Monography of the family Unionidae, or Naiades of Lamarck (fresh water bivalve shells,) of North America, : illustrated by figures drawn on stone from nature. / by T.A. Conrad ...

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First report of intramolluscan stages of a gorgoderid digenean from a marine bivalve

A survey of bivalves from Heron Island on the Great Barrier Reef, Australia, revealed a novel digenean infection in Lioconcha castrensis (Bivalvia: Veneridae). The cercaria has oral and ventral suckers, a dorsoventrally orientated stylet embedded in the oral sucker, penetration glands, and a large tail that is inflated at its base. This morphology is broadly consistent with that of previously described gorgoderid cercariae. Partial large subunit ribosomal RNA gene (D1-D3 domains) was sequenced and aligned with sequences from other gorgoderids and related families. Phylogenetic analysis also suggests that the species belongs to the Gorgoderinae. To our knowledge, this is the first report of a gorgoderid from a marine bivalve.

Fertilisation and larval development in an Antarctic bivalve, Laternula elliptica, under reduced pH and elevated temperatures

Elevated temperatures associated with ocean warming and acidification can influence development and, ultimately, success of larval molluscs. The effect of projected oceanic changes on fertilisation and larval development in an Antarctic bivalve, Laternula elliptica, was investigated through successive larval stages at ambient temperature and pH conditions (-1.6°C and pH 7.98) and conditions representative of projections through to 2100 (-0.5°C to +0.4°C and pH 7.80 to pH 7.65). Where significant effects were detected, increased temperature had a consistently positive influence on larval development, regardless of pH level, while effects of reduced pH varied with larval stage and incubation temperature. Fertilisation was high and largely independent of stressors, with no loss of gamete viability. Mortality was unaffected at all development stages under experimental conditions. Elevated temperatures reduced occurrences of abnormalities in D-larvae and accelerated larval development through late veliger and D-larval stages, with D-larvae occurring 5 d sooner at 0.4°C compared to ambient temperature. Reduced pH did not affect occurrences of abnormalities in larvae, but it slowed the development of calcifying stages. More work is required to investigate the effects of developmental delays of the magnitude seen here in order to better determine the ecological relevance of these changes on longer term larval and juvenile success.