Galeommatoidea J. E. Gray 1840

Figure 1.A–H Waldo arthuri new species A–E paratypes, SBMNH 149934 A–C Exterior of left valve D Prodissoconch E Close up of hinge of both valves F Close up of hinge of right valve G Live animal with extended mantle and mantle tentacles; posterior mantle tentacle (pt); siphon (s), foot (f), lateral mantle tentacle (lt), anterior mantle tentacle (at) H Detail of mantle papillae. A–C, G scale bar = 1 mm; D–F, H scale bar = 100 µm.

Figure 2.Photographs of live Waldo arthuri material sampled in Barkeley Sound in 1989. A Brooding adult attached to its host. Note the papillated mantle (m) that is partially retracted and the presence of ~ 200 µm diameter white yolky early embryos (e) in its ctenidia, visible through the transparent shell B Micrograph of mid-late development embryo (equivalent to the pediveliger stage in pelagic developing bivalves) that was dissected from its brooding parent’s ctenidia. Labels indicate protruding foot (f), modified non-ciliated velum (v) with partially consumed yolk reserves (white areas) and mantle papillae (mp) in addition to a dense mass of yolk (y) sequestered in the anterior shelled half of the embryo C Micrograph of smallest/youngest (20 µm of dissoconch growth) specimen observed attached to an urchin host. Note the protruding foot (f) and the apparent presence of persistent yolk reserves (y) dispersed throughout much of the juvenile’s visceral mass.