Relative body height - MBH/SL: Inversely related to water velocity and directly related to the ability move vertically (Gatz 1979GATZ, A.J. 1979. Ecological morphology of freshwater stream fishes. Tulane Stud. Zoolo. Bot. 21(2):91-124., Watson & Balon 1984WATSON, D.J. & BALON, E.K. 1984. Ecomorphological analysis of fish taxocenes in rainforest streams of northern Borneo. J. Fish Biol. 25:371-384. http://dx.doi.org/10.1111/j.1095-8649.1984.tb04885.x http://dx.doi.org/10.1111/j.1095-8649.19...
, Winemiller 1991WINEMILLER, K.O. 1991. Ecomorphological diversification in lowland freshwater fish assemblages from five biotic regions. Ecol. Monogr. 61(4):343-365. http://dx.doi.org/10.2307/2937046 http://dx.doi.org/10.2307/2937046...
). |
Compression index - MBH/MBW: Higher values indicate fish of structured habitats or with low water velocity (Gatz 1979GATZ, A.J. 1979. Ecological morphology of freshwater stream fishes. Tulane Stud. Zoolo. Bot. 21(2):91-124., Watson & Balon 1984WATSON, D.J. & BALON, E.K. 1984. Ecomorphological analysis of fish taxocenes in rainforest streams of northern Borneo. J. Fish Biol. 25:371-384. http://dx.doi.org/10.1111/j.1095-8649.1984.tb04885.x http://dx.doi.org/10.1111/j.1095-8649.19...
). |
Depression index of the ventral region - BMH/MBH: Lower values indicate benthic fish (Watson & Balon 1984WATSON, D.J. & BALON, E.K. 1984. Ecomorphological analysis of fish taxocenes in rainforest streams of northern Borneo. J. Fish Biol. 25:371-384. http://dx.doi.org/10.1111/j.1095-8649.1984.tb04885.x http://dx.doi.org/10.1111/j.1095-8649.19...
, Winemiller 1991WINEMILLER, K.O. 1991. Ecomorphological diversification in lowland freshwater fish assemblages from five biotic regions. Ecol. Monogr. 61(4):343-365. http://dx.doi.org/10.2307/2937046 http://dx.doi.org/10.2307/2937046...
). |
Caudal peduncle compression index - CPdH/CPdW: Lower values indicate slow-swimmers (Gatz 1979GATZ, A.J. 1979. Ecological morphology of freshwater stream fishes. Tulane Stud. Zoolo. Bot. 21(2):91-124., Watson & Balon 1984WATSON, D.J. & BALON, E.K. 1984. Ecomorphological analysis of fish taxocenes in rainforest streams of northern Borneo. J. Fish Biol. 25:371-384. http://dx.doi.org/10.1111/j.1095-8649.1984.tb04885.x http://dx.doi.org/10.1111/j.1095-8649.19...
). |
Relative length of the caudal peduncle - CPdL/SL: Higher values indicate good-swimmers (Watson & Balon 1984WATSON, D.J. & BALON, E.K. 1984. Ecomorphological analysis of fish taxocenes in rainforest streams of northern Borneo. J. Fish Biol. 25:371-384. http://dx.doi.org/10.1111/j.1095-8649.1984.tb04885.x http://dx.doi.org/10.1111/j.1095-8649.19...
, Winemiller 1991WINEMILLER, K.O. 1991. Ecomorphological diversification in lowland freshwater fish assemblages from five biotic regions. Ecol. Monogr. 61(4):343-365. http://dx.doi.org/10.2307/2937046 http://dx.doi.org/10.2307/2937046...
). |
Relative height of the caudal peduncle – CPdH/MBH: Lower values suggest good maneuverability (Winemiller 1991WINEMILLER, K.O. 1991. Ecomorphological diversification in lowland freshwater fish assemblages from five biotic regions. Ecol. Monogr. 61(4):343-365. http://dx.doi.org/10.2307/2937046 http://dx.doi.org/10.2307/2937046...
,Oliveira et al. 2010OLIVEIRA, E.F., GOULART, E., BREDA, L., MINTE-VERA, C.V., PAIVA, L.R.S. & VISMARA, M.R. 2010. Ecomorphological patterns of the fish assemblage in a tropical floodplain: effects of trophic, spatial and phylogenetic structures. Neotrop. Ichthyol. 8(3):569-586.). |
Relative width of the caudal peduncle – CPdW/MBW: Higher values indicate continuous swimmers or fishes with good propulsion (Winemiller 1991WINEMILLER, K.O. 1991. Ecomorphological diversification in lowland freshwater fish assemblages from five biotic regions. Ecol. Monogr. 61(4):343-365. http://dx.doi.org/10.2307/2937046 http://dx.doi.org/10.2307/2937046...
, Oliveira et al. 2010OLIVEIRA, E.F., GOULART, E., BREDA, L., MINTE-VERA, C.V., PAIVA, L.R.S. & VISMARA, M.R. 2010. Ecomorphological patterns of the fish assemblage in a tropical floodplain: effects of trophic, spatial and phylogenetic structures. Neotrop. Ichthyol. 8(3):569-586.). |
Relative head length – HdL/SL: Directly related to the food size (Watson & Balon 1984WATSON, D.J. & BALON, E.K. 1984. Ecomorphological analysis of fish taxocenes in rainforest streams of northern Borneo. J. Fish Biol. 25:371-384. http://dx.doi.org/10.1111/j.1095-8649.1984.tb04885.x http://dx.doi.org/10.1111/j.1095-8649.19...
, Winemiller 1991WINEMILLER, K.O. 1991. Ecomorphological diversification in lowland freshwater fish assemblages from five biotic regions. Ecol. Monogr. 61(4):343-365. http://dx.doi.org/10.2307/2937046 http://dx.doi.org/10.2307/2937046...
, Pouilly et al. 2003POUILLY, M., LINO, F., BRETENOUX, J.G. & ROSALES, C. 2003. Dietary-morphological relationship in a fish assemblage of the Bolivian Amazonian floodplain. J. Fish Biol. 62:1137-1158. http://dx.doi.org/10.1046/j.1095-8649.2003.00108.x http://dx.doi.org/10.1046/j.1095-8649.20...
). |
Relative head height – HdH/MBH: Directly related to the food size (Winemiller 1991WINEMILLER, K.O. 1991. Ecomorphological diversification in lowland freshwater fish assemblages from five biotic regions. Ecol. Monogr. 61(4):343-365. http://dx.doi.org/10.2307/2937046 http://dx.doi.org/10.2307/2937046...
). |
Relative head width – HdW/MBW: Directly related to the food size (Winemiller 1991WINEMILLER, K.O. 1991. Ecomorphological diversification in lowland freshwater fish assemblages from five biotic regions. Ecol. Monogr. 61(4):343-365. http://dx.doi.org/10.2307/2937046 http://dx.doi.org/10.2307/2937046...
, Oliveira et al. 2010OLIVEIRA, E.F., GOULART, E., BREDA, L., MINTE-VERA, C.V., PAIVA, L.R.S. & VISMARA, M.R. 2010. Ecomorphological patterns of the fish assemblage in a tropical floodplain: effects of trophic, spatial and phylogenetic structures. Neotrop. Ichthyol. 8(3):569-586.). |
Relative mouth height – MH/MBH: Directly related to the food size (Gatz 1979GATZ, A.J. 1979. Ecological morphology of freshwater stream fishes. Tulane Stud. Zoolo. Bot. 21(2):91-124.). Lower values may be associated with a greater suction capacity (Norton & Brainerd 1993NORTON, S.F. & BRAINERD, E.L. 1993. Convergence in the feeding mode of ecomorphologically similar species in the Centrarchidae and Cichlidae. Indian J. Exp. Biol. 176:11-29.). |
Relative mouth width – MW/MBW: Directly related to the food size (Gatz 1979GATZ, A.J. 1979. Ecological morphology of freshwater stream fishes. Tulane Stud. Zoolo. Bot. 21(2):91-124.). Lower values may be associated with a greater suction capacity (Norton & Brainerd 1993NORTON, S.F. & BRAINERD, E.L. 1993. Convergence in the feeding mode of ecomorphologically similar species in the Centrarchidae and Cichlidae. Indian J. Exp. Biol. 176:11-29.). |
Vertical eye position – EH/HdH: Associated with the foraging position in the water column. Higher values for benthic species, lower values for nektonic species (Gatz 1979GATZ, A.J. 1979. Ecological morphology of freshwater stream fishes. Tulane Stud. Zoolo. Bot. 21(2):91-124., Watson & Balon 1984WATSON, D.J. & BALON, E.K. 1984. Ecomorphological analysis of fish taxocenes in rainforest streams of northern Borneo. J. Fish Biol. 25:371-384. http://dx.doi.org/10.1111/j.1095-8649.1984.tb04885.x http://dx.doi.org/10.1111/j.1095-8649.19...
, Freire & Agostinho 2001FREIRE, A.G. & AGOSTINHO, A.A. 2001. Ecomorfologia de oito espécies dominantes da ictiofauna do reservatório de Itaipu (Paraná/Brasil). Acta Limnol. Bras. 13(1):1-9.). |
Relative area of the eye – EA/(SL)2: Related to food detection. It can indicate the position of the species on the water column; benthic species have lower values (Gatz 1979GATZ, A.J. 1979. Ecological morphology of freshwater stream fishes. Tulane Stud. Zoolo. Bot. 21(2):91-124., Wikramanayake 1990WIKRAMANAYAKE, E.D. 1990. Ecomorphology and biogeography of a tropical stream fish assemblage: evolution of assemblage structure. Ecology. 71(5):1756-1764. http://dx.doi.org/10.2307/1937583 http://dx.doi.org/10.2307/1937583...
). |
Index of mouth protrusion – LSO/LSC: Directly related to the ability to capture evasive and large prey (Hulsey & García de León 2005HULSEY, C.D. & GARCÍA DE LEÓN, F.J. 2005. Cichlid jaw mechanics: linking morphology to feeding specialization. Funct. Ecol. 19(3):487-494. http://dx.doi.org/10.1111/j.1365-2435.2005.00987.x http://dx.doi.org/10.1111/j.1365-2435.20...
, Cochran-Biederman & Winemiller 2010COCHRAN-BIEDERMAN, J. L. & WINEMILLER, K. O. 2010. Relationships among habitat, ecomorphology and diets of cichlids in the Bladen River, Belize. Environ. Biol. Fishes. 88(2):143-152. http://dx.doi.org/10.1007/s10641-010-9624-y http://dx.doi.org/10.1007/s10641-010-962...
). |
Relative height of the dorsal fin – DH/MBH: High values related to the stabilization of the movements (Gosline 1971GOSLINE, W.A. 1971. Functional Morphology and Classification of Teleostean Fishes. University Press of Hawaii, Honolulu, 208p., Gatz 1979GATZ, A.J. 1979. Ecological morphology of freshwater stream fishes. Tulane Stud. Zoolo. Bot. 21(2):91-124.). |
Relative area of the dorsal fin – DA/(SL)2: Higher values indicate greater ability for stabilization in braking and acceleration. (Breda et al. 2005BREDA, L., OLIVEIRA, E.F. & GOULART, E. 2005. Ecomorfologia de locomoção de peixes com enfoque para espécies neotropicais. Acta Sci., Biol. SC. 27(4):371-381.). |
Relative area of the caudal fin – CA/(SL)2: Directly related to acceleration capacity (Breda et al. 2005BREDA, L., OLIVEIRA, E.F. & GOULART, E. 2005. Ecomorfologia de locomoção de peixes com enfoque para espécies neotropicais. Acta Sci., Biol. SC. 27(4):371-381.). |
Aspect ratio of the caudal fin –(CH)2/CA: Higher values suggest caudal fin with tendency to bifurcation, typical of continuous swimmers. Lower values indicate fish with larger areas and better performance for acceleration (Breda et al. 2005BREDA, L., OLIVEIRA, E.F. & GOULART, E. 2005. Ecomorfologia de locomoção de peixes com enfoque para espécies neotropicais. Acta Sci., Biol. SC. 27(4):371-381.). |
Relative height of the anal fin – AH/MBH: Directly related to movement stabilization (Breda et al. 2005BREDA, L., OLIVEIRA, E.F. & GOULART, E. 2005. Ecomorfologia de locomoção de peixes com enfoque para espécies neotropicais. Acta Sci., Biol. SC. 27(4):371-381.). |
Relative area of the anal fin – AA/(SL)2: Directly related to the maneuverability capacity and movement stabilization (Breda et al. 2005BREDA, L., OLIVEIRA, E.F. & GOULART, E. 2005. Ecomorfologia de locomoção de peixes com enfoque para espécies neotropicais. Acta Sci., Biol. SC. 27(4):371-381.). |
Aspect ratio of the anal fin – (AL)2/AA: Higher values related to greater capacity to perform rapid regression movements (Breda et al. 2005BREDA, L., OLIVEIRA, E.F. & GOULART, E. 2005. Ecomorfologia de locomoção de peixes com enfoque para espécies neotropicais. Acta Sci., Biol. SC. 27(4):371-381.). |
Relative area of the pectoral fin – PtA/(SL)2: Directly related to movements of braking and acceleration(Gatz, 1979GATZ, A.J. 1979. Ecological morphology of freshwater stream fishes. Tulane Stud. Zoolo. Bot. 21(2):91-124., Watson & Balon 1984WATSON, D.J. & BALON, E.K. 1984. Ecomorphological analysis of fish taxocenes in rainforest streams of northern Borneo. J. Fish Biol. 25:371-384. http://dx.doi.org/10.1111/j.1095-8649.1984.tb04885.x http://dx.doi.org/10.1111/j.1095-8649.19...
). In benthic fish of rapids, larger areas assist the attachment to the substrate (Casatti & Castro 1998CASATTI, L. & CASTRO, R.M. 1998. A fish community of the São Francisco River headwater riffles, southeastern Brazil. Ichthyol. Explor. Freshw, 9(3):229-242., Kerfoot Junior & Schaefer 2006KERFOOT JUNIOR, J.R. & SCHAEFER, J.F. 2006. Ecomorphology and habitat utilization of Cottus species. Environ. Biol. Fishes. 76(1):1-13. http://dx.doi.org/10.1007/s10641-006-9000-0 http://dx.doi.org/10.1007/s10641-006-900...
). |
Aspect ratio of the pectoral fin – (PtL)2/PtA: Directly related to swimming speed. In benthic fish of rapids, high values may favor the attachment to the substrate (Casatti & Castro 1998CASATTI, L. & CASTRO, R.M. 1998. A fish community of the São Francisco River headwater riffles, southeastern Brazil. Ichthyol. Explor. Freshw, 9(3):229-242.). |
Relative area of the pelvic fin – APv/(SL)2: Higher values assist the attachment to the substrate (Kerfoot Junior & Schaefer 2006KERFOOT JUNIOR, J.R. & SCHAEFER, J.F. 2006. Ecomorphology and habitat utilization of Cottus species. Environ. Biol. Fishes. 76(1):1-13. http://dx.doi.org/10.1007/s10641-006-9000-0 http://dx.doi.org/10.1007/s10641-006-900...
, Casatti & Castro 1998CASATTI, L. & CASTRO, R.M. 1998. A fish community of the São Francisco River headwater riffles, southeastern Brazil. Ichthyol. Explor. Freshw, 9(3):229-242.). Lower values indicate pelagic fish (Breda et al. 2005BREDA, L., OLIVEIRA, E.F. & GOULART, E. 2005. Ecomorfologia de locomoção de peixes com enfoque para espécies neotropicais. Acta Sci., Biol. SC. 27(4):371-381.). |
Aspect ratio of the pelvic fin –(PvL)2/PvA: Higher values related to capacity of braking movements (Gatz 1979GATZ, A.J. 1979. Ecological morphology of freshwater stream fishes. Tulane Stud. Zoolo. Bot. 21(2):91-124.). In benthic fish, high values suggest greater capacity to remain onto the substrate amidst a strong flow (Casatti & Castro 1998CASATTI, L. & CASTRO, R.M. 1998. A fish community of the São Francisco River headwater riffles, southeastern Brazil. Ichthyol. Explor. Freshw, 9(3):229-242.). |