Otothyropsis

Calegari, Bárbara B., Lehmann, Pablo & Reis, Roberto E., 2013, Two new species of cascudinhos of the genus Otothyropsis (Siluriformes: Hypoptopomatinae) from the rio Paraná basin, Brazil, Zootaxa 3619 (2), pp. 130-144 : 142

Key to species of Otothyropsis

1a. Middle series of lateral plates truncated at least two plates before the caudal fin; plates in middle lateral series 19–22..... 2

1b. Middle series of lateral plates reaching to the caudal-fin origin; plates in middle lateral series 24–26................... 3

2a. Mid-dorsal series of lateral plates discontinuous with 10–11 total plates with an intermediate gap of 4–5 plates; abdominal region entirely covered by platelets................................................... Otothyropsis marapoama

2b. Mid-dorsal series of lateral plates continuous with 17–18 plates; abdominal region with extensive naked areas.............................................................................................. Otothyropsis piribebuy

3a. Premaxillary and dentary teeth 19–31; pectoral-fin spine 21.4–26.9% SL; hyaline spot on lower lobe of caudal fin always with small dark dots ( Fig. 4 A, B); odontodes on caudal peduncle conspicuously arranged in lines........ Otothyropsis polyodon

3b. Premaxillary and dentary teeth 13–20; pectoral-fin spine 18.6–21.3% SL; hyaline spot on lower lobe of caudal fin completely devoid of dark dots ( Fig. 4 C, D); odontodes on caudal peduncle not arranged in lines............. Otothyropsis biamnicus

Figures

FIGURE 4. Color pattern of caudal fin in Otothyropsis species. Otothyropsis polyodon, MCP 47076, (A) 37.3 mm SL, (B) 35.1 mm SL; O. biamnicus, MCP 11498, (C) 34.5 mm SL, MCP 47289, (D) 30.7 mm SL; O. marapoama, LIRP 4621, (E) 32.6 mm SL, (F) 26.6 mm SL; O. piribebuy, MCP 44394, (G) 23.9 mm SL, (H) 23.3 mm SL.