Revisão taxonômica e morfológica do gênero Paratrygon Duméril (1865) (Chondrichthyes: Myliobatiformes: Potamotrygonidae)

Loboda, Thiago Silva

doi:10.11606/t.41.2016.tde-19072016-114714

Cited by 5 publications

(15 citation statements)

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“…3 to Paratrygon sp. 8 (Loboda, 2016). Although these species need a formal description, we have included them in our analysis due to compelling evidence supporting their validity.…”

Section: Methodsmentioning

confidence: 99%

“…2, have since been described as Paratrygon orinocensis and P. parvaspina , respectively (Loboda et al, 2021), and the others are likely to be formally described in the near future. They are distinguishable based on morphology and DNA (Frederico et al, 2012; Loboda, 2016; Rizo‐Fuentes et al, 2021). Consequently, the total number of species considered amounted to 43.…”

Section: Methodsmentioning

confidence: 99%

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Estimating intrinsic susceptibility to extinction when little ecological information is available: The case of Neotropical freshwater stingrays (Chondrichthyes: Potamotrygoninae)

Vazquez,

Lucifora

2023

Fish and Fisheries

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Determining the extinction risk of poorly known species is difficult, as data on both their biological traits and the threats to which they are exposed are often not available. Neotropical freshwater stingrays (potamotrygonins) represent such a challenge, as limited ecological data prevent formal assessments. Geographic range size (GRS) was computed for the first time for potamotrygonins (as a longitudinal extent of occurrence measured in km of river length) and, together with two other traits correlated with intrinsic susceptibility to extinction—body size, biological productivity (rmax)—was used to rank potamotrygonins according to their intrinsic susceptibility to extinction. Potamotrygonin GRS was only 6%–7% of that of marine elasmobranchs and is likely to be a significant driver of potamotrygonin extinction risk. The relationship between potamotrygonin GRS and body size differed from the expected triangular theoretical pattern; probably a result of the fragmented nature of freshwater habitats. Using K‐medoids clustering, we identified seven groups of species; the most susceptible groups comprised the biggest species such as Potamotrygon brachyura and Paratrygon spp. Intrinsic susceptibility was also highest in the largest hydrographic basins, likely as a result of species with low rmax being more common there. Exposure to anthropogenic threats is highest for the species most intrinsically susceptible to extinction, which consequently have a high‐extinction risk. We recommend the use of longitudinal extents of occurrence as standardized measurements of freshwater taxa GRS. Our ranking method, combining observed and predicted traits, may be a useful tool to assess poorly known taxa to assist conservation prioritization.

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“…3 to Paratrygon sp. 8 (Loboda, 2016). Although these species need a formal description, we have included them in our analysis due to compelling evidence supporting their validity.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Estimating intrinsic susceptibility to extinction when little ecological information is available: The case of Neotropical freshwater stingrays (Chondrichthyes: Potamotrygoninae)

Vazquez,

Lucifora

2023

Fish and Fisheries

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“…Four genera are presently recognised as valid within the subfamily (Carvalho et al, ; Carvalho & Lovejoy, ): Potamotrygon Garman 1877, Paratrygon Duméril 1865, Plesiotrygon Rosa et al, and Heliotrygon Carvalho & Lovejoy, . Paratrygon is currently monotypic (although a recent taxonomic revision recognised seven new species within the genus) (Loboda, ), Heliotrygon and Plesiotrygon have two valid species each (Carvalho & Lovejoy, ; Carvalho & Ragno, ; Rosa et al, ) and Potamotrygon is the most diverse genus, including 35 valid species (Carvalho et al, , ; Silva & Carvalho, , ; Loboda & Carvalho, ; Fontenelle et al, ; Silva & Carvalho, , Carvalho, 2016a,b; Fontenelle & Carvalho, ).…”

Section: Introductionmentioning

confidence: 99%

Potamotrygon marquesi, a new species of neotropical freshwater stingray (Potamotrygonidae) from the Brazilian Amazon Basin

Silva

Loboda

2019

Journal of Fish Biology

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Potamotrygon marquesi, sp. nov., is described and compared with other species of Potamotrygon occurring in the Amazon Basin. The identity of this new species is supported by an extensive external and internal morphological study including coloration pattern, squamation, skeleton and ventral lateral‐line canals. Morphometrics and meristics were used to further distinguish P. marquesi from congeners. Potamotrygon marquesi was first considered to fall within the range of variation found in P. motoro. However, even with an extensive variation in coloration observed in P. motoro, this new species presents a series of autapomorphies that confidently distinguishes it from what is understood as the morphological variation found in P. motoro. Additional morphological characters that diagnose P. marquesi include three angular cartilages, asymmetrical star‐shaped denticles, a single regular row of spines on tail dorsum, lateral row of caudal spines near the sting insertion, dorsal disc background in beige and grey mixed with shades of grey and bearing open and closed bicolored rings, among others. Although presenting a gap of distribution along the west–east extension of the Amazon Basin, its diagnostic charactistics are consistent in both recorded regions. Our study supports the need for many morphological characters to robustly distinguish members of Potamotrygoninae considering their extremely variable dorsal disc color pattern.

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“…Even with important research been done on the biology and ecology of I. oxyrhynchus (e.g., Lessa et al 1999;2000;2016;Feitosa et al 2019), anatomical and systematic knowledge on the species remain precarious. The scarcity of specimens of I. oxyrhynchus in collection means that information of this sort is difficult to obtain.…”

Section: The Daggernose Shark -Isogomphodon Oxyrhynchus (Müller and Henle 1839)mentioning

confidence: 99%

“…provided a vast database on information of Carcharhinidae, which is part of the most complete and detailed work on the anatomy of Carcharhiniformes. Classically relevant and highly detailed anatomical papers on elasmobranchs are not scarce (e.g., Allis 1923;Gilbert 1973;Lima et al 1997;Goto 2001;Maisey 2004;Casas et al 2005), although in the past decade several authors provided significant improvements on the knowledge of elasmobranch anatomy (e.g., Loboda 2013;2016;Fontenelle 2013;Moreira et al 2018;Soares et al 2020). Apart from the present comparisons with the examined specimens, these articles and other relevant literature provided important data to better compare Isogomphodon oxyrhynchus with other Carcharhinidae.…”

Section: Novel Molecular Analysismentioning

confidence: 99%

Skeletal anatomical description of Isogomphodon oxyrhynchus (Müller & Henle, 1839) and discussion of its phylogenetic position within Carcharhinidae (Chondrichthyes, Carcharhiniformes)

Silva¹

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The Daggernose shark Isogomphodon oxyrhynchus (Müller & Henle, 1839), sole species in its genus, is endemic to northern South America, from Southern Maranhão State in Brazil to Trinidad and Tobago. Although the species is traditionally classified as estuarine, it occurs also in entirely marine environments. Such habitat shift is seasonal, related to the rain regimen. I. oxyrhynchus is easily recognized by the elongated snout, enlarged pectoral fins and reduced eyes, characteristics which account for its unique general aspect in the family Carcharhinidae.The anatomy of I. oxyrhynchus remains poorly known and its phylogenetic position is still controversial. In this study, we propose a contribution to the knowledge of I. oxyrhynchus, offering: 1. A description of the entire skeleton and dermal denticles, based on dissections, computerized tomography and Scanning Electron Microscopy; 2. A comparative anatomical study of I. oxyrhynchus with other representatives of Carcharhinidae, which is compared with results from a novel molecular analysis; 3. Review of fossil taxa assigned to Isogomphodon.The skeletal description revealed much new information for I. oxyrhynchus, including new information on complexes which were previously entirely unknown in the taxon, such as the appendicular skeleton, mandibular arch and clasper. The comparative and phylogenetic study is organized into 46 morphological characters, which qualitatively supports Carcharhinus porosus as sister-group of I. oxyrhynchus. Results also support the hypothesis of Isogomphodon as a modified member of the genus Carcharhinus. Lastly, a critical review of the fossil taxa assigned to Isogomphodon demonstrated that from the five species previously assigned to Isogomphodon, only two can be positively attributed to the genus.

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Revisão taxonômica e morfológica do gênero Paratrygon Duméril (1865) (Chondrichthyes: Myliobatiformes: Potamotrygonidae)

Cited by 5 publications

References 0 publications

Estimating intrinsic susceptibility to extinction when little ecological information is available: The case of Neotropical freshwater stingrays (Chondrichthyes: Potamotrygoninae)

Estimating intrinsic susceptibility to extinction when little ecological information is available: The case of Neotropical freshwater stingrays (Chondrichthyes: Potamotrygoninae)

Potamotrygon marquesi, a new species of neotropical freshwater stingray (Potamotrygonidae) from the Brazilian Amazon Basin

Skeletal anatomical description of Isogomphodon oxyrhynchus (Müller & Henle, 1839) and discussion of its phylogenetic position within Carcharhinidae (Chondrichthyes, Carcharhiniformes)

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