Zimmermann, G., Bosc, P., Valade, P., Cornette, R., Améziane, N. and Debat, V. 2012. Geometric morphometrics of carapace of Macrobrachium australe (Crustacea: Palaemonidae) from Reunion Island. -Acta Zoologica (Stockholm) 93: 492-500.We investigated the structure of carapace shape variation in six populations of Macrobrachium australe Guérin-Méneville 1838 (Crustacea: Decapoda: Palaemonidae) from Reunion Island (Indian Ocean) freshwaters. The morphometric analysis revealed the occurrence of two morphotypes corresponding to two different types of habitats. Individuals living in lotic habitats present a thick carapace armed with a short, robust and straight rostrum, while individuals from lentic habitats have a slender carapace armed with a thin long rostrum orientated upward. This difference suggests an adaptation to lotic disturbances and is tentatively interpreted as adaptive phenotypic plasticity. In such amphidromous organisms regressing to freshwaters after a marine larval phase, selection for physiological and developmental flexibility might facilitate further adaptation and allows the colonisation of a wide panel of environmentally different and sometimes geographically distant insular streams.
Due to the sparse and unstable nature of insular freshwater habitats, marine larval dispersal of amphidromous species is considered a critical element of population persistence. We assessed population genetic structure of freshwater prawn Macrobrachium lar across its range that encompasses two biogeographic barriers: the vast open ocean separating Western and Central Pacific regions and the Indo-Malay archipelago separating Indian and Pacific oceans. A total of 173 samples collected from 21 islands throughout the Indo-Pacific were sequenced at 16S and 28S rDNA. We observed distinct genetic isolation of populations located at the eastern and southwestern edge of the species range but no evidence of an effect of the IndoPacific barrier. Differentiation patterns are consistent with a stepping-stone model of dispersal. Genetic differences of Central Pacific populations may reflect founder events associated with colonization of isolated islands, or be a signature of a past bottleneck after population depletion caused by drastic climatic events.
Quatre espèces d'escargots terrestres Endodontidae (Mollusca, Pulmonata) sont décrites, toutes endémiques de l'île de Rurutu (Îles Australes, Polynésie française) : Australdonta collicella n. sp., A. magnasulcatissima n. sp., A. microspiralis n. sp. et A. sulcata n. sp. Le nombre d'espèces d'Endodontidae connu pour Rurutu est porté de sept à 11. Toutes sont considérées comme éteintes sur l'île, seules des coquilles vides ont pu être récoltées.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.