Pimelodus mysteriosus Azpelicueta 1998, previously known only from the lower Paraná and Paraguay River basins, has been also recorded in the upper Paraná River floodplain. The only congeners occurring in syntopy with P. mysteriosus in the upper Paraná River basin are P. maculatus and P. ornatus. New diagnostic characters between P. mysteriosus and P. maculatus are provided.
Canal da piracema; Invasive species; Itaipu; Non-native species; Taxonomy
| P. mysteriosus | P. maculatus | P. microstoma | P. paranaensis | |
|---|---|---|---|---|
| Standard length (mm) | 90.4 – 218.7 | 146.2 – 275.6 | 106.2 – 176.9 | 138.1 – 225.8 |
| % of Standard length | ||||
| Head length | 25.7 – 29.9 | 27.0 – 30.2 | 25.5 – 28.0 | 28.7 – 30.7 |
| Interorbital distance | 8.4 – 11.5 | 7.6 – 8.8 | 4.5 – 6.7 | 5.3 – 8.0 |
| % of Head length | ||||
| Snout length | 43.7 – 50.9 | 42.7 – 50.3 | 44.5 – 50.9 | 44.9 – 49.4 |
| Interorbital distance | 29.8 – 40.6 | 26.4 – 30.4 | 16.7 – 25.3 | 18.3 – 27.3 |
| Eye diameter | 17.1 – 30.3 | 16.8 – 22.2 | 21.3 – 27.7 | 17.4 – 23.2 |
| % of Snout length | ||||
| Interorbital distance | 63.2 – 80.8 | 56.9 – 63.1 | 36.6 – 56.0 | 39.0 – 55.8 |
