Untangling the diversity and evolution of tentacles in scallops, oysters, and their relatives (Bivalvia: Pteriomorphia)

Thumbnail Image
Audino, Jorge
Marian, José Eduardo
Major Professor
Committee Member
Journal Title
Journal ISSN
Volume Title
Serb, Jeanne
Research Projects
Organizational Units
Organizational Unit
Ecology, Evolution and Organismal Biology

The Department of Ecology, Evolution, and Organismal Biology seeks to teach the studies of ecology (organisms and their environment), evolutionary theory (the origin and interrelationships of organisms), and organismal biology (the structure, function, and biodiversity of organisms). In doing this, it offers several majors which are codirected with other departments, including biology, genetics, and environmental sciences.

The Department of Ecology, Evolution, and Organismal Biology was founded in 2003 as a merger of the Department of Botany, the Department of Microbiology, and the Department of Zoology and Genetics.

Dates of Existence

Related Units

Journal Issue
Is Version Of

Tentacles are fascinating, multifunctional organs found in many aquatic invertebrate groups. In bivalves, tentacles are morphologically diverse, performing protective and sensory roles in taxa from different ecological niches. Such diversity is particularly accentuated in Pteriomorphia, a clade comprising scallops, oysters, file clams, and relatives. However, little is known about the evolution of these organs and their role in bivalve radiation. To test hypotheses of convergent tentacular evolution and a possible association between tentacles and body orientation on the substrate, we first examined tentacle morphology in 108 preserved species representing 15 families across Pteriomorphia. Morphological descriptions of tentacle type (inner mantle fold tentacles – IFT; middle mantle fold tentacles – MFT) and position (marginal and submarginal) are provided, expanding the knowledge of less studied bivalve taxa. Then, we placed the morphological dataset under a molecular phylogenetic framework to estimate ancestral states. IFT had likely four independent origins, while MFT emerged twice independently. After being gained, tentacles have not been lost. In addition, evolution of MFT coincides with transitions in body position with the midsagittal plane parallel to the substrate in the clades of scallops (Pectinida) and oysters (Ostreida). Such a shift could be related to the increase of mantle exposure, favoring the emergence of serially repeated organs, such as tentacles. Altogether, our results support the convergent evolution of tentacles across different taxonomic levels, corroborating the plasticity of the molluscan body and the relevance of evolutionary convergences in the radiation of bivalves.


This is a manuscript of an article published as Audino, J.A., Serb, J.M. & Marian, J.E.A.R. Untangling the diversity and evolution of tentacles in scallops, oysters, and their relatives (Bivalvia: Pteriomorphia). Org Divers Evol (2021). doi:10.1007/s13127-021-00482-3. Posted with permission.

Fri Jan 01 00:00:00 UTC 2021