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Microhabitat segregation and physiological differences in two species of intertidal porcellanid crabs (Genus Petrolisthes) on the southern coast of Chile
Marcelo E. Lagos, José L. Muñoz, Daniela A. Contreras and Cristian W. Cáceres

Intertidal crustaceans have a high degree of physiological plasticity, which allows them to withstand periods of water emersion. In this study we examine the physiological constraints that determine the distribution and abundance of the intertidal porcellanid crabs Petrolisthes laevigatus and Petrolisthes violaceus. This study evaluates the distribution and abundance of the two species at different tidal heights, in relation to haemocyanin concentration and LDH activity, resistance to air desiccation, thermal tolerance, and resistance to hypoxic water. The results showed that Petrolisthes laevigatus was more abundant at the high tide level than Petrolisthes violaceus, which was more abundant at the low tide level. Petrolisthes laevigatus showed greater tolerance to high temperatures and lower tolerance to desiccation when exposed to air than P. violaceus, which was also more tolerant to hypoxia during prolonged exposure. No differences were found in haemocyanin concentration and LDH activity. These findings support the idea of an evolutionary gradient towards terrestrial adaptations. Of the two species, Petrolisthes laevigatus showed the most advanced physiological features for semi-terrestrial specialization.

Keywords: zonation, desiccation, hypoxia, physiological tolerance, Petrolisthes, Chile
Contents of this volume Sci. Mar. 75(2) : 273-278 Back PDF
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