Systematic revision of the Potamotrygon scobina Garman, 1913 species-complex (Chondrichthyes: Myliobatiformes: Potamotrygonidae), with the description of three new freshwater stingray species from Brazil and comments on their distribution and biogeography
Bibliographic record
Abstract
Potamotrygon scobina Garman, 1913, described from Cametá, rio Tocantins, lower Amazon basin, is taxonomically reviewed through an extensive morphological study of internal and external features. Specimens identified as P. scobina from different locations of the Amazon basin were also studied. The identity of P. scobina, its morphology, and distribution are redefined. In addition, three new species closely related to P. scobina are described from Brazil: Potamotrygon adamastor, sp. nov., from rio Uraricoera, rio Branco system, upper Amazon basin; Potamotrygon amazona, sp. nov., from rio Juruá, upper Amazon basin; and Potamotrygon garmani, sp. nov., from the mid to upper rio Tocantins. These three new species do not occur sympatrically with P. scobina, as far as known. Together with P. scobina and P. limai Fontenelle, Silva & Carvalho, 2014, the new species have three angular cartilages of different sizes, a condition not seen in any other potamotrygonin (which have either one or two angulars). Diagnostic characters in combination are primarily morphometric proportions, especially tail length and width, dermal denticles and tail thorns (their relative size, number, morphology, and distribution), tooth size and number of rows, and color pattern. Printed copy of this book is available from US$24.6 plus postage, Click here to order.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".