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Morphology–diet relationships in four killifishes (Teleostei, Cyprinodontidae, Orestias) from Lake Titicaca

Authors

  • E. Maldonado,

    Corresponding author
    1. * U.R. 131 Institut de Recherche pour le Développement (IRD), 43 Bd du 11 novembre 1918, 69622 Villeurbanne, France, Instituto de Limnología, Universidad Mayor de San Andrès, La Paz, Bolivia, § U.R. 175 Institut de Recherche pour le Développement (IRD), GAMET, BP 5095, 361 rue JF Breton, 34196 Montpellier Cedex 05, France and UMR CNRS 5023 Ecologie des hydrosystèmes fluviaux, Université Claude Bernard Lyon 1, 43 Bd du 11 novembre 1918, 69622 Villeurbanne, France
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  • N. Hubert,

    1. * U.R. 131 Institut de Recherche pour le Développement (IRD), 43 Bd du 11 novembre 1918, 69622 Villeurbanne, France, Instituto de Limnología, Universidad Mayor de San Andrès, La Paz, Bolivia, § U.R. 175 Institut de Recherche pour le Développement (IRD), GAMET, BP 5095, 361 rue JF Breton, 34196 Montpellier Cedex 05, France and UMR CNRS 5023 Ecologie des hydrosystèmes fluviaux, Université Claude Bernard Lyon 1, 43 Bd du 11 novembre 1918, 69622 Villeurbanne, France
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  • P. Sagnes,

    1. * U.R. 131 Institut de Recherche pour le Développement (IRD), 43 Bd du 11 novembre 1918, 69622 Villeurbanne, France, Instituto de Limnología, Universidad Mayor de San Andrès, La Paz, Bolivia, § U.R. 175 Institut de Recherche pour le Développement (IRD), GAMET, BP 5095, 361 rue JF Breton, 34196 Montpellier Cedex 05, France and UMR CNRS 5023 Ecologie des hydrosystèmes fluviaux, Université Claude Bernard Lyon 1, 43 Bd du 11 novembre 1918, 69622 Villeurbanne, France
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  • B. De MÉrona

    1. * U.R. 131 Institut de Recherche pour le Développement (IRD), 43 Bd du 11 novembre 1918, 69622 Villeurbanne, France, Instituto de Limnología, Universidad Mayor de San Andrès, La Paz, Bolivia, § U.R. 175 Institut de Recherche pour le Développement (IRD), GAMET, BP 5095, 361 rue JF Breton, 34196 Montpellier Cedex 05, France and UMR CNRS 5023 Ecologie des hydrosystèmes fluviaux, Université Claude Bernard Lyon 1, 43 Bd du 11 novembre 1918, 69622 Villeurbanne, France
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Abstract

This study explores the relationship between morphology and diet in four Andean killifishes (Orestias) from Lake Titicaca that are known to differ in habitat use. Species that fed preferentially on amphipods (Orestias albus) or molluscs (Orestias luteus) separated in multivariate space from other species that feed on cladocera and algae (Orestias agassii and Orestias jussiei). Generally, specimens feeding on cladocera were characterized by a short, blunt nose with a small mouth; whereas, specimens feeding on amphipods exhibited a long snout with a large mouth. Specimens including molluscs in their diet tended to have a larger posterior part of the head and the larger opercles than others; while the occurrence of substratum in gut content was generally related to a short but deep head. The present analysis suggests that the littoral O. jussiei has an intermediate phenotype and diet between the pelagic (O. agassii) and benthic (O. albus and O. luteus) species. Results suggest that resource partitioning was occurring and that several morphological traits relate to characteristics of the diet, and it is inferred that the benthic, the pelagic and the littoral zones in the lake host different prey communities constituting distinct adaptive landscapes.

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