 1855), Potamotrygon dumerilii (Castelnau, 1855), Potamotrygon reticulatus (Günther, 1880) and Potamotrygon humerosa Garman, 1913, that are distributed in Amazonic basin, in Venezuela (río Orinoco), Colômbia, Guianas and Suriname, were taxonomically analyzed. The taxonomic analysis revealed, based on a detailed morphological study that Potamotrygon reticulatus and Potamotrygon dumerilii represent actually variation patterns found inside Potamotrygon orbignyi and treated consequently as synonyms. Besides this, the nominal species Potamotrygon humerosa and Potamotrygon marinae presented a set of characters that did not allow including them as synonyms of Potamotrygon orbignyi, confirming thus, as suspected by previous authors, their validity status. (AU) | |