A new characid species is described from the rio Jacuí basin, a coastal drainage from southern Brazil. Itis morphologically most similar to its sympatric congeners Oligosarcus jenynsii and O. jacuiensis , but can be distinguished from both species in having the interorbital region wider and the pectoral fin shorter and additionally from O. jenynsii in having a smaller orbital diameter.
Freshwater fish; Neotropical; South America; Systematics; Taxonomy
| Oligosarcus varii | Oligosarcus jenynsii | Oligosarcus jacuiensis | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Holotype | n | Range | Mean | SD | n | Range | Mean | SD | n | Range | Mean | SD | |
| Standard length (mm) | 184.0 | 6 | 181.0 - 197.0 | 183.8 | 77 | 49.0 - 165.0 | 102.4 | 34 | 92.0 - 205.0 | 142.2 | |||
| Percents of standard length | |||||||||||||
| Depth at dorsal-fin origin | 29.0 | 6 | 29.0 - 31.0 | 29.0 | 0.7 | 77 | 22.2 - 31.5 | 27.6 | 1.7 | 34 | 26.2 - 30.4 | 28.1 | 1.1 |
| Snout to dorsal-fin origin | 55.4 | 6 | 55.3 - 57.0 | 56.0 | 0.7 | 77 | 52.0 - 59.7 | 56.0 | 1.5 | 34 | 53.1 - 57.8 | 55.3 | 1.1 |
| Snout to pectoral-fin origin | 28.2 | 6 | 27.4 - 28.4 | 28.0 | 0.4 | 77 | 26.0 - 31.7 | 28.8 | 1.4 | 34 | 27.3 - 32.7 | 29.8 | 1.2 |
| Snout to pelvic-fin origin | 50.2 | 6 | 50.0 - 52.0 | 50.6 | 0.7 | 76 | 44.3 - 50.7 | 47.4 | 1.5 | 34 | 46.2 - 52.5 | 49.2 | 1.3 |
| Snout to anal-fin origin | 67.4 | 6 | 67.4 - 70.0 | 68.7 | 1.1 | 77 | 61.3 - 70.0 | 65.2 | 2.0 | 34 | 64.2 - 68.6 | 66.8 | 1.0 |
| Caudal peduncle depth | 8.4 | 6 | 8.4 - 8.8 | 8.6 | 0.2 | 77 | 8.0 - 10.3 | 9.0 | 0.5 | 34 | 8.0 - 9.6 | 9.0 | 0.3 |
| Caudal peduncle length | 12.5 | 6 | 11.4 - 12.5 | 12.0 | 0.4 | 76 | 10.8 - 14.6 | 12.4 | 0.8 | 34 | 11.1 - 14.8 | 12.5 | 0.8 |
| Pectoral-fin length | 17.5 | 6 | 17.5 - 18.2 | 17.8 | 0.2 | 77 | 18.3 - 23.0 | 20.4 | 1.1 | 34 | 17.6 - 22.2 | 19.3 | 1.1 |
| Pelvic-fin length | 14.1 | 6 | 14.1 - 14.5 | 14.3 | 0.1 | 76 | 14.1 - 18.0 | 16.2 | 0.8 | 34 | 14.8 - 17.7 | 15.7 | 0.8 |
| Dorsal-fin base length | 11.1 | 6 | 11.1 - 12.0 | 11.5 | 0.3 | 77 | 10.1 - 12.8 | 11.2 | 0.5 | 34 | 10.4 - 12.3 | 11.4 | 0.5 |
| Dorsal-fin height | 20.0 | 6 | 19.3 - 21.0 | 20.2 | 0.6 | 73 | 21.2 - 27.8 | 23.5 | 1.5 | 34 | 20.0 - 24.3 | 22.0 | 1.0 |
| Anal-fin base length | 24.2 | 6 | 21.8 - 24.3 | 23.4 | 1.0 | 76 | 22.5 - 28.3 | 26.1 | 1.1 | 34 | 22.7 - 27.0 | 25.1 | 1.1 |
| Anal-fin lobe length | 15.2 | 6 | 14.2 - 15.5 | 15.0 | 0.5 | 75 | 15.7 - 21.8 | 18.1 | 1.4 | 34 | 14.5 - 18.2 | 16.7 | 1.0 |
| Eye to dorsal-fin origin | 43.4 | 6 | 42.1 - 43.7 | 43.0 | 0.5 | 77 | 38.5 - 43.5 | 41.2 | 1.2 | 34 | 38.6 - 43.0 | 40.6 | 0.9 |
| Bony head length | 27.7 | 6 | 27.7 - 29.3 | 28.5 | 0.5 | 77 | 26.8 - 32.1 | 29.0 | 1.3 | 34 | 28.1 - 32.3 | 30.0 | 1.2 |
| Dorsal-fin origin to caudal-fin base | 49.0 | 6 | 47.5 - 49.1 | 48.0 | 0.7 | 77 | 45.2 - 52.0 | 47.7 | 1.3 | 34 | 46.1 - 50.3 | 47.7 | 1.2 |
| Percents of head length | |||||||||||||
| Horizontal eye diameter | 23.5 | 6 | 22.0 - 23.5 | 22.5 | 0.6 | 77 | 25.0 - 34.3 | 28.7 | 2.6 | 34 | 21.0 - 24.5 | 23.0 | 1.3 |
| Snout length | 30.4 | 6 | 29.0 - 31.7 | 30.3 | 0.9 | 77 | 25.7 - 32.7 | 32.7 | 1.5 | 34 | 30.0 - 34.5 | 31.4 | 1.4 |
| Least interorbital width | 25.5 | 6 | 25.0 - 26.5 | 25.3 | 0.7 | 77 | 18.4 - 24.4 | 21.4 | 1.4 | 34 | 20.0 - 24.4 | 22.0 | 1.1 |
| Upper jaw length | 58.8 | 6 | 55.7 - 58.8 | 57.2 | 2.0 | 77 | 51.6 - 61.8 | 57.2 | 2.1 | 34 | 57.1 - 63.6 | 59.5 | 2.0 |
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