Closely related thyasirid bivalves associate with multiple symbiont phylotypes

• Published in: Marine Ecology
• Main Authors: Batstone, Rebecca T., Dufour, Suzanne C.
• Other Authors: Natural Sciences and Engineering Research Council of Canada, Research and Development Corporation of Newfoundland and Labrador
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2016
• Subjects: Ecology; Aquatic Science; Ecology, Evolution, Behavior and Systematics; Canada; Newfoundland
• Online Access: http://dx.doi.org/10.1111/maec.12310; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmaec.12310; https://onlinelibrary.wiley.com/doi/pdf/10.1111/maec.12310

Abstract Species of thyasirid bivalves are considered to be representative of early stages of chemosymbiosis, given that bacterial symbionts occur outside gill epithelial cells, vary among species in their abundance and nutritional importance, and are environmentally acquired. For these reasons, assessing the extent of host–symbiont specificity in thyasirids could provide valuable information on the evolution of chemosymbiosis. We show that individuals of two closely related and sympatric Thyasira cf. gouldi operational taxonomic units collected from three sites in a fjord in Newfoundland, Canada, associate with one of three distinct, closely related symbiont phylotypes. While associations show some site‐specificity, there is flexibility in host–symbiont pairings within the fjord, further supporting an early and relatively unspecific stage of chemosymbiosis in this family. Morphologic differences observed both within and among symbiont phylotypes suggest physiologic variation, possibly induced by small‐scale differences in sedimentary conditions.