| cestodes of cestodes of peruvian freshwater stingrays. | adult tetraphyllidean tapeworms (platyhelminthes: eucestoda) from the spiral intestines of 3 species of potamotrygonid stingrays (paratrygon aiereba, potamotrygon castexi, and portamotrygon motoro) in the madre de dios river in peru were found to host numerous cysts embedded in their parenchymal tissues. histological sections of the cysts revealed the presence of a scolex bearing 4 suckers and an unarmed apical organ consistent with larval stages of both cyclophyllidea and proteocephalidea. to f ... | 2003 | 14627150 |
| chromosomes of three freshwater stingrays (rajiformes potamotrygonidae) from the rio negro basin, amazon, brazil. | potamotrygonidae is the representative family of south american freshwater elasmobranchs. it is a monophyletic group containing 20 species grouped into three genera. three species belonging to two genera of this family were collected from the middle negro river, amazonas, brazil, and studied cytogenetically: paratrygon aiereba, potamotrygon motoro and potamotrygon orbignyi. paratrygon aiereba presented 2n = 90 chromosomes and 4m+2sm+10st+74a. both species of potamotrygon presented 2n = 66 chromo ... | 2006 | 17028938 |
| intestinal helminths of freshwater stingrays in southeastern peru, and a new genus and two new species of cestode. | helminths of the spiral intestine of neotropical freshwater stingrays (potamotrygonidae) were examined in peru for the first time. the stingrays examined for helminths included paratrygon aiereba, potamotrygon motoro, and potamotrygon cf. castexi. present in p. aiereba were the cestodes nandocestus guariticus (marques, brooks, and lasso, 2001) n. gen. n. comb., rhinebothrium copianullum n. sp., rhinebothrium sp. 1, rhinebothroides sp., potamotrygonocestus cf. fitzgeraldae, and 1 species each of ... | 2008 | 18605776 |
| monogenoidean parasites of freshwater stingrays (rajiformes: potamotrygonidae) from the negro river, amazon, brazil: species of potamotrygonocotyle (monocotylidae) and paraheteronchocotyle (hexabothriidae). | five new species of potamotrygonocotyle (monocotylidae) are described and paraheteronchocotyle amazonense mayes, brooks et thorson, 1981 (hexabothriidae) is redescribed from monogenoideans collected on the gills of species of potamotrygonidae from the negro river, amazon, brazil. potamotrygonocotyle quadracotyle sp. n. and p. umbella sp. n. were found parasitizing an undescribed species of potamotrygon; potamotrygonocotyle rarum sp. n. is described from potamotrygon schroederi; potamotrygonocoty ... | 2007 | 19245189 |
| description of two extraordinary new species of freshwater stingrays of the genus potamotrygon endemic to the rio tapajós basin, brazil (chondrichthyes: potamotrygonidae), with notes on other tapajós stingrays. | stingrays from the rio tapajós basin are reviewed based on material collected from its lower (i.e. from the mouth-lake to itaituba), middle (from about the são luiz rapids to the confluence of rios juruena and teles pires), and upper (above the juruena-teles pires confluence) segments. two new species endemic to the mid and upper tapajós, discovered long ago and common in the ornamental fish trade, are described. potamotrygon albimaculata sp. nov. is part of the black stingray species group, and ... | 2016 | 27701358 |
| mitochondrion-rich cells distribution, na+/k+-atpase activity and gill morphometry of the amazonian freshwater stingrays (chondrichthyes: potamotrygonidae). | detailed measurements of gill area and constituent variables (total filament number, total filament length and mean filament length), and immunolocalization of the α-subunit of na⁺/k⁺-atpase and na⁺/k⁺-atpase activity were performed on both hemibranchs of all five arches of freshwater potamotrygonid stingrays (paratrygon aiereba and potamotrygon sp.). both species exhibit similar mass-specific gill area, 89.8 ± 6.6 and 91.5 ± 4.3 mm² g⁻¹ for p. aiereba and potamotrygon sp., respectively. the den ... | 2011 | 21132527 |