Meeting Abstract
Eyes have evolved numerous times during the evolution and diversification of molluscs. One of the most diverse families of bivalves, the scallops (Pectinidae), have a complex sensory system that includes several hundreds of eyes on a single animal. These single chambered eyes include a mirror-like reflector lining the back of the eye which focuses light onto a double-retina system in the middle of the eye. Other lineages in the superfamily Pectinoidea less morphologically complex eyes. To understand phenotypic evolution, the Pectinidae needs to be placed in a deeper phylogenetic framework within the Pectinoidea. We reconstructed a molecular phylogeny for 60 species from four of the five extant families within the Pectinoidea using a five gene dataset (12S, 16S, 18S, 28S rRNAs and histone H3). Our analyses give consistent support for the non-monophyly of the Propeamussiidae, with a subset of species as the sister group to the Pectinidae, the Propeamussidae type species as sister to the Spondylidae, and the majority of propeamussiid taxa sister to the Spondylidae + Pr. dalli. This topology represents a previously undescribed relationship of pectinoidean families. Our results suggest a single origin for eyes within the superfamily and likely multiple instances of loss associated with habitat shifts.
