A new species of Limatulichthys Isbrücker & Nijssen (Loricariidae, Loricariinae) from the western Guiana Shield
Bibliographic record
Abstract
Limatulichthys nasarcus n. sp. is described as a new species based on 15 specimens from the Ventuari and Caura Rivers in Southern Venezuela. The new species can be distinguished from its only congener, L. griseus, by the presence of anterior abdominal plates half the size of those at center of abdomen (vs. plates similar in size); distinct spots less than half of diameter of naris across entire dorsum, including snout and head (vs. indistinct dorsal spots larger or equal than diameter of naris); lateral portions of head and opercle with dark well-defined spots larger than those on dorsum (vs. spots on lateral portions of head and opercle equal in size to those on remainder of body); snout profile in dorsal view broadly rounded (vs. acutely triangular); head longer (21.4-24.2 SL vs. 17.7-21.0%); and anal fin longer (15.7-18.0 SL vs. 13.7-15.6%). Distinctiveness of the two species is further supported by their non-overlapping distribution in multivariate morphospace. The disjunct distribution of L. nasarcus across both the Caura and Ventuari rivers exclusive of the main Orinoco River channel contributes to a growing body of evidence supporting the historical connection between headwaters of these drainages. The hypothesized existence of a 'proto-Berbice' paleodrainage provides one explanation for such a connection.
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 machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 source (direct Gemma or distilled Codex), 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".