title: Where's Waldo? A new commensal species, Waldo arthuri (Mollusca, Bivalvia, Galeommatidae), from the Northeastern Pacific Ocean.
abstract: A galeommatid bivalve mollusk, representing a new species, is described from off the coasts of California and Vancouver Island, British Columbia. The new bivalve has a commensal relationship with the heart urchin, Brisaster latifrons. It has been observed crawling between the oral spines of this urchin, frequently near the peristome. The bivalve has been recorded from 80 (Vancouver Island) to 444 (southern California) meters depth, in muddy sediments. In common with other galeommatoideans, the new species broods its young; however it differs from the large majority of commensal members in lacking planktotrophic larval development. Waldo arthuri, new species, has multiple morphological, ecological and developmental similarities to other members of the genus Waldo Nicol, 1966, from the southern Atlantic and Antarctic Oceans. This is most pronounced for the Argentine species, Waldo paucitentaculatus Zelaya & Ituarte, 2013, Waldo arthuri's sister speciesin nuclear and mitochondrial gene trees. Despite this close relationship, Waldo arthuri is phylogentically distinct and possesses several hinge, shell sculpture, foot, and mantle tentacle characteristics that merit its description as new.
authors.affiliation: Santa Barbara Museum of Natural History, 2559 Puesta del Sol Road, Santa Barbara, California 93105 USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Valentich-Scott
authors.forename: Diarmaid
authors.initials: D
authors.lastname: O Foighil
authors.forename: Jingchun
authors.initials: J
authors.lastname: Li
keywords: Bivalvia; Commensal relationships; Echinodea; Galeommatidae; Waldo; taxonomy; urchin