Waldo arthuri is a new species of commensal clam (a galeommatid bivalve mollusk) that has been discovered off the coast of California and Vancouver Island by Paul Valentich-Scott, Diarmaid Ó Foighil, and Jingchun Li (2013). The authors says: " 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."
These authors describe galeommatid bivalves as follows: "The unusual lifestyles of galeommatoidean bivalve mollusks have been extensively studied for over 185 years (Turton 1825). They are found in all oceans, occupy benthic habitats from the intertidal to continental shelf depths, and comprise large numbers of both free-living and commensal species. A spectrum of commensal relationships has been documented involving diverse invertebrate hosts including echinoderms, crustaceans, and annelids (Boss 1965, Chavan 1960, 1969, Dall 1884, 1899, Gage 1966, 1979, Goto et al. 2012, Morton and Scott 1989). This commensal lifestyle is robustly correlated with living in soft sediments, and the evolution of biotic associations with infaunal bioturbating hosts may have been a prerequisite for the diversification of Galeommatoidea in soft-bottom benthos (Li et al. 2012)."
In British Columbia, this species is reported from Sanford Island, Barkley Sound, at depths of 80 meters (Paul Valentich-Scott, Diarmaid Ó Foighil, and Jingchun Li, 2013).
Read more here.
