Habitat modulated shell shape and spatial segregation in a Patagonian limpet (Siphonaria lessonii)

LIVORE, JP; MENDEZ, MM; BIGATTI, G; MÁRQUEZ, F

MARINE ECOLOGY PROGRESS SERIES

INTER-RESEARCH

Año: 2018

0171-8630

Environmental stressors that characterize intertidal habitats such as exposure to air, thermal amplitude and wave action influence biological patterns of distribution. The effects of these stressors on intertidal organisms are often associated with their shape and size. Rocky intertidal shores in Patagonia are particularly stressful environments in which a species of limpet occurs abundantly in two contrasting habitats. In this study we describe size and shape segregation of the limpet Siphonaria lessonii across multiple shores on two contrasting shore levels where limpets are abundant, namely the high (HT) and mid (MT) intertidal. We test for differences in resistance to desiccation and recovery from heat stress and lastly define two ecomorphs using classic and geometric morphometrics analysis. Individuals from the HT lost significantly less water under stressful heat conditions, and showed higher recovery rates than those from the MT. Limpets from the HT had a broad aperture, flatter margin and larger size. Limpets from the MT, instead, had a narrow aperture, arched margin and smaller size. Together these results suggest the existence of two ecomorphs modulated by each contrasting habitat. The observed small-scale spatial segregation of the two ecomorphs may be providing ecological advantages by allowing the exploitation of resources from two contrasting habitats. The two ecomorphs may provide S. lessonii with a broad thermal tolerance breadth, potentially improving resistance of the species to extreme climatic events.